U.S. flag

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

  • Publications
  • Account settings
  • Advanced Search
  • Journal List
  • Int J Environ Res Public Health

Logo of ijerph

Climate Change, Water Quality and Water-Related Challenges: A Review with Focus on Pakistan

Toqeer ahmed.

1 Centre for Climate Research and Development, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad 45550, Pakistan; [email protected]

Mohammad Zounemat-Kermani

2 Department of Water Engineering, Shahid Bahonar University of Kerman, Kerman 7616913439, Iran; [email protected]

Miklas Scholz

3 Division of Water Resources Engineering, Faculty of Engineering, Lund University, PO Box 118, 22100 Lund, Sweden

4 Department of Civil Engineering Science, School of Civil Engineering and the Built Environment, University of Johannesburg, Kingsway Campus, Aukland Park 2006, Johannesburg PO Box 524, South Africa

5 Civil Engineering Research Group, School of Computing, Science and Engineering, The University of Salford, Newton Building, Peel Park Campus, Salford M5 4WT, UK

Climate variability is heavily impacting human health all around the globe, in particular, on residents of developing countries. Impacts on surface water and groundwater resources and water-related illnesses are increasing, especially under changing climate scenarios such as diversity in rainfall patterns, increasing temperature, flash floods, severe droughts, heatwaves and heavy precipitation. Emerging water-related diseases such as dengue fever and chikungunya are reappearing and impacting on the life of the deprived; as such, the provision of safe water and health care is in great demand in developing countries to combat the spread of infectious diseases. Government, academia and private water bodies are conducting water quality surveys and providing health care facilities, but there is still a need to improve the present strategies concerning water treatment and management, as well as governance. In this review paper, climate change pattern and risks associated with water-related diseases in developing countries, with particular focus on Pakistan, and novel methods for controlling both waterborne and water-related diseases are discussed. This study is important for public health care, particularly in developing countries, for policy makers, and researchers working in the area of climate change, water quality and risk assessment.

1. Introduction

Climate variability involving changes in temperature, rainfall pattern and precipitation is increasing and heavily impacting on water resources, water-related diseases and, subsequently, human health, which is reliant on clean water. Water-related infectious diseases like malaria, dengue fever, chikungunya, along with their causative agents and the mode of transmission of these diseases have been affected by climate variability. Similarly, waterborne diseases like typhoid and cholera are influenced by climate change patterns, and subsequent risks related to these diseases are increasing [ 1 , 2 , 3 , 4 ]. About five cases of dengue develop into a hemorrhagic fever from 390 million dengue fever infections around the globe [ 5 ]. In order to save people from disaster, it has been suggested that poor and developing countries need to save, grow, invest, and protect poor and vulnerable people from economic crises [ 6 ]. Adaptation strategies related to these changes are important for policy and impact assessments [ 7 ].

Globally, almost all countries are affected by climate change impacts, particularly the developing countries, which are more vulnerable and prone to disasters like extreme floods, droughts, storms and heatwaves. In the last decade, a decline in economic growth has been observed in some developing countries, and people living in these countries are most affected as they do not have the resources to cope with the occurring natural disasters [ 8 , 9 ]. Half of the world’s poor population lives in Sub-Saharan Africa. Significant poverty reductions have been observed in East Asia, especially China and Indonesia, between 2012 and 2013 [ 6 ]. However, developing countries are still suffering from economic problems, especially people living in rural agricultural areas with no access to essential resources in order to gain education [ 6 , 10 ].

Roser and Ortiz-Ospina [ 11 ] reported that people earning less than 3.10 US $/day (less than Pak Rs (PKR). 500) mostly live in countries such as Pakistan, India, Bangladesh and Ethiopia. Poor people are more vulnerable to natural disasters. Pakistan is at number 7 in a list of endangered countries, with 70% of its population exposed to natural hazards [ 12 ]. Millions of people in India and Bangladesh are exposed to floods. Due to climate variability, even developed countries like Japan, Hong Kong and Taiwan have been exposed to at least one type of natural hazard in the past few years. The global Climate Risk Index indicates the extent of vulnerability of a country from weather-related events like flooding, drought, heat waves and storms [ 13 ]. A low climate risk index (CRI) value indicates the highest vulnerability as some countries are more prone to frequent disaster. Of the top ten most affected countries by natural disasters, nine were from developing countries with low-middle-income, all except for Thailand ( Table 1 ). Among them, Serbia, Afghanistan and Bosnia and Herzegovina were the most affected [ 14 ]. Pakistan and the Philippines are affected recurrently by catastrophes. They are commonly ranked among the most affected countries. According to CRI 2018, the Philippines are the second most affected country among the top ten climate change-affected countries. The CRI [ 10 ] indicated that Pakistan was at number eight in the list of most affected countries between 1995 and 2014 ( Table 1 ) [ 10 ].

The list of the top 10 countries most affected in the Climate Risk Index (CRI; annual averages; adopted from [ 14 ]) between 1995 and 2014.

More than 2.5 billion individuals (30% of the world’s residents) are at risk of dengue fever, particularly in Southeast Asia, the Americas, and the Western Pacific. According to the UN water report [ 15 ], world water demand will increase by up to 55% by 2050 due to more demand by industry, domestic consumption, food production and electric generation use. Similarly, global demand for food will increase by 60% (100% in the developing countries) by 2050 due to an increase in population [ 15 ]. Stress on sustainable water management will increase due to poverty, unequal distribution of resources, inequitable access to resources and poor management.

The current situation indicates that mitigation and improved adaptation strategies are required to minimize the impacts of climate variability. This study analyzes recent scenarios impacted on by population increase, water-related disasters, water pollution and how to control diseases linked to water. The main objectives of this paper are to analyze climate variability and water-related disasters as well as their impacts on human health. Finally, some key recommendations are made for policy-makers.

2. Methodology and Review

2.1. literature selection.

In this study, the authors assessed peer reviewed research papers, reports and grey literature published after 1979. Websites including google scholar ( https://scholar.google.com.pk ), Web of Knowledge ( http://isiknowledge.com ), ScienceDirect ( http://www.sciencedirect.com ) and Scopus ( https://www.scopus.com ) were searched for relevant literature. More attention has been paid to recent but already well-referenced literature. Relevant literature was selected based predominantly on the following inclusion criteria: (a) peer-reviewed research papers published by impact factor-listed research journals; (b) peer-reviewed scientific reports from world-known publishers; (c) literature was screened by using keywords (climate variability; climate and water quality; waterborne; water-related disease; dengue fever and health impacts; Zika virus; Chikungunya; method for controlling waterborne diseases; temperature and precipitation effects; developing countries; population and water quality; climate change impacts on chemical water quality; water quality in Pakistan; water governance; water management; and water pollution); and (d) preference was given to studies published in English language.

2.2. Climate Variability

Climate variability is a growing concern worldwide [ 16 ]. Climate change deeply impacts on social and natural environments and is one of the major threats to public health [ 17 , 18 ]. The water quality of recreational waterbodies such as coastal waters is considerably affected by extreme weather conditions like storms and typhoons, which increase the contamination of drinking water leading to water-borne diseases [ 19 ].

Changes in climate have varied greatly and influenced water resources, groundwater contamination, health and subsequently human life [ 20 , 21 ]. High uncertainty regarding expected changes in temperature and rainfall in the upcoming years has been reported in some studies [ 22 ]. It has been estimated that the average global temperature for the last hundred years has increased overall by approximately 0.8 °C due to the emission of greenhouse gases, and recent years were announced as the hottest in recent history. Due to the increase in global temperature, changes in precipitation levels have not been uniform in recent decades. As a result, monsoon rainfalls are more likely to happen in humid and sub-humid areas, whereas there will be a decrease in winter and summer rainfalls in coastal and hyper-arid areas. Besides, it has been claimed that sea levels will rise to a range of 1 to 3 mm per year [ 23 , 24 ]. There is also uncertainty about rainfalls with uneven temporal and spatial distribution, and longer dry spells evoking drought conditions [ 25 ].

Indeed, due to human activities, the mean temperature on the surface of the earth has been increasing over the past century [ 26 ]. It has been estimated that hot summer days have also become more extended and regular in some parts of the globe. Increased surface temperature is leading to an increase in evaporation from the oceans and land. Accordingly, there will be an increase in global average precipitation. Some regions also experience droughts due to high evaporation levels and shifting of wind patterns while some parts of the world receive flash floods. However, it is very difficult to differentiate whether an extreme weather event is caused by natural or human influences [ 27 ]. In a study by Levy et al. [ 28 ], the general effects of climate change on water-borne diseases have been investigated. Other studies have focused on specific components of climate change such as the impact of short-term extreme flood events on infectious diseases [ 20 , 29 ].

Global warming causes the temperature to rise and, as a result, low-level glaciers are melting [ 30 ]. About 76 lakes covering an average area of 545 ha in high mountainous regions were studied. Regular monitoring of glaciers was recommended to support water management in the context of climate variability [ 31 ]. Temperature may increase this century by 2%–6 °C, which will particularly impact negatively on water resources in Central Asia which depend commonly on river water for agriculture [ 32 ].

Glaciers are one of the most important sources of water for Asian countries. About 41% of the area of glaciers are vulnerable to climate change in China [ 33 ]. Climate change is linked to an increase in mean temperature [ 23 ] and is the main factor in the melting of glaciers [ 34 ]. This has also led to changes in precipitation pattern, diversity and rate. Since 1900, changes in precipitation patterns amounted to an approximately 2% increase over the land area of the globe [ 35 , 36 ]. Likewise, a correlation between the increase in streamflow and precipitation has been identified [ 37 , 38 , 39 ].

It was reported that roughly 80% of diseases in developing countries such as Pakistan are related to waterborne diseases [ 40 ]. In Pakistan, water quality is being impacted by climate change through temperature and rainfall fluctuations [ 41 ]. A study showed that the maximum temperature has significantly augmented (in over 30% of sites) during the pre-monsoon season annually [ 42 ]. A considerable increase was observed in March. The minimum temperature showed positive trends for the pre-monsoon season at the annual scale. There was a cooling trend in the northern areas during the study period. The maximum temperature increased faster than the minimum temperature in the northern areas during all seasons studied and at annual resolution, while the opposite occurred for the rest of the country (except during the pre-monsoon season). It has been estimated that the highest correlation coefficients between patterns and both minimum and maximum temperatures were observed in the months of the pre-monsoon season [ 43 ].

2.3. Water Pollution, Population and Water Quality

The world population is expanding, with a total of 7.4 billion in 2016, and is expected to increase in the upcoming decades [ 44 ]. The eight most populous countries have a combined population of over 4.054 billion, which is expected to increase to 4.980 billion by 2050 ( Table 2 ). With this increase in population, water resources are under stress, especially in the developing countries.

Eight most populous countries in 2016 and their prospective population by 2050 (adapted from [ 44 , 46 ]).

Water pollution is directly related to population growth and has a direct impact on human health. Population growth and anthropogenic activities heavily influence water resources. The demand for water is augmented along with an increase of population, and ultimately the quality of water resources will be affected [ 45 ]. According to data for the world’s most water-stressed countries [ 46 ], Pakistan is among the most vulnerable, and will become a water-stressed country by 2040 [ 47 , 48 ].

According to Vineis et al. [ 49 ], about 884 million people are living without access to clean drinking water in 2019. Poor quality of water, especially drinking water, increases the chances of waterborne diseases [ 40 ]. About 1.8 million people die every year due to cholera and diarrhea, and 3900 children die every day due to poor water and sanitation conditions [ 50 ]. Similarly, more than one billion people lack access to improved drinking water, particularly those living in Asia [ 51 ]. In developing countries, the population is increasing, and cities will be overpopulated in the next 20 years. Accordingly, demand for improved water resources management, water quality control and enhanced flood and drought management will increase [ 52 ].

As reported by the WHO [ 53 ], half of the world’s population will suffer water stress conditions by 2025. Similarly, along with water shortage, water quality is also negatively affected, so that 1.8 billion people around the world are obliged to consume water contaminated by sewerage for drinking, which practice transfers diseases like cholera, typhoid, dysentery and polio. Empirical studies have already indicated the downside effects on human health of pollution and poor water quality due to the rapid increase in population and urbanization [ 54 ]. Regions or countries facing climate challenges and natural disasters such as drought and floods have also to endure population growth problems, and inevitably anthropogenic activities alter water systems [ 55 ]. A decrease in water resources due to less income and slow development will increase the problems of water quality and health issues. Water availability has been decreasing in all sectors by 7–11% during the last two decades [ 41 ]. Water availability is affected by climate change as well as water governance and management issues. There is a need to increase water storage capacity and installation of water retention wells for groundwater recharge. Groundwater regulations have been approved by all provinces of Pakistan except for Sindh, but implementation of polices in the true sense are lacking. By area, Sindh is the third largest province of Pakistan and by population the second largest. This is important as Karachi city (the former capital) is the largest city of Sindh province. Incentives should be implemented for the general public to obey governmental rules for water saving and fines imposed on violators. The government should implement licensing for the installation of new bore wells and there should be a record of the number of tube and bore wells installed, as no such data exist especially for private bore wells.

Water quality is linked with water availability. Water quality analysis of the major cities of Pakistan has been recently completed by the government. Similarly, other research and development organizations and non-governmental organizations (NGO) are performing water quality analysis especially in rural areas. Bacteriological water quality is often more important than chemical water quality as water resources are contaminated with fecal matter. No data on gastroenteritis have been found in allied hospitals when asked for records of patients suffering from food or waterborne diseases. It is strongly recommended in hospitals that records of people suffering from waterborne diseases are maintained.

2.4. Climate, Water-Related Diseases, and Health Impacts

Climate variability effects climate-sensitive diseases like dengue fever, diarrhea and cholera [ 56 , 57 , 58 , 59 ]. Microclimatic parameters, especially precipitation and temperature, play a key role in spreading waterborne and water-related diseases [ 60 , 61 , 62 , 63 , 64 ]. Microbiological, bioinformatics and genomic tools have provided some evidence that El Niño is the main key element in triggering long distance spread of cholera [ 65 ]. Climate change has a direct effect on the reemergence of waterborne infectious diseases such as cholera [ 66 ]. It is expected that diarrhea rates will be aggravated in many developing countries due to changes in climate, but the extent will vary depending on the nature of change, region and local climate [ 67 , 68 ]. A direct relation has been observed between climate-related disasters such as floods, heavy rainfalls and waterborne diseases. Typically, waterborne diseases and zoonotic infections increase after floods and rainfall, and high temperature also supports the growth of waterborne diseases [ 69 ]. There is a correlation between waterborne diseases and wet summer and humid weather. Typhoid is linked to dry weather in Europe [ 70 ]. Climate change could also pose an increased health risk linked to pathogens like Campylobacter, Cryptosporidium and norovirus. Norovirus and Cryptosporidium are less temperature-sensitive and are more resilient than Campylobacter [ 71 ]. Legionella species are ubiquitous in natural settings, share common habitat with human beings and transfer to humans, causing infection on exposure. Rainfall may cause exposure to Legionella infections and lead to the corresponding disease called Legionellosis [ 72 ]. Multiple studies have been devoted to infections related to contaminated water [ 73 ]. Similarly, drought can aggravate the effluent concentration runoff, pH and chemical quality. Contamination of surface water puts treatment plants at risk, leading to poor drinking water quality, which is especially detrimental for the elderly [ 74 ]. Likewise, rainfall and floods may increase waterborne diseases. A study conducted in Vietnam linked the impact of floods to dengue, pink fever, skin problems like dermatitis, and related psychological impacts [ 75 ].

According to the WHO, “Emerging pathogens are defined as pathogens seemed to have existence in a human population for the first time, or previously but are growing in frequency into areas where they have not been reported previously, generally over the last 20 years” [ 76 ]. According to this criterion, 96 genera containing 175 species are considered to be emerging pathogens. Other than common waterborne pathogens, Helminths, Giardia lamblia, Entamoeba histolytica , Legionella, Cryptosporidium, H. pylori, E. coli O157 and viruses like norovirus, hepatitis E virus and rotavirus have been confirmed as emerging pathogens that may spread through water [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ]. These pathogens spread through changes in climate such as change in rainfall and global weather pattern, and deterioration in the ozone layer along with the destruction associated with UV light [ 54 ]. Different aspects of climate change including rising sea levels, flooding, extreme rainfall and rising temperature have previously been assessed in terms of their transmission and spread of water-borne diseases such as cholera and malaria [ 77 ].

In developing countries like Pakistan, the literacy rate is low, especially in rural areas, and people have no awareness about water quality, waterborne diseases and water pollution. People are using the same water for drinking and agriculture purposes. There is a direct relationship between education, income and awareness about water pollution, waterborne diseases and health impacts. According to a survey, individuals with higher levels of education are well-aware of the consequences of waterborne diseases [ 78 ]. It is worth mentioning that diseases linked to the marine and water ecosystems can be caused by waterborne pathogens, as these microbes are naturally present in different settings.

This literature review shows that there is a research gap in studies that deal with waterborne diseases and climate variability, and, therefore, more research is needed to specifically explore the impacts of climate change on waterborne diseases. Figure 1 represents some of the most important factors regarding climate change-related health impacts on human beings.

An external file that holds a picture, illustration, etc.
Object name is ijerph-17-08518-g001.jpg

Health impacts of climate change (adapted from [ 79 ]).

2.5. Climate Impacts on Chemical Water Quality, Water-Related Diseases, and Health Perspectives

Climate change has significant impacts on chemical water quality when compared to changes in meteorological parameters [ 80 ]. Storm, snowmelt, drought and elevated air temperature have a significant impact on drinking water quality [ 81 ]. For instance, heavy rainfall can increase the turbidity of water resources. Similarly, an imbalance in chemical water quality has been observed due to a rise in temperature [ 82 ]. Chlorine used for decontamination of water may produce more trihalomethanes after reaction with organic acids at high temperature [ 83 ]. As stated earlier, average temperature has been increasing due to global warming, and this can impact on water resources including chemical water quality. Similarly, dissolution of chemicals, especially agriculture waste and fertilizers, can change the quality of water resources. According to Quevauviller and Umezawa [ 84 ], climate change may impact on water chemistry and sea-level rise, so salinization may be affected, which influences the depletion of freshwater and river environments. Different factors like acidification and remobilization of contaminants in sediments due to flooding and an increase in temperature can modify pollutants in water resources, which can affect aquatic life [ 85 ]. A study conducted in the Mekong Delta on climate change impacts on water-related diseases reported that limited work has been done on the relationship of climate change impacts on water quality [ 86 ].

Due to the effects of climate change, the salinization of drinking water has introduced problems for low income countries [ 49 ]. For example, salt intrusion and related health issues are common in Bangladesh [ 87 ]. Approximately 20 million people are at risk of hypertension in Bangladesh, which is a major cause of cardiovascular diseases [ 88 , 89 ], since more salt in water can cause hypertension and associated diseases. A study conducted in Bangladesh using an integrated salinity flux model and hydrodynamic model reported that both salinity and intrusion length has increased in the Gorai river due to the sea-level rise [ 90 ]. A similar study investigated the effects of saline contamination in drinking water on human health hazards in Bangladesh [ 91 ]. Another study reported high levels of arsenic in surface water and 2–4 times the amount, in drinking water in Bangladesh, with respect to the average eligible standards [ 92 ]. The problem of salinity and hypertension will be exacerbated in the future among people living in coastal areas due to the high intake of sodium through drinking water [ 93 , 94 ].

In another study conducted in Beijing, China, post-flood water quality was reported to have quality samples unfit for drinking purposes [ 95 ]. Indeed, both floods and drought conditions deteriorate the chemical quality of water, which leads to significant health impacts and high risks for consumers ( Table 3 ).

Potential health impacts of major physico-chemical contaminants in developing countries including Pakistan.

According to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) Climate Change [ 103 ], climate change-related amendment can affect diseases caused by water, which are categorized as waterborne, water-related, water-washed and water-based. The main considerations proposed in AR4 in order to find the relationship between climate change, water quality and water availability are below:

  • 1. The linkage between water availability, access to improved water, and health burden due to diarrheal diseases;
  • 2. The role of rainfall in waterborne disease outbreaks through water supply;
  • 3. The effect of temperature both on chemical and biological water quality; and
  • 4. The direct effect of increased temperature on diarrheal diseases.

It has been reported that climate change can affect water-related diseases like malaria, dengue fever, and other infectious diseases. According to Rogers [ 104 ], one-third of the global population lives in places linked to dengue transmission. Similarly, malaria is a rainfall-dependent disease and decreases with reductions in rainfall.

2.6. Elucidation to Diminish Water-Related Issues

Numerous methods and remedies have been used to control mosquito-related diseases, and the best of these is to control the existence of mosquitoes, which involves chemical, biological, environmental management, personal protective measures and physical methods [ 105 ]. Chemical methods include the use of tested and recommended insecticides, e.g., pyrethroids for killing adults and larvae. These should be used under the supervision of experts and trained staff such as a team of entomologists, a vector control supervisor and field staff [ 106 ].

Direct chemical spraying or aerial spraying of chemicals by low flying aircraft (to cover a large area or when there is limited access by vehicles) should be accomplished at the habitats, resting sites and breeding places of the target insects at regular intervals of 2–3 weeks. In-house spraying should also be done in all bedrooms, washrooms, wall corners, etc. For dengue control, man-made habitats should be screened, and Methoperene/Altosid (Briquets) and Diflubenzuron (Dimlin) should be applied.

As reported by Yi et al. [ 107 ], diesel oil is effective in killing larvae and pupae of mosquitoes in small waterbodies, but this can also kill other aquatic animals and is unsustainable. They suggested golden bear oil as an alternative, but this product is only available in the USA. They also suggested various methods to control mosquitoes using mosquito traps, genetically modified male mosquitoes and mosquito counter devices. Furthermore, indoor fogging or space spraying is an effective way to control dengue [ 108 ]. Larvicides should be applied on clean and stagnant water.

Multi-purpose environmental management of marshes, open drains, standing water in open fields, surface water, gardens and waste is required for disease control. Personal protection measures include personal protective clothing, bed nets (long lasting insecticide treated nets and curtains at doors), use of gauze on doors, and insect repellent lotions. Picaridin/Icaradine and N,N-diethyl-meta-toluamide (also called DEET) are recommended repellents that can be used in emergency cases. Cloth can be treated with permethrin to control mosquitoes, at the recommended dose of 1.25 mg/m 2 after every five washes. Even simple physical methods such as closing doors, especially in the morning and evening, have a positive impact on preventing diseases. Rapid population growth and urbanization, especially encroachments, provide ideal places for breeding of mosquitoes. In the absence of medicine and therapy, it is better to control this growth and breeding of mosquitoes and other vector-spreading microbes [ 109 , 110 , 111 ].

Concerning the environmental consequences of changing climate, more attention is required from experts, authorities and health departments on preventing the spreading of lethal diseases such as dengue and malaria. It is advisable that malaria and dengue control programs should be a part of national health policy with strong resource commitment and implementation. Increasing awareness and educating society is a vital element to cope with spreading of waterborne diseases (e.g., dengue fever). These programs can be started by educational institutions, offices, meetings, community reunions, etc. Besides, cleaning at household level with detergents, insecticides and other surface cleaning agents is highly recommended. Media can also play an important role in enhancing awareness through newspapers, TV programs, talk shows, etc. Likewise, a reduction of breeding sources of mosquitos and the introduction of waste management campaigns are important at community level. Indeed, health protection campaigns should be the top priority.

According to the literature, people in South Africa spent about eight hours daily in fetching water and only 19% treat their water before use. Government subsidies on water treatment chemicals and fuels for boiling water may help in increasing the percentage of people treating their drinking water and reducing waterborne diseases [ 112 ]. Regarding improving water quality, both adaptation and mitigation measures are required. In this respect, infrastructure improvements, reduction of pipe leakage, introduction of advanced water purification systems, and direct supply of clean water are necessary for the provision of safe drinking water [ 82 ]. During periods of flooding, water treatment is of great importance in controlling waterborne diseases [ 113 ]. Other interventions and home water treatments including chlorination and UV treatment [ 114 ]. There is a strong need to establish new sustainable development policies to preserve water. Without inaugurating new policies, around 40% of the world’s population is projected to experience severe water stress by 2050, especially in Africa and Asia, where the population is projected to increase from 7 billion to over 9 billion by 2050 [ 115 ].

3. Pakistan’s Perspective, the Status Quo

3.1. water quality issues.

Based on the long-term CRI, Pakistan was the fifth most affected country in the world during the period between 1999 and 2018 [ 116 ]. Moreover, Pakistan severely suffers from water shortage and lack of clean drinking water [ 85 ]. In general, just 20% of the country’s residents have access to clean potable water, which makes the remaining 80% dependent on polluted and unhealthy drinking water [ 117 , 118 ]. Many empirical studies have been conducted on water quality issues in Pakistan, but some important studies on biological and chemical water quality conducted in different cities across all the provinces of Pakistan have reported on the deterioration of water quality throughout Pakistan and highlighted an increase in waterborne bacterial and other related diseases ( Table 4 ). The lack of access to safe drinking water causes waterborne diseases, which constitute about 33% of all deaths [ 118 ]. Another study reported that between 20% and 40% of all diseases in Pakistan are due to poor quality of water [ 119 ]. This can be explained by deficiencies in waste management, lack of protection of water resources, poor sanitation, adverse anthropogenic activities and lack of social awareness [ 120 ]. A general analysis of water quality data indicates the poor circumstances of water resources in Pakistan ( Table 4 ), highlighting the need for new water treatment policies. Roughly 60 million Pakistani residents are affected by high levels of arsenic in their drinking water [ 121 ]. Rural areas are more vulnerable in terms of access to safe drinking water compared to major cities or the capital city. A study of the Tehsil of Jehlum district found more than 80% contaminated water [ 122 ]. Even water supplied to schools was poor in terms of drinking quality [ 123 ]. It is worth noting that Pakistan mainly relies on the Indus River as one of the main surface water resources. However, climate change has been negatively impacting on the Indus River, which has increased the pressure on sustainable water resources [ 124 ]. A 50% reduction of the flow rate of the Indus River would have a detrimental impact on public health, environmental protection and public finances [ 125 ]. Similar consequences can be envisaged for other developing countries like Ethiopia, where major rivers have faced decreases in both water quality and quantity [ 126 ].

Water quality situation in different provinces of Pakistan and associated impacts on the parameters studied.

Clean and healthy drinking water has a high impact on recreational activities, fisheries, tourism and sports. However, potable water resources can become polluted, which negatively impacts on both economic and health aspects [ 126 ]. According to reports by the Pakistan Council of Research in Water Resources, a survey was conducted in 23 major cities of Pakistan; four major contaminants prevailed in Pakistan; most contaminants were of bacterial nature (69%). This was followed by arsenic (24%), nitrate (14%) and fluoride (5%) [ 167 ]. According to the report, 69% of sources were contaminated according to the National Standards for Drinking Water Quality. According to a Khyber Pakhtunkhwa (KP) health survey, in 2017 89% of households had access to improved drinking water. This is similar to the 94% figure regarding Punjab province as reported by the Punjab Government [ 168 ]. Efforts have been made by the Punjab Government to provide clean and contaminant-free water. For example, some important projects including the Punjab Saaf Pani (PSP) project, worth 70 billion PKR (1 US $ = 158 PKR), have been launched to provide clean drinking water to poor urban and rural areas. For 2015–2016, 11 billion PKR were allocated for medium-term development goals. The PSP is designed to provide 3 L of clean drinking water per capita as part of the approved plan. The program promotes the installation of filtration plants, new water supply schemes and rehabilitation of existing schemes. Water treatment plants have been installed in Bahawalpur, Bahawalnagar, Lodhran and Rahimyar to supply safe and clean water to these cities.

