Water Resources Management for Rural Development: Challenges and Mitigation

Water Resources Management for Rural Development: Challenges and Mitigation provides an overview of the current challenges of rural water and its management strategies. The content contains practical and theoretical aspects of the water crisis in rural areas in a changing climate era, with an emphasis on recent water crisis research and management strategies. The book's structure contains fundamentals of water resources, pollution, remediation, supply and management strategies. Case studies included provide different water-related issues around the globe, introducing the reader to the paths of reducing the burden on the groundwater and the alternative options for the supply of water in rural areas.

Decision-makers and water supply authorities will benefit from this unique resource that comprehensively covers rural water management in ways no comparable book has achieved.

• Includes case studies that follow a consistent template, providing the reader with easy to find real-life examples
• Covers a wide spectrum of topics related to water resources as written by experts in their field
• Provides information on the identification of technologies and instruments required for the management of, and safe supply of, water

• Language: English
• Publisher: Elsevier Science
• Release date: Sep 29, 2023
• ISBN: 9780443187797

Book preview

Challenges in rural water management

1. Water pollution: Primary sources and associated human health hazards with special emphasis on rural areas 3

2. Water pollution in rural areas: Primary sources, associated health issues, and remedies 15

3. Water pollution in rural areas: Primary sources and associated health issues 29

4. Impact of climate change on rural water resources and its management strategies 45

5. Traditional methods of water purification in rural areas 55

6. Traditional techniques of water purification in rural areas 65

Chapter 1

Water pollution: Primary sources and associated human health hazards with special emphasis on rural areas

Krati Sharma, Shijin Rajan and Soumya Kanta Nayak

School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India

1.1 Introduction

Despite making up nearly 71% of the earth's surface, water is one of the scarcest commodities in the world. Only 2.5% of the world's total water resources are fresh water, and the remaining 97.5% of water consists of saline water. Out of that, around 87% of freshwater resources are stored in ice sheets, glaciers, and snow, followed by about 13% in the surface and sub-surface water (Hoogesteger & Wester, 2015). This 13% freshwater is only accessible for human consumption and economic needs (agricultural, domestic, and industrial) and sustains the freshwater aquatic ecosystem. Water has many uses, including drinking, domestic, agricultural, industrial, commercial, hydroelectric power, transportation, and recreational services (Igwe et al., 2017). Water resources are essential for supporting life and economic development, especially in rural areas. Water quality and quantity of an area are controlled by several factors, including precipitation, vegetation, climate, geology, soil type, flow conditions, and anthropogenic activities (Chaudhry et al., 2017). The quantity of water resources is important; at the same time, the quality is equally relevant and plays a significant role in sustainable water resource management. Globally, water scarcity is not only caused by physical shortage; a decline in water quality also leads to a substantial reduction in available safe water resources (Borah & Bera, 2004; Mateo-Sagasta et al., 2017).

Water pollution is a global concern as they pose a threat to humans, other organisms, and the climate and has the potential to alter the ecosystem dynamics. Water pollution is a qualitative term representing the condition when the levels of pollutants impede the desired use (Walker et al., 2019). Contamination of any water resources is considered water pollution, i.e., rivers, oceans, streams, lakes, and groundwater aquifers. Any changes in the chemical, physical, or biological properties of water resources lead to water pollution. Once a water resource is contaminated to a certain extent, water quality restoration becomes difficult and expensive. Water pollution has drastically increased in developed and developing nations, impacting billions of people's physical and environmental health and economic development. Water resources are contaminated by natural and anthropogenic activities that bring different organic and inorganic contaminants into the water system. Organic pollutants are majorly introduced by anthropogenic activities, which include agrochemicals, industrial effluents, domestic sewage, etc. Also, anthropogenic activities introduce emerging contaminants into the water system, such as pharmaceuticals, personal care products (PPCP), detergents, poly-fluorinated compounds, micro-plastics, etc., which impose a high risk to human health (Ajith & Rajamani, 2021). Inorganic pollutants are introduced by natural as well as anthropogenic sources, including geogenic processes; weathering, erosion, runoff, and other activities such as atmospheric deposition, biological contaminants, etc. (Ahamad et al., 2020). Global reports indicate that about 80% of municipal wastewater discharged into the water bodies is not treated. Additionally, industries dump millions of tons of toxic sludge, heavy metals, solvents, and other waste materials into the water bodies each year (United Nations, 2017).

The demand for water resources and water pollution has increased over time due to increasing population and related exploitation. Excess water resources have been used for agriculture, energy production, industrialization, urbanization, and improving living standards. Around 35% of the world's renewable freshwater resources are used for domestic, industrial, and agricultural purposes (Schwarzenbach et al., 2006). Global data reveals that approximately one-third of the global population lives in countries with moderate to high water scarcity. In addition, about 20% of the population worldwide lacks appropriate access to clean and safe water, and around 40% experience the effects of appalling sanitary conditions (UNESCO, 2003). Between the years 1900 to 1995, global freshwater consumption increased six folds, which is more than twice the rate of human population increase (Postel, 1997; UNEP, 2002). Hence, the coinciding of limited water resources with a growing population results in water scarcity in many parts of the globe. Constant use or exposure to polluted water can cause mild to severe health impacts in humans, ranging from carcinogenic to non-carcinogenic effects. Globally, about 14,000 people die every day due to water contamination and related diseases (Chaudhry et al., 2017). In addition, water-related diseases claim the lives of 1.5 million children under the age of five every year globally.

