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Global Status of Nitrate Contamination in Groundwater: Its Occurrence, Health Impacts, and Mitigation Measures

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Abstract

Nitrate has emerged as one of the most alarming and widespread contaminant of groundwater and surface water resources reported around the globe. Nitrate formation is an integral part of nitrogen cycle and is added either by the natural processes (atmospheric fixation, lightning storms) or through anthropogenic activities (fertilizer applications, septic tanks). Nitrate enters the hydrosphere easily, and its ingestion causes various health risks such as methemoglobinemia, cancer, diabetes, etc. on humans and to some extent on livestock populations as well. Agricultural practices and subsequent fertilizer application along with other anthropogenic activities are assumed to be the primary reason behind elevated levels of nitrate in groundwater. However, even under the similar ecological conditions, the reported occurrence of nitrate in groundwater is sporadic in nature, indicating the possible interference from other complex factors (including geogenic factors) and a dynamic release mechanism. Various concepts for the different sources and occurrence of nitrate in groundwater along with its health impacts are discussed in this chapter. Several existing and upcoming technologies are there to remove excess nitrate from potable water; these are also discussed in the chapter.

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... Most septic tanks have leakage problems in developing countries, directly contributing to nitrate leaching into the groundwater. Open defecation practices are also reported for the contamination of nitrate in groundwater systems (Shukla and Saxena, 2018). Waste generated from diaries, live stocks, faecal from livestock farming, cattle population, feedlots, and other poultry system is a potent source of nitrate inputs into groundwater (Serio et al., 2018). ...
... Various anthropogenic interventions, such as cutting down trees, result in the leaching of nitrogenous compounds. These compounds are further transformed into convertible forms of nitrogen such as nitrate, nitrite which easily migrate to the groundwater (Shukla and Saxena, 2018). ...
... During lightning storms, the atmospheric nitrogen is first transformed into ammonia and later to nitrate, which deposits on the soil through different precipitation and rainfall modes (Shukla and Saxena, 2018). ...
Article
Nitrate pollution is eminent in almost all the developing nations as a result of increased natural activities apart from anthropogenic pollution. The release of nitrates in more than critical quantities into the water bodies causes accretion impacts on living creatures, environmental receptors, and human vigour by accumulation through the food chain. Nitrates have recently acquired researchers' huge attention and extend their roots in environmental contamination of surface and groundwater systems. The presence of nitrate in high concentrations in surface and groundwater triggers several health problems, for instance, methemoglobinemia, diabetes, eruption of infectious disorders, harmfully influence aquatic organisms. Sensing nitrate is an alternate option for monitoring the distribution of nitrate in different water bodies. Here we review electrochemical, spectroscopic, and electrical modes of nitrate sensing. It is concluded that, among the various sensors discussed in this review, FET sensors are the most desirable choice. Their sensitivity, ease of use and scope for miniaturization are exceptional. Advanced functional materials need to be designed to satiate the growing need for environmental monitoring. Different sources of nitrate contamination in ground and surface water can be estimated using different techniques such as nitrate isotopic composition, co contaminants, water tracers, and other specialized techniques. This review intends to explore the research work on remediation of nitrate from wastewater and soil using different processes such as reverse osmosis, chemical denitrification, biological denitrification, ion exchange, electrodialysis, and adsorption. Denitrification proves as a promising alternative over previously reported techniques in terms of their nitrate removal because of its high cost-effectiveness.
... Nitrate is one of the most common contaminants in drinking water worldwide. 1 Contamination results primarily from animal manure and the use of nitrogen fertilizers. It is of particular concern to communities that have intensive animal farming and extensive use of ...
... Our findings were unchanged when we restricted our analyses to children of mothers who had average exposures that were below the current EU standard of 50 mg/L nitrate, which is nearly equivalent to the US Environmental Protection Agency standard of 44 mg/L. 1 Our findings add to mounting evidence that the current nitrate in drinking water standards may not be sufficient to prevent an increased risk of BD and other adverse birth outcomes. 1 The U.S. EPA's MCL for nitrate in drinking water is 10 mg/L measured as nitrogen (NO 3 --N). ...