Pakistan’s gross domestic product in 2018 was 314.6 billion US $. A project entitled “Changa Pani Programme” was launched to maintain sanitation schemes and provide rural water supply. A total of PKR 1 billion have been allocated for this program. Sustainable operation and maintenance mechanisms of rural water supply schemes are another initiative running in Punjab. Under this scheme, 199 dysfunctional water supply systems have been identified, while an initiative has been taken to rehabilitate 135 rural water supply schemes in Rajanpur, Chakwal, Vehari and DG Khan with the assistance of UNICEF. Similarly, in the 2020–2021 budget, PKR 6 billion were spent on clean drinking water (Punjab Aab-e-Pak Authority) and PKR 3.29 billion on water supply and sanitation [ 169 ]. For KP, 18.6 PKR billion were invested in the water sector [ 170 ]. For Sindh province, PKR 19.3 billion were spent on water supply and sanitation, while PKR 39 billion were invested on water supply and sanitation schemes including 398 projects in 2019–2020. PKR 1.94 billion were spent by Karachi city [ 171 ]. For Azad Jammu and Kashmir (AJK), PKR 700 million were invested on water use charges schemes and PKR 540 million on none-specified water categories. Similarly, GB and Balochistan did not specify water investments, but overall allocations for development work have been recorded. More initiatives and fair use of budgets for clean drinking water and water supply schemes are required in other provinces of Pakistan to fulfill the demand for clean drinking water, and to reduce waterborne diseases.

No specified data have been found on waterborne diseases in hospitals. However, dengue-related data are available, as surveillance teams of public health departments along with the government are monitoring dengue-related cases. It is highly recommended that patients are registered as suffering from, for example, gastroenteritis or shigellosis for proper monitoring at the national level. Typhoid, abdominal cramps and diarrhea are the most common water- and food-related illnesses; the number of patients varies from district to district in each province, but without registration it is very difficult to find and distinguish patients suffering from different specific diseases.

3.2. Water Governance and Sustainability

Water availability and linked water quality are being heavily impacted upon by climate change throughout the world, especially in Pakistan. Changes in rainfall patterns, shifting of seasons, increase in temperature, droughts, heatwaves and storms are affecting water resources. Demand for water is increasing due to an increase in population, urbanization and industrialization. It is important to manage the existing water resources. In order to achieve Sustainable Development Goal 6, ensuring availability and sustainable management of water sanitation for all, water governance is essential.

Water governance is concerned with the social, economic, administrative and political organization that influences the use of water and its management. It is important to discuss the management of water, rights to water, service provider roles and allied beneficiaries. Water governance discusses the formulation and implementation of water policies, legislation, the role of institutions, civil society and the general public in relation to provision of services and water usage.

A Pakistani national water policy has been approved in April 2018 and the water act has been implemented in almost all provinces except Sindh Province. Lack of coordination among the institutions as well as capacity building and funding constraints are important challenges to be addressed. Equity and social balance are important in addressing water governance-related issues. There are opportunities to address these issues with, for example, IT-based monitoring systems for dealing with accountability and water theft. Public–private partnerships are important in tackling water-related challenges. A good example is the water metering and pricing program of Bhalwal City in the Sargodha District of Punjab Province, where authorities have successfully implemented 24/7 supply of safe drinking water. Similarly, smart water metering has been installed in one of the sectors, named I-8, of Islamabad for the said initiative. (In Islamabad, different sectors are named alphabetically). International collaboration can help in capacity building and knowledge sharing. Awareness regarding water conservation and strategies to conserve water at all levels is necessary to save water. The inclusion of information on climate change and water conservation in the educational curricula at all levels is recommended. Fines should be imposed on violators and incentives should be given to the general public by the water authorities for water conservation and for following water laws. These kinds of initiative can help in water governance and sustainability in the future.

4. Conclusions and Recommendations

This literature review indicates that global warming has led to an increase in the average temperature around the globe, which has been heavily impacting on water resources, especially in Africa and Asia, as agriculture is mostly dependent on river water flow. Several developing Asian countries have already encountered the consequences of water stress. Hence, river water monitoring is an essential requirement, especially due to the impacts of climate change such as glacier melting, rainstorms and droughts.

Increases in population and anthropogenic activities have heavily influenced water resources and increased water pollution. Indeed, various studies have reported that water pollution has increased in the last decades, and consequently water-related diseases influence the health of many citizens in developing countries. The following are important recommendations which can be helpful in coping with the consequences of climate change in terms of water-related challenges:

  • Due to the shift in seasons, in some locations as a result of climate variability, new water resources (e.g., melting glaciers) have been emerging. However, there is a need to manage and store water for present and future use. For instance, watershed management with dam systems might alleviate drought and floods.
  • Developing effective treatment methods e.g., [ 172 , 173 , 174 ], for addressing the sixth United Nations sustainable development goal, which deals with fecal contamination (69% fecal pollution has been reported in 23 major cities) and provision of safe drinking water to the general public.
  • Adaptation strategies such as protection of water resources and watershed management should be adopted to cope with unforeseen situations and to decrease the water-related disease burden.
  • Education and social awareness play a major role in confronting and controlling water pollution, waterborne, and water-related diseases, and subsequently in improving human health in developing countries.

These recommendations are also valid for many other countries with similar challenges to Pakistan.

Acknowledgments

The authors gratefully acknowledge the support received from Centre for Climate Research and Development (CCRD), COMSATS University Islamabad, for providing resources and funding the under COMSATS Research Grant Program No. 16-59/CRGP//CIIT/ISB/17/1092.

Author Contributions

Conceptualization, T.A., M.Z.-K. and M.S.; methodology, T.A.; investigation, T.A., M.Z.-K. and M.S.; writing—original draft preparation, T.A; writing—review and editing, M.Z.-K. and M.S.; visualization, T.A. All authors have read and agreed to the published version of the manuscript.

Gratefully acknowledge the support received from COMSATS University Islamabad under the grant No. 16-59/CRGP//CIIT/ISB/17/1092.

Conflicts of Interest

The authors declare no conflict of interest.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Accessibility Links

  • Skip to content
  • Skip to search IOPscience
  • Skip to Journals list
  • Accessibility help
  • Accessibility Help

Click here to close this panel.

Purpose-led Publishing is a coalition of three not-for-profit publishers in the field of physical sciences: AIP Publishing, the American Physical Society and IOP Publishing.

Together, as publishers that will always put purpose above profit, we have defined a set of industry standards that underpin high-quality, ethical scholarly communications.

We are proudly declaring that science is our only shareholder.

Water pollution Its causes and effects

Suaad Hadi Hassan Al-Taai 1

Published under licence by IOP Publishing Ltd IOP Conference Series: Earth and Environmental Science , Volume 790 , First International Virtual Conference on Environment & Natural Resources 24-25 March 2021, College of Science, University of Al-Qadisiyah, Iraq Citation Suaad Hadi Hassan Al-Taai 2021 IOP Conf. Ser.: Earth Environ. Sci. 790 012026 DOI 10.1088/1755-1315/790/1/012026

Article metrics

8585 Total downloads

Share this article

Author e-mails.

[email protected]

Author affiliations

1 University of Baghdad, College of Education Ibn Rushd for Humanities, Department of History

Buy this article in print

The topic of water contamination is one of the significant studies that, because of its great effect on the lives of humans, animals and plants alike, has attracted the attention of researchers and those interested in the environment. It is not less harmful than contamination of the air and soil, but more closely linked to them. The research centered on the study of the notion of pollution in general, then the notion of water pollution and its sources. In addition to groundwater contamination, there have been many pollution processes, the most important of which are biological, physical, and by dumping solid and liquid waste into waters of rivers, lakes and seas.

Export citation and abstract BibTeX RIS

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

SYSTEMATIC REVIEW article

Impacts of surface water quality in the awash river basin, ethiopia: a systematic review.

\nEndaweke Assegide,,

  • 1 Ethiopian Institute of Water Resource, Addis Ababa University, Addis Ababa, Ethiopia
  • 2 Water and Land Resource Center of Addis Ababa University, Addis Ababa, Ethiopia
  • 3 Department of Geomatic Engineering, Adama Science and Technology University, Adama, Ethiopia
  • 4 Department of Agricultural and Biological Engineering, Tropical Research and Education Center, University of Florida, Homestead, FL, United States
  • 5 Spatial Sciences Laboratory, Texas A&M University, College Station, TX, United States

Water quality impairment, due to anthropogenic activities and limited enforcement capacity, is a rapidly growing threat to water security as well as public health in developing countries. Cumulative effects of deteriorating water quality undoubtedly put pressure on public health and socio-economic developments. For example, most industries in Ethiopia discharge their effluent directly into freshwater systems without any treatment process. The problem is severe for rivers such as the Awash that pass through major cities. Although there were a few studies that looked into the issue, there is a lack of comprehensive water quality impact assessment on agriculture, health, and socio-economics. This article systematically summarizes current research on water quality issues in the Awash River Basin to generate comprehensive information that captures the water quality status of the river and impacts of water contamination, and identify information and management gaps. Results showed that water quality degradation along the river course and in selected tributaries exceeds water quality standards by the WHO and national guidelines. For example, E-coli bacteria concentration in two tributaries, Tinishu and Tiliku Akaki, reach up to 6.68 and 6.61 billion CFU 100 ml/L. Virological profile of creeks receiving wastewater from hospitals in the City of Addis Ababa contains coliphages levels reaching as high as 5.2 × 10 3 pfu/100 ml for urban rivers and up to 4.92 × 10 3 pfu/100 ml. Heavy metals that far exceed the tolerable levels for humans were also detected in vegetables produced using impaired water. Heavy metals such as Cd, Cr, Cu, Hg, Ni, and Zn were detected in potato, Zn and Hg in Cabbage, and Cr in onion and red beet. Lettuce irrigated with Akaki river water found to contain 0.263 (Cd), 420 (Fe), 13.44 (Zn), 7.87 (Cr), 7.49 (Cu), and 6.55 (Pb) in mg/kg both in excess of WHO guideline. In addition, a high concentration of Cr has been also found in fish tissues. There has never been a systematic evaluation of the impact of contaminated water in the Awash Basin. Comprehensive impact of water quality investigation that takes into account the different pollutants dynamic needs to be made to protect the well being of downstream beneficiaries including the aquatic ecosystem. In conclusion the systematic review has shown that for a river that cross-through emerging mega-city like Addis Ababa, the human and ecosystem health impact of aquatic ecosystems pollution should not afterthought action

Introduction

The role of clean water in social development, economic growth, and sustaining a healthy economic system has been well established ( Katko and Hukka, 2015 ). The global community has been mainstreaming water supply and sanction as one of its core activities. Ensuring the availability and sustainable management of water and sanitation for all (SDG 6) is among the 17 sustainable development goals the global community is grabbling to achieve by 2030 ( Kroll et al., 2019 ). Moreover, due to its cross-sectoral nature, improved water security has a catalyst role in the achievement of other SDGs targets.

Despite this, water security particularly in developing countries tends to be at a cross road ( Yomo et al., 2019 ). Growing population, expansion of cities, rapid urbanization, the expansion of industrial activities, the difference in inter-sectoral priorities, and the low enforcement capacity are threatening the rivers, and lakes ( McGrane, 2016 ; Berg et al., 2019 ). Environmental law enforcement in South Africa, as in other developing nations, has suffered significant setbacks due to a lack of technical expertise, insufficient finances, corruption, and penalties with low deterrent effects ( Edokpayi et al., 2017 ).

Anthropogenic activities are responsible for the majority of water quality degradation in several rivers, where indiscriminate dumping of domestic and industrial wastes, as well as waste from other sources such as agriculture and health facilities, is common ( Igwe et al., 2017 ; Amoatey and Baawain, 2019 ) and justified in Ethiopia ( Tadesse et al., 2018 ), Bangladesh ( Hasan et al., 2019 ; Islam et al., 2020 , 2021 ), India ( Pareek et al., 2020 ; Rakhecha, 2020 ), Rakiraki town in Fiji ( Kumar et al., 2021 ), Kenya ( Chebet et al., 2020 ) and South Africa ( Edokpayi et al., 2017 ). Land and water quality degradation in Ethiopia, in general, was not impacted much by anthropogenic activities for the past decades due to the low population density that practice slash and burn agriculture with minimum fertilizer use ( Ligdi et al., 2010 ). However, in the recent past, a wide range of pollutants including organic matter, salts, nutrients, sediments, heavy metals, etc. due to natural processes and anthropogenic sources are posing a serious threat to the land and water qualities of many of the basins in Ethiopia ( Moges et al., 2017 ). The problem is aggravated further due to climate change, rapid population growth, urbanization, and agricultural practices that put intense pressure on natural resources including the availability and quality of freshwater resources ( Berg et al., 2019 ).

The environmental impact on local rivers increases as a city gets bigger, especially if the city cannot properly handle solid waste and wastewater. Untreated wastewater from industries and households may be discharged into rivers, where solid waste may accumulate along the course of the river ( Dagnachew et al., 2019 ; Chebet et al., 2020 ), especially in developing countries where wastewater treatment facilities are not well developed. The discharge of untreated municipal and industrial wastes into water bodies, which resulted in increased heavy metal concentrations in river water, is linked to severe water quality degradation ( Islam et al., 2020 ). Most cities of developing countries generate on the average of 30–70 mm 3 of wastewater per person per year ( Edokpayi et al., 2017 ). Urban development interferes with water resources by altering the biophysical processes and fluxes of water, sediment, chemicals, microorganisms, and heat ( McGrane, 2016 ). As cities develop in population, so does the total amount of water required for adequate municipal service. This rise in total municipal water demand is due to a combination of factors, including an increase in urban population and a trend toward economic development ( McDonald et al., 2014 ). The rapid economic development of China has come at a cost to the environment, increasing volumes of untreated wastewater from households, and industrial and agricultural runoff all contributing to severe pollution of the aquatic environment ( Ma et al., 2020 ). Water quality is becoming a serious problem in some basins in Ethiopia. For example, the Rift Valley Lakes and their contributing rivers are used for irrigation, soda abstraction, fish farming, and recreation ( Ayenew and Legesse, 2007 ).

The pollution of surface water with trace elements has gotten a lot of attention around the world ( Islam et al., 2020 ). Because of their extreme toxicity, abundance, and ease of accumulation by different organisms, heavy metals are regarded one of the most dangerous environmental pollutants ( Islam et al., 2021 ). Industries in developing countries generate volumetric wastes which are discharged without treatment into nearby water bodies. For example, most industries in Uganda use outdated manufacturing technologies and do not have functional effluent treatment plants ( Srinivasan and Reddy, 2009 ) and in Bangladesh and Ethiopia often discharge their wastewater into the freshwater system without any treatment ( Naser et al., 2014 ; Girma, 2016 ). Therefore, raw and harmful wastes are discharged into the surrounding water bodies. Textile industries are huge industrial consumers of water and producers of wastewaters, with growing demand for textile products leading to an increase in textile wastewater output, making the textile sector one of the most serious sources of pollution globally ( Mehari et al., 2015 ). Dadi et al. (2017) investigated the environmental and health impacts of effluents from four different textile and garment plants in Gelan and Dukem areas around Addis Ababa and found that the bacteriological pollutants in the effluent are higher than the permissible limit given by the Federal Environmental Protection Authority (FEPA) ( Dadi et al., 2017 ). Such practices lead to water quality deterioration of many freshwater systems making them unsuitable for irrigation, domestic or industrial purposes ( Keraga et al., 2017b ).

Point and non-point source pollutions from towns and cities contribute nutrient-rich effluents that are conducive for eutrophication where an upsurge of algae growth in the lakes will happen, and thereby depletes the oxygen needed by fish and other ecosystems ( Girma, 2016 ). Addis Ababa, which is part of the Akaki catchment, has a rapidly growing population, unregulated urbanization and industrialization, poor sanitation, and uncontrolled waste disposal, all of which contribute to a substantial deterioration in surface water quality ( Kassegne et al., 2018 ). Rapid loss of ecosystems and land-use change, in part due to agricultural intensification, have been among the major drivers for recent increases in water in sedimentation and water quality issues in Ethiopia ( Moges et al., 2017 ).

The river basin is convenient for irrigated agriculture and industrial development due to its proximity to major cities such as Addis Ababa, Nazert, Debre Zeit, Dessie, and Dire Dawa. It has been impaired by pollutants from large-scale irrigation scheme ( Alemayehu, 2001 ; Keraga et al., 2017b ). On top of these, most of the industrial plants and cities do not have wastewater treatment plants ( Rooijen and Taddesse, 2009 ) releasing their effluents directly to the river basin. Therefore, the discharges of these domestic, industrial, and agricultural wastes have been polluting freshwater systems jeopardizing socio-economic and ecological assets in the river basin ( Mengistie et al., 2017 ).

The costs of water scarcity, misallocation, and pollution can be difficult to measure, and they are not always visible ( Mekonnen and Amsalu, 2018 ). Smallholder farmers grow a variety of vegetables in and around Addis Ababa. Without developed modern irrigation techniques, water scarcity is rampant and these farmers rely on the Akaki River as their primary source of water for irrigation. Due to a scarcity of freshwater, partially treated and untreated wastewater from a variety of industries, as well as gray water from the Addis Ababa city environment, are now used for irrigation ( Mengesha et al., 2021 ). While water quality is a complex issue and involves multiple disciplines, this review focuses on water quality with respect cation, metals and heavy metals in surface water, and their impacts on vegetables, soil, biodiversity, human health, toxic and socioeconomic effects. The river collects untreated and unmanaged domestic, industrial, and agricultural pollutants from the catchment immediately along its course, which could lead to a change in quality of water. As a result, among the major rivers of Ethiopia, the Awash River is the most vulnerable to many types of serious pollution ( Keraga et al., 2017b ).

There has been little research on the impact of contaminated water on human and animal health, as well as the socio-economic implications on the riverine community, the downstream population, the basin, and the country as a whole. Although it is not complete and does not cover the entire basin and sub-basins, this systematic review provides valuable insight into the positive aspects of several studies that reveal the state of rivers pollution by heavy metals and their sources.

Although various initiatives have to investigate the state of pollution in Awash ( Keraga et al., 2017a ), basin-wide synthesis of the state of surface water pollution is lacking. Hence, the purpose of this article is to synthesize and generate information that captures the impact of contaminated water on human health, vegetables, and soil, as well as toxic, biological, and socio-economic effects that rely on river systems, as well as to identify knowledge gaps that are needed for the basin's long-term development and management. The following clear, logical, and well defined research question was formulated: what is the impact of contaminated water in Awash Bain and the knowledge gap that is needed for the sustainable development and management of the basin?

Methodology

Systematic review (SR) is useful to synthesize trends and conceptualizing findings from large bodies of information ( Özerol et al., 2018 ). The recent and innovative approach in undertaking SR is the PRISMA (Preferred Reporting Items for Systematic Review and Meta-analysis statement) ( Moher et al., 2009 ). Synthesis of impact of water quality in the Awash Basin has been a valid explanatory topic for our review.

For this SR, we developed a search strategy to identify relevant literature. This search strategy was tailored to three databases: Web of sciences, Scopus, Google and Google scholar, and the search terms used were the following: water quality, Impact of water quality, water pollution, industrial pollutants, and heavy metals. All searches included journal articles, books and book chapters. The selection criteria were based on the PRISMA checklist. The search mainly focused on the mapping existing literature on the impact of water quality, water pollution, and heavy metals in the field of environmental sciences, and earth sciences. The search span was from the year 2000–2021 in English only. The search was mainly focused on Ethiopia. The search from any other country was considered accordingly. A total of 85 research articles were excluded at this stage. There were 105 records extracted at this stage.

All duplications were extensively examined to maintain the quality of the review. For the analysis and purification of the papers, the abstracts were checked deeply to ensure the quality and relevance of research papers included in the review process. We read the abstracts of 182 studies to see if they were relevant to the study topic and research questions. We got the full-text article for quality assessment after a total of 97 studies were deemed relevant. In a later stage, a careful examination of each study publication was carried out. We looked through the full-text publications to assess the quality and relevance of the studies. One article was not included in the study since it was written in a language other than English. In addition, 29 more publications were excluded from the study once the duplicate records were filtered out. After evaluating each article against the aforementioned inclusion and exclusion criteria, we chose 68 papers. The literature inclusion and removal at each level is depicted in Figure 1 . Sixty eight papers were chosen for data extraction, and the following aspects were extracted: Articles must be published journal articles. Reports, dissertations, and unpublished documents were excluded. Through cited references, we discovered an additional 31 studies. In total, 99 studies were considered in this review.

www.frontiersin.org

Figure 1 . Literature search and evaluation process and decision making for inclusion.

We extracted information on the following subtopics from each study: (1) water quality status of rivers in the Awash Basin; (2) seasonal fluctuations of trace metals in lakes and reservoirs in the Awash Basin; (3) point source pollutants; and (4) health, vegetable, soil, biological, socioeconomic, and toxic effects of water pollution. All data extraction and coding were performed using Microsoft Excel and Mendeley Reference Manager.

The Awash Basin

The Awash River originates from the Ethiopian highland plateau around the Ginchi area and drains part of the northern rift valley system in Ethiopia ( Figure 2 ). The river has no outlet to an ocean; rather it joins Lake Abe at the Ethio-Djibouti border. Most of the ~113,304 km 2 catchment area of the basin is within the Ethiopian boundary. Elevation in the basin ranges between 250 and 3,000 masl. The basin covers the central highlands of Ethiopia including west of Addis Ababa and the north-eastern part of the Ethiopian Rift Valley system. The main river's length is about 1,200 km ( Taye et al., 2018 ).

www.frontiersin.org

Figure 2 . Map of the Awash River Basin with administrative and Basin Management boundaries. The river basin is divided into four major stretches based on altitudinal variation, i.e., Upper basin which represents the areas from the headwater to Koka reservoir (>1,500 masl); Upper Awash Valley which ranges from Koka reservoir to Awash Station (1,500–1,000 masl); Middle Awash Valley which represents the area from Awash Station to Gewane (1,000–500 masl), and; Lower Awash Valley which is the area that extends from Gewane up to Lake Abe (<500 masl) ( Duguma et al., 2021 ; Jin et al., 2021 ).

The basin has varied topography, vegetation, rainfall, temperature, and soils. The climate ranges from semi-arid lowlands to cold highland mountains. The average total rainfall in the highlands is 1,600 mm, while in the lowlands it is 160 mm ( Taye et al., 2018 ). Awash is fed by several major tributaries in the upper, middle and lower parts of the basin. Ginchi, Berga, Holleta, Bantu, Leman, Akaki, Mojo, Hombole, Arba I, Arba II, Keleta, Kesem, Najeso and Logia are the major tributaries of the upper Awash ( Amenu, 2013 ). Land use in the basin is mainly agricultural which is used for rain-fed crops, shrub land, and grazing land. The basin accounting over 60% of the irrigated agriculture in the country ( Keraga et al., 2017b ). Crops cultivated in the basin include cereals (e.g., teff, beans, wheat, barley, and oilseeds), vegetables, flowers, cotton, perennial fruit trees, and sugarcane ( Tufa, 2021 ). The other land uses/covers include urban areas, industrial zones, forests, and swamps. Major cities in Ethiopia such as Addis Ababa, Dire Dawa, Adama, Bishoftu, Dessie, and Semera are located in the basin. More than 65% of the national industries are located in the basin ( Keraga et al., 2017b ). The Awash River Basin is one of Ethiopia's 12 major river basins, which is shared by five administrative regions (Amhara, Oromia, Somali, Afar and the Southern Region) ( Mersha et al., 2018 ).

Water Quality Issues In The Awash River Basin

The purpose of this systematic review was to discuss the current situation of water quality in the Awash Basin. It evaluates the principal impacts of contaminated water in the Awash Basin on the biological aquatic environment, toxicity, health, irrigated crops using contaminated surface water and soil, and socio-economic impacts of trace metals in lakes and reservoirs.

Water Quality Status of Rivers in Awash Basin

The population living in the Awash River Basin was estimated to be more than 18.6 million ( FAO and IHE Delft, 2020 ) with a population density > 6452.4 persons/km 2 , in Addis Ababa and 0-10 persons/km2 in the low land areas ( Andualem and Takele, 2018 ). Substantial rain-fed and commercial agricultural farms, and several industries exist in the basin that is sources of pollutants ( Eliku and Leta, 2018 ). The basin is experiencing severe point source water pollution due to rapid urbanization and industrialization ( Gebre et al., 2016 ) and non-point sources from agricultural fields ( Alemayehu, 2001 ; Keraga et al., 2017a ). The Akaki catchment is located in central Ethiopia along the western margin of the main Ethiopian Rift Valley. Addis Ababa, which lies within the Akaki catchment. Tinishu Akaki River contained a higher load of trace metals than the other regions, which is due to the existence of most of the industrial establishments and commercial activities ( Kassegne et al., 2018 ). The Akaki River is heavily polluted, owing to the emission of harmful industrial effluents with little or no treatment ( Abebe, 2019 ). Untreated pollutants from industries, residential, and commercial activities are discharged into the Tinishu Akaki River, which runs through the Addis Ababa City Administration. Several studies have found that discharges of inadequately treated and untreated industrial wastewaters, residential wastes, and sewerages into waterways pollute rivers and streams ( Abebe, 2019 ; Mekuria et al., 2021 ). Figure 3 shows water quality monitoring stations used by different studies in the Akaki sub-basin. Another main tributary of the Awash River is the Mojo River. Shoa and Ethiotanneries, Mojo oil mill plant, abattoir houses, and poultry farms are major sources of wastewater effluents downstream of the Awash River, which release their raw effluent directly into the Mojo river, a tributary of the upper Awash and eventually into the Koka Reservoir. The Akaki River is a major tributary of the Awash River, which drains its effluents from its source to the Koka reservoir ( Degefu et al., 2013 ).

www.frontiersin.org

Figure 3 . Water quality monitoring stations used by several studies in the Akaki sub-basin.

Kassegne et al. (2018) reported that trace metals occurred in varying concentrations along the course of the sampling stations in Tinishu Akaki River and Aba Samuel reservoir. Relatively lower levels of trace metals were recorded at Aba Samuel reservoir due to the lower residence time of the sediment. Ecological risk assessment using USEPA sediment guidelines, geoaccumulation index, contamination factor, and pollution load index revealed the widespread pollution by Cd and Pb, these were followed by Mn, Ni, and Zn.

In addition, mean concentrations of heavy metals including Mn, Cr, Ni, Pb, As and Zn were also above their allowable limits in these rivers ( Keraga et al., 2017a ). Arsenic and zinc were found higher in irrigated areas using water from the Akai River ( Itanna, 2002 ) than rain-fed agricultural areas. Beyene et al. (2017) on these Tinishu and Tiliku rivers reported that Cu, Cr and Pb concentrations were greater than the standard limit set by the European directives for soil contaminants.

The water quality of the Tinishu and Great Akaki river basins has been classified, according to the WHO drinking water guideline ( WHO, 2004 ), as “badly polluted” to “very badly polluted,” making the water non-suitable for drinking. The presence of trace metals in the tested samples indicates that industries have a significant contribution to surface water pollution. Gebre and Rooijen (2009) reported that E-coli bacteria concentrations in Tinishu and Tiliku Akaki rivers were 6.68 x 10 9 and 6.61 x 10 9 CFU 100 ml/L, respectively. The mean E.coli and Non-E.coli values in the measured water in Akaki river were 2.09 and > 3.48 log10 CFU 10 mL −1 , respectively, which were higher than the WHO recommended standard ( WHO, 2006 ; Mengesha et al., 2021 ). The presence of trace metals in the tested samples indicates that industries have a significant contribution to surface water pollution and the high concentrations of E.coli bacteria indicate fecal pollution ( Gebre and Rooijen, 2009 ).

Rooijen and Taddesse (2009) also reported that heavy metal concentrations that exceeded the natural levels were observed from vegetables grown in Tinishu and Tiliku Akaki Rivers and found that Cd, Cr, Cu, Hg, Ni, and Zn in potato; Zn and Hg in Cabbage; and Cr in onion and red beet. Water quality studies in different parts of Awash Basin are summarized in Supplementary Table S2 . Another study by Itanna (2002) showed that cabbage was, in general, the least accumulator of metals/metalloids compared to other leafy vegetables with the exception of Ni and Cr. Lettuce had the highest concentrations of Cd, Co, Cr, Fe, and Mn; while Swiss chard contained the highest concentrations of As, Cu, Ni, Pb, and ZN ( Itanna, 2002 ). Observed concentrations of As, Cr, Fe, and Pb were also greater than the maximum permitted levels in leafy vegetables and pose greater health concerns.