India has 2.4% of the global land, 18% of the global population, and only 4% of the global water resources. As India is one of the world's fastest-growing economies, there is a high demand for water supply and tremendous pressure on natural resources (water, soil, and air). India has one of the largest water resource systems in the Indo-Gangetic plain and Brahmaputra alluvial plain, which have high-yield aquifers (Mukherjee et al., 2015). The precipitation recharges the sub-surface water resource in different parts of India due to the southwest and northwest monsoon. Irrigation accounts for about 87% of freshwater resource use in the country, followed by domestic and industrial purposes (Mukherjee et al., 2015). Even though abundant water resources are available in the country, over-extraction and mismanaged water consumption lead to scarcity and drinking water shortage. The groundwater table in the country is shifting downward with time due to exceeding withdrawal rates than the recharge rates (Gleeson et al., 2012). In India, more than 70% of the freshwater resources are unfit for consumption (Dwivedi, 2017). Lack of adequate amount of water, poor sanitization, and hygiene lead to the loss of 400,000 lives per year in India.

Studies have revealed that urban civilization requires more water resources than rural areas, and the quality of water discharged in the urban regions worsens and is chemically more toxic (Bandy, 1984). However, water pollution in rural areas is in primary concern worldwide due to a lack of monitoring and studies. In rural areas, agriculture is the major profession of local communities and a source of income. Hence, water resources are highly contaminated due to excessive water abstraction for irrigation and the addition of agrochemicals. Globally, 70% of the water is abstracted for agriculture, which substantially leads to water contamination (Mateo-Sagasta et al., 2017). Agricultural farms discharge huge amounts of agrochemicals, drug residues, organic substances, sediments, and saline drainage into water bodies. Groundwater resources are over-exploited in rural areas for irrigation, substantially reducing groundwater tables and introducing geogenic contaminants. Leaching and infiltration from the agricultural field introduce various agrochemicals such as pesticides and fertilizers into the aquifers. Similarly, the agricultural field's erosion and runoff add agrochemicals to the surface water bodies. Also, increased livestock farming and aquaculture in rural water bodies are increasing the rate of water pollution in rural areas. However, small-scale industries, domestic wastes, waste dumping, sewages, etc., also lead to considerable water pollution in rural areas. The availability of clean and safe water in sufficient amounts and quality is a basic need; sustainable development will be impossible without that. The 2030 agenda for sustainable development acknowledges the significance of improving the water quality, drinking water, sanitation, and hygiene, and includes a specific water quality target in the sustainable development goal (SDG). To achieve the sustainable development goal for a better future, health, and safe water resources, there is an urgent need for proper monitoring, management, and protection of water resources in rural areas. This article intends to briefly discuss rural water pollution, investigate its primary sources, and major health impacts on rural communities, and elaborated on the key contaminants of concern in rural water health hazards. Such studies are necessary to address rural water pollution and related health issues as limited studies have only taken place in rural settings.

1.2 Types of water pollution

Natural waters are divided into groundwater and surface water. Groundwater exists beneath the earth's surface in the porous rock, whereas surface water exists above the surface in contact with the underlying terrestrial surface and atmosphere. Surface water includes rivers, lakes, streams, ponds, reservoirs, creeks, and oceans, each with unique characteristics. Hence the water resources are of different types, and the source of pollutants and the process involved also varies. The subsequent sections will discuss various sources, pathways, and mechanisms by which groundwater and surface water are being contaminated.

1.2.1 Groundwater pollution

Groundwater is the primary source of potable freshwater resources, which can be used for drinking, domestic, agricultural, and industrial activities. In 2003, groundwater contributed 50% of the drinking water supply, 40% to industrial, and 20% to irrigation (Foster et al., 2003). Globally, groundwater supplies 40% and 43% of the total water required for drinking and irrigation, respectively (Salman et al., 2018). One-third of the world's population uses groundwater for drinking (Pawari & Gawande, 2015). In rural areas, the ratio is higher; more than half of all drinking water is supplied from groundwater (Harter, 2003). Therefore, groundwater pollution is a major concern as most of the global population relies on groundwater for survival.