... Our findings were unchanged when we restricted our analyses to children of mothers who had average exposures that were below the current EU standard of 50 mg/L nitrate, which is nearly equivalent to the US Environmental Protection Agency standard of 44 mg/L. 1 Our findings add to mounting evidence that the current nitrate in drinking water standards may not be sufficient to prevent an increased risk of BD and other adverse birth outcomes. 1 The U.S. EPA's MCL for nitrate in drinking water is 10 mg/L measured as nitrogen (NO 3 --N). The EU standard is based on measurement of the whole nitrate ion (NO 3 -). ...
Article
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Background A few studies have reported an increased risk of birth defects (BD) with maternal exposure to nitrate in drinking water. We examined this association in a large cohort study with well-characterized exposure. Methods Danish singletons liveborn to Danish-born parents from 1991–2013 were identified using civil and patient registries (n=1,018,914). Exposure to nitrate was estimated using a spatial model based on national data linked with individual addresses. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression. Findings In total, 33,182 cases of BD were identified. Nitrate concentrations were generally well below US and EU standards. We observed an exposure-response relationship (p=0·004) between nitrate during pregnancy and eye BD, and increased risk in the highest exposure group (≥25 mg/L nitrate) (OR: 1·29; 95% CI: 1·00, 1·66). An interaction was observed between maternal age and continuous nitrate exposure for nervous system BD (p<0·001) indicating an increased risk among mothers <25 years-of-age (OR for 10 mg/L (OR10): 1·20; 95% CI: 1·06, 1·35). An interaction (p<0.01) with maternal age and continuous nitrate exposure was also observed for ear, face, and neck BD indicating an increased risk among babies born to mothers <25 years-of-age (OR10: 1·35; 95% CI: 1·11, 1·66). There was evidence of an inverse exposure-response relationship for any, digestive system, female genital, and urinary BD. Interpretation Our study is the first to report an association between nitrate and eye BD and BD of the ear, face, and neck. It also provides support to prior reports of increased risk of nervous system BD. Funding This study was supported by a grant from the United States National Institute of Environmental Health Sciences (R01 ES027823-01A1).
... In another context, the water is affected by the anthropogenic pollution derives from the excessive use of fertilizers, pesticides and the incorrect management of animal and rural sewage that end up being deposited in groundwater (Wang et al. 2016;Daud et al. 2017;Serio et al. 2018;Amano et al. 2018;Huang et al. 2019). It is important to mention that global studies indicate an accumulation and an increase in the levels of these compounds in water, mainly derived from anthropogenic activities, which exceed the international water quality standards proposed by the World Health Organization (WHO), being a serious problem that should concern us since these activities are increasingly frequent given the demand for products from agriculture, livestock, and industry (Lawniczak et al. 2016;Pennino et al. 2017;Shalev et al. 2015;Nakagawa et al. 2016;Adimalla and Li 2019;Elisante and Muzuka 2017;Calleros-Rincon et al. 2012;Shukla and Saxena 2018). ...
... Another of the reviews that have been considered in this regard is the one made by Parvizishad et al. (2017), but the author considers nitrate intake in both water and food, which can result in a synergistic or additive effect and not only by the action of nitrate in water; the meta-analysis conducted by Bahadoran et al. (2015) conclude that only in high exposure to nitrate from both diet and drinking water can lead to the risk of thyroid cancer at a significantly statistical level; here, we emphasize the importance of nitrates present not only in high levels, but also in minor and chronic exposures by drinking water as recent research highlights the increase in aquifer contamination by these compounds worldwide. (Lawniczak et al. 2016;Pennino et al. 2017;Shalev et al. 2015;Nakagawa et al. 2016;Adimalla and Li 2019;Elisante and Muzuka 2017;Calleros-Rincón et al. 2012;Shukla and Saxena 2018). The results from reports indicating that there is no association between exposure to nitrate and endocrine disorders (Hunault et al. 2007;Mehrnejat et al. 2015) can be partially explained by the participants ingesting the optimal levels of iodine, variations in the periods of their exposure, and even their susceptibility based on genetic polymorphisms in the different proteins involved in the synthesis of THs, and in the case of the study of Below et al. (2008), the reason could be the intake of nitrates through aliments only. ...
Article
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Nowadays, the nitrates have been established as carcinogenic components due to the endogenous formation of N-nitroso compounds, however, the consumption of water contaminated with nitrates has only been strongly related to the presence of methemoglobinemia in infants, as an acute effect, leaving out other side effects that demand attention. The thyroid gland takes relevance because it can be altered by many pollutants known as endocrine disruptors, which are agents capable of interfering with the synthesis of hormones, thus far, it is known that nitrates may disrupt the amount of iodine uptake causing most of the time hypothyroidism and affecting the metabolic functions of the organism in all development stages, resulting in an important health burden for the exposed population. Here, this review and update highlighted the impact of consumption of water contaminated with nitrates and effects on the thyroid gland in humans, concluding that nitrates could act as true endocrine disruptor.