Fecal coliform levels in most vegetables in the Akaki River, except swish Chard, cabbage, and spinach in the wet season, were higher than the World Health Organization (WHO) and International Commission on Microbiological Specifications for Food (ICMSF) recommended level of 103 fecal coliform g/L fresh weights in both dry and wet season campaigns ( Beyene et al., 2017 ). This was attributed to the Akaki River water, which is higher than the WHO recommended standard used for irrigation of vegetables particularly in dry seasons due to flows from upstream through the major industrial, commercial, institutional, and residential areas of the town. In addition, the application of organic manures is a common practice of farmers for the production of crops in that area.

Seasonal Fluctuations of Trace Metals in Lakes and Reservoirs in the Awash Basin

Rivers pick up heavy metals as they carry surface water through areas with a variety of human induced inputs. Changes in the spatial distribution patterns of heavy metals in surface water and sediments may result as a result of this ( Kumar et al., 2021 ). The presence, transport, and fate of toxic and persistent heavy metals and organic compounds in water bodies is a major area of concern around the world ( Edokpayi et al., 2017 ). One of the world's greatest worries is the contamination of the environment with hazardous heavy metals ( Kumar et al., 2021 ). Because of their non-biodegradability, extended biological half-lives, and water solubility, the majority of heavy metals are extremely toxic ( Naser et al., 2014 ). The buildup of high levels of Pb, Cd, Cr, Ni, and Zn in river basins is most prevalent in areas with a lot of industrial and commercial activity ( Islam et al., 2020 ). Most lakes and reservoirs in the Awash Basin are experiencing water quality degradation. There are 22 lakes and reservoirs within the Awash Basin. This section summarizes the water quality status of selected lakes and reservoirs within the basin. Speciation of selected trace elements on samples collected from the Koka reservoir showed that Cr, Mn, Co, Ni, Cu, Zn, and Pb were predominantly present at high molecular masses (HMM), i.e., > 10 kilo Daltons. The presence of trace elements at higher masses during the wet season suggests the reduced mobility of elements along with colloids and particles ( Masresha et al., 2011 ).

Because Lake Beseka water is saline (EC~6.3 dS m −1 ), sodic (SAR~300), or alkaline (pH~9.6), it cannot be used for irrigation or drinking ( Dinka, 2012 ). The drastic expansion of the lake has led to many problems in the surrounding area, and is a severe threat to the well being of the indigenous people and the economic welfare of the nation in general. Between 1960 to 2015, salinity and alkalinity levels in Lake Beseka showed decreasing trends in ionic concentrations of quality parameters due to the dilution effect ( Dinka, 2017 ). In general, the water quality of the Awash river downstream of Lake Beseka has deteriorated between 2013 and 2017 due to the release of unregulated Lake Water into the Awash River ( Yimer and Jin, 2020 ). At the Awash inlet, Koka reservoir and Awash outlet, reported that the mean concentrations of metals ranked (high to low) was Fe > Cr > Cu > Zn > Pb > Cd > Ni and Fe > Cu > Zn > Pb > Cr > Cd > Ni during dry and wet seasons, respectively. Overall, concentration of heavy metals during dry season was higher than the wet season except for Fe. Increases in concentration of Fe during the wet season was attributed to increased runoff during the rainy season that eroded the soil particles containing iron ( Eliku and Leta, 2018 ). Some heavy meatal related water quality studies in lakes, reservoirs and rivers in different parts of the Awash basin is annexed in Supplementary Table S2 .

Masresha et al. (2011) also observed differences in metal concentrations in Koka reservoir during dry/wet seasons with reported dry/wet season values (mg/L) of 46.6 /11, 6.4/1, 31.6/ 22, and 6.9/8.2 for Na ++ , K ++ , Ca ++ and Mg ++ , respectively. In addition, heavy metals like Fe, Cr, and Ni were in higher concentrations than the WHO limit ( Table 1 ). The lakes have primarily been used for commercial fishing, irrigation, recreation, and residential uses. Although these limited water resources are critical to the population's survival, there are signs that Koka reservoir is undergoing changes that could lead to water quality degradation.

www.frontiersin.org

Table 1 . Lake Koka cations and heavy metal study result by different studies.

The temporal and regional fluctuations of trace heavy metal concentrations in Mojo river in the extreme wet rainy season, semi-wet and semi-dry period (autumn), and extreme dry season (winter), according to Tamene and Seyoum (2015) showed that the level of As rises as the year progress from wet to dry, indicating dilution effects. Except for one result, all of the assessed As results are higher than the WHO Drinking Water Guidelines (DWG) (0.01 mg/L) ( WHO, 2004 ). In all study locations and sampling periods, the average Cd pollution load was found to be 0.12 ± 0.075 mg/L. All of the Hg experimental results are significantly higher than the WHO guidelines for fresh water (0.05 mg/L) and maximum allowable DW for livestock (0.003 mg/L), respectively ( Carr et al., 2004 ). More than half of the examined results of Pb was above the WHO's maximum acceptable limit for DWG (0.01 mg/L).

Dagnachew et al. (2019) observed higher concentrations of Cr (VI) in Tinishu Akaki and Jemo rivers. Figure 4 shows Cr (VI), CU, Mn, and Zn concentrations from studies conducted on different rivers. Overall, Cr (VI) and Mn concentrations exceeded the Ethiopian standard in both the dry and wet seasons in most locations. However, concentrations were greater during dry seasons compared to the wet season. This is probably due to the dilution effect of the wet season. In the different studies, there is very limited temporal heavy metal load analysis in rivers as well as in reservoirs/lakes in the different parts of the basin. The three rivers are the western side of the Akaki catchment Figure 2 which receives untreated wastewater from industries as well as from urban waste.

www.frontiersin.org

Figure 4 . Trace metal content in Addis Ababa rivers in dry (D) and wet (W) seasons. Sources ( Dagnachew et al., 2019 ).

Point Source Pollution

Water contamination is caused by a variety of factors, including industrial wastewater and hazardous chemicals. Although Ethiopia has a small number of industries, its pollution impact is substantial. Industrial waste from poorly managed industries is a major source to water pollution, particularly in Ethiopian rivers. This is because most Ethiopian factories lack wastewater treatment facilities ( Menbere, 2019 ). In Ethiopia, most industries just dump their untreated toxic wastewater into adjacent rivers, lakes, and streams. Pollution from industrial wastewater discharge has increased as a result of hazardous chemicals ( Alayu and Yirgu, 2018 ). The city of Addis Ababa hosts about 65% of industries in the country and more than 90% of those industries discharge their waste to the nearby river without proper treatment ( Yohannes and Elias, 2017 ). However, in recent years, industrial activity is extending beyond Addis Ababa into towns like Mojo, Debrezeit and Nazret, increasing the influence of industrial pollution to the Awash and the Mojo rivers, and Koka reservoir as shown in Figure 2 . The Awash River is polluted by liquid and solid effluents released from industries and households that release untreated their domestic and industrial effluents ( Teshome, 2019 ). One of the major sources of pollution for the Awash River is untreated domestic discharge from the city of Addis Ababa. In Addis Ababa, for example, there are roughly 1,200 significant industrial enterprises, which combined with institutions, commercial centers, and hotels generate 18 percent of the city's entire solid wastes ( Menbere, 2019 ). The majority of the waste produced by residents and industries is deposited in the city's streams and rivers, which are consumed by livestock and also used for various purposes like as irrigating vegetables and crops ( Weldegebriel et al., 2012 ).

Mengesha et al. (2021) reported the Akaki River, like many Addis Ababa streams, is heavily contaminated by anthropogenic influences from upstream to downstream. The causes are specifically indiscriminate dumping of refuses into the river, indiscriminate dumping of industrial wastes ( Mekonnen and Amsalu, 2018 ). The majority of pollutants are discharged into a single collection location, such as reservoirs that can act as a sink for a variety of contaminants. Heavy metal concentrations in stream sediments are relatively high, according to several studies, due to significant anthropogenic metal loadings carried by tributary rivers. As a result, surficial sediments may act as a metal puddle, releasing metals into the underlying water and potentially harming riverine ecosystems ( Astatkie et al., 2021 ).

Most industries in Gelan and Dukem have established neither treatment plants nor adequate storage or discharge channels for their wastes. As a result, polluted liquids are directly discharged into the open landscape ( Dadi et al., 2017 ). A study by Dadi et al. (2017) on the environmental and health impacts of effluents from textile industries in the Gelan and Dukem watersheds of the Upper Awash river showed the presence of substantial concentrations of Zn in industry effluents. Zerihun and Eshetu (2018) reported that both raw and treated effluents from the Anmol product paper factory contained higher concentrations of heavy metals that significantly deteriorated the water quality of the Awash river ( Table 2 ). The study found that, very high Na and Ca concentrations, greater than the national and WHO discharge limits, in both raw and treated effluents.

www.frontiersin.org

Table 2 . Metals and heavy metals Anmol product paper factory.

The Mojo watershed is one of the sub-watersheds of the Awash Basin. The Mojo river Basin is experiencing rapid population growth, industrialization, and agricultural activities, all of which are potential causes of surface and groundwater contamination. Residents along the Mojo River use the river water for many purposes. However, the discharge of domestic and industrial pollutants of the town severely restricts the use of surface water ( Tamene and Seyoum, 2015 ). Kolba Tannery, Ethio-Japan Textile, Soap factory, Gelan Tannery, Organic Export Abattoir, Derartu Tannery, Mojo Tannery, and Food and Oil Complex drain their influent into the Mojo river. A study by Gebre et al. (2016) found that mean concentration values of Cr in water samples ranged between 0 and 8.02 mg/L. Cr concentrations downstream of the Mojo, Kolba, Gelan and Derartu Tanneries were greater than NEQS standard (1 mg/L).

Impacts of Water Pollution

Water quality affects the economic, social and political development of society ( Mekonnen and Amsalu, 2018 ). This article focuses on the effects of water quality on biological, toxic, health as well as vegetable production and soil.

Biological Effects

Nutrient loadings affect water quality throughout the world and have resulted in the eutrophication of many fresh water lakes ( Ligdi et al., 2010 ; Jonathan et al., 2012 ; Alemu et al., 2017 ). Water pollution in the basin is found to have contributed to the disappearance of aquatic species ( Rooijen and Taddesse, 2009 ). Dissolved phosphorus plays an important role in the eutrophication of water bodies ( Moges et al., 2016 ). Phosphates entering the water from detergents urban areas, industrial waste (such as sugar cane production), and intensive agriculture ( Rooijen and Taddesse, 2009 ; Girma, 2016 ; Moges et al., 2016 ) can cause the nutrient levels in the water to rise and lead to algal blooms ( Girma, 2016 ). A study by Ingwani et al. (2010) describes eutrophication from anthropogenic drivers as the main cause for the rapid spreading of water hyacinth over reservoirs. Water hyacinth is one of the biodiversity issues that contribute to the degradation of aquatic ecosystems. This is a case in Ethiopia where by degradation in water quality results in water hyacinth (Eichhornia crassipes) invasion ( Hailu et al., 2020 ). This can increase the incidental occurrence and spread of water hyacinths in Lake Tana ( Moges et al., 2017 ), as also observed in Lake Koka and Aba Samuel Lakes are indictors of the effect. Similarly, very high chlorophyll a values were observed upstream of Sebeta River ( Tassew, 2007 ). The most severe area coverage by water hyacinths in Lake Tana was noticed at the mouth of the Megech River, which stretched both east and north with an estimated area coverage of 80–100 ha and wide distribution of daughter plants that pushed forward with the wave's assistance ( Tewabe, 2015 ).

When nutrient-rich effluents enter a lake, it overloads the ability of the lake to provide oxygen to aquatic lives in it. This is a eutrophication process in which there is an upsurge of algae growth in the lake, which then results in the depletion of oxygen and fouling up of the lake water ( Rooijen and Taddesse, 2009 ; Girma, 2016 ). This, in turn, can alter the food chain and ionic composition of the water, increase organic matter in the sediment, decrease metalimnetic and hypolimnetic oxygen (which causes fish suffocation), and cause changes in the water temperature ( Girma, 2016 ).

In many places of the world, the occurrence of harmful toxic algal occurrences has increased over the last three decades. Many bloom-forming algae species can produce biologically active secondary metabolites that are extremely harmful to humans and other animals ( Reddy and Mastan, 2011 ; Edokpayi et al., 2017 ). Water pollution in the basin is found to have contributed to the disappearance of aquatic species ( Keraga et al., 2017b ).

Heavy metals concentrations in water and tissue samples from edible fish species from Hwassa and Koka lakes showed that metal concentration in Koka from highest to lowest was Cr > As > Pb > Cd > Se > Hg ( Dsikowitzky et al., 2013 ). Metal concentrations in fish tissues also showed significant differences with average concentrations of metal in the gills from highest to lowest was: Cr > Pb > Hg > As > Cd > Se. In fish muscles, the rank was Cr > Hg > As > Pb > Cd > Se and in fish livers Cr > Hg > Cd > As > Pb > Se. Overall, Cr concentration was the highest in both water and fish tissue samples.

Toxicity Effects

Toxic substances from farms, towns, and factories readily dissolve into and mix with it causing water pollution. Heavy metals are known to pose a variety of health risks such as cancer, mutation ( Itanna, 2002 ). Metals such as arsenic, lead, cadmium, nickel, mercury, chromium, cobalt, zinc and selenium present in natural waters are highly toxic even in minor quantities ( Masindi and Khathutshelo, 2018 ). Long-term exposure to heavy metals can cause significant toxicity in the dermal and ingestion pathways of contaminated materials ( Islam et al., 2020 ). Some of the cations and heavy metal investigation results by different researchers in Lake Koka are shown in Table 1 . For example, Fe, Cr, and Ni are higher than the maximum permissible limit of the WHO standard. The investigation made by Bahiru (2021) showed that concentrations (mg/L) of metals in the Akaki river water samples were found to be in the ranges of 0.18–0.28, 1.40–2.67, 0.97–1.40, 0.037–0.087, 0.037–0.080, and 01–0.14 for Fe, Zn, Cu, Cd, Pb, and Cr, respectively. All are above the recommended limit of both ( Fewtrell and Bartram, 2001 ).

The Tinishu Akaki catchment area has a high influx of trace metals. High levels of trace metals in sediments probably have adverse effects on the bottom-dwelling aquatic organisms as well as to the health of the people who depend on the water for various activities ( Kassegne et al., 2018 ). The poor quality of river water in Addis Ababa cause and affect the production of different crops/vegetables ( Bedada et al., 2019 ); this is justified by an investigation made by Gebre and Rooijen (2009) trace metal content in vegetable leaves (Cd, Cr, Cu, Hg, Ni and Zn in potato and Cr in onion and red beet in Addis Ababa). The concentrations of trace metals in vegetables cultivated with wastewater are shown in Figures 5A,B . Although all of these metals have not yet reached phytotoxic levels, some plants have exceeded the normally occurring amounts. This is especially true in the case of Cd, Cr, Cu, Hg, Ni, and Zn in potatoes, as well as Cr in onion and red beet.

www.frontiersin.org

Figure 5 . Trace metal levels in vegetables ( Gebre and Rooijen, 2009 ). (A) Concentration of As, Cd, Hg and Ni in vegetables and (B) Concentration of Zn, Cu, and Cr in vegetables.

Health Effects

Excessive anthropogenic activities, such as the discharge of industrial effluents, agricultural waste, and toxic waste into surface waters, have a negative impact on human health ( Islam et al., 2021 ). Typhoid, cholera, encephalitis, hepatitis, skin infection, hair loss, liver cirrhosis, renal failure, and neural disorder spread through dermal and oral ingestion of metals contaminated water ( Islam et al., 2021 ). Virological Quality of Addis Ababa rivers and Hospitals total coliphages enumerations ranged from <1 pfu/100 ml to 5.2 × 103 pfu/100 ml for urban rivers and <1 pfu/100 ml to 4.92 × 103 pfu/100 ml for hospitals wastewaters. Coliphages were detected in 44 (52.4%) and 3 (10%) samples of 30 streams and rivers and four hospital waste waters, respectively.

Novel contaminants continue to pose new challenges to monitoring and treatment regimes in urban settings, where a variety of contaminants have an impact on water quality ( McGrane, 2016 ). For example, as a result of fast population growth, uncontrolled urbanization and industrialization and poor waste management practices Addis Ababa's water resources are highly polluted which threatens human health and ecosystem function as a whole ( Yohannes and Elias, 2017 ). Since downstream Addis river water is being used for various purposes such as drinking water supply (example, Nazareth town) and irrigation, public health risks are high ( Rooijen and Taddesse, 2009 ). Contaminated drinking water has been linked to substantial illness and mortality around the world. It is used to spread communicable diseases such as diarrhea, cholera, dysentery, typhoid, and guinea worm infection ( Wolde et al., 2020 ). For example, the negative impact on human health and the ecosystems as a result of the elevated level of several pollutants and irrigation products (vegetable) will ultimately affect the people that depend on the Akaki River water ( Zinabu and Desta, 2002 ). An investigation conducted by Bedada et al. (2019) , in nine sub-Cities of thirteen rivers and four hospitals wastewaters of Addis Ababa, reported poor water quality in all rivers and one-half of the hospitals (detection of coliphages) will continue to cause a major health risk and will result in more number of deaths and also will affect the aquatic life and drinking water.

The overall mean count of E. coli and Non E. coli from water samples from Akaki River was 2.09 and >3.48 log 10 CFU 10 mL −1 which is higher than the WHO recommended standard ( Beyene et al., 2017 ). A high level of total E. coli was recorded in effluents from ALSAR and ALMHADI textile industries in Gelan and Dukem ( Dadi et al., 2017 ). Downstream residents use river water for domestic and agricultural purposes. Such practices have created major health risks to people who rely on the river for their livelihood. Despite the varied character of the Kebena River's and its neighboring buffer zones' environmental concerns, pollution remains the dominant worry ( Asnake et al., 2021 ). Consumption of heavy metal-contaminated food crops is one of the most common routes for harmful compounds to enter the human body, with some symptoms appearing only after several years of exposure ( Srinivasan and Reddy, 2009 ). The existence of total coliforms across the River has been a major threat to human health. Water pollution does not only have adverse health impacts, but it also imposes medical expenses to the population ( Gebre and Rooijen, 2009 ). According to the World Health Organization (WHO), around 80% of diseases are transmitted through water, making surface water a major source of infection for marine species and humans ( Islam et al., 2021 ). Some research activities around Addis Ababa recognized there is a signal that human health and life are threatened due to crop production using polluted water ( EFDR, 2000 ). The negative impact on human health and the ecosystem as a result of the elevated level of several pollutants and irrigation products such as vegetables will ultimately affect the people that depend on the river water ( Zinabu and Desta, 2002 ).

The local environment, people, and livestock of Gelan and Dukem towns are exposed to highly contaminated effluents. For example related to skin allergies and stomach health problems in humans and bacteriological infections specifically “Salmonella” in cattle and donkeys diagnosed in veterinary clinics ( Dadi et al., 2017 ).

Impact on Vegetable and Soil

Urban and industrial wastes are common sources of anthropogenic metal pollution in soils. Because of the negative impacts on food quality, crop growth, and soil environmental health, heavy metal deposition in soil is a key concern in agricultural production ( Naser et al., 2014 ). The use of water with poor quality for agricultural activities can affect crop yield and cause food insecurity. Several studies have reported higher levels of heavy metal concentrations from different part of the country ( Edokpayi et al., 2017 ). Heavy metals are easily accumulated in the edible parts of leafy vegetables compared to grain or fruit crops ( Mapanda et al., 2005 ). Heavy metals accumulate in the edible and inedible sections of vegetables in sufficient concentrations to induce clinical issues in animals and humans who consume these metal-rich plants ( Arora et al., 2008 ). Haile and Mohammed (2019) reported that Cr, Zn, Fe, K, Cu, and Mn exceeded the ( WHO, 2008 ) standards in lake Hawassa. Abate and Fitamo (2015) stated that the concentration of Na + and K + >200 mg/L permissible limit by WHO (2008) . Worako (2015) also showed that Total Coliform and Fecal Coliform were greater than the acceptable limit of 1,000 MPN/100 ml set by WHO (2008) and CCME (1999 ); and above the 14 MPN/100 ml recommended limit by USEPA (1976 ).

Due to the high metal retention capacity of agricultural soil, it has been suggested that it is the most important sink for heavy metals. As a result of increased anthropogenic activity, there is evidence to suggest that agricultural soil has elevated amounts of heavy metals. The chemical contents of irrigation water can affect plant growth directly through toxicity or inadequacy, or indirectly by influencing plant nutrient availability Due to the high metal retention capacity of agricultural soil, it has been suggested that it is the most important sink for heavy metals. As a result of increased anthropogenic activity, there is evidence to suggest that agricultural soil has elevated amounts of heavy metals. The chemical contents of irrigation water can affect plant growth directly through toxicity or inadequacy, or indirectly by influencing plant nutrient availability ( Belay, 2019 ). Heavy metals are inorganic pollutants with a wide range of negative effects on aquatic organisms, plants, and human ( Inyinbor et al., 2018 ). The heavy metal concentration of irrigation water has been demonstrated to surpass the irrigation water standard ( Keraga et al., 2017b ).

Excessive accumulation of pollutants in soils, such as heavy metals, causes increased heavy metal uptake by crops, affecting food quality and safety ( Srinivasan and Reddy, 2009 ). Mean concentration of heavy metals including Mn, Cr, Ni, Pb, As, and Zn reported more in vegetables irrigated by Awash River than their allowable limits ( Keraga et al., 2017b ). Vegetables like, Ethiopian mustard, Lettuce and Swiss chard, were collected and subsequently analyzed for selected heavy metals, Fe, Mn, Zn, Pb, Cr, and Cd. Zn was detected in all vegetable types, where around 51% of the samples have exceeded the amount of Zn when compared to the standard limit of 99 mg/kg in Akaki Rivers ( Weldegebriel et al., 2012 ). Some of the vegetables tested in Tinishu and Tiliku Akakai Rivers have heavy metals exceeded the naturally expected levels. Based on the investigation, Cd, Cr, Cu, Hg, Ni, and Zn in potato, Zn and Hg in Cabbage, and Cr in onion and red beet ( Rooijen and Taddesse, 2009 ; Teshome, 2019 ).

The mean counts of TC, FC, and total aerobic count (TAC) on collected vegetables irrigated with Akaki River were 3.22, 1.37, and 4.72 in the dry season, and 3.87, 2.57, and 5.09 log10CFU per gram in the wet season, respectively. All fresh vegetables were contaminated with total coliform, fecal coliform and total aerobic in the dry season ( Beyene et al., 2017 ). In addition to this, as stated by Bahiru (2021) , Cd, Pb, Fe, Zn, Cr, and Cu concentration in lettuce samples irrigated by Akaki river water are in the range of (0.047–0.263), (0.42–6.55), (339.83–420.00), (2.96–13.44), (0.95–7.87) and (1.68–7.49) (mg /Kg) respectively, all heavy metal concentration are above recommended level set by WHO (2008) .

The investigation made by Itanna (2002) showed that Arsenic (As) and zinc (Zn) in soil irrigated by the Akaki River were higher than the normal limit. The concentrations of Pb, Cd, Mn, Ni and Zn in sediments in the Tinishu Akaki river were relatively greater than other trace metals at levels that may have adverse biological effects on the surrounding biota ( Kassegne et al., 2018 ). Similarly, high concentration of tributary rivers and lakes (high concentration of salt) increases the pH level of the Awash River and this affects the producing of companies that engaged in cotton production, wheat, and other cereal crops and vegetables ( Teshome, 2019 ). Akaki river water irrigated soil samples concentration (mg/kg) was found Cd (0.47–3.47), Pb (8.00–118.00), Fe (13,557.30–16,800.00), Zn (40.00–224.67), Cr (4.91–39.36) and Cu (35.00–149.88). All metals except Cd and Fe in the soil samples are below the recommended level set by Fewtrell and Bartram (2001) , Bahiru (2021) . Heavy metal levels in soil samples from Mojo sub-basin farmlands were measured. In soil samples from tomato cultivation, the mean concentration of arsenic (As) was found to be 21.00 mg/kg, and in soil samples from cabbage cultivation, it was found to be 30.73 mg/kg. Arsenic levels were found to be higher than the European Union's acceptable limit of 20 mg/kg in both soil samples tested ( Gebeyehu and Bayissa, 2020 ). According to findings in Mojo river, the mean Cr value was 2.515.794 mg/L, with half of the findings falling below the FAO standard for surface water irrigation (0.1 mg/L) and WHO DWG (0.05 mg/L) ( Tamene and Seyoum, 2015 ).

Soil pH varied between 6.9 to 8.9 for Melka Sedi and 7.06 to 9.1 for Melka Werer farm areas. EC value ranges from 0.33 to 82.1 deci Siemens per meter (dS/m) and 0.4 to 37.5 dS/m, respectively for soil samples taken from Melka Sedi and Melka Werer farms ( Abebe et al., 2015 ). Soil salinity and sodicity assessment by Abebe et al. (2015) in the Amibara area revealed that substantial parts of farm areas were consistently and continuously affected by salinity problems.

Socio-Economic Effects

The economic effect of water quality can be seen in different perspectives. Decrease in water quality can lead to increased treatment costs of potable and industrial process water. Crops will be prone to hunger and quality deterioration as a result of poor water quality, resulting in a drop in agricultural yield. Water contamination has a considerable impact on agricultural economic growth, as detailed by Li and Li (2021) , which is a major roadblock to China's rural revitalization plan. China's water pollution has a cumulative effect on agricultural economic growth that is increasing in time and space, harming the agricultural ecology. Agricultural economic growth in China dropped by 27.994 units for every unit increase in wastewater discharge intensity.

In case of Ethiopia, the mixing of lake Beseka (extremely saline) water with Awash river (fresh water) was done to slow down lake Beseka rapid expansion rather than to alleviate the basin's water scarcity problem. After the lake Beseka mix, the Awash River serves as an important water source for cattle, domestic use, and irrigation water for nearby wheat, vegetable, cotton, and sugar plantations. These crops are extremely important economically for both the local community and the country. The water utilized for irrigation in the downstream community has a variety of negative consequences, including decreased crop yield and financial benefits, decreased irrigable or fertile land, and increased domestic water shortages ( Yimer and Jin, 2020 ). For example, Tadesse et al. (2018) from their study Rebu River in the Oromia region reported that Cr, Zn, Fe, K, Cu, Na, Mn and Pb concentrations were greater than the ESA (2013 ) and WHO (2008) standards as shown in summary of major water quality studies from different parts of Ethiopia supportive Supplementary Table S1 . Water pollution does not only have adverse health impacts but it also imposes medical expenses on the population ( Gebre and Rooijen, 2009 ). The town of Awash with a population of 30,000 has to shirt from abstracting water from river to groundwater primarily because of the pollution ( Parker et al., 2016 ).

High concentration of salt in tributary rivers and lakes increase the pH level of the Awash River and this affects the production of companies that engaged in cotton production, wheat, and other cereal crops and vegetables ( Teshome, 2019 ).

Research Gaps and Problems Identified Future Agenda

This review identifies several impact-related contaminated water research efforts, but it also identifies research gaps. The most important relates to the scope and delimitation of the study. Much of the reports are either separate graduate thesis research limited to specific location and or time. Consequently, there is no thorough integrated spatial and temporal water quality impact mapping to portray the overall picture of the sub watershed or the entire basin. There is little evidence-based research on the effects of contaminated water on agriculture, health, and socioeconomics. There is limited research on the socio-economic effects of water contamination and their estimated costs, human and animal health-related impacts of contaminated water and all vegetables species grown by contaminated river waters. In addition to this, there is lack of regular biological water quality monitoring in the basin.

It is expected to participate in a comprehensive spatial and temporal study of the impact of contaminated water on irrigated vegetable production, human and animal health, socio-economic effects, and impact on living organisms living in the aquatic environment in the basin or subbasin, utilizing the gaps identified in this review effort.

The water quality of the Awash Basin's rivers, lakes and reservoirs is deteriorating. Rapid urbanization and industrialization have resulted in serious point source water contamination in the basin and endangering the basin's socio-economic and ecological values. The majority of the factories in the basin lack wastewater treatment facilities, simply discharge their toxic wastewater into nearby rivers, lakes, and streams. There is also untreated domestic discharge. The industries in the Akaki and Mojo sub-basins discharge their waste into nearby rivers and streams. They haven't built any treatment plants, nor have they set up suitable storage or discharge pathways for their waste.