Deterioration in the adequate quality or introduction of any contaminants in groundwater is considered groundwater pollution. Groundwater pollution is a result of both anthropogenic and natural processes. Natural processes like geological weathering and aquifer characteristics primarily contribute to the inorganic constituents in groundwater, whereas anthropogenic activities also contribute significantly (Dixit et al., 2022). However, various anthropogenic activities mainly introduce organic pollutants into groundwater. Geogenic contaminants are the primary natural source of groundwater pollution in rural areas and were introduced due to the over-extraction of groundwater for irrigation purposes. Geogenic contaminants such as fluoride, nitrate, arsenic, iron, and other toxic metals are introduced into the groundwater by contacting the rocks, weathering, or during the percolation process (Madhav et al., 2021). The primary sources of anthropogenic contamination in rural groundwaters are the leaching and percolation of agrochemicals such as fertilizers and pesticides. Over-extraction of groundwater and groundwater pollution in rural areas can lead to poor drinking water quality, degrading surface water systems, high purification and alternative source cost, and potential health hazards. The global groundwater reserve is approximately 70,000 km³, and the global annual demand for water resources is between 6000 km³ and 7000 km³ (Dwivedi, 2017). Overexploitation and limited rainfall lowered groundwater resources and the water table replenishment. Hence, groundwater, a life-sustaining resource is facing extremely vulnerable situations in most countries, and predictions have indicated its lesser availability in the future.

1.2.2 Surface water pollution

Surface waters such as rivers, lakes, and streams are the most available and accessible water sources for domestic purposes in developing countries. The human population benefits from a wide range of services provided by surface water sources, including drinking, irrigation, recreation, power generation, and habitat for fisheries with significant economic value. Surface waters are majorly contaminated with agricultural, industrial, and domestic wastes through direct dumping and runoff. Surface water and sediments substantially contribute to assimilating pollutants from agricultural runoff and municipal and industrial wastewater discharge. Rural aquaculture in surface water bodies has introduced an enormous amount of chemicals and organic contaminants into the water. This may lead to eutrophication and dying of water bodies. Seventy percent of the surface water in India is unsuitable for human consumption (Martin, 1998). It is estimated that about 40 million liters of wastewater in India are discharged into rivers and other surface water bodies. Only a small fraction is adequately treated before discharging (World Economic Forum, 2019). According to the World Bank report, such releases of pollutants upstream can lower the economic growth in the downstream area. It can cause a 16% reduction in downstream agricultural yield and a 9% decrease in agricultural revenue. Moreover, 351 river stretches across India are identified as polluted, among which Maharashtra has the highest number of polluted river stretches (CPCB, 2018).

Rural river pollution in India is primarily due to agricultural runoff and erosion, discharge of industrial effluents, partially or untreated treated sewage, and dumping of solid wastes (Singh et al., 2023). Despite the nation's sewage treatment capacity of 31,841 million liters per day (MLD), urban areas generate about 72,368 MLD of sewage (CPCB, 2021). Globally, many rural communities are identified to be in threat of polluted surface water resources. About 15% of the rural population in South Africa relies on contaminated river water for domestic purposes (Rapu, 2003). About 70% of the people in Sudan rely on a surface water supply, which is highly contaminated by agrochemicals and untreated industrial effluents (Khalil, 2005). Similarly, 40% of people in Nigeria rely on contaminated surface water or wells for their basic needs (Shuaib, 2007).

1.3 Primary sources

Water is a widely distributed natural substance and a constantly recharging resource on the earth. We think water resources are infinite and bountiful, but it is a finite resource. Any changes in its natural characteristics and distribution can have devastating environmental impacts. Under the pre-conceptions of natural properties of water to retain the quantity and quality for a longer period, tradition has arisen of a carefree attitude towards the usage of water resources. Water pollution may come from a point or non-point source; point sources are single identifiable sources such as discharge from an industry or a sewage plant, whereas non-point sources do not originate from a single source; instead, they may come from various sources. The primary source of water quality degradation can either be of natural or anthropogenic origin, directly impacting human health, agricultural output, and a country's economy (Raju et al., 2009). Each primary water pollution source is illustrated in Fig. 1.1 and discussed detailed in the below section.

Figure 1.1 Figurative representation of major natural and anthropogenic sources of water pollution.

1.3.1 Natural sources

1.3.1.1 Geogenic

In water bodies, the excess presence of naturally occurring elements can cause potential human health hazards are referred to as "geogenic pollution." Dissolution and weathering of minerals or rocks are dominant mechanisms responsible for adding geogenic contaminants into the water. Several parts of India are affected by the geogenic contamination of fluoride and arsenic, which is still a severe health issue and a continuing obstacle to providing clean safe drinking water. The background concentration of each element in the aquifer depends on the geological formation, climatic conditions, ion exchange processes, and past and present vegetation cover around the vicinity (Foster et al., 1999). High concentrations of elements, including salinity, iron, manganese, uranium, radon, and chromium, may also have geogenic origins in groundwater (Etikala et al., 2021). These pollutants may enter the surface waters due to subsurface recharge, erosion, and runoff.