... It was a direct consequence of applying large quantities of fertilizer N in these countries. Globally, 60% of areas with elevated nitrate-N in ground water occur in croplands [5]. As only 20% of the total cultivated land is under irrigated agriculture and accounts for about 40% of the global food production, fertilizer N use and loss of nitrate-N to natural water bodies from the irrigated cropland is much higher than from rain-fed agriculture (http:// www. ...
... The changes in fertilizer N consumption patterns in different parts of the world have discernible impacts on nitrate pollution of ground and surface water bodies in different regions. Thus, although leaching of nitrate-N from the soil-plant system is influenced also by climate, soil and other factors, in recent decades nitrate pollution of surface and ground water has emerged as a serious environmental issue in several countries in East and South Asia along with already affected regions in North America and western and central Europe [5]. Keeping in view that even in countries with low average fertilizer N consumption there exist regions with intensive agriculture and substantial fertilizer N use, nitrate pollution of ground and surface waters as linked with fertilizer N use is now a global issue. ...
Article
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Nitrate pollution of ground and surface water bodies all over the world is generally linked with continually increasing global fertilizer nitrogen (N) use. But after 1990, with more fertilizer N consumption in developing countries especially in East and South Asia than in the industrialized nations in North America and Europe, nitrate pollution of freshwaters is now increasingly becoming a pervasive global problem. In this review it has been attempted to review the research information generated during the last two decades from all over the world on different aspects of nitrate pollution of natural water bodies. It is now evident that not more than 50% of the fertilizer N is directly used by the crops to which it is applied. While a small portion may directly leach down and may reach ground and surface water bodies, a large proportion ends up in the soil organic N pool from where N is mineralized and is taken up by plants and/or lost via leaching during several decades. Present trends of nitrate pollution of freshwaters, therefore, reflect legacies of current and past applications of fertilizers and manures. Tools such as simulation models and the natural variation in the stable isotopes of N and oxygen are now being extensively used to study the contribution of fertilizers and other sources to nitrate enrichment of freshwaters. Impacts of agricultural stewardship measures are being assessed and nitrate enrichment of water bodies is being managed using modern digital models and frameworks. Improved water and fertilizer management in agroecosystems can reduce the contribution of fertilizers to nitrate pollution of water bodies but a host of factors determine the magnitude. Future research needs are also considered.
... Globally, groundwater is the most important source for drinking water [1], a key resource for food production [2] and is characterized by a unique biodiversity as well as essential ecosystem services [3]. Simultaneously, groundwater bodies are threatened by massive overexploitation [4] and pollution [5]. Regarding these threats, uncertainty persists in the interaction between quality and quantity under conditions of climate change [6], the impacts from diffuse pollution [5], pharmaceuticals and personal care products [7], the response of endemic invertebrate groundwater species to anthropogenic pressures [8], and future developments of societal groundwater demands [9]. ...
... Simultaneously, groundwater bodies are threatened by massive overexploitation [4] and pollution [5]. Regarding these threats, uncertainty persists in the interaction between quality and quantity under conditions of climate change [6], the impacts from diffuse pollution [5], pharmaceuticals and personal care products [7], the response of endemic invertebrate groundwater species to anthropogenic pressures [8], and future developments of societal groundwater demands [9]. This is also the case for Europe, where the European Union (EU) Water Framework Directive (WFD) provides an extensive regulatory context, which is considered a blueprint for other world regions [10]. ...
Article
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Groundwater is essential for drinking water provision and food production while hosting unique biodiversity and delivering key ecosystem services. However, overexploitation and contamination are prevailing threats in many regions worldwide. Even integrated governance schemes like the European Union Water Framework Directive often fail to ensure good quality and quantity conditions of groundwater bodies. Contributing factors are knowledge gaps on groundwater characteristics, limited financial, staff and land resources, as well as policy incoherencies. In this paper, we go further and argue that current groundwater challenges cannot be understood when considering the local situation within hydrologic boundaries only. New long-distance processes are at stake—so called telecouplings—that transgress watershed and administrative boundaries and significantly influence the state of local groundwater bodies. We provide three literature-based examples of European groundwater systems that are impacted by telecouplings, and we show how research and solution perspectives may change when acknowledging the de-localization of groundwater(s). We elaborate on virtual water trade, remote water supply, and seasonal tourist flows that connect sending, receiving and spillover systems. These processes can induce groundwater depletion and contamination but may also help to conserve the resource. Our hypothesis calls for a new spatial paradigm to groundwater management and highlights the need for transdisciplinary research approaches as envisioned in socio-hydrogeology.