Heavy metal concentrations in rivers, as well as in plants irrigated by these river waters and in the soil, were beyond their permissible levels. Even in little amounts, heavy metals are extremely hazardous. This study found evidence of the presence of these harmful compounds over the WHO recommended limit in rivers, lakes, edible fish tissues, and vegetables, primarily in upper Awash. Despite the fact that no previous study has been conducted to determine the influence on human and animal health, it is thought that they have negative impacts on aquatic organisms as well as the health of people who rely on water for various purposes. The amounts of cations, metals, viruses, and bacteria in most water sources of the basin exceed WHO and EPA legal limits, leaving them unsafe for human consumption. Water hyacinth (Eichhornia crassipes) invasion and harmful toxic algal occurrence owing to eutrophication caused by anthropogenic factors have been observed in the Koka and Aba Samuel reservoirs, as well as the Sebeta river. As a result, the food chain and ionic composition of the water can be altered, making people and other animals particularly harmful.

A comprehensive and systematic research spanning from identifying sources of pollution and its impact the health of humans, livestock and ecosystem at regular interval is vital. Moreover, a vulnerable ecosystem, it is vital to have an institutional arrangement responsible for regular monitoring and evaluation to protect vulnerable riparian communities and ecosystems. More research is needed to fully comprehend pollution dynamics and cleaning capacity of aquatic and wetland ecosystems. including a comprehensive study of the effects of contaminated water on human and livestock health, a comprehensive spatial extent investigation of the impact of contaminated water on growing vegetables, and the magnitude of the polluted water's socioeconomic effects in the downstream community as well as the country as a whole. The novelty of this SR in that it is the first to combine information from many recognized research works on the impact of contaminated water on humans, vegetables, and soil, as well as toxic and socioeconomic effects. The output will give background information for future research as well as preliminary policy direction for water resource managers and policymakers.

This SR is unique in that there has not been such a comprehensive including the accessing reports from different institution in the country. The review also combines information from works on the impact of contaminated water on humans, vegetables, and soil, as well as toxic and socio-economic effects. The output will inform future research as well as plan management interventions. Building from narratives of different reports, the following immediate interventions: (1) absence of accountability for industries that discharge effluents directly into water bodies without sufficient treatment; (2) widespread vegetable production in the upper Awash sub-basin using contaminated water. In the last decade, the Upper Awash River Basin has experienced rapid urbanization. If things keep going this way, the dawn stream's water quality will deteriorate dramatically. Wastewater reuse, such as that from Addis Ababa, is often used by the poor for vegetable growing. This is therefore water quality protection in the basin necessitates effective management and policy guidelines.

Recommendation

A more extensive investigation of water pollution socio-economic, human, and animal health consequences, influence on aquatic creatures, and irrigated crop productivity in the upper Awash basin is needed, based on the findings of this systematic review. It is laudable to have strong institutions capable of formulating new laws and implementing the present environmental legal framework. Wastewater reuse, such as that from Addis Ababa, is often used by the poor for vegetable growing. This is therefore water quality protection in the basin necessitates effective management and policy guidelines.

Data Availability Statement

The original contributions presented in the study are included in the article/ Supplementary Material , further inquiries can be directed to the corresponding author/s.

Author Contributions

EA is a researcher and lead author. GZ and TA contributed to project design, conceptual framework development, and manuscript preparation. YD, HB, and BT reviewed different versions of the manuscript. All authors contributed to the article and approved the submitted version.

This work was supported by the Water Security and Sustainable Development Hub funded by the UK Research and Innovation's Global Challenges Research Fund (GCRF) (Grant Number: ES/S008179/1).

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Acknowledgments

This work was financially supported by Water and Land Resource Center (WLRC), Addis Ababa University (AAU) funded by the UKRI GCRF Water Security and Sustainable Development Hub Project. The authors gratefully acknowledge use of the services and facilities of the WLRC, AAU.

Supplementary Material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/frwa.2021.790900/full#supplementary-material

Abate, A., and Fitamo, D. (2015). Water quality assessment of lake Hawassa for multiple designated water uses. Water Utility J . 9,11.

Abebe, A. (2019). Corporate environmental responsibility in Ethiopia: a case study of the Akaki River Basin. Ecosyst. Health Sustain. 5, 57–66. doi: 10.1080/20964129.2019.1573107

CrossRef Full Text | Google Scholar

Abebe, F., Alamirew, T., and Abegaz, F. (2015). Appraisal and mapping of soil salinity problem in amibara irrigation farms, Middle Awash Basin, Ethiopia. Int. J. Innov. Scientific Res. 13, 298–314.

Alayu, E., and Yirgu, Z. (2018). Advanced technologies for the treatment of wastewaters from agro-processing industries and cogeneration of by-products: a case of slaughterhouse, dairy and beverage industries. Int. J. Environ. Sci. Technol. 15, 1581–1596. doi: 10.1007/s13762-017-1522-9

Alemayehu, T. (2001). The impact of uncontrolled waste disposal on surface watwer quality in addis ababa, Ethiopia. SINET: Ethiop. J. Sci. 24, 93–104. doi: 10.4314/sinet.v24i1.18177

Alemu, M. L., Geset, M., Mosa, H. M., Zemale, F. A., Moges, M. A., Giri, S. K., et al. (2017). Spatial and temporal trends of recent dissolved phosphorus concentrations in lake tana and its four main tributaries. Land Degrad. Develop. 28, 1742–1751. doi: 10.1002/ldr.2705

Amenu, K. (2013). “Assessment of water sources and quality for livestock and farmers in the Rift Valley area of Ethiopia: Implications for health and food safety,” in Psychology Applied to Work: An Introduction to Industrial and Organizational Psychology, Tenth Edition Paul .

Amoatey, P., and Baawain, M. S. (2019). Effects of pollution on freshwater aquatic organisms. Water Environ. Res. 91, 1272–1287. doi: 10.1002/wer.1221

PubMed Abstract | CrossRef Full Text | Google Scholar

Andualem, A., and Takele, N. (2018). Analysis of the spatial accessibility of addis ababa's light rail transit: the case of east–west corridor. Urban Rail Transit 4, 35–48. doi: 10.1007/s40864-018-0076-6

Arora, M., Kiran, B., Rani, S., Rani, A., Kaur, B., and Mittal, N. (2008). Heavy metal accumulation in vegetables irrigated with water from different sources. Food Chemistr. 111, 811–815. doi: 10.1016/j.foodchem.2008.04.049

Asnake, K., Worku, H., and Argaw, M. (2021). Integrating river restoration goals with urban planning practices: the case of Kebena river, Addis Ababa. Heliyon 7:7. doi: 10.1016/j.heliyon.2021.e07446

Astatkie, H., Ambelu, A., and Mengistie, E. (2021). Contamination of stream sediment with heavy metals in the awetu watershed of Southwestern Ethiopia. Front. Earth Sci. 9, 1–13. doi: 10.3389/feart.2021.658737

Ayenew, T., and Legesse, D. (2007). The changing face of the Ethiopian rift lakes and their environs: call of the time. Lakes Reserv. Res. Manage. 12, 149–165. doi: 10.1111/j.1440-1770.2007.00332.x

Bahiru, D. B. (2021). Evaluation of Heavy Metals Uptakes of Lettuce (Lactuca sativa L.) Under Irrigat. Water Akaki River . 5, 6–14. doi: 10.11648/j.ajese.20210501.12

Bedada, T. L., Eshete, T. B., Gebre, S. G., Dera, F. A., Sima, W. G., Negassi, T. Y., et al. (2019). Virological quality of urban rivers and hospitals wastewaters in Addis Ababa, Ethiopia. Open Microbiol. J. 13, 164–170. doi: 10.2174/1874285801913010164

Belay, T. (2019). Assessment of pollution status of soils and vegetables irrigated by awash river and its selected tributaries. Int. J. Environ. Sci. Nat. Resourc. 18, 163–168. doi: 10.19080/IJESNR.2019.18.556000

Berg, H. v d, Rickert, B., Ibrahim, S., Bekure, K., Gichile, H., Girma, S., et al. (2019). Linking water quality monitoring and climate-resilient water safety planning in two urban drinking water utilities in Ethiopia. J. Water Health 17, 989–1001. doi: 10.2166/wh.2019.059

Beyene, Y., Alemu, Z. A., Mengesha, S. D., Kidane, A. W., Teklu, K. T., Getachew, M., et al. (2017). Pollution status of Akaki river and its contamination effect on surrounding environment and agricultural products: technical report .

Carr, R. M., Blumenthal, U. J., and Mara, D. D. (2004). Guidelines for the safe use of wastewater in agriculture: Revisiting WHO guidelines. Water Sci. Tech. 50, 31–38. doi: 10.2166/wst.2004.0081

CCME. (1999). Canadian Water Quality Guidelines for the Protection of Aquatic Life - Dissolved Oxygen (Freshwater). Canadian Council of Ministers of the Environment, Winnipeg, Manitoba, Canada . p. 1–6. Available online at: https://ccme.ca/en/res/dissolved-oxygen-freshwater-en-canadian-water-quality-guidelines-for-the-protection-of-aquatic-life.pdf

Google Scholar

Chebet, E. B., Kibet, J. K., and Mbui, D. (2020). The assessment of water quality in river Molo water basin, Kenya. Appl. Water Sci. 10, 1–10. doi: 10.1007/s13201-020-1173-8

Dadi, D., Stellmacher, T., Senbeta, F., Van Passel, S., and Azadi, H. (2017). Environmental and health impacts of effluents from textile industries in Ethiopia: the case of Gelan and Dukem, Oromia Regional State. Environ. Monitor. Assess. 4, 189. doi: 10.1007/s10661-016-5694-4

Dagnachew, A., Lemma, B., Gebrie, G. S., Larsen, L., Yeshitela, K., and Jensen, M. B. (2019). Stormwater impact on water quality of rivers subjected to point sources and urbanization–the case of Addis Ababa, Ethiopia. Water Environ. J. 33, 98–110. doi: 10.1111/wej.12381

Degefu, F., Lakew, A., Tigabu, Y., and Teshome, K. (2013). The water quality degradation of upper Awash River, Ethiopia. Ethiopian J. Environ. Stud. Manage. 6, 7. doi: 10.4314/ejesm.v6i1.7

Dinka, M. O. (2012). Analysing the extent (size and shape) of Lake Basaka expansion (Main Ethiopian Rift Valley) using remote sensing and GIS. Lakes Reserv. Res. Manage. 17, 131–141. doi: 10.1111/j.1440-1770.2012.00500.x

Dinka, M. O. (2017). Delineating the Drainage Structure and Sources of Groundwater Flux for Lake Basaka, Central Rift.

Dsikowitzky, L., Mengesha, M., Dadebo, E., De Carvalho, C. E. V., and Sindern, S. (2013). Assessment of heavy metals in water samples and tissues of edible fish species from Awassa and Koka Rift Valley Lakes, Ethiopia. Environ. Monitor. Assess. 185, 3117–3131. doi: 10.1007/s10661-012-2777-8

Duguma, F. A., Feyessa, F. F., Demissie, T. A., and Januszkiewicz, K. (2021). Hydroclimate trend analysis of upper awash basin, Ethiopia. Water (Switzerland) 13, 1–17. doi: 10.3390/w13121680

Edokpayi, J. N., Odiyo, J. O., and Durowoju, O. S. (2017). Impact of wastewater on surface water quality in developing countries: a case study of South Africa. Water Qual. 17, 6651 doi: 10.5772/66561

EFDR. (2000). Federal negarit gazeta of the federal democratic republic of Ethiopia, Public Health Proclamation . London: BERHANENA SELAMPRINTING ENTERPRISE.

Eliku, T., and Leta, S. (2018). Spatial and seasonal variation in physicochemical parameters and heavy metals in Awash River, Ethiopia. Appl. Water Sci. 8, 1–13. doi: 10.1007/s13201-018-0803-x

ESA. (2013). Compulsory Ethiopian drinking water quality specifications. Ethiopian Standards Agency . p. 1–7). Available online at: https://www.cmpethiopia.org/content/download/1531/6997/file/EthiopianDrinkingWaterQualityStandard2013.pdf

FAO and IHE Delft (2020). “ Water accounting in the Awash River Basin REMOTE SENSING FOR WATER PRODUCTIVITY ,” in the Food and Agriculture Organization of the United Nations and IHE Delft Institute for Water Education . Available online at: www.fao.org/publications (accessed July 2, 2021).

Fasil, D., Kibru, T., Gashaw, T., Fikadu, T., and Aschalew, D. (2011). Some limnological aspects of Koka reservoir, a shallow tropical artificial lake, Ethiopia. J. Recent Trends Biosci. 1, 94–100.

Fewtrell, L., and Bartram, J. (2001). Water Quality Guidelines, Standards and Health?: Assessment of risk and risk management for water-related infectious disease. IWA Publishing . Available online at: www.iwapublishing.com

Gebeyehu, H. R., and Bayissa, L. D. (2020). Levels of heavy metals in soil and vegetables and associated health risks in Mojo area, Ethiopia. PLoS One 15, 1–22. doi: 10.1371/journal.pone.0227883

Gebre, A. E., Demissie, H. F., Mengesha, S. T., and Segni, M. T. (2016). The pollution profile of modjo river due to industrial wastewater discharge, in Modjo Town, Oromia, Ethiopia. Environ. Analytic. Toxicol. 6, 3. doi: 10.4172/2161-0525.1000363

Gebre, G., and Rooijen, D. (2009). “Urban water pollution and irrigated vegetable farming Urban water pollution and irrigated vegetable farming in Addis Ababa,” in Water, Sanitation and Hygiene: Sustainable Development and Multisectoral Approaches - Proceedings of the 34th WEDC International Conference , p. 166.

Girma, K. (2016). “The State of Freshwaters in Ethiopia,” in Freshwater (Haldey, MA: Mount Holyoke College South Hadley), p. 52.

Haile, M. Z., and Mohammed, E. T. (2019). Evaluation of the current water quality of Lake Hawassa, Ethiopia. Int. J. Water Resour. Environ. Eng. 11, 120–128. doi: 10.5897/IJWREE2019.0857

Hailu, D., Negassa, A., and Kebede, B. (2020). Study on the status of some physico-chemical parameters of Lake Koka and its relation with water hyacinth (Eichhornia crassipes). Invasion . 8, 405–412.

Hasan, M. K., Shahriar, A., and Jim, K. U. (2019). Water pollution in Bangladesh and its impact on public health. Heliyon 5, e02145. doi: 10.1016/j.heliyon.2019.e02145

Igwe, P. U., Chukwudi, C. C., Ifenatuorah, F. C., Fagbeja, I. F., and Okeke, C. A. (2017). A Review of Environmental Effects of Surface Water Pollution. Int. J. Adv. Eng. Res. Sci. 4, 128–137. doi: 10.22161/ijaers.4.12.21

Ingwani, E., Gumbo, T., and Gondo, T. (2010). The general information about the impact of water hyacinth on Aba Samuel dam, Addis Ababa, Ethiopia: Implications for ecohydrologists. Ecohydrol. Hydrobiol. 10, 341–345. doi: 10.2478/v10104-011-0014-7

Inyinbor, A., Adebesin Babatunde, O., Oluyori Abimbola, P., and Adelani-Akande Tabitha, A. (2018). Water Pollution: Effects, Prevention, and Climatic Impact. In Water Challenges of an Urbanizing World .

Islam, A. R. M. T., Islam, H. M. T., Mia, M. U., Khan, R., Habib, M. A., Bodrud-Doza, M., et al. (2020). Co-distribution, possible origins, status and potential health risk of trace elements in surface water sources from six major river basins, Bangladesh. Chemosphere 20, 249. doi: 10.1016/j.chemosphere.2020.126180

Islam, M. S., Idris, A. M., Islam, A. R. M. T., Ali, M. M., and Rakib, M. R. J. (2021). Hydrological distribution of physicochemical parameters and heavy metals in surface water and their ecotoxicological implications in the Bay of Bengal coast of Bangladesh. Environ. Sci. Pollut. Res. 21, 9. doi: 10.1007/s11356-021-15353-9

Itanna, F. (2002). Metals in leafy vegetables grown in Addis Ababa and toxicological implications. Ethiop. J. Health Develop. 16, 3. doi: 10.4314/ejhd.v16i3.9797

Jin, L., Whitehead, P. G., Bussi, G., Hirpa, F., Taye, M. T., Abebe, Y., et al. (2021). Natural and anthropogenic sources of salinity in the Awash River and Lake Beseka (Ethiopia): Modelling impacts of climate change and lake-river interactions. J. Hydrol. Reg. Stud. 36, 100865. doi: 10.1016/j.ejrh.2021.100865

Jonathan, M., Abell, and Deniz Özkundakci, D. P. H. J. R. J. (2012). Latitudinal variation in nutrient stoichiometry and chlorophyll-nutrient relationships in lakes: a global study. Fundament. App. Limnol. 181, 1–14. doi: 10.1127/1863-9135/2012/0272

Kassegne, A. B., Esho, T. B., Okonkwo, J. O., and Asfaw, S. L. (2018). Distribution and ecological risk assessment of trace metals in surface sediments from Akaki River catchment and Aba Samuel reservoir, Central Ethiopia. Environ. Syst. Res. 7, 1. doi: 10.1186/s40068-018-0127-8

Katko, T. S., and Hukka, J. J. (2015). Social and economic importance of water services in the built environment: need for more structured thinking. Procedia Econ. Finance 21, 217–223. doi: 10.1016/S2212-5671(15)00170-7

Keraga, A. S., Kiflie, Z., and Engida, A. N. (2017a). Evaluating water quality of Awash River using water quality index. Int. J. Water Resour. Environ. Eng. 9, 243–253. doi: 10.5897/IJWREE2017.0736

Keraga, A. S., Kiflie, Z., and Engida, A. N. (2017b). Spatial and temporal water quality dynamics of Awash River using multivariate statistical techniques. Afric. J. Environ. Sci. Technol. 11, 565–577. doi: 10.5897/AJEST2017.2353

Kroll, C., Warchold, A., and Pradhan, P. (2019). Sustainable Development Goals (SDGs): Are we successful in turning trade-offs into synergies? Palgrave Commun. 5, 1–11. doi: 10.1057/s41599-019-0335-5

Kumar, S., Islam, A. R. M. T., Hasanuzzaman, M., Salam, R., Khan, R., and Islam, M. S. (2021). Preliminary assessment of heavy metals in surface water and sediment in Nakuvadra-Rakiraki River, Fiji using indexical and chemometric approaches. J. Environ. Manage. 298, 113517. doi: 10.1016/j.jenvman.2021.113517

Li, C., and Li, G. (2021). Impact of China's water pollution on agricultural economic growth: an empirical analysis based on a dynamic spatial panel lag model. Environ. Sci. Pollut. Res. 28, 6956–6965. doi: 10.1007/s11356-020-11079-2

Ligdi, E. E., Kahloun, M., El, and Meire, P. (2010). Ecohydrological status of Lake Tana - A shallow highland lake in the Blue Nile (Abbay) basin in Ethiopia: review. Ecohydrol. Hydrobiol. 10, 109–122. doi: 10.2478/v10104-011-0021-8

Ma, T., Sun, S., Fu, G., Hall, J. W., Ni, Y., He, L., et al. (2020). Pollution exacerbates China's water scarcity and its regional inequality. Nat. Commun. 11, 1–9. doi: 10.1038/s41467-020-14532-5

Mapanda, F., Mangwayana, E. N., Nyamangara, J., and Giller, K. E. (2005). The effect of long-term irrigation using wastewater on heavy metal contents of soils under vegetables in Harare, Zimbabwe. Agricult. Ecosyst. Environ. 107, 151–165. doi: 10.1016/j.agee.2004.11.005

Masindi, V., and Khathutshelo, L. M. (2018). “Environmental contamination by heavy metals,” in Heavy Metals, eds H. E. M. Saleh and R. F. Aglan (Intechopen), 115–133. doi: 10.5772/intechopen.76082

Masresha, A. E., Skipperud, L., Rosseland, B. O. G.M Z, Meland, S., et al. (2011). Speciation of selected trace elements in three ethiopian rift valley lakes (koka, ziway, and awassa) and their major inflows. Sci. Total Environ. 409, 3955–3970. doi: 10.1016/j.scitotenv.2011.06.051

McDonald, R. I., Weber, K., Padowski, J., Flörke, M., Schneider, C., Green, P. A., et al. (2014). Water on an urban planet: Urbanization and the reach of urban water infrastructure. Global Environ. Change 27, 96–105. doi: 10.1016/j.gloenvcha.2014.04.022

McGrane, S. J. (2016). Impacts of urbanisation on hydrological and water quality dynamics, and urban water management: a review. Hydrol. Sci. J. 61, 2295–2311. doi: 10.1080/02626667.2015.1128084

Mehari, A. K., Gebremedhin, S., and Ayele, B. (2015). Effects of bahir dar textile factory effluents on the water quality of the head waters of Blue Nile River, Ethiopia. Int. J. Anal. Chemistr. 2015, 247. doi: 10.1155/2015/905247

Mekonnen, R., and Amsalu, D. (2018). Causes and impacts of shankila river water pollution in Addis Ababa, Ethiopia. Environ Risk Assess Remediat . 2, 21–30.

Mekuria, D. M., Kassegne, A. B., and Asfaw, S. L. (2021). Assessing pollution profiles along Little Akaki River receiving municipal and industrial wastewaters, Central Ethiopia: implications for environmental and public health safety. Heliyon 7, e07526. doi: 10.1016/j.heliyon.2021.e07526

Menbere, M. P. (2019). Industrial wastes and their management challenges in Ethiopia. Chemistr. Mater. Res. 19, 1–6. doi: 10.7176/CMR/11-8-01

Mengesha, S. D., Kidane, A. W., and Dinssa, D. A. (2021). Microbial risk assessment of vegetables irrigated with akaki river water in Addis Ababa. Res. Square 21, 1–22. doi: 10.21203/rs.3.rs-492022/v1

Mengistie, B. T., Mol, A. P. J., and Oosterveer, P. (2017). Pesticide use practices among smallholder vegetable farmers in Ethiopian Central Rift Valley. Environ. Develop. Sustain. 19, 301–324. doi: 10.1007/s10668-015-9728-9

Mersha, A., Masih, I., de Fraiture, C., Wenninger, J., and Alamirew, T. (2018). Evaluating the Impacts of IWRM Policy Actions on Demand Satisfaction and Downstream Water Availability in the Upper Awash Basin, Ethiopia. Water 10, 892. doi: 10.3390/w10070892

Moges, M. A., Schmitter, P., Tilahun, S. A., Ayana, E. K., Ketema, A. A., Nigussie, T. E., et al. (2017). Water quality assessment by measuring and using landsat 7 etm+ images for the current and previous trend perspective: Lake Tana Ethiopia. J. Water Resour. Protect > 09, 1564–1585. doi: 10.4236/jwarp.2017.912099

Moges, M. A., Tilahun, S. A., Ayana, E. K., Moges, M. M., Gabye, N., Giri, S., et al. (2016). Non-point source pollution of dissolved phosphorus in the ethiopian highlands: the awramba watershed Near Lake Tana. Clean - Soil, Air, Water 44, 703–709. doi: 10.1002/clen.201500131

Moher, D., Liberati, A., Tetzlaff, J., and Altman, D. G. (2009). Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. BMJ (Online) 339, 332–336. doi: 10.1136/bmj.b2535

Naser, H., Sultana, S., Haque, M. M., Akhter, S., and Begum, R. (2014). Lead, cadmium and nickel accumulation in some common spices grown in industrial Areas of Bangladesh. The Agriculturists 12, 122–130. doi: 10.3329/agric.v12i1.19867

Özerol, G., Vinke-De Kruijf, J., Brisbois, M. C., Flores, C. C., Deekshit, P., Girard, C., et al. (2018). Comparative studies of water governance: a systematic review. Ecology and Society 23(4). doi: 10.5751/ES-10548-230443

Pareek, D. R., Kkahn, D. A. S., and Srivastava, D. P. (2020). Impact on Human Health Due to Ghaggar Water Pollution. Curr. World Environ. 15, 211–217. doi: 10.12944/CWE.15.2.08

Parker, H., Mosello, B., and Roger, C. (2016). A thirsty future? Water strategies for Ethiopia's new development era. In Report (Issue August) . Available Online at: https://www.sdgfund.org/thirsty-future-water-strategies-ethiopias-new-development-era (accessed February 10, 2020).

Rakhecha, P. R. (2020). Water environment pollution with its impact on human diseases in India. Int. J. Hydrol. 4, 152–158. doi: 10.15406/ijh.2020.04.00240

Reddy, R. K., and Mastan, S. A. (2011). Algal toxins and their impact on human health. Biomed. Pharmacol. J. 4, 129–134. doi: 10.13005/bpj/270

Rooijen, D., and Taddesse, G. (2009). “Urban sanitation and wastewater treatment in Addis Ababa in the Awash Basin, Ethiopia,” in Water, Sanitation and Hygiene: Sustainable Development and Multisectoral Approaches - Proceedings of the 34th WEDC International Conference .

Srinivasan, J. T., and Reddy, V. R. (2009). Impact of irrigation water quality on human health: a case study in India. Ecol. Econ. 68, 2800–2807. doi: 10.1016/j.ecolecon.2009.04.019

Tadesse, M., Tsegaye, D., and Girma, G. (2018). Assessment of the level of some physico-chemical parameters and heavy metals of Rebu river in oromia region. Ethiopia . 2, 885. doi: 10.15406/mojbm.2018.03.00085

Tamene, D., and Seyoum, T. (2015). Temporal and spatial variations on heavy metals concentration in River Mojo, Oromia State, East Ethiopia. Int. J. Sci. Res. 4, 1424–1432.

Tassew, A. (2007). Assessment of biological integrity using physico-chemical parameters and macroinvertebrate community index along sebeta river, Ethiopia [Addis Ababa University] . Available online at: http://etd.aau.edu.et/bitstream/handle/123456789/787/Admasu~Tassew.pdf?sequence=1andisAllowed=y (accessed February 10, 2020).

Taye, M. T., Dyer, E., Hirpa, F. A., and Charles, K. (2018). Climate change impact on water resources in the Awash basin, Ethiopia. Water 10, 1–16. doi: 10.3390/w10111560

Teshome, M. (2019). The Ethiopian Hearald. BERHANENA SELAM PRINTING ENTERPRISE, LXXV . Available online at: https://press.et/english/wp-content/uploads/2019/03/mar27.pdf (accessed February 10, 2020).

Tewabe, D. (2015). Preliminary survey of water hyacinth in Lake. Glob. J. Allerg. 12, 013–018. doi: 10.17352/2455-8141.000003

Tufa, K. N. (2021). Review on status, opportunities and challenges of irrigation practices in awash River Basin, Ethiopia Agrotechnology. Agrotechnology 10, 4.

USEPA. (1976). United States Environmental Protection Agency. Quality Criteria for Water, Office of Water Planning and Standards . Washington, DC: U S Environmental Protection Agency (USEPA). Available online at: https://www.epa.gov/sites/default/files/2018-10/documents/quality-criteria-water-1976.pdf

Weldegebriel, Y., Chandravanshi, B. S., and Wondimu, T. (2012). Concentration levels of metals in vegetables grown in soils irrigated with river water in Addis Ababa, Ethiopia. Ecotoxicol. Environ. Safety 77, 57–63. doi: 10.1016/j.ecoenv.2011.10.011

WHO. (2004). Guidelines for Drinking-water Quality, Vol. 1. World Health Organization. p. 564.