1.3.1.2 Atmospheric deposition

Atmospheric deposition is a primary source of pollutants (gases, particulates, metals, nutrients, etc.) to the terrestrial and aquatic environments. Atmospheric deposition of pollutants can occur through dry and wet deposition. Via atmospheric deposition, pollutants can carry from longer distances and distribute into broad uncontaminated areas. Likewise, urban pollutants may be introduced to rural areas through atmospheric deposition. The health of people, animals, and the ecosystem can be adversely affected by the atmospheric deposition of pollutants. The deposition of sulfur and nutrients may contribute to the acidification and eutrophication of various water bodies (Shi et al., 2021). Once pollutants are deposited on the water's surface, they are assimilated in water and sediments for longer. Either these pollutants are directly ingested by biota, or in the case of acidifying pollutants, it accelerates the leaching of soil base cation, metals, and plant nutrients. Pollutants can also be moved from their original deposition sites through groundwater fluxes, surface runoff, and soil erosion. Pollutant uptake and toxicity in biota can be impacted by physical, chemical, and biological factors.

1.3.1.3 Erosion and runoff

Majorly, three processes; soil loosening, transport, and deposition are defined as soil erosion. The topsoil rich in organic matter, nutrients, and soil life is typically removed due to these activities. At the same time, these eroded materials may transport and deposit in some other regions, especially in surface water bodies (Shi et al., 2012). The mechanisms of soil erosion have an impact on how much water the soil can hold, how quickly water flows over the soil, and how quickly water travels below the surface. Rainfall is one of the leading causes of soil erosion because it erodes the soil, moves it from its natural position, and then washes it away as runoff. The impact of soil erosion can be very significant, not only in reducing soil productivity but also in depleting water quality. As a result of sediment buildup in lakes and rivers, light cannot easily pass through the water. So, aquatic plants that require sunlight for photosynthesis are impeded by this. Sediments are also a good source of nitrogen and phosphorus. These nutrients promote excessive algae growth and it can affect the natural processes occurring in water bodies. Plant growth, agricultural productivity, water quality, and recreation are all negatively impacted by soil erosion. Considering that it happens naturally in all areas, it is a significant factor in soil and water quality degradation (Posthumus et al., 2015).

The surplus liquid travels across the surface of the land before draining into nearby creeks, streams, or ponds. Runoff can result from human actions as well as natural phenomena. Additionally, runoff happens naturally as soil erodes and is moved to different bodies of water. Even harmful substances are carried into streams by natural events like volcanic eruptions. Volcanic gases eventually make their way back into the water or land as precipitation.

1.3.1.4 Water pathogens

Pathogen contamination is present in all forms of ambient water bodies, and it is crucial to recognize and comprehend this problem (USEPA, 2012). Water pathogens primarily enter the water bodies through a lack of sanitization, hygiene, and infrastructure in rural areas. Especially through open defecation, leakage of sewers and septic systems, open dumping, and introduction of animal wastes. Worldwide, a major water quality concern is the contamination of ambient water bodies with waterborne pathogens and their associated diseases. Numerous outbreaks have been driven by waterborne illnesses such as diarrhea, vomiting, nausea, and gastrointestinal disorders by different waterborne bacteria, viruses, and protozoa (Craun et al., 2006).

1.3.2 Anthropogenic sources

Expanding human population increased the demand for food supply, leading to an expansion in the irrigated agricultural area, increased demand for water supply, and the use of chemical fertilizers and pesticides. Maintaining the demand can increase the probability of contaminating water resources rapidly. Other than agricultural sources, small-scale industries, domestic wastes, sewage, open dumping, solid wastes, mining, etc., lead to considerable water contamination in rural areas (Ahamad et al., 2020). Water basins can get naturally revived either by rainfall or sub-surface recharge, but the processes are slow compared to the extraction rates. If the extraction rate exceeds the revival rate from a particular groundwater basin, the aquifer is said to be mined, which can lead to disastrous consequences. Anthropogenically induced chemicals, hazardous wastes, effluents, and treated/untreated waste discharged into the aquatic system degrade the ecosystem and cause potential human health impacts.