... It can also appear as the result of anthropogenic activities like fertilizers, septic tanks, sewage, and improper use of animal manures for agriculture. NO 3 is innocuous to human beings, and its formation is a fundamental part of the nitrogen cycle (Shukla and Saxena 2018). Nitrate, which is ingested through drinking water, however, is reduced from nitrate to nitrite in the gut by bacteria. ...
... In addition, there are many other diseases such as thyroid dysfunctions, breathing problems, nuisance and tiredness, and multiple sclerosis that can result from high nitrate intake (Ahada and Suthar 2018;Gatseva and Argirova 2008;Vanhatalo et al. 2018;WHO 2011). Groundwater NO − 3 contamination is highly discussed around the globe and has become a predominant threat because of the uncontrolled use of pesticides (Shukla and Saxena 2018;Spalding and Exner 1993). In India, nitrate contamination is an emerging issue regarding groundwater safety and human health. ...
Article
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Anthropogenic factors are contaminating crystalline aquifers more rapidly than natural sources and affecting human health in many states in India. Since a large population depends on untreated groundwater, identifying the sources of this contamination and assessing the related human health risk are essential to ensure a good-quality water supply. Nitrate is one of the most widespread means of groundwater contamination in many parts of India. Coimbatore and Tirupur districts are the most rapidly growing industrial urban areas in southern India. This paper deals with nitrate contamination and possible health risks for children and adults in the Coimbatore and Tirupur districts based on 93 groundwater samples. To achieve this goal, classical hydrochemical and deterministic hazard identification methods coupled with spatial mapping technologies were applied. A wide variation in nitrate concentration, between 1 and 415 mg/L, was observed, with 37% of the samples exceeding the WHO permissible limit of 50 mg/L. The distinct concentrations of nitrate and other ions observed spatially can be attributed to the diverse geochemical and land use settings in the study area. The bivariate plots of NO3 with other ions suggested that the principal origin of nitrate in this study is related to the excess application of fertilizers and sewages. The spatial variation of NO3, in comparison with the land use map, confirmed these results. The values of hazard quotient (HQ) via ingestion exceeded the critical value, one in 40% in males, 42% in females, and 45% in children. However, HQ values via oral pathways are within one and pose no exposure risk. Thus, the hazard index corresponds to HQingestion only. The health risk was in the increasing order of male>female>children, and shows that body weight is the most critical factor that is influencing the health impact to children as compared to adults. The spatial variation of hazard index values showed that groundwater quality is highly polluted with NO3 in the north and northeastern parts of the study area, mainly due to intensive agricultural practices, and poses critical health concerns. Considering the increasing population and higher dependencies on groundwater, immediate and sufficient measures are proposed.
... Nitrates NO − 3 have emerged as one of the most widespread pollutants, and have been detected in groundwater and surface water on a global scale [1]. Nitrate pollution is caused through the introduction of excessive amounts of nitrogen to surface water and groundwater. ...
... This is mainly the result of agricultural practices related to the improper use of nitrogen-based fertilizers and animal manure, with rural activities classified as the main sources of the extended nitrate pollution [2]. Additionally, various industries that use nitrogen-rich compounds as well as seepage from wastewater and sewage are aggravating factors in groundwater degradation due to the presence of NO − 3 [1]. NO − 3 is particularly mobile with water and through soil, and nitrates from sewage and agricultural fertilizers can thus easily make their way into both groundwater and surface waters. ...