WHO. (2006). WHO Guidelines for Drinking-Water Quality. World Health Organization . p. 1–16. Available online at: https://www.who.int/water_sanitation_health/dwq/gdwq0506.pdf

WHO. (2008). WHO Guidelines for Drinking-Water Quality, Vol. 1. World Health Organization . Available online at: https://www.who.int/water_sanitation_health/dwq/fulltext.pdf

Wolde, A. M., Jemal, K., Woldearegay, G. M., and Tullu, K. D. (2020). Quality and safety of municipal drinking water in Addis Ababa City, Ethiopia. Environ. Health Prevent. Med. 25, 1–6. doi: 10.1186/s12199-020-00847-8

Worako, W. (2015). Physicochemical and biological water quality assessment of lake Hawassa for multiple. Water Uses. 15, 265. doi: 10.4090/juee.2015.v9n2.146157

Yimer, Y. A., and Jin, L. (2020). Impact of lake beseka on the water quality of Awash River, Ethiopia. Am. J. Water Resour. 8, 21–30. doi: 10.12691/ajwr-8-1-3

Yohannes, H., and Elias, E. (2017). Contamination of rivers and water reservoirs in and Around Addis Ababa City and Actions to Combat It. Environ. Pollut.Climate Change 01, 116. doi: 10.4172/2753-458X.1000116

Yomo, M., Mourad, K. A., and Gnazou, M. D. T. (2019). Examining water security in the challenging environment in Togo, West Africa. Water 11, 1–19. doi: 10.3390/w11020231

Zerihun, F., and Eshetu, B. (2018). Physicochemical characterization of upper awash river of ethiopia polluted by anmol product paper factory. Int. J. Water Wastewater Treat. 4, 154. doi: 10.16966/2381-5299.154

Zinabu, E., and Desta, Z. (2002). Long-term changes in chemical features of waters of seven Ethiopian rift-valley lakes. Hydrobiologia 477, 81–91. doi: 10.1023/A:1021061015788

Keywords: impact, water quality, pollution, toxicity, Awash Basin, Ethiopia, Awash River

Citation: Assegide E, Alamirew T, Bayabil H, Dile YT, Tessema B and Zeleke G (2022) Impacts of Surface Water Quality in the Awash River Basin, Ethiopia: A Systematic Review. Front. Water 3:790900. doi: 10.3389/frwa.2021.790900

Received: 07 October 2021; Accepted: 31 December 2021; Published: 29 March 2022.

Reviewed by:

Copyright © 2022 Assegide, Alamirew, Bayabil, Dile, Tessema and Zeleke. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Endaweke Assegide, endawokassegid@yahoo.com

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

Wastewater Treatment and Reuse: a Review of its Applications and Health Implications

  • Open access
  • Published: 10 May 2021
  • Volume 232 , article number  208 , ( 2021 )

Cite this article

You have full access to this open access article

  • Kavindra Kumar Kesari   ORCID: orcid.org/0000-0003-3622-9555 1   na1 ,
  • Ramendra Soni 2   na1 ,
  • Qazi Mohammad Sajid Jamal 3 ,
  • Pooja Tripathi 4 ,
  • Jonathan A. Lal 2 ,
  • Niraj Kumar Jha 5 ,
  • Mohammed Haris Siddiqui 6 ,
  • Pradeep Kumar 7 ,
  • Vijay Tripathi 2 &
  • Janne Ruokolainen 1  

45k Accesses

111 Citations

4 Altmetric

Explore all metrics

Water scarcity is one of the major problems in the world and millions of people have no access to freshwater. Untreated wastewater is widely used for agriculture in many countries. This is one of the world-leading serious environmental and public health concerns. Instead of using untreated wastewater, treated wastewater has been found more applicable and ecofriendly option. Moreover, environmental toxicity due to solid waste exposures is also one of the leading health concerns. Therefore, intending to combat the problems associated with the use of untreated wastewater, we propose in this review a multidisciplinary approach to handle wastewater as a potential resource for use in agriculture. We propose a model showing the efficient methods for wastewater treatment and the utilization of solid wastes in fertilizers. The study also points out the associated health concern for farmers, who are working in wastewater-irrigated fields along with the harmful effects of untreated wastewater. The consumption of crop irrigated by wastewater has leading health implications also discussed in this review paper. This review further reveals that our current understanding of the wastewater treatment and use in agriculture with addressing advancements in treatment methods has great future possibilities.

Similar content being viewed by others

water pollution research paper pdf

Municipal solid waste management and landfilling technologies: a review

Sonil Nanda & Franco Berruti

water pollution research paper pdf

An overview of the environmental pollution and health effects associated with waste landfilling and open dumping

Ayesha Siddiqua, John N. Hahladakis & Wadha Ahmed K A Al-Attiya

Drinking water contamination and treatment techniques

S. Sharma & A. Bhattacharya

Avoid common mistakes on your manuscript.

1 Introduction

Rapidly depleting and elevating the level of freshwater demand, though wastewater reclamation or reuse is one of the most important necessities of the current scenario. Total water consumption worldwide for agriculture accounts 92% (Clemmens et al., 2008 ; Hoekstra & Mekonnen, 2012 ; Tanji & Kielen, 2002 ). Out of which about 70% of freshwater is used for irrigation (WRI, 2020 ), which comes from the rivers and underground water sources (Pedrero et al., 2010 ). The statistics shows serious concern for the countries facing water crisis. Shen et al. ( 2014 ) reported that 40% of the global population is situated in heavy water–stressed basins, which represents the water crisis for irrigation. Therefore, wastewater reuse in agriculture is an ideal resource to replace freshwater use in agriculture (Contreras et al., 2017 ). Treated wastewater is generally applied for non-potable purposes, like agriculture, land, irrigation, groundwater recharge, golf course irrigation, vehicle washing, toilet flushes, firefighting, and building construction activities. It can also be used for cooling purposes in thermal power plants (Katsoyiannis et al., 2017 ; Mohsen, 2004 ; Smith, 1995 ; Yang et al., 2017 ). At global level, treated wastewater irrigation supports agricultural yield and the livelihoods of millions of smallholder farmers (Sato et al., 2013 ). Global reuse of treated wastewater for agricultural purposes shows wide variability ranging from 1.5 to 6.6% (Sato et al., 2013 ; Ungureanu et al., 2018 ). More than 10% of the global population consumes agriculture-based products, which are cultivated by wastewater irrigation (WHO, 2006 ). Treated wastewater reuse has experienced very rapid growth and the volumes have been increased ~10 to 29% per year in Europe, the USA, China, and up to 41% in Australia (Aziz & Farissi, 2014 ). China stands out as the leading country in Asia for the reuse of wastewater with an estimated 1.3 M ha area including Vietnam, India, and Pakistan (Zhang & Shen, 2017 ). Presently, it has been estimated that, only 37.6% of the urban wastewater in India is getting treated (Singh et al., 2019 ). By utilizing 90% of reclaimed water, Israel is the largest user of treated wastewater for agriculture land irrigation (Angelakis & Snyder, 2015 ). The detail information related to the utilization of freshwater and treated wastewater is compiled in Table 1 .

Many low-income countries in Africa, Asia, and Latin America use untreated wastewater as a source of irrigation (Jiménez & Asano, 2008 ). On the other hand, middle-income countries, such as Tunisia, Jordan, and Saudi Arabia, use treated wastewater for irrigation (Al-Nakshabandi et al., 1997 ; Balkhair, 2016a ; Balkhair, 2016b ; Qadir et al., 2010 ; Sato et al., 2013 ).

Domestic water and treated wastewater contains various type of nutrients such as phosphorus, nitrogen, potassium, and sulfur, but the major amount of nitrogen and phosphorous available in wastewater can be easily accumulated by the plants, that’s why it is widely used for the irrigation (Drechsel et al., 2010 ; Duncan, 2009 ; Poustie et al., 2020 ; Sengupta et al., 2015 ). The rich availability of nutrients in reclaimed wastewater reduces the use of fertilizers, increases crop productivity, improves soil fertility, and at the same time, it may also decrease the cost of crop production (Chen et al., 2013 a; Jeong et al., 2016 ). The data of high nutritional values in treated wastewater is shown in Fig. 1 .

figure 1

Nutrient concentrations (mg/L) of freshwater/wastewater (Yadav et al., 2002 )

Wastewater reuse for crop irrigation showed several health concerns (Ungureanu et al., 2020 ). Irrigation with the industrial wastewater either directly or mixing with domestic water showed higher risk (Chen et al., 2013). Risk factors are higher due to heavy metal and pathogens contamination because heavy metals are non-biodegradable and have a long biological half-life (Chaoua et al., 2019 ; WHO, 2006 ). It contains several toxic elements, i.e., Cu, Cr, Mn, Fe, Pb, Zn, and Ni (Mahfooz et al., 2020 ). These heavy metals accumulate in topsoil (at a depth of 20 cm) and sourcing through plant roots; they enter the human and animal body through leafy vegetables consumption and inhalation of contaminated soils (Mahmood et al., 2014 ). Therefore, health risk assessment of such wastewater irrigation is important especially in adults (Mehmood et al., 2019 ; Njuguna et al., 2019 ; Xiao et al., 2017 ). For this, an advanced wastewater treatment method should be applied before release of wastewater in the river, agriculture land, and soils. Therefore, this review also proposed an advance wastewater treatment model, which has been tasted partially at laboratory scale by Kesari and Behari ( 2008 ), Kesari et al. ( 2011a , b ), and Kumar et al. ( 2010 ).

For a decade, reuse of wastewater has also become one of the global health concerns linking to public health and the environment (Dang et al., 2019 ; Narain et al., 2020 ). The World Health Organization (WHO) drafted guidelines in 1973 to protect the public health by facilitating the conditions for the use of wastewater and excreta in agriculture and aquaculture (WHO, 1973 ). Later in 2005, the initial guidelines were drafted in the absence of epidemiological studies with minimal risk approach (Carr, 2005 ). Although, Adegoke et al. ( 2018 ) reviewed the epidemiological shreds of evidence and health risks associated with reuse of wastewater for irrigation. Wastewater or graywater reuse has adverse health risks associated with microbial hazards (i.e., infectious pathogens) and chemicals or pharmaceuticals exposures (Adegoke et al., 2016 ; Adegoke et al., 2017 ; Busgang et al., 2018 ; Marcussen et al., 2007 ; Panthi et al., 2019 ). Researchers have reported that the exposure to wastewater may cause infectious (helminth infection) diseases, which are linked to anemia and impaired physical and cognitive development (Amoah et al., 2018 ; Bos et al., 2010 ; Pham-Duc et al., 2014 ; WHO, 2006 ).

Owing to an increasing population and a growing imbalance in the demand and supply of water, the use of wastewater has been expected to increase in the coming years (World Bank, 2010 ). The use of treated wastewater in developed nations follows strict rules and regulations. However, the direct use of untreated wastewater without any sound regulatory policies is evident in developing nations, which leads to serious environmental and public health concerns (Dickin et al., 2016 ). Because of these issues, we present in this review, a brief discussion on the risk associated with the untreated wastewater exposures and advanced methods for its treatment, reuse possibilities of the treated wastewater in agriculture.

2 Environmental Toxicity of Untreated Wastewater

Treated wastewater carries larger applicability such as irrigation, groundwater recharge, toilet flushing, and firefighting. Municipal wastewater treatment plants (WWTPs) are the major collection point for the different toxic elements, pathogenic microorganisms, and heavy metals. It collects wastewater from divergent sources like household sewage, industrial, clinical or hospital wastewater, and urban runoff (Soni et al., 2020 ). Alghobar et al. ( 2014 ) reported that grass and crops irrigated with sewage and treated wastewater are rich in heavy metals in comparison with groundwater (GW) irrigation. Although, heavy metals classified as toxic elements and listed as cadmium, lead, mercury, copper, and iron. An exceeding dose or exposures of these heavy metals could be hazardous for health (Duan et al., 2017 ) and ecological risks (Tytła, 2019 ). The major sources of these heavy metals come from drinking water. This might be due to the release of wastewater into river or through soil contamination reaches to ground water. Table 2 presenting the permissible limits of heavy metals presented in drinking water and its impact on human health after an exceeding the amount in drinking water, along with the route of exposure of heavy metals to human body.

Direct release in river or reuse of wastewater for irrigation purposes may create short-term implications like heavy metal and microbial contamination and pathogenic interaction in soil and crops. It has also long-term influence like soil salinity, which grows with regular use of untreated wastewater (Smith, 1995 ). Improper use of wastewater for irrigation makes it unsafe and environment threatening. Irrigation with several different types of wastewater, i.e., industrial effluents, municipal and agricultural wastewaters, and sewage liquid sludge transfers the heavy metals to the soil, which leads to accumulation in crops due to improper practices. This has been identified as a significant route of heavy metals into aquatic resources (Agoro et al., 2020 ). Hussain et al. ( 2019 ) investigated the concentration of heavy metals (except for Cd) was higher in the soil irrigated with treated wastewater (large-scale sewage treatment plant) than the normal ground water, also reported by Khaskhoussy et al. ( 2015 ).

In other words, irrigation with wastewater mitigates the quality of crops and enhances health risks. Excess amount of copper causes anemia, liver and kidney damage, vomiting, headache, and nausea in children (Bent & Bohm, 1995 ; Madsen et al., 1990 ; Salem et al., 2000 ). A higher concentration of arsenic may lead to bone and kidney cancer (Jarup, 2003 ) and results in osteopenia or osteoporosis (Puzas et al., 2004 ). Cadmium gives rise to musculoskeletal diseases (Fukushima et al., 1970 ), whereas mercury directly affects the nervous system (Azevedo et al., 2014 ).

3 Spread of Antibiotic Resistance

Currently, antibiotics are highly used for human disease treatment; however, uses in poultries, animal husbandries, biochemical industries, and agriculture are common practices these days. Extensive use and/or misuse of antibiotics have given rise to multi-resistant bacteria, which carry multiple resistance genes (Icgen & Yilmaz, 2014 ; Lv et al., 2015 ; Tripathi & Tripathi, 2017 ; Xu et al., 2017 ). These multidrug-resistant bacteria discharged through the sewage network and get collected into the wastewater treatment plants. Therefore, it can be inferred that the WWTPs serve as the hotspot of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Though, these antibiotic-resistant bacteria can be disseminated to the different bacterial species through the mobile genetic elements and horizontal gene transfer (Gupta et al., 2018 ). Previous studies indicated that certain pathogens might survive in wastewater, even during and after the treatment processes, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) (Börjesson et al., 2009 ; Caplin et al., 2008 ). The use of treated wastewater in irrigation provides favorable conditions for the growth and persistence of total coliforms and fecal coliforms (Akponikpe et al., 2011 ; Sacks & Bernstein, 2011 ). Furthermore, few studies have also reported the presence of various bacterial pathogens, such as Clostridium , Salmonella , Streptococci , Viruses, Protozoa, and Helminths in crops irrigated with treated wastewater (Carey et al., 2004 ; Mañas et al., 2009 ; Samie et al., 2009 ). Goldstein ( 2013 ) investigated the survival of ARB in secondary treated wastewater and proved that it causes serious health risks to the individuals, who are exposed to reclaimed water. The U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have already declared the ARBs as the imminent hazard to human health. According to the list published by WHO, regarding the development of new antimicrobial agents, the ESKAPE ( Enterococcus faecium , S. aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , and Enterobacter species) pathogens were designated to be “priority status” as their occurrence in the food chain is considered as the potential and major threat for the human health (Tacconelli et al., 2018 ).

These ESKAPE pathogens have acquired the multi drug resistance mechanisms against oxazolidinones, lipopeptides, macrolides, fluoroquinolones, tetracyclines, β-lactams, β-lactam–β-lactamase inhibitor combinations, and even those antibiotics that are considered as the last line of defense, including carbapenems and glycopeptides (Giddins et al., 2017 ; Herc et al., 2017 ; Iguchi et al., 2016 ; Naylor et al., 2018 ; Zaman et al., 2017 ), by the means of genetic mutation and mobile genetic elements. These cluster of ESKAPE pathogens are mainly responsible for lethal nosocomial infections (Founou et al., 2017 ; Santajit & Indrawattana, 2016 ).

Due to the wide application of antibiotics in animal husbandry and inefficient capability of wastewater treatment plants, the multidrug-resistant bacteria such as tetracyclines, sulfonamides, β-lactam, aminoglycoside, colistin, and vancomycin in major are disseminated in the receiving water bodies, which ultimately results in the accumulation of ARGs in the irrigated crops (He et al., 2020 ).

4 Toxic Contaminations in Wastewater Impacting Human Health

The release of untreated wastewater into the river may pose serious health implications (König et al., 2017 ; Odigie, 2014 ; Westcot, 1997 ). It has been already discussed about the household and municipal sewage which contains a major amount of organic materials and pathogenic microorganisms and these infectious microorganisms are capable of spreading various diseases like typhoid, dysentery, diarrhea, vomiting, and malabsorption (Jia & Zhang, 2020 ; Numberger et al., 2019 ; Soni et al., 2020 ). Additionally, pharmaceutical industries also play a key role in the regulation and discharge of biologically toxic agents. The untreated wastewater also contains a group of contaminants, which are toxic to humans. These toxic contaminations have been classified into two major groups: (i) chemical contamination and (ii) microbial contamination.

4.1 Chemical Contamination

Mostly, various types of chemical compounds released from industries, tanneries, workshops, irrigated lands, and household wastewaters are responsible for several diseases. These contaminants can be organic materials, hydrocarbons, volatile compounds, pesticides, and heavy metals. Exposure to such contaminants may cause infectious diseases like chronic dermatoses and skin cancer, lung infection, and eye irritation. Most of them are non-biodegradable and intractable. Therefore, they can persist in the water bodies for a very long period and could be easily accumulated in our food chain system. Several pharmaceutical personal care products (PPCPs) and surfactants are available that may contain toxic compounds like nonylphenol, estrone, estradiol, and ethinylestradiol. These compounds are endocrine-disrupting chemicals (Bolong et al., 2009 ), and the existence of these compounds in the human body even in the trace amounts can be highly hazardous. Also, the occurrence of perfluorinated compounds (PFCs) in wastewater, which is toxic in nature, has been significantly reported worldwide (Templeton et al., 2009 ). Furthermore, PFCs cause severe health menaces like pre-eclampsia, birth defects, reduced human fertility (Webster, 2010 ), immunotoxicity (Dewitt et al., 2012 ), neurotoxicity (Lee & Viberg, 2013 ), and carcinogenesis (Bonefeld-Jorgensen et al., 2011 ).

4.2 Microbial Contamination

Researchers have reported serious health risks associated with the microbial contaminants in untreated wastewater. The diverse group of microorganisms causes severe health implications like campylobacteriosis, diarrhea, encephalitis, typhoid, giardiasis, hepatitis A, poliomyelitis, salmonellosis, and gastroenteritis (ISDH, 2009 ; Okoh et al., 2010 ). Few bacterial species like P. aeruginosa , Salmonella typhimurium , Vibrio cholerae , G. intestinales , Legionella spp., E. coli , Shigella sonnei have been reported for the spreading of waterborne diseases, and acute illness in human being (Craun et al., 2006 ; Craun et al., 2010 ). These aforementioned microorganisms may release in the environment from municipal sewage water network, animal husbandries, or hospitals and enter the food chain via public water supply systems.

5 Wastewater Impact on Agriculture

The agriculture sector is well known for the largest user of water, accounting for nearly 70% of global water usage (Winpenny et al., 2010 ). The fact that an estimated 20 million hectares worldwide are irrigated with wastewater suggests a major source for irrigation (Ecosse, 2001 ). However, maximum wastewater that is used for irrigation is untreated (Jiménez & Asano, 2008 ; Scott et al., 2004 ). Mostly in developing countries, partially treated or untreated wastewater is used for irrigation purpose (Scott et al., 2009 ). Untreated wastewater often contains a large range of chemical contaminants from waste sites, chemical wastes from industrial discharges, heavy metals, fertilizers, textile, leather, paper, sewage waste, food processing waste, and pesticides. World Health Organization (WHO) has warned significant health implications due to the direct use of wastewater for irrigation purposes (WHO, 2006 ). These contaminants pose health risks to communities (farmers, agricultural workers, their families, and the consumers of wastewater-irrigated crops) living in the proximity of wastewater sources and areas irrigated with untreated wastewater (Qadir et al., 2010 ). Wastewater also contains a wide variety of organic compounds. Some of them are toxic or cancer-causing and have harmful effects on an embryo (Jarup, 2003 ; Shakir et al., 2016 ). The pathway of untreated wastewater used in irrigation and associated health effects are shown in Fig. 2 .

figure 2

Exposure pathway representing serious health concerns from wastewater-irrigated crops

Alternatively, in developing countries, due to the limited availability of treatment facilities, untreated wastewater is discharged into the existing waterbodies (Qadir et al., 2010 ). The direct use of wastewater in agriculture or irrigation obstructs the growth of natural plants and grasses, which in turn causes the loss of biodiversity. Shuval et al. ( 1985 ) reported one of the earliest evidences connecting to agricultural wastewater reuse with the occurrence of diseases. Application of untreated wastewater in irrigation increases soil salinity, land sealing followed by sodium accumulation, which results in soil erosion. Increased soil salinity and sodium accumulation deteriorates the soil and decreases the soil permeability, which inhibits the nutrients intake of crops from the soil. These causes have been considered the long-term impact of wastewater reuse in agriculture (Halliwell et al., 2001 ). Moreover, wastewater contaminated soils are a major source of intestinal parasites (helminths—nematodes and tapeworms) that are transmitted through the fecal–oral route (Toze, 1997 ). Already known, the helminth infections are linked to blood deficiency and behavioral or cognitive development (Bos et al., 2010 ). One of the major sources of helminth infections around the world is the use of raw or partially treated sewage effluent and sludge for the irrigation of food crops (WHO, 1989 ). Wastewater-irrigated crops contain heavy metal contamination, which originates from mining, foundries, and metal-based industries (Fazeli et al., 1998 ). Exposure to heavy metals including arsenic, cadmium, lead, and mercury in wastewater-irrigated crops is a cause for various health problems. For example, the consumption of high amounts of cadmium causes osteoporosis in humans (Dickin et al., 2016 ). The uptake of heavy metals by the rice crop irrigated with untreated effluent from a paper mill has been reported to cause serious health concerns (Fazeli et al., 1998 ). Irrigating rice paddies with highly contaminated water containing heavy metals leads to the outbreak of Itai-itai disease in Japan (Jarup, 2003 ).

Owing to these widespread health risks, the WHO published the third edition of its guidelines for the safe use of wastewater in irrigating crops (WHO, 2006 ) and made recommendations for threshold contaminant levels in wastewater. The quality of wastewater for agricultural reuse have been classified based on the availability of nutrients, trace elements, microorganisms, and chemicals contamination levels. The level of contamination differs widely depending on the type of source, household sewage, pharmaceutical, chemical, paper, or textile industries effluents. The standard measures of water quality for irrigation are internationally reported (CCREM, 1987 ; FAO, 1985 ; FEPA, 1991 ; US EPA, 2004 , 2012 ; WHO, 2006 ), where the recommended levels of trace elements, metals, COD, BOD, nitrogen, and phosphorus are set at certain limits. Researchers reviewed the status of wastewater reuse for agriculture, based on its standards and guidelines for water quality (Angelakis et al., 1999 ; Brissaud, 2008 ; Kalavrouziotis et al., 2015 ). Based on these recommendations and guidelines, it is evident that greater awareness is required for the treatment of wastewater safely.

6 Wastewater Treatment Techniques

6.1 primary treatment.

This initial step is designed to remove gross, suspended and floating solids from raw wastewater. It includes screening to trap solid objects and sedimentation by gravity to remove suspended solids. This physical solid/liquid separation is a mechanical process, although chemicals can be used sometimes to accelerate the sedimentation process. This phase of the treatment reduces the BOD of the incoming wastewater by 20–30% and the total suspended solids by nearly 50–60%.

6.2 Secondary (Biological) Treatment

This stage helps eliminate the dissolved organic matter that escapes primary treatment. Microbes consume the organic matter as food, and converting it to carbondioxide, water, and energy for their own growth. Additional settling to remove more of the suspended solids then follows the biological process. Nearly 85% of the suspended solids and biological oxygen demand (BOD) can be removed with secondary treatment. This process also removes carbonaceous pollutants that settle down in the secondary settling tank, thus separating the biological sludge from the clear water. This sludge can be fed as a co-substrate with other wastes in a biogas plant to obtain biogas, a mixture of CH 4 and CO 2 . It generates heat and electricity for further energy distribution. The leftover, clear water is then processed for nitrification or denitrification for the removal of carbon and nitrogen. Furthermore, the water is passed through a sedimentation basin for treatment with chlorine. At this stage, the water may still contain several types of microbial, chemical, and metal contaminations. Therefore, to make the water reusable, e.g., for irrigation, it further needs to pass through filtration and then into a disinfection tank. Here, sodium hypochlorite is used to disinfect the wastewater. After this process, the treated water is considered safe to use for irrigation purposes. Solid wastes generated during primary and secondary treatment processes are processed further in the gravity-thickening tank under a continuous supply of air. The solid waste is then passed into a centrifuge dewatering tank and finally to a lime stabilization tank. Treated solid waste is obtained at this stage and it can be processed further for several uses such as landfilling, fertilizers and as a building.

Other than the activated sludge process of wastewater treatment, there are several other methods developed and being used in full-scale reactors such as ponds (aerobic, anaerobic, facultative, and maturation), trickling filters, anaerobic treatments like up-flow anaerobic sludge blanket (UASB) reactors, artificial wetlands, microbial fuel cells, and methanogenic reactors.

UASB reactors are being applied for wastewater treatment from a very long period. Behling et al. ( 1996 ) examined the performance of the UASB reactor without any external heat supply. In their study, the COD loading rate was maintained at 1.21 kg COD/m 3 /day, after 200 days of trial. They achieved an average of 85% of COD removal. Von-Sperling and Chernicharo ( 2005 ) presented a combined model consisted of an Up-flow Anaerobic Sludge Blanket-Activated Sludge reactor (UASB–AS system), using the low strength domestic wastewater with a BOD 5 amounting to 340 mg/l. Outcomes of their experiment have shown a 60% reduction in sludge construction and a 40% reduction in aeration energy consumption. In another experiment, Rizvi et al. ( 2015 ) seeded UASB reactor with cow manure dung to treat domestic wastewater; they observed 81%, 75%, and 76% reduction in COD, TSS, and total sulfate removal, respectively, in their results.

6.3 Tertiary or Advanced Treatment Processes

The tertiary treatment process is employed when specific constituents, substances, or contaminants cannot be completely removed after the secondary treatment process. The tertiary treatment processes, therefore, ensure that nearly 99% of all impurities are removed from wastewater. To make the treated water safe for drinking purposes, water is treated individually or in combination with advanced methods like the US (ultrasonication), UV (ultraviolet light treatment), and O 3 (exposure to ozone). This process helps to remove bacteria and heavy metal contaminations remaining in the treated water. For the purpose, the secondarily treated water is first made to undergo ultrasonication and it is subsequently exposed to UV light and passed through an ozone chamber for the complete removal of contaminations. The possible mechanisms by which cells are rendered inviable during the US include free-radical attack and physical disruption of cell membranes (Phull et al., 1997 ; Scherba et al., 1991 ). The combined treatment of US + UV + O 3 produces free radicals, which are attached to cell membranes of the biological contaminants. Once the cell membrane is sheared, chemical oxidants can enter the cell and attack internal structures. Thus, the US alone or in combination facilitates the deagglomeration of microorganisms and increases the efficiency of other chemical disinfectants (Hua & Thompson, 2000 ; Kesari et al., 2011a , b ; Petrier et al., 1992 ; Phull et al., 1997 ; Scherba et al., 1991 ). A combined treatment method was also considered by Pesoutova et al. ( 2011 ) and reported a very effective method for textile wastewater treatment. The effectiveness of ultrasound application as a pre-treatment step in combination with ultraviolet rays (Blume & Neis, 2004 ; Naddeo et al., 2009 ), or also compared it with various other combinations of both ultrasound and UV radiation with TiO 2 photocatalysis (Paleologou et al., 2007 ), and ozone (Jyoti & Pandit, 2004 ) to optimize wastewater disinfection process.

An important aspect of our wastewater treatment model (Fig. 3 ) is that at each step of the treatment process, we recommend the measurement of the quality of treated water. After ensuring that the proper purification standards are met, the treated water can be made available for irrigation, drinking or other domestic uses.

figure 3

A wastewater treatment schematic highlighting the various methods that result in a progressively improved quality of the wastewater from the source to the intended use of the treated wastewater for irrigation purposes

6.4 Nanotechnology as Tertiary Treatment of Wastewater Converting Drinking Water Alike

Considering the emerging trends of nanotechnology, nanofillers can be used as a viable method for the tertiary treatment of wastewater. Due to the very small pore size, 1–5-nm nanofillers may eliminate the organic–inorganic pollutants, heavy metals, as well as pathogenic microorganisms and pharmaceutically active compounds (PhACs) (Mohammad et al., 2015 ; Vergili, 2013 ). Over the recent years, nanofillers have been largely accepted in the textile industry for the treatment of pulp bleaching pharmaceutical industry, dairy industry, microbial elimination, and removal of heavy metals from wastewater (Abdel-Fatah, 2018 ). Srivastava et al. ( 2004 ) synthesized very efficient and reusable water filters from carbon nanotubes, which exhibited effective elimination of bacterial pathogens ( E. coli and S. aureus ), and Poliovirus sabin-1 from wastewater.