1.3.2.1 Agricultural activities

Pollution in the ground and surface water has increased steadily due to extensive agricultural activities worldwide (Kumazawa, 2002; Parween et al., 2021). In rural areas, agriculture is the primary source of income as well as the major source of water contamination. The use of chemical fertilizers and pesticides has extremely increased to enhance production and meet the food demand. Since 1970, the world population has increased by 78%, and fertilizer use raised to 120% (Galloway et al., 2008). It anticipates that one billion hectares of natural habitat, primarily in developing countries, will need to be converted for agricultural production to maintain the demand and supply in the future. As a result, the amount of nitrogen and phosphate inputs may double or triple, the amount of water required may increase by two-fold, and the amount of pesticides used may be threefold (Hole et al., 2005). As the population increases, the excess demand for food and energy continues, and the amount of reactive nitrogen created, and the magnitude of the consequences will also be increased. India consumes around 14 million tons of fertilizers per annum, of which more than 75% are nitrogenous fertilizers (Pathak, 1999). Consumption of nutrient fertilizers (N + P2O5 + K2O) worldwide was estimated to reach 186.9 million in 2014, up by 2% over 2013. World demand for nutrient fertilizers was calculated to increase by 1.8% per annum from 2014 to 2018 (Gutiérrez et al., 2018), and it was expected to reach 200.5 million by the end of 2018. During this period, the demand for nitrogen, potassium, and potash was estimated to grow annually by 1.4%, 2.2%, and 2.6%, respectively. The researcher also finds that the global capacity of fertilizer products, intermediates, and raw materials will increase in the upcoming years. The overall increased demand for nitrogen fertilizer was 630 million between 2014 to 2018, with 58% from Asia (mainly China 18% and India 17%), 22% from America (a major portion coming from Latin America 18%), 11% from Europe (mainly east Europe and Central Asia 9%), 8% is from Africa, and 1% from Oceanic. The intensive use of fertilizers causes the depletion of resources and the environment (FAO, 2018). Pesticide accumulation in the water system and the food chain has a detrimental effect on humans and animals, which prompted the global ban on persistent pesticides like DDT and organophosphates. However, some such pesticide is still in use in poor countries and cause acute and chronic health effects. Such pollution leads to health risks for infants to adults, global acidification, and stratospheric ozone loss. The pace at which pollutants and nutrients are released into the aquatic environment has grown due to the overuse of agrochemicals. Increased nutrient levels in the aquatic system may cause eutrophication, increased water turbidity, oxygen depletion, coral reef destruction, and high marine life susceptibility (Kalff, 2002; Nazneen et al., 2022).

1.3.2.1.1 Livestock

Livestock farming and raising animals is a common practice of livelihood around the world. Domesticated animals rose to produce commodities such as meat, milk, egg, fur, leather, and wool. It is common in rural and suburban areas in developing nations to do animal husbandry for consumption or commercialization. The livestock population in only Rajasthan's rural areas is 1.62 million (Suthar et al., 2009). Somasundaram et al. (1993) and Tellam (1993) studied the pollution status in the watersheds of Madras, India, and observed that animal farming (several oxen, cows, and buffaloes) is the primary source of water pollution. Dung, excreta, and urine of animals are rich sources of contaminants such as nitrate, potassium, and pathogens (Sankararamakrishnan et al., 2008). They reach the aquifers through stormwater channels or river recharge basins. The improper management of manure and animal waste results in the leaching and infiltration of contaminates from the soil to streams and aquifers. In the last 10 years, veterinary drugs have become a brand-new agricultural pollutant class (antibiotics, vaccines, and growth promoters).

1.3.2.1.2 Aquaculture

Aquaculture has been a fast-growing industry because of the sharp rises in global demand for fish and seafood, and it is experiencing rapid growth. Compared to other animal culture industry segments, it is expanding more quickly (Gang et al., 2005). Aquaculture is more prominent in rural water bodies like ponds, lakes, wetlands, etc., and inland aquaculture using artificial ponds is also booming in rural areas. The usage of antibiotics, fungicides, and anti-fouling chemicals has also increased in aquaculture, leading to pollution in downstream ecosystems. Aquaculture wastes contaminate and potentially threaten the water system and the surrounding aquatic ecology. Aquaculture may worsen the environment, but ironically, it still depends on the availability of clean waterways. Aquaculture production is dominated by traditional farming approaches in many rural regions (such as extensive pond farming), although these are now gradually being displaced by intense western-oriented techniques. An intensive mariculture system's rapid scale expansion is frequently associated with adverse environmental effects. As throughput-based systems, intensive fish and shrimp aquaculture have a constant or intermittent release of nutrients that contributes to eutrophication (Troell et al., 1999). These contaminants may leach into the nearby aquifers and contaminate the groundwater.

1.3.2.2 Other sources

1.3.2.2.1 Leakage from septic tanks and sewer lines

Many regions worldwide face water contamination problems related to damaged sewer lines, septic tanks, and cesspits. In rural areas, such amenities are still missing, especially sewer lines and septic tanks, and are disposed of openly. They are the main source of sulfate, chloride, and nitrogen contamination in various water systems in rural areas (Eiswirth & Hötzl, 1997). Leakage of sewer lines and water supply networks in urban areas around the world accounts for the biggest proportion of water recharge to aquifers (Yang et al., 1999). The leakage is due to improper installation of sewer lines and water supply systems, cracks, and joint defects. Underground sewer leaks naturally develop over time, and the leak-outs gradually enter the water system and deteriorate the water quality (Ly & Chui, 2012). Since many people lack access to clean water and sanitary conditions, sewage disposal is a serious issue in rural areas. One percent of the nation's useable aquifers are contaminated by septic tanks (USEPA, 1980). In freshwater environments, sewage pollution increases the concentration of pathogens, which are thought to be responsible for potential waterborne health hazards to humans annually. Additionally, sewage contamination makes heavy metal toxicity more common in humans and fish (Alves et al., 2014). Sewage discharge causes dangerously low oxygen levels in freshwater environments because of the use of available oxygen for breaking down organic matter.