Article
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The scope of the present study is the estimaThe scope of the present study is the estimation of the concentration of nitrates in groundwater using artificial neural networks (ANNs) based on easily measurable in situ data. For the purpose of the current study, two feedforward neural networks were developed to determine whether including land use variables would improve the model results. In the first network, easily measurable field data were used, i.e., pH, electrical conductivity, water temperature, air temperature, and aquifer level. This model achieved a fairly good simulation based on the root mean squared error (RMSE in mg/L) and the Nash–Sutcliffe Model Efficiency (NSE) indicators (RMSE = 26.18, NSE = 0.54). In the second model, the percentages of different land uses in a radius of 1000 m from each well was included in an attempt to obtain a better description of nitrate transport in the aquifer system. When these variables were used, the performance of the model increased significantly (RMSE = 15.95, NSE = 0.70). For the development of the models, data from chemical and physical analyses of groundwater samples from wells located in the Kopaidian Plain and the wider area of the Asopos River Basin, both in Greece, were used. The simulation that the models achieved indicates that they are a potentially useful tools for the estimation of groundwater contamination by nitrates and may therefore constitute a basis for the development of groundwater management plans.tion of the concentration of nitrates
... This excess NO 3¯ contamination in drinking water can cause increased cancer risk (Suthara et al., 2009;Shukla and Saxena, 2018) as well as various health risks such as methemoglobinemia, diabetes, etc. on humans and to some extent on livestock populations as well (Shukla and Saxena, 2018). ...
... This excess NO 3¯ contamination in drinking water can cause increased cancer risk (Suthara et al., 2009;Shukla and Saxena, 2018) as well as various health risks such as methemoglobinemia, diabetes, etc. on humans and to some extent on livestock populations as well (Shukla and Saxena, 2018). ...
Article
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Groundwater plays a pivotal role as the largest potable water sources in Bangladesh. As agriculture is widely practiced in Bangladesh, potential nitrate (NO 3¯) pollution may occur. Besides, excess amount of arsenic (As) has already been found in groundwater in many parts of Bangladesh including the present study area. Thus, this study was conducted to assess the NO 3¯ status along with some trace metals and associated human health risk in the Central Bangladesh. A total of 99 groundwater samples were analyzed to assess human health risk due to high level of NO 3¯ and other trace elements i.e. arsenic (As), iron (Fe), and manganese (Mn). Concentration of NO 3¯ was determined using column chromatography and inductively coupled plasma optical emission spectrometer (ICP-OES) was used to measure As, Fe and Mn concentrations. It was found that the mean concentration of NO 3¯ 253.17 (mg/L) in the groundwater samples exceeds the recommended guideline value by the WHO (50 mg/L). Moreover, this study area also characterized with elevated concentration of As (19.44 µg/L), Fe (811.35 µg/L), and Mn (455.18 µg/L) in the groundwater. Non-carcinogenic human health risk was calculated by justifying HQ (Hazard Quotient) and HI (Hazard Index) and attributed potential conjunctive human health risks due to NO 3¯, As, Fe and Mn in the study area. Child (9.941) is more vulnerable than adult (7.810) considering non-carcinogenic human health risk. Moreover, high carcinogenic risk was found due to As contamination in the groundwater samples and children (1.94×10-3) are more susceptible to carcinogenic risk compared to adults (9.2×10-4).
... Long term exposure to NO3and NO2may also result in the inadequate supply of oxygen to organs, leading to brain damage and even death in minors (Ahada and Suthar, 2018) including other health risks (Parvizishad et al., 2017). Water with elevated NO3used as a drinking source and watering of farm animals have also been reported to cause low feeding among livestock (Shukla and Saxena, 2018). Therefore, the dependence on both the groundwater and surface water as sources of drinking and watering of flocks by farmers in the area similarly has the potential to induce low appetite in the animals resulting in their loss of weight and possible financial consequences to their owners. ...
... Long term exposure to NO3and NO2may also result in the inadequate supply of oxygen to organs, leading to brain damage and even death in minors (Ahada and Suthar, 2018) including other health risks (Parvizishad et al., 2017). Water with elevated NO3used as a drinking source and watering of farm animals have also been reported to cause low feeding among livestock (Shukla and Saxena, 2018). Therefore, the dependence on both the groundwater and surface water as sources of drinking and watering of flocks by farmers in the area similarly has the potential to induce low appetite in the animals resulting in their loss of weight and possible financial consequences to their owners. ...
... To develop management strategies, groundwater characteristics have been studied to establish hydrogeological settings. Studies have been conducted to evaluate fertilizers as a source for drinking water NO 3 contamination (Chen et al. 2017;Daud et al. 2017;Shukla et al. 2018), but the role of coal and coal mining practices as a nitrate source to groundwater is less well understood. ...