Nanofiltration requires lower operating pressure and lesser energy consumption in comparison of RO and higher rejection of organic compounds compared to UF. Therefore, it can be applied as the tertiary treatment of wastewater (Abdel-Fatah, 2018 ). Apart from nanofilters, there are various kinds of nanoparticles like metal nanoparticles, metal oxide nanoparticles, carbon nanotubes, graphene nanosheets, and polymer-based nanosorbents, which may play a different role in wastewater treatment based on their properties. Kocabas et al. ( 2012 ) analyzed the potential of different metal oxide nanoparticles and observed that nanopowders of TiO 2 , FeO 3 , ZnO 2 , and NiO can exhibit the exceeding amount of removal of arsenate from wastewater. Cadmium contamination in wastewater, which poses a serious health risk, can be overcome by using ZnO nanoparticles (Kumar & Chawla, 2014 ). Latterly, Vélez et al. ( 2016 ) investigated that the 70% removal of mercury from wastewater through iron oxide nanoparticles successfully performed. Sheet et al. ( 2014 ) used graphite oxide nanoparticles for the removal of nickel from wastewater. An exceeding amount of copper causes liver cirrhosis, anemia, liver, and kidney damage, which can be removed by carbon nanotubes, pyromellitic acid dianhydride (PMDA) and phenyl aminomethyl trimethoxysilane (PAMTMS) (Liu et al., 2010 ).

Nanomaterials are efficiently being used for microbial purification from wastewater. Carbon nanotubes (CNTs) are broadly applied for the treatment of wastewater contaminated with E. coli , Salmonella , and a wide range of microorganisms (Akasaka & Watari, 2009 ). In addition, silver nanoparticles reveal very effective results against the microorganisms present in wastewater. Hence, it is extensively being used for microbial elimination from wastewater (Inoue et al., 2002 ). Moreover, CNTs exhibit high binding affinity to bacterial cells and possess magnetic properties (Pan & Xing, 2008 ). Melanta ( 2008 ) confirmed and recommended the applicability of CNTs for the removal of E. coli contamination from wastewater. Mostafaii et al. ( 2017 ) suggested that the ZnO nanoparticles could be the potential antibacterial agent for the removal of total coliform bacteria from municipal wastewater. Apart from the previously mentioned, applicability of the nanotechnology, the related drawbacks and challenges cannot be neglected. Most of the nanoengineered techniques are currently either in research scale or pilot scale performing well (Gehrke et al., 2015 ). Nevertheless, as discussed above, nanotechnology and nanomaterials exhibit exceptional properties for the removal of contaminants and purification of water. Therefore, it can be adapted as the prominent solution for the wastewater treatment (Zekić et al., 2018 ) and further use for drinking purposes.

6.5 Wastewater Treatment by Using Plant Species

Some of the naturally growing plants can be a potential source for wastewater treatment as they remove pollutants and contaminants by utilizing them as a nutrient source (Zimmels et al., 2004 ). Application of plant species in wastewater treatment may be cost-effective, energy-saving, and provides ease of operation. At the same time, it can be used as in situ, where the wastewater is being produced (Vogelmann et al., 2016 ). Nizam et al. ( 2020 ) analyzed the phytoremediation efficiency of five plant species ( Centella asiatica , Ipomoea aquatica , Salvinia molesta , Eichhornia crassipes , and Pistia stratiotes ) and achieved the drastic decrease in the amount of three pollutants viz. total suspended solids (TSS), ammoniacal nitrogen (NH 3 -N), and phosphate levels . All the five species found to be efficient removal of the level of 63.9-98% of NH 3 -N, TSS, and phosphate. Coleman et al. ( 2001 ) examined the physiological effects of domestic wastewater treatment by three common Appalachian plant species: common rush or soft rush ( Juncus effuses L.), gray club-rush ( Scirpus Validus L.), and broadleaf cattail or bulrush ( Typha latifolia L.). They observed in their experiments about 70% of reduction in total suspended solids (TSS) and biochemical oxygen demand (BOD), 50% to 60% of reduction in nitrogen, ammonia, and phosphate levels, and a significant reduction in feacal coliform populations. Whereas, Zamora et al. ( 2019 ) found the removal efficiency of chemical oxygen demand (COD), total solids suspended (TSS), nitrogen as ammonium (N-NH 4 ) and nitrate (N-NO 3 ), and phosphate (P-PO 4 ) up to 20–60% higher using the three ornamental species of plants viz. Canna indica , Cyperus papyrus , and Hedychium coronarium . The list of various plant species applied for the wastewater treatment is shown in Table 3 .

6.6 Wastewater Treatment by Using Microorganisms

There is a diverse group of bacteria like Pseudomonas fluorescens , Pseudomonas putida , and different Bacillus strains, which are capable to use in biological wastewater systems. These bacteria work in the cluster forms as a floc, biofilm, or granule during the wastewater treatment. Furthermore, after the recognition of bacterial exopolysaccharides (EPS) as an efficient adsorption material, it may be applied in a revolutionary manner for the heavy metal elimination (Gupta & Diwan, 2017 ). There are few examples of EPS, which are commercially available, i.e., alginate ( P. aeruginosa , Azotobacter vinelandii ), gellan (Sphingomonas paucimobilis ), hyaluronan ( . aeruginosa , Pasteurella multocida , Streptococci attenuated strains ), xanthan (Xanthomonas campestris ), and galactopol ( Pseudomonas oleovorans ) (Freitas et al., 2009 ; Freitas, Alves, & Reis, 2011a ; Freitas, Alves, Torres, et al., 2011b ). Similarly, Hesnawi et al. ( 2014 ) experimented biodegradation of municipal wastewater using local and commercial bacteria (Sludge Hammer), where they achieved a significant decrease in synthetic wastewater, i.e., 70%, 54%, 52%, 42% for the Sludge Hammer, B. subtilis , B. laterosponus , and P. aeruginosa , respectively. Therefore, based on the above studies, it can be concluded that bioaugmentation of wastewater treatment reactor with selective and mixed strains can ameliorate the treatment. During recent years, microalgae have attracted the attention of researchers as an alternative system, due to their applicability in wastewater treatment. Algae are the unicellular or multicellular photosynthetic microorganism that grows on water surfaces, salt water, or moist soil. They utilize the exceeding amount of nutrients like nitrogen, phosphorus, and carbon for their growth and metabolism process through their anaerobic system. This property of algae also inhibits eutrophication; that is to avoid over-deposit of nutrients in water bodies. During the nutrient digestion process, algae produce oxygen that is constructive for the heterotrophic aerobic bacteria, which may further be utilized to degrade the organic and inorganic pollutants. Kim et al. ( 2014 ) observed a total decrease in the levels of COD (86%), total nitrogen (93%), and total phosphorus (83%) after using algae in the municipal wastewater consortium. Nmaya et al. ( 2017 ) reported the heavy metal removal efficiency of microalga Scenedesmus sp. from contaminated river water in the Melaka River, Malaysia. They observed the effective removal of Zn (97-99%) on the 3 rd and 7 th day of the experiment. The categorized list of microorganisms used for wastewater treatment is presented in Table 4 .

7 The Computational Approach in Wastewater Treatment

7.1 bioinformatics and genome sequencing.

A computational approach is accessible in wastewater treatment. Several tools and techniques are in use such as, sequencing platforms (Hall, 2007 ; Marsh, 2007 ), metagenome sequencing strategies (Schloss & Handelsman, 2005 ; Schmeisser et al., 2007 ; Tringe et al., 2005 ), bioinformatics tools and techniques (Chen & Pachter, 2005 ; Foerstner et al., 2006 ; Raes et al., 2007 ), and the genome analysis of complex microbial communities (Fig. 4 ). Most of the biological database contains microorganisms and taxonomical information. Thus, these can provide extensive details and supports for further utilization in wastewater treatment–related research and development (Siezen & Galardini, 2008 ). Balcom et al. ( 2016 ) explored that the microbial population residing in the plant roots immersed in the wastewater of an ecological WWTP and showed the evidence of the capacity for micro-pollutant biodegradation using whole metagenome sequencing (WMS). Similarly, Kumar et al. ( 2016 ) revealed that bioremediation of highly polluted wastewater from textile dyes by two novel strains were found to highly decolorize Joyfix Red. They were identified as Lysinibacillus sphaericus (KF032717) and Aeromonas hydrophila (KF032718) through 16S rDNA analysis. More recently, Leddy et al. ( 2018 ) reported that research scientists are making strides to advance the safety and application of potable water reuse with metagenomics for water quality analysis. The application of the bio-computational approach has also been implemented in the advancements of wastewater treatment and disease detection.

figure 4

A schematic showing the overall conceptual framework on which depicting the computational approach in wastewater treatment

7.2 Computational Fluid Dynamics in Wastewater Treatment

In recent years, computational fluid dynamics (CFD), a broadly used method, has been applied to biological wastewater treatment. It has exposed the inner flow state that is the hydraulic condition of a biological reactor (Peng et al., 2014 ). CFD is the application of powerful predictive modeling and simulation tools. It may calculate the multiple interactions between all the water quality and process design parameters. CFD modeling tools have already been widely used in other industries, but their application in the water industry is quite recent. CFD modeling has great applications in water and wastewater treatment, where it mechanically works by using hydrodynamic and mass transfer performance of single or two-phase flow reactors (Do-Quang et al., 1998 ). The level of CFD’s capability varies between different process units. It has a high frequency of application in the areas of final sedimentation, activated sludge basin modeling, disinfection, and greater needs in primary sedimentation and anaerobic digestion (Samstag et al., 2016 ). Now, researchers are enhancing the CFD modeling with a developed 3D model of the anoxic zone to evaluate further hydrodynamic performance (Elshaw et al., 2016 ). The overall conceptual framework and the applications of the computational approach in wastewater treatment are presented in Fig. 4 .

7.3 Computational Artificial Intelligence Approach in Wastewater Treatment

Several studies were obtained by researchers to implement computer-based artificial techniques, which provide fast and rapid automated monitoring of water quality tests such as BOD and COD. Recently, Nourani et al. ( 2018 ) explores the possibility of wastewater treatment plant by using three different kinds of artificial intelligence methods, i.e., feedforward neural network (FFNN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM). Several measurements were done in terms of effluent to tests BOD, COD, and total nitrogen in the Nicosia wastewater treatment plant (NWWTP) and reported high-performance efficiency of artificial intelligence (Nourani et al., 2018 ).

7.4 Remote sensing and Geographical Information System

Since the implementation of satellite technology, the initiation of new methods and tools became popular nowadays. The futuristic approach of remote sensing and GIS technology plays a crucial role in the identification and locating of the water polluted area through satellite imaginary and spatial data. GIS analysis may provide a quick and reasonable solution to develop atmospheric correction methods. Moreover, it provides a user-friendly environment, which may support complex spatial operations to get the best quality information on water quality parameters through remote sensing (Ramadas & Samantaray, 2018 ).

8 Applications of Treated Wastewater

8.1 scope in crop irrigation.

Several studies have assessed the impact of the reuse of recycled/treated wastewater in major sectors. These are agriculture, landscapes, public parks, golf course irrigation, cooling water for power plants and oil refineries, processing water for mills, plants, toilet flushing, dust control, construction activities, concrete mixing, and artificial lakes (Table 5 ). Although the treated wastewater after secondary treatment is adequate for reuse since the level of heavy metals in the effluent is similar to that in nature (Ayers & Westcot, 1985 ), experimental evidences have been found and evaluated the effects of irrigation with treated wastewater on soil fertility and chemical characteristics, where it has been concluded that secondary treated wastewater can improve soil fertility parameters (Mohammad & Mazahreh, 2003 ). The proposed model (Fig. 3 ) is tested partially previously at a laboratory scale by treating the wastewater (from sewage, sugar, and paper industry) in an ultrasonic bath (Kesari et al., 2011a , b ; Kesari & Behari, 2008 ; Kumar et al., 2010 ). Advancing it with ultraviolet and ozone treatment has modified this in the proposed model. A recent study shows that the treated water passed quality measures suited for crop irrigation (Bhatnagar et al., 2016 ). In Fig. 3 , a model is proposed including all three (UV, US, nanoparticle, and ozone) techniques, which have been tested individually as well as in combination (US and nanoparticle) (Kesari et al., 2011a , b ) to obtain the highest water quality standards acceptable for irrigation and even drinking purposes.

A wastewater-irrigated field is a major source of essential and non-essential metals contaminants such as lead, copper, zinc, boron, cobalt, chromium, arsenic, molybdenum, and manganese. While crops need some of these, the others are non-essential metals, toxic to plants, animals, and humans. Kanwar and Sandha ( 2000 ) reported that heavy metal concentrations in plants grown in wastewater-irrigated soils were significantly higher than in plants grown in the reference soil in their study. Yaqub et al. ( 2012 ) suggest that the use of US is very effective in removing heavy or toxic metals and organic pollutants from industrial wastewater. However, it has been also observed that the metals were removed efficiently, when UV light was combined with ozone (Samarghandi et al., 2007 ). Ozone exposure is a potent method for the removal of metal or toxic compounds from wastewater as also reported earlier (Park et al., 2008 ). Application of US, UV, and O 3 in combination lead to the formation of reactive oxygen species (ROS) that oxidize certain organics, metal ions and kill pathogens. In the process of advanced oxidizing process (AOP) primarily oxidants, electricity, light, catalysts etc. are implied to produce extremely reactive free radicals (such as OH) for the breakdown of organic matters (Oturan & Aaron, 2014 ). Among the other AOPs, ozone oxidization process is more promising and effective for the decomposition of complex organic contaminants (Xu et al., 2020 ). Ozone oxidizes the heavy metal to their higher oxidation state to form metallic oxides or hydroxides in which they generally form limited soluble oxides and gets precipitated, which are easy to be filtered by filtration process. Ozone oxidization found to be efficient for the removal of heavy metals like cadmium, chromium, cobalt, copper, lead, manganese, nickel, and zinc from the water source (Upadhyay & Srivastava, 2005 ). Ultrasonic-treated sludge leads to the disintegration of biological cells and kills bacteria in treated wastewater (Kesari, Kumar, et al., 2011a ; Kesari, Verma, & Behari, 2011b ). This has been found that combined treatment with ultrasound and nanoparticles is more effective (Kesari, Kumar, et al., 2011a ). Ultrasonication has the physical effects of cavitation inactivate and lyse bacteria (Broekman et al., 2010 ). The induced effect of US, US, or ozone may destroy the pathogens and especially during ultrasound irradiation including free-radical attack, hydroxyl radical attack, and physical disruption of cell membranes (Kesari, Kumar, et al., 2011a ; Phull et al., 1997 ; Scherba et al., 1991 ).

8.2 Energy and Economy Management

Municipal wastewater treatment plants play a major role in wastewater sanitation and public health protection. However, domestic wastewater has been considered as a resource or valuable products instead of waste, because it has been playing a significant role in the recovery of energy and resource for the plant-fertilizing nutrients like phosphorus and nitrogen. Use of domestic wastewater is widely accepted for the crop irrigation in agriculture and industrial consumption to avoid the water crisis. It has also been found as a source of energy through the anaerobic conversion of the organic content of wastewater into methane gas. However, most of the wastewater treatment plants are using traditional technology, as anaerobic sludge digestion to treat wastewater, which results in more consumption of energy. Therefore, through these conventional technologies, only a fraction of the energy of wastewater has been captured. In order to solve these issues, the next generation of municipal wastewater treatment plants is approaching total retrieval of the energy potential of water and nutrients, mostly nitrogen and phosphorus. These plants also play an important role in the removal and recovery of emerging pollutants and valuable products of different nature like heavy and radioactive metals, fertilizers hormones, and pharma compounds. Moreover, there are still few possibilities of improvement in wastewater treatment plants to retrieve and reuse of these compounds. There are several methods under development to convert the organic matter into bioenergy such as biohydrogen, biodiesel, bioethanol, and microbial fuel cell. These methods are capable to produce electricity from wastewater but still need an appropriate development. Energy development through wastewater is a great driver to regulate the wastewater energy because it produces 10 times more energy than chemical, thermal, and hydraulic forms. Vermicomposting can be utilized for stabilization of sludge from the wastewater treatment plant. Kesari and Jamal ( 2017 ) have reported the significant, economical, and ecofriendly role of the vermicomposting method for the conversion of solid waste materials into organic fertilizers as presented in Fig. 5 . Solid waste may come from several sources of municipal and industrial sludge, for example, textile industry, paper mill, sugarcane, pulp industry, dairy, and intensively housed livestock. These solid wastes or sewage sludges have been treated successfully by composting and/or vermicomposting (Contreras-Ramos et al., 2005 ; Elvira et al., 1998 ; Fraser-Quick, 2002 ; Ndegwa & Thompson, 2001 ; Sinha et al., 2010 ) Although collection of solid wastes materials from sewage or wastewater and further drying is one of the important concerns, processing of dried municipal sewage sludge (Contreras-Ramos et al., 2005 ) and management (Ayilara et al., 2020 ) for vermicomposting could be possible way of generating organic fertilizers for future research. Vermicomposting of household solid wastes, agriculture wastes, or pulp and sugarcane industry wastes shows greater potential as fertilizer for higher crop yielding (Bhatnagar et al., 2016 ; Kesari & Jamal, 2017 ). The higher amount of solid waste comes from agricultural land and instead of utilizing it, this biomass is processed by burning, which causes severe diseases (Kesari & Jamal, 2017 ). Figure 3 shows the proper utilization of solid waste after removal from wastewater; however, Fig. 5 showing greater possibility in fertilizer conversion which has also been discussed in detail elsewhere (Bhatnagar et al., 2016 ; Nagavallemma et al., 2006 )

figure 5

Energy production through wastewater (reproduced from Bhatnagar et al., 2016 ; Kesari & Jamal, 2017 )

9 Conclusions and future perspectives

In this paper, we have reviewed environmental and public health issues associated with the use of untreated wastewater in agriculture. We have focused on the current state of affairs concerning the wastewater treatment model and computational approach. Given the dire need for holistic approaches for cultivation, we proposed the ideas to tackle the issues related to wastewater treatment and the reuse potential of the treated water. Water resources are under threat because of the growing population. Increasing generation of wastewater (municipal, industrial, and agricultural) in developing countries especially in India and other Asian countries has the potential to serve as an alternative of freshwater resources for reuse in rice agriculture, provide appropriate treatment, and distribution measures are adopted. Wastewater treatment is one of the big challenges for many countries because increasing levels of undesired or unknown pollutants are very harmful to health as well as environment. Therefore, this review explores the ideas based on current and future research. Wastewater treatment includes very traditional methods by following primary, secondary, and tertiary treatment procedures, but the implementation of advanced techniques is always giving us a big possibility of good water quality. In this paper, we have proposed combined methods for the wastewater treatment, where the concept of the proposed model works on the various types of wastewater effluents. The proposed model not only useful for wastewater treatment but also for the utilization of solid wastes as fertilizer. An appropriate method for the treatment of wastewater and further utilization for drinking water is the main futuristic outcome. It is also highly recommendable to follow the standard methods and available guidelines provided WHO. In this paper, the proposed role of the computational model, i.e., artificial intelligence, fluid dynamics, and GIS, in wastewater treatment could be useful in future studies. In this review, health concerns associated with wastewater irrigation for farmers and irrigated crops consumers have been discussed.

The crisis of freshwater is one of the growing concerns in the twenty-first century. Globaly, about 330 km 3 of municipal wastewater is generated annually (Hernández-Sancho et al., 2015 ). This data provides a better understanding of why the reuse of treated wastewater is important to solve the issues of the water crisis. The use of treated wastewater (industrial or municipal wastewater or Seawater) for irrigation has a better future for the fulfillment of water demand. Currently, in developing countries, farmers are using wastewater directly for irrigation, which may cause several health issues for both farmers and consumers (crops or vegetables). Therefore, it is very imperative to implement standard and advanced methods for wastewater treatment. A local assessment of the environmental and health impacts of wastewater irrigation is required because most of the developed and developing countries are not using the proper guidelines. Therefore, it is highly required to establish concrete policies and practices to encourage safe water reuse to take advantage of all its potential benefits in agriculture and for farmers.

Abdel-Fatah, M. A. (2018). Nanofiltration systems and applications in wastewater treatment: Review article. Ain Shams Engineering Journal, 9 , 3077–3092.

Google Scholar  

Adegoke, A. A., Faleye, A. C., Singh, G., & Stenström, T. A. (2016). Antibiotic resistant superbugs: Assessment of the interrelationship of occurrence in clinical settings and environmental niches. Molecules, 22 , E29.

Adegoke, A. A., Stenström, T. A., & Okoh, A. I. (2017). Stenotrophomonas maltophilia as an emerging ubiquitous pathogen: Looking beyond contemporary antibiotic therapy. Frontiers in Microbiology, 8 , 2276.

Adegoke, A. A., Amoah, I. D., Stenström, T. A., Verbyla, M. E., & Mihelcic, J. R. (2018). Epidemiological evidence and health risks associated with agricultural reuse of partially treated and untreated wastewater: A review. Frontiers in Public Health, 6 , 337.

Adewumia, J. R., Ilemobadea, A. A., & Vanzyl, J. E. (2010). Treated wastewater reuse in South Africa: Overview, potential, and challenges. Resources, Conservation and Recycling, 55 , 221–231.

Agoro, M. A., Adeniji, A. O., Adefisoye, M. A., & Okoh, O. O. (2020). Heavy metals in wastewater and sewage sludge from selected municipal treatment plants in Eastern Cape Province, South Africa. Water, 12 , 2746.

CAS   Google Scholar  

Akasaka, T., & Watari, F. (2009). Capture of bacteria by flexible carbon nanotubes. Acta Biomaterialia, 5 , 607–612.

Akponikpe, P., Wima, K., Yakouba, H., & Mermoud, A. (2011). Reuse of domestic wastewater treated in macrophyte ponds to irrigate tomato and eggplants in semi-arid West-Africa: Benefits and risks. Agricultural Water Management, 98 , 834–840.

Alghobar, M. A., Ramachandra, L., & Suresha, S. (2014). Effect of sewage water irrigation on soil properties and evaluation of the accumulation of elements in Grass crop in Mysore city, Karnataka, India. American Journal of Environmental Protection, 3 , 283–291.

Al-Nakshabandi, G. A., Saqqar, M. M., Shatanawi, M. R., Fayyad, M., & Al-Horani, H. (1997). Some environmental problems associated with the use of treated wastewater for irrigation in Jordan. Agricultural Water Management, 34 , 81–94.

Amabilis-Sosa, L. E., Vázquez-López, E., García Rojas, J. L., Roé-Sosa, A., & Moeller-Chávez, G. E. (2018). Efficient bacteria inactivation by ultrasound in municipal wastewater. Environments, 5 , 47.

Amoah, I. D., Adegoke, A. A., & Stenström, T. A. (2018). Soil-transmitted helminth infections associated with wastewater and sludge reuse: A review of current evidence. Tropical Medicine & International Health, 23 (7), 692–703.

Anastasi, A., Spina, F., Prigione, V., Tigini, V., Giansanti, P., & Varese, G. C. (2010). Scale-up of a bioprocess for textile wastewater treatment using Bjerkandera adusta. Bioresource Technology, 101 , 3067–3075.

Angelakis, A., & Snyder, S. (2015). Wastewater treatment and reuse: Past, present, and future. Water, 7 , 87–95.

Angelakis, A. N., Marecos do Monte, M. H. F., Bontoux, L., & Asano, T. (1999). The status of wastewater reuse practice in the Mediterranean basin: Need for guidelines. Water Research, 33 , 2201–2217.

Asaithambi, P., & Matheswaran, M. (2016). Electrochemical treatment of simulated sugar industrial effluent: Optimization and modeling using a response surface methodology. Arabian Journal of Chemistry, 9 , S981–S987.

Ayers, R. S., & Westcot, D. W. (1985). Water quality for agriculture; Food and Agriculture Organization of the United . Nations.

Ayilara, M. S., Olanrewaju, O. S., Babalola, O. O., & Odeyemi, O. (2020). Waste management through composting: Challenges and potentials. Sustainability, 12 , 4456.

Azevedo, B. F., Furieri, L. B., Peçanha, F. M., Wiggers, G. A., Vassallo, P. F., Simões, M. R., et al. (2014). Toxic effects of mercury on the cardiovascular and central nervous systems. Journal of Preventive Medicine and Public Health, 47 , 74–83.

Aziz, F., & Farissi, M. (2014). Reuse of treated wastewater in agriculture: solving water deficit problems in arid areas. Annals of West University of Timişoara Series of Biology, 17 , 95–110.

Balcom, I. N., Driscoll, H., Vincent, J., & Leduc, M. (2016). Metagenomic analysis of an ecological wastewater treatment plant’s microbial communities and their potential to metabolize pharmaceuticals. F1000 Research, 5 , 1881.

Balkhair, K. S. (2016a). Microbial contamination of vegetable crop and soil profile in arid regions under controlled application of domestic wastewater. Saudi Journal of Biological Sciences, 23 (1), S83–S92.

Balkhair, K. S. (2016b). Impact of treated wastewater on soil hydraulic properties and vegetable crop under irrigation with treated wastewater, field study and statistical analysis. Journal of Environmental Biology, 37 (5), 1143–1152.

Balkhair, K. S., & Ashraf, M. A. (2016). Field accumulation risks of heavy metals in soil and vegetable crop irrigated with sewage water in western region of Saudi Arabia. Saudi Journal of Biological Science, 23 , S32–S44.

Behling, E., Diaz, A., Colina, G., Herrera, M., Gutierrez, E., Chacin, E., et al. (1996). Domestic wastewater treatment using a UASB reactor. Bioresource Technology, 61 , 239–245.

Bent, S., & Bohm, K. (1995). Copper induced liver cirrhosis in a 13-month-old boy. Gesundheitswesen (health system in German), 57 , 667–669.

Bhatnagar, A., Kesari, K. K., & Shurpali, N. (2016). Multidisciplinary approaches to handling wastes in sugar industries. Water, Air, & Soil Pollution, 11 , 1–30.

Blume, T., & Neis, U. (2004). Improved wastewater disinfection by ultrasonic pre-treatment. Ultrasonics Sonochemistry, 11 , 333–336.

Bolong, N., Ismail, A. F., Salim, M. R., & Matsuura, T. (2009). A review of the effects of emerging contaminants in wastewater and options for their removal. Desalination, 239 , 229–246.

Bonefeld-Jorgensen, E. C., Long, M., Bossi, R., Ayotte, P., Asmund, G., Kruger, T., et al. (2011). Perfluorinated compounds are related to breast cancer risk in Greenlandic Inuit: A case control study. Environmental Health Perspectives, 10 , 88–95.

Börjesson, S., Melin, S., Matussek, A., & Lindgren, P. E. (2009). A seasonal study of the mecA gene and Staphylococcus aureus including methicillin-resistant S. aureus in a municipal wastewater treatment plant. Water Research, 43 , 925–932.

Bos, R., Carr, R., & Keraita, B. (2010). Assessing and mitigating wastewater-related health risks in low income countries: An introduction. In P. Drechsel, C. A. Scott, L. Raschid-Sally, M. Redwood, & A. Bahri (Eds.), In: Wastewater irrigation and health: Assessing and mitigating risk in low-income countries (pp. 29–47). Earthscan.

Briffa, J., Sinagra, E., & Blundell, R. (2020). Heavy metal pollution in the environment and their toxicological effects on humans. Heliyon, 6 , e04691.

Brissaud, F. (2008). Criteria for water recycling and reuse in the Mediterranean countries. Desalination, 218 , 24–33.

Broekman, S., Pohlmann, O., Beardwood, E. S., & de Meulenaer, E. C. (2010). Ultrasonic treatment for microbiological control of water systems. Ultrasonics Sonochemistry, 17 , 1041–1048.