1.3.2.2.2 Solid waste disposal

Solid waste management is a worldwide challenge, especially due to the growing population, waste generation, and unsustainable developmental activities. Proper solid waste management is lacking in many parts of the world, especially in rural areas. People still practice open dumping instead of appropriate solid waste management in rural areas. Lack of awareness and infrastructural development is the major cause in rural settings. Improper disposal of solid wastes can introduce various chemical contaminants into the environment, especially into the water systems, including lead, copper, cadmium, manganese, nitrate, phosphate, etc. These contaminants may leach into aquifers and contaminate the groundwater. Direct dumping of solid wastes in surface water bodies results in the accumulation of toxic substances in the food chains, especially toxic chemicals such as mercury, cyanides, and polychlorinated biphenyls (PCBs). Improper solid waste disposal can lead to the discharge of storm water into the aquatic system, and storm water is a great source of N and P in the aquatic environment (Odell, 1994). Poor solid waste management in rural areas could cause potential health hazards for humans and animals, which in turn causes losses in terms of economy, environmental health, and biological diversity in most developing countries. Another high-risk population includes individuals who live close to waste dumps as their water supply may get contaminated due to garbage dumping or landfill leaks. This may increase the risk of illness and infection in the community.

1.3.2.2.3 Land use and land cover (LULC)

The land is one of the primary natural resources. An area's development does not only depend on population density but is also measured by alteration in spatial dimensions. The conversion of land from one land type to another and the alteration of land cover have significantly impacted a sizable section of the earth's land surface. The natural process of land transformation cannot be stopped, but it can be regulated. Whether positive or negative, all land uses have an impact on the quality of the water. The majority of rainfall soaks into the soil rather than evaporating in forests and other vegetated places with little human disturbance, which also have constant stream flows and good water quality. In paved and built-up areas, little rainfall seeps into the soil, resulting in an excessive runoff, stream flow with high peaks and low flows in between, and decreased water quality. In rural areas, a large proportion of land is converted for agricultural and developing activities. Additionally, land-use changes brought on by industrialization, urbanization, and agriculture can influence the watershed's surface features, affecting the quantity and quality of runoff (Tu, 2011). Such activities demand massive deforestation and ultimately impact an area's water infiltration, erosion, runoff, and ecosystem dynamics.

1.4 Potential health hazards

Water pollution has severe impacts on human health. According to the UNESCO (2021), over 829,000 people die each year from diarrhea led by poor hand hygiene, sanitation, and drinking water. Among them, about 300,000 are children under the age group of five, representing 5.3% of total death. In many nations around the world, groundwater is the main supply of water for household, agricultural, and industrial uses (Naik et al., 2008; UNESCO, 2004). Due to its widespread distribution, affordable construction costs, and high quality, groundwater is a primary source of drinking water for most rural residents. Yet anthropogenic activities have considerably deteriorated the quality and availability of groundwater. Except for groundwater, rural communities worldwide are exposed to a higher level of water pollution due to the consumption of untreated surface water. Discharge of large amounts of untreated domestic sewage into the river, hazardous substances, solid waste, plastic litter, runoff from agricultural fields, and bacteria are the primary source of waterborne illnesses (Haseena et al., 2017). Population growth has increased waste generation and its discharge into the rivers and other water bodies in rural areas, which is harmful to human health.

Heavy metals are the elements naturally present in the earth's crust and are a major concern for human health as they contaminate the groundwater, surface water, and soil (Ajith et al., 2020). The heavy metals are introduced into the water environment naturally by weathering and decomposition of rocks or via human-made activities (Jafari et al., 2018). The major heavy metals found in the water environment are arsenic (As), chromium (Cr), lead (Pb), cadmium (Cd), molybdenum (Mo), copper (Cu), zinc (Zn), nickel (Ni), and barium (Ba). Similarly, in rural areas, the primary health hazard is due to agrochemical contamination, especially chemical fertilizers and pesticides. Agrochemicals are widely identified in rural waters, groundwater due to leaching, and surface waters due to runoff and erosion from the agricultural field. The major pesticides identified in rural waters are organochlorine (OCPs) and organophosphate (OPPs) compounds, especially DDT, HCH, endosulfan, drins, atrazine, etc. Once these contaminants are entered the water environment, they reach the human body through various pathways like inhalation through the nose and mouth, direct ingestion, and dermal contact (Sardar et al., 2013). Long-term consumption of polluted water could cause potential health risks to humans. It can cause extensive damage to human health due to its toxicity, bioaccumulation, and poor biodegradability. In addition, it can accumulate in human body tissue over time owing to exposure, posing significant health risks to the brain, kidneys, liver, and bones (Kamunda et al., 2016). Health risk assessment is a method followed by researchers to estimate the exposure of these contaminants to the human body and evaluate the probable health impacts of the water environment (Sharma et al., 2022). According to studies, drinking water pollution is to blame for 70% of all diseases and 20% of all cancer cases worldwide (WHO, 2020). Carcinogens are the agents or compound that causes cancer. There are several metals and other cancer-causing pollutants, and prolonged exposure to these can cause cancer and even death. Major contaminants in concern to rural water health hazards have been discussed below.