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To assess the loading profiles of groundwater nitrate (NO 3-) and fluoride (F-), their spatial distributions, geochemistry and associated health risks were determined for 131 groundwater samples from eastern (ESR), central (CSR) and Trans-Indus Salt Ranges (TSR) in Pakistan. Groundwater NO 3-concentrations were 0.2-308 mg/L (mean 59 mg/L) in ESR, 2.7-203 mg/L (mean 73 mg/L) in CSR and 1.1-259 mg/L (mean 69 mg/L) in the TSR. Forty-one %, 57% and 36% of the ESR, CSR and TSR samples, respectively, exceeded the WHO and Pak-NEQs permissible limit of 50 mg/L NO 3-. Likewise, groundwater F-concentrations ranged from 0.1-1.8 mg/L (mean 0.6 mg/L), 0.1-2.7 mg/L (mean 0.9 mg/L) and 0.3-2.5 mg/L (mean 1.6 mg/L) mg/L in the ESR, CSR and TSR sites, respectively. In this case, 3%, 17% and 27% of the ESR, CSR and TSR samples, respectively, exceeded the WHO and Pak-NEQs permissible limit of 1.5 mg/L F. Oxidation of coal and coal waste resulted in the release of NO 3-to groundwater. By contrast, enrichment of Fin groundwater was due to dissolution and cation exchange processes. Elevated values of the Higher Pollution Index (PI) and Health Risk Index (HRI) reflect a non-acceptable carcinogenic risk for drinking water NO 3-and F-which should be addressed on a priority basis to protect human health.
... Surface water and groundwater nitrate concentrations have been increasing globally due to the increased use of synthetic fertilizers in the second half of the 20th century (Mitsch et al., 2001;Almasri and Kaluarachchi, 2004;Burt et al., 2010;Shukla and Saxena, 2018). In extreme cases, the ingestion of water high in nitrate leads to methemoglobinemia in young children (Shearer et al., 1972). ...
Article
There is a need to evaluate high surface nitrate concentrations across agricultural watersheds, both spatially and temporally, to increase understanding of source and timing of nitrogen loads in streams and rivers. Bazile Creek is a high-nitrate stream originating in the agriculturally intensive Bazile Groundwater Management Area of Eastern Nebraska, USA. It is a gaining stream that receives groundwater with high nitrate concentrations originating from nonpoint sources. The objective of this study was to determine spatial and temporal variability of baseflow nitrate concentrations in Bazile Creek and its tributaries and to relate this variability to watershed characteristics. Surface-water nitrate samples were collected monthly from July 2018 through September 2019 from nine sites in the watershed and were analyzed for nitrate concentration. Average surface water nitrate-N concentrations within the watershed ranged from 2.7 to 15 mg L⁻¹ and were significantly different between the sites (p < 0.05). Surface water nitrate-N concentrations varied seasonally in the main channel, recording the highest concentrations in winter (December-February, average = 14.4 mg L⁻¹) when the discharge was minimum. High nitrate-N concentrations were observed in two of the five sampled tributaries, suggesting steady inputs of high-nitrate groundwater. The results of this study reveal substantial spatial variation in surface-water nitrate concentrations in the headwaters despite the close proximity of sampling sites. This study demonstrates that sampling tributaries along with the main channel of a stream is beneficial in determining nitrate inputs, variability and overall contaminant loading to a watershed.
... Nitrate which is originated from various sources (Power et al. 1989) has recently been introduced as a driving factor in groundwater pollution (Almasri 2007;Lasagna et al. 2016;Rezaei et al. 2017;Srivastava et al. 2018). Several studies Showers et al. 2008;Umezawa et al. 2008;Hajhamad et al. 2009;Wongsanit et al. 2015;Ehteshami et al. 2016;Shukla et al. 2019;Taufiq et al. 2019) argue that human activities including fertilizer and animal manure overuse and domestic and industrial wastewater production bring about the nitrate concentration rise in groundwater primarily. The point source (e.g., septic tanks and septic systems) and non-point sources (e.g., fertilizers and manure overuse, leguminous crops, dissolved nitrogen in precipitation, irrigation, and dry deposition) are the two main nitrate nourishing of groundwater (Umezawa et al. 2008;Hajhamad et al. 2009;Lawniczak et al. 2016). ...