Brumer, L. (2000). Use of aquatic macrophytes to improve the quality of effluents after chlorination. Ph.D. Dissertation, Technion Israel Institute of Technology, Haifa.

Busgang, A., Friedler, E., Gilboa, Y., & Gross, A. (2018). Quantitative microbial risk analysis for various bacterial exposure scenarios involving greywater reuse for irrigation. Water, 10 , 413.

Caplin, J. L., Hanlon, G. W., & Taylor, H. D. (2008). Presence of vancomycin and ampicillin-resistant Enterococcus faecium of epidemic clonal complex-17 in wastewaters from the south coast of England. Environmental Microbiology, 10 , 885–892.

Carey, C., Lee, H., & Trevors, J. (2004). Biology, persistence and detection of Cryptosporidium parvum and Cryptosporidium homynis oocyst. Water Research, 38 , 818–868.

Carr, R. (2005). WHO guidelines for safe wastewater use-more than just numbers. Irrigation and Drainage, 54 , 103–111.

CCREM. (1987). Canadian Water Quality Guidelines . Prepared by the Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers.

Chang, J. S., Chou, C., & Chen, S. Y. (2001). Decolorization of azo dyes with immobilized Pseudomonas luteola. Process Biochemistry, 36 , 757–763.

Chaoua, S., Boussaa, S., Gharmali, A. E., & Boumezzough, A. (2019). Impact of irrigation with wastewater on accumulation of heavy metals in soil and crops in the region of Marrakech in Morocco. Journal of the Saudi Society of Agricultural Sciences, 18, 429–436.

Chen, K., & Pachter, L. (2005). Bioinformatics for whole-genome shotgun sequencing of microbial communities. PLoS Computational Biology, 1 , 106–112.

Chen, W., Lu, S., Pan, N., & Jiao, W. (2013). Impacts of long-term reclaimed water irrigation on soil salinity accumulation in urban green land in Beijing. Water Resources Research, 49 , 7401–7410.

City of Cape Town (CoCT). 2007 Water services Development plan 2007/2008. www.capetown.gov.za/en/Water/WaterservicesDevPlan/Pages/WaterServDevPlan200708.aspx Accessed 12 June 2008.

Clemmens, A. J., Allen, R. G., & Burt, C. M. (2008). Technical concepts related to conservation of irrigation and rainwater in agricultural systems. Water Resources Research, 44 , 1–16.

Coleman, J., Hench, K., Garbutt, K., Sexstone, A., Bissonnette, B., & Skousen, J. (2001). Treatment of domestic wastewater by three plant species in constructed wetlands. Water, Air, and Soil Pollution, 3 , 283–295.

Contreras, J. D., Meza, R., Siebe, C., Rodríguez-Dozal, S., López-Vidal, Y. A., Castillo-Rojas, G., et al. (2017). Health risks from exposure to untreated wastewater used for irrigation in the Mezquital Valley, Mexico: A 25-year update. Water Research, 123 , 834–850.

Contreras-Ramos, S. M., Escamilla-Silva, E. M., & Dendooven, L. (2005). Vermicomposting of biosolids with cow manure and wheat straw. Biological Fertility of Soils, 41 , 190–198.

Craun, M. F., Craun, G. F., Calderon, R. L., & Beach, M. J. (2006). Waterborne outbreaks in the United States. Journal of Water and Health, 4 (suppl 2), 19–30.

Craun, G. F., Brunkard, J. M., Yoder, J. S., Roberts, V. A., Carpenter, J., Wade, T., et al. (2010). Causes of outbreaks associated with drinking water in the United States from 1971 to 2006. Clinical Microbiology Reviews, 23 , 507–528.

Dang, Q., Tan, W., Zhao, X., Li, D., Li, Y., Yang, T., et al. (2019). Linking the response of soil microbial community structure in soils to long-term wastewater irrigation and soil depth. The Science of the total environment, 688, 26–36.

Delgado, A., Anselmo, A. M., & Novais, J. M. (1998). Heavy metal biosorption by dried powdered mycelium of Fusarium Flocci ferum. Water Environmental Research, 70 , 370.

Dewitt, J. C., Peden-Adams, M. M., Keller, J. M., & Germolec, D. R. (2012). Immunotoxicity of perfluorinated compounds: Recent developments. Toxicologic Pathology, 40 , 300–311.

Dickin, S. K., Schuster-Wallace, C. J., Qadir, M., & Pizzacalla, K. (2016). A review of health risks and pathways for exposure to wastewater use in agriculture. Environmental Health Perspectives, 124 , 900–909.

Do-Quang, Z., Cockx, A., Line, A., & Roustan, M. (1998). Computational fluid dynamics applied to water and wastewater treatment facility modeling. Environmental Engineering and Policy, 1 , 137–147.

Drechsel, P., Scott, A., Sally, R., Redwood, M., Bachir, A. (2010). Wastewater Irrigation and Health: Assessing and Mitigating Risk in Low-Income Countries; International Water Management Institute, Ed.; Earthscan: London, UK.

Duan, J. J., Zhao, J. N., Xue, L. H., & Yang, L. Z. (2016). Nutrient removal of a floating plant system receiving low- pollution wastewater: Effects of plant species and influent concentration. IOP Conference Series: Earth and Environmental Science, 41 , 1.

Duan, B., Zhang, W., Zheng, H., Wu, C., Zhang, Q., & Bu, Y. (2017). Comparison of health risk assessments of heavy metals and as in sewage sludge from wastewater treatment plants (WWTPs) for adults and children in the Urban district of Taiyuan, China. International Journal of Environmental Research and Public Health, 14 , 1194.

Duncan, M. (2009). Waste stabilization ponds: Past, present and future. Desalination and Water Treatment, 4 , 85–88.

Ecosse, D. (2001). Alternative techniques in order to meet the shortage of water in the world. Mem DESS Quality and Management of Water, Fac. Science, Amiens 62.

EEA CSI (2018). https://www.eea.europa.eu/themes/water/water-resources/water-use-by-sectors . Accessed 3 Oct 2019.

EPA (Environmental Protection Agency) (2002).National Recommended Water Quality Criteria: 2002. Office of Water, Office of Science and Technology. EPA-822-R-02-047.

Elshaw, A., Hassan, N. M. S., Khan, M. M. K. (2016). CFD modelling and optimisation of a wastewater treatment plant bioreactor—A case study. In Proceedings of the 2016 3rd Asia-Pacific World Congress on Computer science and Engineering (APWC on CSE), 232–239 https://doi.org/10.1109/APWC-on-CSE.2016.046 .

Elvira, C., Sampedro, L., Benitez, E., & Nogales, R. (1998). Vermicomposting of sludges from paper mills and dairy industries with Elsenia anderi. A pilot scale study. Journal of Bioresource Technology, 63 , 205–211.

Falkenberg, T., & Saxena, D. (2018). Impact of wastewater-irrigated urban agriculture on diarrhea incidence in Ahmedabad, India. Indian Journal of Community Medicine, 43 , 102–106.

FAO, (1985) Water Quality for Agriculture. Irrigation and Drainage Paper No. 29, Rev. 1. Food and Agriculture Organization of the United Nations, Rome.

Fazeli, M. S., Khosravan, F., Hossini, M., Sathyanarayan, S., & Satish, P. N. (1998). Enrichment of heavy metals in paddy crops irrigated by paper mill effluents near Nanjangud, Mysore District, Karnataka, India. Environmental Geology, 34 , 297–302.

FEPA. (1991). Proposed National Water Quality Standards . Federal Environmental Protection Agency.

Foerstner, K. U., Von-Mering, C., & Bork, P. (2006). Comparative analysis of environmental sequences: potential and challenges. Philosophical transactions of the Royal Society of London Series B, Biological sciences, 361 , 519–523.

Founou, R. C., Founou, L. L., & Essack, S. Y. (2017). Clinical and economic impact of antibiotic resistance in developing countries: A systematic review and meta-analysis. PLoS One, 12 , e0189621. https://doi.org/10.1371/journal.pone.0189621 .

Article   CAS   Google Scholar  

Fraser-Quick, G. (2002). Vermiculture – A sustainable total waste management solution. What’s New in Waste Management?, 4 , 13–16.

Freitas, F., Alves, V. D., Pais, J., Costa, N., Oliveira, C., & Mafra, L. (2009). Characterization of an extracellular polysaccharide produced by a Pseudomonas strain grown on glycerol. Bioresource Technology, 100 , 859–865.

Freitas, F., Alves, V. D., & Reis, M. A. (2011a). Advances in bacterial exopolysaccharides: From production to biotechnological applications. Trends in Biotechnology, 29 , 388–398.

Freitas, F., Alves, V. D., Torres, C. A., Cruz, M., Sousa, I., & Melo, M. J. (2011b). Fucose-containing exopolysaccharide produced by the newly isolated Enterobacter strain A47 DSM 23139. Carbohydrate Polymers, 83 , 159–165.

Frontistis, Z., Xekoukoulotakis, N. P., Hapeshi, E., Venieri, D., Fatta-Kassinos, D., & Mantzavinos, D. (2011). Fast degradation of estrogen hormones in environmental matrices by photo-Fenton oxidation under simulated solar radiation. Chemical Engineering Journal, 178 (15), 175–182.

Fukushima, M., Ishizaki, A., & Sakamoto, M. (1970). On distribution of heavy metals in rice field soil in the “Itai-itai” disease epidemic district. Japanese Journal of Hygiene, 24 , 526–535.

Gatta, G., Libutti, A., Gagliardi, A., Disciglio, G., Beneduce, L., d’Antuono, M., Rendina, M., & Tarantino, E. (2015a). Effects of treated agro-industrial wastewater irrigation on tomato processing quality. Italian Journal of Agronomy, 10 (2), 97–100.

Gatta, G., Libutti, A., Gagliardi, A., Beneduce, L., Borruso, L., Disciglio, G., & Tarantino, G. (2015b). Treated agro-industrial wastewater irrigation of tomato crop: Effects on qualitative/quantitative characteristics of production and microbiological properties of the soil. Agricultural Water Management, 149 , 33–43.

Gehrke, I., Geiser, A., & Somborn-Schulz, A. (2015). Innovations in nanotechnology for water treatment. Nanotechnology, Science and Applications, 8 , 1–17.

Genchi, G., Sinicropi, M. S., Lauria, G., Carocci, A., & Catalano, A. (2020). The effects of cadmium toxicity. International Journal of Environmental Research and Public Health, 17 , 3782.

Giddins, M. J., Macesic, N., Annavajhala, M. K., Stump, S., Khan, S., McConville, T. H., Mehta, M., Gomez-Simmonds, A., & Uhlemann, A. C. (2017). Successive emergence of ceftazidime-avibactam resistance through distinct genomic adaptations in bla(KPC-2)-harboring Klebsiella pneumoniae sequence type 307 isolates. Antimicrobial Agents and Chemotherapy, 62 , e02101–e02117.

Goel, J., Kadirvelu, K., Rajagopal, C., Kumar, G., & V. (2005). Removal of lead (II) by adsorption using treated granular activated carbon: Batch and column studies. Journal of Hazardous Materials, 125 (1-3), 211–220.

Goldstein, R. E. R. (2013). Antibiotic-resistant bacteria in wastewater and potential human exposure through wastewater reuse. PhD Dissertation, University of Maryland.

Gupta, P., & Diwan, B. (2017). Bacterial Exopolysaccharide mediated heavy metal removal: A review on biosynthesis, mechanism and remediation strategies. Biotechnology Reports, 13 , 58–71.

Gupta, S. K., Shin, H., Han, D., Hur, H. G., & Unno, T. (2018). Metagenomic analysis reveals the prevalence and persistence of antibiotic- and heavy metal-resistance genes in wastewater treatment. Plant Journal of Microbiology, 56 , 408–415.

GWI Global Water Intelligence. (2009). PUB study: Perspectives of water reuse . GWI Publishing.

Hall, N. (2007). Advanced sequencing technologies and their wider impact in microbiology. Journal of Experimental Biology, 210 , 1518–1525.

Halliwell, D. J., Barlow, K. M., & Nash, D. M. (2001). A review of the effects of wastewater sodium on soil physical properties and their implications for irrigation systems. Australian Journal of Soil Research, 39 , 1259–1267.

He, Y., Yuan, Q., Mathieu, J., Stadler, L., Senehi, N., Sun, R., & Alvarez, P. J. J. (2020). Antibiotic resistance genes from livestock waste: Occurrence, dissemination and treatment. npj Clean Water, 3 , 4.

Herc, E. S., Kauffman, C. A., Marini, B. L., Perissinotti, A. J., & Miceli, M. H. (2017). Daptomycin nonsusceptible vancomycin resistant Enterococcus bloodstream infections in patients with hematological malignancies: Risk factors and outcomes. Leukemia & Lymphoma, 58 , 2852–2858.

Hernández-Sancho, F., Lamizana-Diallo, B., Mateo-Sagasta, J., & Qadeer, M. (2015). Economic valuation of wastewater –The cost of action and the cost of no action . United Nations Environment Programme.

Hesnawi, R., Dahmani, K., Al-Swayah, A., Mohamed, S., & Mohammed, S. A. (2014). Biodegradation of municipal wastewater with local and commercial bacteria. Procedia Engineering, 70 , 810–814.

Hoekstra, A. Y., & Mekonnen, M. M. (2012). The water footprint of humanity. Proceedings of the National Academy of Sciences, 109 , 3232–3237.

Hua, I., & Thompson, J. E. (2000). Inactivation of E. coli by sonication at discrete ultrasonic frequencies. Water Research, 34 , 3888–3893.

Hussain, A., Priyadarshi, M., & Dubey, S. (2019). Experimental study on accumulation of heavy metals in vegetables irrigated with treated wastewater. Applied Water Science, 9 , 122.

Icgen, B., & Yilmaz, F. (2014). Co-occurrence of antibiotic and heavy metal resistance in Kizilirmak River isolates. Bulletin of Environmental Contamination and Toxicology, 93 , 735–743.

Iguchi, S., Mizutani, T., Hiramatsu, K., & Kikuchi, K. (2016). Rapid acquisition of linezolid resistance in methicillin-resistant Staphylococcus aureus: Role of hypermutation and homologous recombination. PLoS One, 11 , e0155512.

Indiana State Department of Health, 2009. Diseases Involving Sewage. https://www.in.gov/isdh/22963.htm

Inoue, Y., Hoshino, M., Takahashi, H., Noguchi, T., Murata, T., & Kanzaki, Y. (2002). Bactericidal activity of Ag-zeolite mediated by reactive oxygen species under aerated conditions. Journal of Inorganic Biochemistry, 92 , 37–42.

Jacquez, R. B., Walner, H. Z. (1985). Combining nutrient removal with protein synthesis using a water hyacinth-freshwater prawn polyculture wastewater treatment system. New Mexico Water Resources Research Institute . 92.

Jaishankar, M., Tseten, T., Anbalagan, N., Mathew, B. B., & Beeregowda, K. N. (2014). Toxicity, mechanism and health effects of some heavy metals. Interdisciplinary Toxicology, 7 (2), 60–72.

Jarup, L. (2003). Hazards of heavy metal contamination. British Medical Bulletin, 68 , 167–182.

Jeong, H., Kim, H., & Jang, J. (2016). Irrigation water quality standards for indirect wastewater reuse in agriculture: A contribution toward sustainable wastewater reuse in South Korea. Water, 8 , 169.

Jia, S., Zhang, X. (2020). Biological HRPs in wastewater. In High-risk pollutants in wastewater. Eds. Ren, H. and Zhang, X. 41-67.

Jiménez, B., & Asano, T. (2008). Water reclamation and reuse around the world. In B. Jiménez & T. Asano (Eds.), In: Water reuse: An International Survey of Current Practice, Issues and Needs (pp. 3–26). IWA Publishing .

Jindal, A., Kamat, S. (2011). Water recycling and reuse for domestic and industrial sectors. Chemical Engineering World , 52-62.

Jyothi, N.R. (2020). Heavy metal sources and their effects on human health, heavy metals - Their environmental impacts and mitigation. Ed. Nazal, M. 95370.

Jyothi, N.R. and Farook, N.A.M. (2020). Mercury toxicity in public health, Heavy Metal Toxicity in Public Health. 1-12.

Jyoti, K. K., & Pandit, A. B. (2004). Ozone and cavitation for water disinfection. Biochemical Engineering Journal, 38 , 2249–2258.

Kalavrouziotis, I. K., Kokkinos, P., Oron, G., Fatone, F., Bolzonella, D., Vatyliotou, M., et al. (2015). Current status in wastewater treatment, reuse and research in some mediterranean countries. Desalination and Water Treatment, 53 , 2015–2030.

Kanwar, J., & Sandha, M. (2000). Waste water pollution injury to vegetable crops: A review. Agricultural Research Communication Centre, India, 21 , 133–136.

Katsoyiannis, I. A., Gkotsis, P., Castellana, M., Cartechini, F., & Zouboulis, A. I. (2017). Production of demineralized water for use in thermal power stations by advanced treatment of secondary wastewater effluent. Journal of Environmental Management, 1 (190), 132–139.

Kenny, J. F., Barber, N. L., Hutson, S. S., Linsey, K. S., Lovelace, J. K., & Maupin, M. A. (2009). Estimated use of water in the United States in 2005. U.S. Geological Survey Circular, 1344 , 52.

Kesari, K. K., & Behari, J. (2008). Ultrasonic impact on bacterial population in sewage sample. International Journal of Environment and Waste Management, 2 , 233–244.

Kesari, K. K., Jamal, Q. M. S. (2017). Review Processing, properties and applications of agricultural solid waste: Effect of an open burning in environmental toxicology. In: Kesari K. (eds) Perspectives in Environmental Toxicology. Environmental Science and Engineering . Springer, Cham. Chapter 8:161-181.

Kesari, K. K., Kumar, S., Verma, H. N., & Behari, J. (2011a). Influence of ultrasonic treatment in sewage sludge. Hydrology: Current Research, 2 , 115.

Kesari, K. K., Verma, H. N., & Behari, J. (2011b). Physical methods in wastewater treatment. International Journal of Environmental Technology and Management, 14 , 43–66.

Khaskhoussy, K., Kahlaoui, B., Messoudi, N. B., Jozdan, O., Dakheel, A., & Hachicha, M. (2015). Effect of treated wastewater irrigation on heavy metals distribution in a Tunisian soil. Engineering Technology and Applied Science Research, 5 , 805–810.

Kim, S. Y., Kim, J. H., Kim, C. J., & Oh, D. K. (1996). Metal adsorption of the polysaccharide produced from Methylobacterium organophilum. Biotechnology Letters, 18 , 1161–1164.

Kim, B. H., Kang, Z., Ramanan, R., Choi, J. E., Cho, D. H., Oh, H. M., et al. (2014). Nutrient removal and biofuel production in high rate algal pond using real municipal wastewater. Journal of Microbiology and Biotechnology, 24 , 1123–1132.

Kinuthia, G. K., Ngure, V., Beti, D., Lugalia, R., Wangila, A., & Kamau, L. (2020). Levels of heavy metals in wastewater and soil samples from open drainage channels in Nairobi, Kenya: community health implication. Scientific Reports, 10 , 8434 .

Kocabas, Z. O., Aciksoz, B., Yurum, Y. (2012). Binding mechanisms of As(III) on activated carbon/titanium dioxide nanocomposites: a potential method for arsenic removal from water, MRS online proceedings library. Published online by Cambridge University Press 1449.

König, M., Escher, B. I., Neale, P. A., Krauss, M., Hilscherová, K., Novák, J., et al. (2017). Impact of untreated wastewater on a major European river evaluated with a combination of in vitro bioassays and chemical analysis. Environmental Pollution, 220 (Part B), 1220–1230.

Kumar, R., & Chawla, J. (2014). Removal of cadmium ion from water/wastewater by nano-metal oxides. Water Quality Exposure and Health, 5 , 4.

Kumar, M., Kesari, K. K., & Behari, J. (2010). Low frequency ultrasonic irradiation of activated sludge. International Journal of Environment and Pollution, 43 , 52–65.

Kumar, S. S., Shantkriti, S., Muruganandham, T., Murugesh, E., Rane, N., & Govindwar, N. P. (2016). Bioinformatics aided microbial approach for bioremediation of wastewater containing textile dyes. Ecological Informatics, 31 , 112–121.

Kumar, A., Ali, M., Kumar, R., Kumar, M., Sagar, P., Pandey, R. K., et al. (2021). Arsenic exposure in Indo Gangetic plains of Bihar causing increased cancer risk. Scientific Reports, 11 , 2376.

Leddy, M. B., Plumlee, M. H., Kantor, R. S., Nelson, K. L., Miller, S. E., Kennedy, L. C., et al. (2018). High-throughput DNA sequencing to profile microbial water quality of potable reuse. Water online, 1-4.

Lee, I., & Viberg, H. (2013). A single neonatal exposure to perfluorohexane sulfonate (PFHxS) affects the levels of important neuroproteins in the developing mouse brain. Neurotoxicology, 37 , 190–196.

Libutti, A., Gatta, G., Gagliardi, A., Vergine, P., Pollice, A., Beneduce, L., Disciglio, G., & Tarantino, E. (2018). Agro-industrial wastewater reuse for irrigation of a vegetable crop succession under Mediterranean conditions. Agricultural Water Management, 196 , 1–14.

Liu, J., Ma, Y., Xu, T., & Shao, G. (2010). Preparation of zwitterionic hybrid polymer and its application for the removal of heavy metal ions from water. Journal of Hazardous Materials, 178 , 1021–1029.

Lv, L., Yu, X., Xu, Q., & Ye, C. (2015). Induction of bacterial antibiotic resistance by mutagenic halogenated nitrogenous disinfection byproducts. Environmental Pollution, 205 , 291–298.

Madsen, H., Poultsen, L., & Grandjean, P. (1990). Risk of high copper content in drinking water. Ugeskr Laeger (Journal of the Danish Medical Association), 152 (25), 1806–1809.

Mahendran, R., Ramli, N. H., & Abdurrahman, H. N. (2014). Study the effect of using ultrasonic membrane anaerobic system in treating sugarcane waste and methane gas production. International Journal of Research in Engineering and Technology, 3 , 299–303.

Mahfooz, Y., Yasar, A., Guijian, L., Islam, Q. U., Akhtar, A. B. T., Rasheed, R., Irshad, S., & Naeem, U. (2020). Critical risk analysis of metals toxicity in wastewater irrigated soil and crops: a study of a semi-arid developing region. Scientific Reports, 10 , 12845.

Mahmood, A., & Malik, R. N. (2014). Human health risk assessment of heavy metals via consumption of contaminated vegetables collected from different irrigation sources in Lahore. Pakistan, Arabian Journal of Chemistry, 7 (1), 91–99.

Mañas, P., Castro, E., & Heras, J. (2009). Irrigation with treated wastewater: effects on soil, lettuce (Lactuca sativa L.) crop and dynamics of microorganisms. Journal of Environmental Science and Health, 44 , 1261.

Marchal, M., Briandet, R., Koechler, S., Kammerer, B., & Bertin, P. N. (2010). Effect of arsenite on swimming motility delays surface colonization in Herminiimona sarsenicoxydans. Microbiology, 156 , 2336–2342.

Marcussen, H., Holm, P. E., Ha, L. T., & Dalsgaard, A. (2007). Food safety aspects of toxic element accumulation in fish from wastewater-feed ponds in Hanoi, Vietnam . Tropical Medicine & International Health, 12 , 34–39.

Marsh, S. (2007). Pyrosequencing applications. Methods in Molecular Biology, 373 , 15–24.

Meehan, C., Bjourson, A. J., & McMullan, G. (2001). Paeni bacillus azoreducens sp. nov., a synthetic azo dye decolorizing bacterium from industrial wastewater. International Journal of Systematic and Evolutionary Microbiology, 51 , 1681–1685.

Mehmood, A., Mirza, A. S., Choudhary, M. A., Kim, K. H., Raza, W., Raza, N., Lee, S. S., Zhang, M., Lee, J. H., & Sarfraz, M. (2019). Spatial distribution of heavy metals in crops in a wastewater irrigated zone and health risk assessment. Environmental Research, 168 , 382–388.

Melanta, S. (2008). Aquatic bacteria removal using carbon nanotubes. Biological and Agricultural Engineering Undergraduate Thesis . University of Arkansas.

Mohammad, M., & Mazahreh, N. (2003). Changes in soil fertility parameters in response to irrigation of forage crops with secondary treated wastewater. Communications in Soil Science and Plant Analysis, 34 , 181–1294.

Mohammad, A. W., Teow, Y. H., Ang, W. L., Chung, Y. T., Oatley-Radcliffe, D. L., & Hila, N. (2015). Nanofiltration membranes review: Recent advances and future prospects. Desalination, 356 , 226–254.

Mohsen, M. S. (2004). Treatment and reuse of industrial effluents: Case study of a thermal power plant. Desalination, 167 , 75–86.

Mostafaii, G., Chimehi, E., Gilasi, H. R., & Iranshahi, L. (2017). Investigation of zinc oxide nanoparticles effects on removal of total coliform bacteria in activated sludge process effluent of municipal wastewater. Journal of Environmental Science and Technology, 1 , 49–55.

Naddeo, V., Belgiorno, V., Ricco, D., & Kassinos, D. (2009). Degradation of diclofenac by sonolysis, ozonation and their simultaneous application. Ultrasonics Sonochemistry, 16 , 790–794.

Nagavallemma, K. P., Wani, S. P., Lacroix, S., Padmaja, V. V., Vineela, C., Babu, R. M., & Sahrawat, K. L. (2006). Vermicomposting: recycling wastes into valuable organic fertilizer. SAT eJournal, 2 , 1–16.

Narain, D. M., Bartholomeus, R. P., Dekker, S. C., & Van Wezel, A. P. (2020). Natural purification through soils: Risks and opportunities of sewage effluent reuse in sub-surface irrigation. In In: Reviews of Environmental Contamination and Toxicology (Continuation of Residue Reviews) (pp. 1–33). Springer. https://doi.org/10.1007/398_2020_49 .

Naylor, N. R., Atun, R., Zhu, N., Kulasabanathan, K., Silva, S., Chatterjee, A., Knight, G. M., & Robotham, J. V. (2018). Estimating the burden of antimicrobial resistance: a systematic literature review. Antimicrobial Resistance and Infection Control, 7 , 58.

Ndegwa, P. M., & Thompson, S. A. (2001). Integrated composting and vermicomposting in the treatment and bioconversion of biosolids. Bioresource Technology, 76 , 107–112.

Nizam, N. U. M., Hanafiah, M. M., Noor, I. M., & Karim, H. I. A. (2020). Efficiency of five selected aquatic plants in phytoremediation of aquaculture wastewater. Applied Sciences, 10 , 2712.

Njuguna, S. M., Makokha, V. A., Yan, X., Gituru, R. W., Wang, Q., & Wang, J. (2019). Health risk assessment by consumption of vegetables irrigated with reclaimed wastewater: A case study in Thika (Kenya). Journal of Environmental Management, 231 , 576–581.

Nmaya, M. M., Agam, M. A., Matias-Peralta, H. M., Yabagi, J. A., & Kimpa, M. I. (2017). Freshwater green microalga for bioremediation of river melaka heavy metals contamination. Journal of Science and Technology, 9 , 118–123.

Nour, A. H., & Zainal, Z. (2014). Membrane fouling control by ultrasonic membrane anaerobic system (UMAS) to produce methane gas. International Journal of Engineering Science Research Technology, 3 , 487–497.

Nourani, V., Elkiran, G., & Abba, S. I. (2018). Wastewater treatment plant performance analysis using artificial intelligence – An ensemble approach. Water Science and Technology, 78 (10), 2064–2076.

Numberger, D., Ganzert, L., Zoccarato, L., Mühldorfer, K., Sauer, S., & Grossart, H. P. (2019). Characterization of bacterial communities in wastewater with enhanced taxonomic resolution by full-length 16S rRNA sequencing. Scientific Reports, 9 , 9673.

Odigie, J. O. (2014). Harmful effects of wastewater disposal into water bodies: A case review of the Ikpoba river, Benin city, Nigeria. Tropical Freshwater Biology, 23 , 87–101.