1.4.1 Chemical contaminants

1.4.1.1 Nitrate

In the subsurface, nitrate is one of the most prevalent contaminants because it easily percolates through soil (Chen et al., 2016). In rural areas, high nitrate contamination in groundwater is reported due to the excess use of nitrogen-bearing fertilizers in agricultural fields (Singh et al., 2006). Drinking water with a higher nitrate concentration can cause various human health disorders, namely hypertension, birth malformations, and even gastric cancer (Majumdar & Gupta, 2000). Long-term consumption of high levels of nitrate-contaminated water reduces the oxygen-carrying capacity leading to methemoglobinemia, i.e., Blue Baby Syndrome, seen particularly in infants below 6 months of age. Additionally, long-term consumption of nitrate-contaminated water has been linked to thyroid, colorectal, breast, and neural tube abnormalities. Nitrate consumption results in the endogenous synthesis of N-nitroso compounds (NOC), which have the potential to cause cancer. Studies also have reported that early life exposure to nitrogen-related pollution leads to low birth weight, shorter height in adulthood, and even infant mortality. Low birth weight can lead to coronary heart disease, decreased glucose tolerance, and an increased mortality rate. According to a recent study (Ahada & Suthar, 2018), chronic toxicity is more likely to affect 93.42% of adults and 100% of children in Malwa (a rural area in the Punjab district) as a result of excessive NO3 intake.

1.4.1.2 Fertilizers and pesticides

Pesticides cause severe health impacts due to their rapid fat solubility and tend to bioaccumulate. It has been reported that even small concentrations of pesticides can have various adverse consequences at biochemical, molecular, and behavioral levels (Anju et al., 2010). Over the past 20 years, there has been a sharp increase in the use of nitrogen-containing herbicides and fertilizers in rural regions, which has contaminated the nearby surface and groundwater. Consumption of these contaminants creates various health hazards to the rural community ranging from chronic neurotoxicity to lung damage and infant methemoglobinemia. In addition to these different types of cancers, especially hematopoietic cancer, immunological disorder, and adverse reproductive and developmental disorders have been reported (Sankhla et al., 2018). According to studies, drinking water tainted with herbicides has increased the incidence of breast cancer in Kentucky (Kettles et al., 1997) and low birth weight infants born as a result of water tainted with herbicides. Furthermore, due to pesticide contamination in drinking water, males in rural areas had lower sperm counts than those in metropolitan areas (Sankhla et al., 2018). In general effects of pesticides on human health can be linked to immune system deficiencies, pulmonary and hematological morbidity, and levels of oncological disease due to contaminated water ingestion (WHO, 2010).

1.4.1.3 Arsenic (As)

The earth's crust naturally contains arsenic, which is also extensively found in the air, water, and soil. Arsenic in its inorganic form is considered to be extremely toxic. The inorganic form of arsenic is exposed to humans through consuming contaminated water and food (Raju, 2022). Arsenic poisoning can become chronic if consumed over an extended period. Skin disease and even skin cancer are the common health impacts of arsenic contamination. Exposure to arsenic during early childhood negatively impacts cognitive development and is the primary cause of increased death in young adults. Bangladesh, India, China, Argentina, Chile, the United States of America, and Mexico are among the nations where high levels of arsenic have been found in groundwater. The main sources of arsenic exposure in these nations are drinking water, food made using arsenic-affected water, and crops grown using contaminated water. Besides contaminated groundwater, fish, dairy products, meat, and poultry can also be the source of arsenic but are comparably low. The early symptoms of arsenic poising are vomiting, abdominal pain, and diarrhea. If not diagnosed, it leads to numbness, muscle cramps, and even death in extreme cases. Long-term exposure to high levels of arsenic causes skin changes in pigmentation and hard patches on the palms and soles of the feet (Hyperkeratosis), which can progress to skin cancer. Long-term exposure to arsenic can also result in bladder and lung cancer. Arsenic in drinking water has been classified by the International Agency for Research on Cancer (IARC) as human carcinogenic. Besides cancer, long-term consumption of arsenic also causes cardiovascular disease, pulmonary disease, and diabetes. Blackfoot disease is a severe case of blood vessels leading to gangrene reported in China due to arsenic contamination. Arsenic contamination is also associated with young adult infant mortality and lung diseases. Additionally, it has been claimed that consuming excessive amounts of arsenic from groundwater over time causes bronchiectasis, skin cancer, bladder cancer, and arsenicosis. Additionally, 230 million people worldwide and 180 million in Asia are at high risk of developing arsenic poisoning, with South Asian countries being the most afflicted (Shaji et al., 2021). In India, rural areas of West Bengal, Bihar, Jharkhand, Uttar Pradesh, Chhattisgarh, Manipur, and Assam are the worst affected states by arsenic contamination, which cause potential health hazard risk to humans.