Oilgae Guide to Algae-based Wastewater Treatment. (2014). Commonly used algae strains for wastewater treatment. http://www.oilgae.com/blog/2014/01/commonly-used-algae-strains-for-waste-water-treatment.html . Accessed 5 May 2021

Okoh, A. I., Sibanda, T., & Gusha, S. S. (2010). Inadequately treated wastewater as a source of human enteric viruses in the environment. International Journal of Environmental Research and Public Health, 7 , 2620–2637.

Oturan, M. A., & Aaron, J. J. (2014). Advanced oxidation processes in water/wastewater treatment: Principles and applications. A review. Critical Reviews in Environmental Science and Technology, 44 , 2577–2641.

Paleologou, A., Marakas, H., Xekoukoulotakis, N. P., Moya, A., Vergara, Y., Kalogerakis, N., Gikas, P., & Mantzavinos, D. (2007). Disinfection of water and wastewater by TiO2 photocatalysis, sonolysis and UV-C irradiation. Catalysis Today, 129 , 136–142.

Pan, B., & Xing, B. S. (2008). Adsorption mechanisms of organic chemicals on carbon nanotubes. Environmental Science and Technology, 42 , 9005–9013.

Panthi, S., Sapkota, A. R., Raspanti, G., Allard, S. M., Bui, A., Craddock, H. A., Murray, R., et al. (2019). Pharmaceuticals, herbicides, and disinfectants in agricultural water sources. Environmental Research, 174 , 1–8.

Park, K. Y., Maeng, S. K., Song, K. G., & Ahn, K. H. (2008). Ozone treatment of wastewater sludge for reduction and stabilization. Journal Environmental Science Health. Part A, Toxic/Hazardous Substances & Environmental Engineering, 43 , 1546–1550.

Pedrero, F., Kalavrouziotis, I., Alarcón, J. J., Koukoulakis, P., & Asano, T. (2010). Use of treated municipal wastewater in irrigated agriculture. Review of some practices in Spain and Greece. Agricultural Water Management, 97 , 1233–1241.

Peng, S. M., Chen, Y. D., Guo, W. Q., Yang, S. S., Wu, Q. L., Luo, H. C., & Ren, N. Q. (2014). The Application of computational fluid dynamics (CFD) in wastewater biological treatment field. Applied Mechanics and Materials, 507 , 711–715.

Pesoutova, R., Hlavinek, P., & Matysikova, J. (2011). Use of advanced oxidation processes for textile wastewater treatment- A review. Food and Environmental Safety, 10 , 59–65.

Petrier, C., Jeunet, A., Luche, J. L., & Reverdy, G. (1992). Unexpected frequency effects on the rate of oxidative processes induced by ultrasound. Journal of the American Chemical Society, 25 , 148–3150.

Pham-Duc, P., Nguyen-Viet, H., Hattendorf, J., et al. (2014). Diarrhoeal diseases among adult population in an agricultural community Hanam province, Vietnam, with high wastewater and excreta reuse. BMC Public Health, 14 , 978.

Phull, S. S., Newman, A. P., Lorimer, J. P., Pollet, T. J., & Mason, T. J. (1997). The development and evaluation of ultrasound in the biocidal treatment of water. Ultrasonics Sonochemistry, 4 , 157–164.

Poustie, A., Yang, Y., Verburg, P., Pagilla, K., & Hanigan, D. (2020). Reclaimed wastewater as a viable water source for agricultural irrigation: A review of food crop growth inhibition and promotion in the context of environmental change. Science of the Total Environment, 739 , 139756.

Punshon, T., Jackson, B. P., Meharg, A. A., Warczack, T., Scheckel, K., & Guerinot, M. L. (2017). Understanding arsenic dynamics in agronomic systems to predict and prevent uptake by crop plants. Science of the Total Environment, 581–582 , 209–220.

Puzas, J. E., Campbell, J., O’Keefe, R. J., & Rosier, R. N. (2004). Lead toxicity in the skeleton and its role in osteoporosis. In Nutrition and Bone Health (pp. 373–376). Humana Press.

Qadir, M., Wichelns, D., Raschid-Sally, L., McCornick, P. G., Drechsel, P., Bahri, A., et al. (2010). The challenges of wastewater irrigation in developing countries. Agricultural Water Management, 97 , 561–568.

Raes, J., Foerstner, K. U., & Bork, P. (2007). Get the most out of your metagenome: Computational analysis of environmental sequence data. Current Opinion in Microbiology, 10 , 490–498.

Ramadas, M., & Samantaray, A. K. (2018). Applications of remote sensing and GIS in water quality monitoring and remediation: A state-of-the-art review. In S. Bhattacharya, A. Gupta, A. Gupta, & A. Pandey (Eds.), Water remediation. Energy, Environment, and Sustainability . Springer.

Rizvi, H., Ahmad, N., Abbas, F., Bukhari, I. H., Yasar, A., Ali, S., Yasmeen, T., & Riaz, M. (2015). Start-up of UASB reactors treating municipal wastewater and effect of temperature/sludge age and hydraulic retention time (HRT) on its performance. Arabian Journal of Chemistry, 8 , 780–786.

Russ, R., Rau, J., & Stolz, A. (2000). The function of cytoplasmic flavin reductases in the reduction of azodyes by bacteria. Applied and Environmental Microbiology, 66 , 1429–1434.

Sacks, M., & Bernstein, N. (2011). Utilization of reclaimed wastewater for irrigation of field-grown melons by surface and subsurface drip irrigation. Israel Journal of Plant Sciences, 59 , 159–169.

Sağ, Y. (2001). Biosorption of heavy metals by fungal biomass and modeling of fungal biosorption: A review. Separation and Purification Reviews, 30 , 1–48.

Salem, H. M., Eweida, E. A., & Farag, A. (2000). Heavy metals in drinking water and their environmental impact on human health (pp. 542–556). ICEHM .

Samarghandi, M. R., Nouri, J., Mesdaghinia, A. R., Mahvi, A. H., Nasseri, S., & Vaezi, F. (2007). Efficiency removal of phenol, lead and cadmium by means of UV/TiO2/H2O2 processes. International journal of Environmental Science and Technology, 4 , 19–25.

Samie, A., Obi, L., Igumbor, O., & Momba, B. (2009). Focus on 14 sewage treatment plants in the Mpumalanga province, South Africa in order to gauge the efficiency of wastewater treatment. African Journal of Microbiology Research, 8 , 3276–3285.

Samstag, R. W., Ducoste, J. J., Griborio, A., Nopens, I., Batstone, D. J., Wicks, J., & Laurent, J. (2016). CFD for wastewater treatment: An overview. Water Science and Technology, 74 , 549–563.

Santajit, S., & Indrawattana, N. (2016). Mechanisms of antimicrobial resistance in ESKAPE pathogens. BioMed Research International, 2016 , 2475067.

Sato, T., Qadir, M., Yamamoto, S., Endo, T., & Zahoor, A. (2013). Global, regional, and country level need for data on wastewater generation, treatment, and use. Agricultural Water Management, 130 , 1–13.

Scherba, G., Weigel, R. M., & Obrien, W. D. (1991). Quantitative assessment of the germicidal efficacy of ultrasonic energy. Applied and Environmental Microbiology, 57 , 2079–2084.

Schloss, P. D., & Handelsman, J. (2005). Metagenomics for studying unculturable microorganisms: Cutting the Gordian knot. Genome Biology, 6 , 229.

Schmeisser, C., Steele, H., & Streit, W. R. (2007). Metagenomics, biotechnology with non-culturable microbes. Applied Microbiology and Biotechnology, 75 , 955–962.

Scott, C. A., Faruqui, N. I., & Raschid-Sally, L. (2004). Wastewater use in irrigated agriculture: Management challenges in developing countries. In C. A. Scott, N. I. Faruqui, & L. Raschid-Sally (Eds.), Wastewater use in irrigated agriculture: Confronting the livelihood and environmental realities (pp. 1–10). CABI Publishing.

Scott, C. A., Drechsel, P., Raschid-Sally, L., Bahri, A., Mara, D., Redwood, M., et al. (2009). Wastewater irrigation and health: Challenges and Outlook for mitigating risks in low-income countries. In P. Drechsel, C. A. Scott, L. Raschid-Sally, M. Redwood, & A. Bahri (Eds.), In: Wastewater irrigation and health: Assessing and mitigating risk in low-income countries (pp. 381–394). Earthscan .

Sengupta, S., Nawaz, T., & Beaudry, J. (2015). Nitrogen and phosphorus recovery from wastewater. Current Pollution Reports, 1 , 155–166.

Shakir, R., Davis, S., Norrving, B., Grisold, W., Carroll, W. M., Feigin, V., & Hachinski, V. (2016). Revising the ICD: Stroke is a brain disease. Lancet, 19 , 2475–2476.

Sharma, N. K., Bhardwaj, S., Srivastava, P. K., Thanki, Y. J., Gadhia, P. K., & Gadhia, M. (2012). Soil chemical changes resulting from irrigating with petrochemical effluents. International journal of Environmental Science and Technology, 9 , 361–370.

Sheet, I., Kabbani, A., & Holail, H. (2014). Removal of heavy metals using nanostructured graphite oxide, silica nanoparticles and silica/ graphite oxide composite. Energy Procedia, 50 , 130–138.

Shen, Y., Oki, T., Kanae, S., Hanasaki, N., Utsumi, N., & Kiguchi, M. (2014). Projection of future world water resources under SRES scenarios: An integrated assessment. Hydrological Sciences Journal, 59 , 1775–1793.

Shuval, H. I., Yekutiel, P., & Fattal, B. (1985). Epidemiological evidence for helminth and cholera transmission by vegetables irrigated with wastewater. Jerusalem - Case study. Water Science and Technology, 17 , 433–442.

Siezen, R. J., & Galardini, M. (2008). Genomics of biological wastewater treatment. Microbial Biotechnology, 1 , 333–340.

Singh, A., Sawant, M., Kamble, S. J., Herlekar, M., Starkl, M., Aymerich, E., et al. (2019). Performance evaluation of a decentralized wastewater treatment system in India. Environmental Science and Pollution, 26 , 21172–21188.

Sinha, R. K., Herat, S., Bharambe, G., & Brahambhatt, A. (2010). Vermistabilization of sewage sludge (biosolids) by earthworms: Converting a potential biohazard destined for land disposal into a pathogen free, nutritive and safe biofertilizer for farms. Waste Management and Research, 28 , 872–881.

Smith, R. G. (1995). Water reclamation and reuse. Water Environment Research, 67 , 488–495.

Soni, R., Pal, A. K., Tripathi, P., Lal, J. A., Kesari, K., & Tripathi, V. (2020). An overview of nanoscale materials on the removal of wastewater contaminants. Applied Water Science, 10 , 189.

Spina, F., Anastasi, A., Prigione, V., Tigini, V., & Varese, G. C. (2012). Biological treatment of industrial wastewaters: A fungal approach. Chemical Engineering Transactions, 27 , 175–180.

Srivastava, A., Srivastava, O. N., Talapatra, S., Vajtai, R., & Ajayan, P. M. (2004). Carbon nanotube filters. Nature Materials, 3 , 610–614.

SWRCB (2011) Order No. R3-2011-0222: waste discharge requirements NPDES general permit for discharges of highly treated groundwater to surface waters, NPDES NO. CAG993002, California State Water Quality Control Board.

Tacconelli, E., Carrara, E., Savoldi, A., Harbarth, S., Mendelson, M., Monnet, D. L., et al. (2018). Discovery, research, and development of new antibiotics: The WHO priority list of antibiotic-resistant bacteria and tuberculosis. The Lancet Infectious Diseases, 18 , 318–327.

Tanji, K. K., & Kielen, N. C. (2002). Agricultural drainage water management in arid and semi-arid areas. In FAO Irrigation and Drainage Paper (p. 61). Food and Agriculture Organization.

Taylor, A. A., Tsuji, J. S., Garry, M. R., McArdle, M. E., Goodfellow Jr., W. L., Adams, W. J., et al. (2020). Critical review of exposure and effects: Implications for setting regulatory health criteria for ingested copper. Environmental Management, 65 , 131–159.

Templeton, M. R., Graham, N., & Voulvoulis, N. (2009). Emerging chemical contaminants in water and wastewater. Philosophical Transactions of the Royal Society A, 367 , 3873–3875.

Toze, S. (1997). Microbial pathogens in wastewater. CSIRO Land and Water Technical report 1/97.

Tringe, S. G., Von-Merling, C., Kobayashi, A., Salamov, A. A., Chen, K., & Chang, H. W. (2005). Comparative metagenomics of microbial communities. Science, 308 , 554–557.

Tripathi, V., Tripathi, P. (2017). Antibiotic resistance genes: An emerging environmental pollutant. K.K. Kesari (ed.), Perspectives in Environmental Toxicology , 183-201.

Tsagarakis, K. P., Tsoumanis, P., Chartzoulakis, K., & Angelakis, A. N. (2001). Water resources status including wastewater treatment and reuse in Greece. Water International, 26 , 252–258.

Tytła, M. (2019). Assessment of heavy metal pollution and potential ecological risk in sewage sludge from municipal wastewater treatment plant located in the most industrialized region in Poland—Case study. International Journal of Environmental Research and Public Health, 16 , 2430.

Ungureanu, N., Vlăduț, V., Dincă, M., Zăbavă, B. Ș. (2018). Reuse of wastewater for irrigation, a sustainable practice in arid and semi-arid regions. In Proceedings of the 7th International Conference on Thermal Equipment, Renewable Energy and Rural Development (TE-RE-RD), Drobeta-Turnu Severin, Romania, 31 May–2 June. pp. 379–384.

Ungureanu, N., Vlăduț, V., & Voicu, G. (2020). Water Scarcity and wastewater reuse in crop irrigation. Sustainability, 12 (21), 9055.

Upadhyay, K., & Srivastava, J. K. (2005). Application of ozone in the treatment of industrial and municipal wastewater. Journal of Industrial Pollution Control, 21 , 235–245.

US EPA. (2004). Guidelines for Water Reuse 625/R-04/108 . Environmental Protection Agency.

US EPA. (2012). Guidelines for Water Reuse 600/R-12/618 . Environmental Protection Agency.

Vélez, E., Campillo, G. E., Morales, G., Hincapié, C., Osorio, J., Arnache, O., et al. (2016). Mercury removal in wastewater by iron oxide nanoparticles. Journal of Physics: Conference Series, 687 , 012050.

Vergili, I. (2013). Application of nanofiltration for the removal of carbamazepine, diclofenac and ibuprofen from drinking water sources. Journal of Environmental Management, 127 , 177–187.

Vogelmann, E. S., Awe, G. O., & Prevedello, J. (2016). Selection of plant species used in wastewater treatment. In Wastewater treatment and reuse for metropolitan regions and small cities in developing countries (pp. 1–10). Publisher.

Volesky, B. (1994). Advances in biosorption of metals: Selection of biomass types. FEMS Microbiology Reviews (Amsterdam), 14 , 291–302.

Von-Sperling, M., & Chernicharo, C. A. L. (2005). Biological Wastewater treatment in warm climate regions (1st ed.p. 810). IWA Publishing.

Wani, A. L., Ara, A., & Usmani, J. A. (2015). Lead toxicity: a review. Interdisciplinary Toxicology, 8 , 55–64.

Webster, G. M. (2010). Chemicals, Health and Pregnancy Study (CHirP). Vancouver, BC: University of British Columbia, Centre for Health and Environment Research (CHER) and School for Occupational and Environmental Hygiene (SOEH). http://www.ncceh.ca/sites/default/files/Health_effects_PFCs_Oct_2010.pdf . Accessed Sept 2019.

Westcot, D. W. (1997). Quality control of wastewater for irrigated crop production. In In Chapter 2 - Health risks associated with wastewater use FAO Water Report (10th ed., p. 86).

WHO (1973) WHO meeting of experts on the reuse of effluents: Methods of wastewater treatment and health safeguards & World Health Organization. Reuse of effluents: Methods of wastewater treatment and health safeguards, report of a WHO meeting of experts [meeting held in Geneva from 30 November to 6 December 1971].

WHO. (1989) Health guidelines for the use of wastewater in agriculture and aquaculture. Technical Report Series No. 74. World Health Organization, Geneva.

WHO (2003).Copper in drinking-water. Background document for preparation of WHO Guidelines for drinking-water quality. Geneva, World Health Organization (WHO/SDE/WSH/03.04/88).

WHO-World Health Organization. (2006). Guidelines for the Safe Use of Wastewater, Excreta and Greywater . In Wastewater Use in Agriculture (2nd ed.). WHO-World Health Organization.

Winpenny, J., Heinz, I., Koo-Oshima, S., Salgot, M., Collado, J., Hernandex, F., et al. (2010). The Wealth of waste: The economics of wastewater use in agriculture. In Food and Agriculture Organization of the United Nations (p. 35). FAO Water Reports .

World Bank. (2010). Improving wastewater use in agriculture: An emerging priority (p. 169). A report of the Water Partnership Program.

World Resources Institute (WRI), (2020) Aqueduct country rankings. Available online: https://www.wri.org/applications/aqueduct/country-rankings/ Accessed 3 Sept 2020.

Xiao, R., Wang, S., Li, R., Wang, J. J., & Zhang, Z. (2017). Ecotoxicology and environmental safety soil heavy metal contamination and health risks associated with artisanal gold mining in Tongguan, Shaanxi, China. Ecotoxicology and Environmental Safety, 141 , 17–24.

Xu, Y. B., Hou, M., Li, Y. F., Huang, L., Ruan, J. J., Zheng, L., et al. (2017). Distribution of tetracycline resistance genes and AmpC β-lactamase genes in representative non-urban sewage plants and correlations with treatment processes and heavy metals. Chemosphere, 170 , 274–281.

Xu, S., Yan, N., Cui, M., & Liu, H. (2020). Decomplexation of Cu(II)/Ni(II)-EDTA by ozone-oxidation process. Environmental Science and Pollution Research, 27 , 812–822.

Yadav, R. K., Goyal, B., Sharma, R. K., Dubey, S. K., & Minhas, P. S. (2002). Post-irrigation impact of domestic sewage effluent on composition of soils, crops and ground water—A case study. Environment International, 28 , 481–486.

Yang, J., Jia, R., Gao, Y., Wang, W., & Cao, P. (2017). The reliability evaluation of reclaimed water reused in power plant project. IOP Conference Series: Earth and Environmental Science, 100 , 012189.

Yaqub, A., Ajab, H., Isa, M. H., Jusoh, H., Junaid, M., & Farooq, R. (2012). Effect of ultrasound and electrode material on electrochemical treatment of industrial wastewater. Journal of New Materials for Electrochemical Systems, 15 , 289–292.

Yuen, H. W., & Becker, W. (2020). Iron toxicity. [Updated 2020 Jun 30]. In: StatPearls [Internet]. StatPearls Publishing; Available from: https://www.ncbi.nlm.nih.gov/books/NBK459224/ .

Zahmatkesh, M., Spanjers, H., Jules, B., & Lier, V. (2018). A novel approach for application of white rot fungi in wastewater treatment under non-sterile conditions: Immobilization of fungi on sorghum. Environmental Technology, 39 (16), 2030–2040.

Zaman, S. B., Hussain, M. A., Nye, R., Mehta, V., Mamun, K. T., & Hossain, N. (2017). A review on antibiotic resistance: Alarm bells are ringing. Cureus, 9 , e1403.

Zamora, S., Marín-Muñíz, J. L., Nakase-Rodríguez, C., Fernández-Lambert, G., & Sandoval, L. (2019). Wastewater treatment by constructed wetland eco-technology: Influence of mineral and plastic materials as filter media and tropical ornamental plants. Water, 11 , 2344.

Zekić, E., Vuković, Z., & Halkijević, I. (2018). Application of nanotechnology in wastewater treatment. GRAĐEVINAR, 70 , 315–323.

Zhang, H., & Reynolds, M. (2019). Cadmium exposure in living organisms: A short review. Science of the Total Environment, 678 , 761–767.

Zhang, Y., & Shen, Y. (2017). Wastewater irrigation: Past, present, and future. Wastewater treatment: Aims and challenges. Water, 6 (3), e1234. https://doi.org/10.1002/wat2.1234 .

Article   Google Scholar  

Zhou, X., & Wang, G. (2010). Nutrient concentration variations during Oenantheja vanica growth and decay in the ecological floating bed system. Journal of Environmental Sciences (China), 22 , 1710–1717.

Zhu, L., Li, Z., & Ketola, T. (2011). Biomass accumulations and nutrient uptake of plants cultivated on artificial floating beds in China’s rural area. Ecological Engineering, 37 , 1460–1466.

Zimmels, Y., Kirzhner, F., & Roitman, S. (2004). Use of naturally growing aquatic plants for wastewater purification. Water Environmental Research, 76 , 220.

Download references

Acknowledgements

All the authors are highly grateful to the authority of the respective departments and institutions for their support in doing this research. The author VT would like to thank Science & Engineering Research Board, New Delhi, India (Grant #ECR/2017/001809). The Author RS is thankful to the University Grants Commission for the National Fellowship (201819-NFO-2018-19-OBC-UTT-78476).

Open access funding provided by Aalto University.

Author information

Kavindra Kumar Kesari and Ramendra Soni contributed equally to this work.

Authors and Affiliations

Department of Applied Physics, Aalto University, Espoo, Finland

Kavindra Kumar Kesari & Janne Ruokolainen

Department of Molecular and Cellular Engineering, Sam Higginbottom University of Agriculture, Technology and Sciences, Naini, Allahabad, India

Ramendra Soni, Jonathan A. Lal & Vijay Tripathi

Department of Health Informatics, College of Public Health and Health Informatics, Qassim University, Al Bukayriyah, Saudi Arabia

Qazi Mohammad Sajid Jamal

Department of Computational Biology and Bioinformatics, Sam Higginbottom University of Agriculture, Technology and Sciences, Naini, Allahabad, India

Pooja Tripathi

Department of Biotechnology, School of Engineering & Technology, Sharda University, Greater Noida, UP, India

Niraj Kumar Jha

Department of Bioengineering, Faculty of Engineering, Integral University, Lucknow, India

Mohammed Haris Siddiqui

Department of Forestry, NERIST, Nirjuli, Arunachal Pradesh, India

Pradeep Kumar

You can also search for this author in PubMed   Google Scholar

Corresponding authors

Correspondence to Kavindra Kumar Kesari , Mohammed Haris Siddiqui or Vijay Tripathi .

Ethics declarations

Conflict of interest.

The authors declare that they have no conflict of interest.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .

Reprints and permissions

About this article

Kesari, K.K., Soni, R., Jamal, Q.M.S. et al. Wastewater Treatment and Reuse: a Review of its Applications and Health Implications. Water Air Soil Pollut 232 , 208 (2021). https://doi.org/10.1007/s11270-021-05154-8

Download citation

Received : 12 January 2020

Accepted : 25 April 2021

Published : 10 May 2021

DOI : https://doi.org/10.1007/s11270-021-05154-8

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

  • Bio-computation
  • Environmental pollution
  • Human health
  • Sustainable agriculture
  • Find a journal
  • Publish with us
  • Track your research

COMMENTS

  1. (PDF) WATER POLLUTION-SOURCES,EFFECTS AND CONTROL

    WATER POLLUTION-SOURCES,EFFECTS AND CONTROL January 2016 Authors: Asha Gupta Manipur University Discover the world's research Content uploaded by Asha Gupta Author content Content may be...

  2. Frontiers

    Methods: This paper selected 85 relevant papers finally based on the keywords of water pollution, water quality, health, cancer, and so on. Results: The impact of water pollution on human health is significant, although there may be regional, age, gender, and other differences in degree.

  3. A Current Review of Water Pollutants in American Continent: Trends and

    In the case of the American continent, the detection of contaminants (inorganic and organic) has been studied; the research works show alarming results in which the impact of water pollution is demonstrated, how the ecosystem is being affected, and consequently the repercussion towards human health [ 5, 6, 7, 8 ].

  4. The widespread and unjust drinking water and clean water ...

    Using these two measures of poor water quality, we find 2.44% of community water systems, a total of 1165, were Safe Drinking Water Act Serious Violators and 3.37% of Clean Water Act permittees in ...

  5. Climate Change, Water Quality and Water-Related Challenges: A Review

    2.3. Water Pollution, Population and Water Quality. The world population is expanding, with a total of 7.4 billion in 2016, and is expected to increase in the upcoming decades . The eight most populous countries have a combined population of over 4.054 billion, which is expected to increase to 4.980 billion by 2050 (Table 2). With this increase ...

  6. Effects of pollution on freshwater aquatic organisms

    First published: 04 September 2019 https://doi.org/10.1002/wer.1221 Citations: 112 Sections PDF Tools Share Abstract This paper presents the reviews of scientific papers published in 2018 issues on the effects of anthropogenic pollution on the aquatic organisms dwelling in freshwater ecosystem at global scale.

  7. PDF Water: From Pollution to Purification

    This special issue WPP (Water: From Pollution to Purification) of Environmental Science and Pollution Research presents se-lected papers presented at the second International conference on Water: From Pollution to Purification (ICW2016) conducted during Dec.12-15, 2016, in Kottayam (Kerala, India) hosted jointly by Inter University Instrumentati...

  8. Water environment and recent advances in pollution control ...

    This special issue (SI) of Environmental Science and Pollution Research (ESPR) entitled "Water Environment and Recent Advances in Pollution Control Technologies" collected the best papers that were formally presented at "The 6 th International Conference on Water Resource and Environment (WRE2020)" from August 23rd to 26th, 2020.

  9. IOP Conference Series: Earth and Environmental Science PAPER OPEN

    1. Introduction: The study of water pollution is very important for most researchers and interested people. Its importance lies the fundamental changes that it makes in the lives of humans, animals, plants, soil, and the environment in general.

  10. Water pollution Its causes and effects

    The research centered on the study of the notion of pollution in general, then the notion of water pollution and its sources. In addition to groundwater contamination, there have been many pollution processes, the most important of which are biological, physical, and by dumping solid and liquid waste into waters of rivers, lakes and seas.

  11. [PDF] Water Pollution Research

    Water Pollution Research A. Parker Published in Nature 1 November 1932 Environmental Science THE growth of industry and of the population during the last century, especially in the north of England, gave rise to several undesirable conditions, including gross contamination of rivers, which in some cases became little better than open sewers.

  12. Frontiers

    While water quality is a complex issue and involves multiple disciplines, this review focuses on water quality with respect cation, metals and heavy metals in surface water, and their impacts on vegetables, soil, biodiversity, human health, toxic and socioeconomic effects. The river collects untreated and unmanaged domestic, industrial, and ...

  13. Water Pollution and its Sources, Effects & Management: A Case ...

    Water pollution is a national and global issue. Humans and all living species in the world are facing worst results of polluted water. The present study investigates the level of awareness about water pollution in Delhi, its causes, its health effects and solutions among the youth in Delhi.

  14. Wastewater Treatment and Reuse: a Review of its Applications ...

    Water scarcity is one of the major problems in the world and millions of people have no access to freshwater. Untreated wastewater is widely used for agriculture in many countries. This is one of the world-leading serious environmental and public health concerns. Instead of using untreated wastewater, treated wastewater has been found more applicable and ecofriendly option. Moreover ...

  15. Water pollution in India

    Volume 16, August 2022, 100119 Water pollution in India - Current scenario Niti B.Jadeja1, TuhinBanerji1, AtyaKapley, RakeshKumar Show more Add to Mendeley https://doi.org/10.1016/j.wasec.2022.100119Get rights and content Highlights • Scenario of wastewater treatment with respect to its discharge and reuse in India. •

  16. PDF Water Pollution: Causes, Consequences, Prevention Method and ...

    WATER POLLUTION Water pollution may be defined as alteration in the physical, chemical and biological characteristics of water which may cause harmful effects on human and aquatic life.(Report,1965,restoring the quality of our Environment, president science committee, Washington USA) Olaniran (1995) defined water pollution to be presence of exce...

  17. PDF MASTER THESIS

    world average (J. Liu & Yang, 2012). The water resources of China are affected by both severe water shortages and severe water pollution. Water demand and water pollution increased accompanying with the growing population and rapid economic development as well as lax environmental supervision. Every year, 190 million people in China fall

  18. PDF November 19, 1932] Nature 761

    The principal industrial effluents are those derived from coke ovens which contain tar acids, naphthalene, cyanide, etc., and spent pickle liquor, which is an acid solution of iron produced during ...