1.4.1.4 Fluoride (F−)

Fluoride is naturally occurring in the water bodies as a result of weathering and runoff from fluoride-bearing rocks. Similarly, atmospheric deposition of fluoride-containing emissions from coal-fired power plants, small-scale industries, and agrochemicals introduce fluoride into rural water bodies. Fluoride is an essential compound for human health, but when exposed to higher concentrations, it leads to a severe disease called fluorosis, categorized as skeletal and dental fluorosis. In addition, it also impacts the human organs/systems like the cardiovascular, endocrine, renal, gastrointestinal, brain, and reproductive systems . Additionally, it has been observed that fluoride contamination in drinking water can cause infertility, hypertension, arthritis, and liver, kidney, and lung tissue damage, as well as hypertension. In a rural community with limited access to safe drinking water, prolonged consumption of fluoride-contaminated water can affect the teeth, bones, and joints, including knees, hips, back, and neck, and may lead to reduced mobility. Further, the bones become stiffer, causing severe pain and may lead to permanent disability (Del Bello., 2020). Countries like the United States, China, Saudi Arabia, India, Australia, Pakistan, South Korea, Indonesia, Sri Lanka, Iran, Turkey, Mexico, and Canada are worst affected by fluoride contamination in groundwater (Solanki et al., 2022). Fluoride pollution has been documented in 230 districts across 20 states in India.

1.4.2 Microbial contaminants

The World Health Organization (WHO) states that pathogenic bacteria cannot be found in drinking water (Gorchev & Ozolins, 2011). However, in a rural area where a large population depends on groundwater for daily activities, the water source is susceptible to contamination from micro-bacterial sources (Bogena, 2015). Especially in rural areas, these contaminations cause many water contamination-related illnesses like cholera, dysentery, and typhoid fever. Most micro-bacterial contaminants are produced by the fecal source/gastrointestinal wall of warm-blooded animals, including humans. The presence of Escherichia coli and salmonella are typically signs of fecal contamination (Odonkor & Ampofo, 2013). Many rural areas in developing countries lack access to sewerage systems and efficient municipal waste disposal, which severely pollutes their surroundings and causes microbial contamination. Some people may be aware that wastewater can include a variety of toxins, while others may not be aware that untreated wastewater serves as an ideal habitat for various human infections (Raja et al., 2015). However, multiple studies show that untreated urban wastewater contains dangerous microbes; if they get into surface and groundwater sources, they could cause disease outbreaks (Pandey et al., 2014; Rivera-Jaimes et al., 2018).

Conclusion

The importance of groundwater is ever-increasing all around the globe, especially in countries like India where agriculture is practiced extensively. Groundwater supply is immensely important in both the urban and rural areas of developing nations. Each organism depends on the presence of water resources to survive. From the human perspective, water resources are vital for their existence and economic development. The lack of accessible freshwater and water scarcity is prominent around the world. Global water scarcity results from a physical shortage of resources and a decline in quality. Water resources have widely deteriorated and been polluted all around the world. Irrespective of water resource types, groundwater and surface water has been highly polluted to an extent where water quality cannot reinstate. Both natural and artificial sources cause water contamination, but the degree of anthropogenic pollution is exceptionally severe and intolerable. Water pollution in rural areas has been increasing over the past few decades, but very few studies have been conducted on rural water pollution. People residing in rural areas are mainly dependent on natural water resources, so it is important to have clean water. The availability of safe and potable water in the rural region continues to be a distant dream for the rural population, mainly in developing nations. In rural areas, the origin of water pollution includes, run-off from agricultural land containing substances including pest control products, animal medicines, slurry, sewage sludge, and manure. Excessive groundwater abstraction for irrigation and agrochemicals used for farming are considered primary sources of water pollution in rural areas. It is recommended that regular monitoring is important for sustainable groundwater management and long-term protection of water quality from depletion.

• The poor water quality zone in rural areas must be properly treated before being subjected to drinking and other purposes.

• Due to the lack of proper education and awareness related to water quality, the probability of potential human health hazards increases immensely in rural areas. Awareness programs should be conducted mainly in rural areas to aware the local community regarding water pollution and water quality.

• Unauthorized extraction of groundwater should be prohibited for irrigation and commercial uses.

• The increasing population led to an enormous rise in waste generation, it has to be controlled and properly disposed of.

• It is vital to optimize the use of agrochemicals and reduce the dependency on chemical pesticides. And there is a need to implement an eco-friendly agricultural model and develop agroecological practices in rural settings.

• Rainwater harvesting and water recycling practices should be adopted to mitigate the effects of scarcity. It can be a good alternative source for irrigation and domestic purposes.

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