Article
Groundwater contamination has been on the rise in Afghanistan. It has become a major concern among the policy makers. This paper aims to propose practical options for the management of nitrate contamination in one of Afghanistan’s groundwater polluted provinces, Kabul. The management framework utilized Mann-Kendall and Sen Slope tests to detect nitrate trend and geostatistical analysis option in ArcGIS 10.5 to assess the nitrate change. To explore the impact of various management options, a number of legislative documents were reviewed. The results indicate a decline in the nitrate storage of Kabul aquifers from 108 mg/L in 2005 to 0.044 mg/L in 2010. Considering the whole period of the study, the results show that the nitrate volumes remain lower than the nitrate concentration range proposed by World Health Organization (50 mg/L). Groundwater dynamics in Kabul aquifers were influenced by nitrate derived from precipitation and nitrate input from root zones in agricultural areas. Finally, different management options for groundwater pollution from nitrate and corresponding authorities, incorporated urban, rural and agriculture, were proposed. It is expected that this study will help policy makers to better manage the nitrate storage of Kabul aquifers by implementing the proposed management options.
... Nitrate has emerged as one of the foremost alarming and widespread contaminants of groundwater and surface water resources in many parts of the world (Shukla & Saxena 2018). Nitrate contamination has been reported in groundwater sources in Sri Lanka in the range of 10-366 mg/L, especially in areas such as Anuradhapura, Jaffna, Kilinochchi, Mannar, Vavuniya, and Puttalam (Herath 2018). ...
Article
Groundwater pollution by nitrate contamination has become a significant issue in some areas of Sri Lanka, giving rise to health concerns and a dearth in good quality potable water. In this study, the effectiveness of nano zerovalent iron (nZVI) for the removal of nitrate in potable groundwater under oxic conditions was investigated to meet the drinking water quality standards stipulated by World Health Organization (WHO) and Sri Lanka Standards Institution (SLSI) (nitrate level <50 mg/L). Under oxic conditions, the nZVI was synthesized and batch experiments were conducted using an artificial nitrate (150 mg/L) contaminated water sample. Our results corroborated that with an optimum nZVI dose of 1 g/L and optimum contact time of 30 minutes, 80% nitrate removal could be achieved and the remaining nitrate level was ≈ 30 mg/L as nitrate (<50 mg/L), which was equivalent to ≈ 7 mg/L as nitrate–N (≈21% of the total–N). Ammonium ions were the main product of nitrate reduction by nZVI and at 30 minutes contact time, ≈ 20 mg/L of ammonium as ammonium–N was detected (≈ 59% of the total–N). Ammonia stripping took place under the basic solution pH (pH > 9.5). At 30 minutes of contact time, ≈7 mg/L of ammonia as ammonia–N was accounted for ammonia stripping, which is 20% of the total–N. Ammonia stripping resulted in a decrease in nitrogen-containing species in the aqueous phase. The spent nZVI particles were recovered (99.9%) from the treated water using an external magnetic field. In conclusion, nZVI particles synthesized under oxic conditions are viable to successfully treat the nitrate-contaminated groundwater under aerobic conditions to reduce the nitrate levels to meet the WHO/SLSI drinking water quality standards.
... Worldwide, fertilizers applied to cropland account for 60% of nitrate contamination in groundwater (Shukla and Saxena, 2018). Nitrate contamination sources and contributions vary locally. ...
Article
Environmental health hazards are known to disproportionately burden marginalized communities. Agriculture, wastewater, and industrial waste contaminate surface and groundwater, used for drinking, with nitrates. High nitrate concentrations in drinking water have been linked to methemoglobinemia and, recently, thyroid cancer. With a large proportion of the nation's agriculture grown in California, thyroid cancer linked to nitrate water contamination is of concern. This research entailed geographic and statistical analysis of water, nitrate, health, and disadvantaged communities (DACs) in California. DACs are Californian defined areas that experience a combination of hardships from socioeconomic, health, and environmental fields. Our analysis of the California Cancer Registry and California Water Board's well data shows statistically significant correlation (p < 0.05) between nitrate contamination (wells >5 and 10 ppm NO3-N per square mile and percentage of total wells) and thyroid cancer incidence. DACs had twice the rate of thyroid cancer compared with non-DACs, and higher numbers of nitrate-contaminated wells and hot spots compared with the state averages. Almost half (47%) of the Central Valley's area contained DACs and 27% of wells >10 ppm NO3-N contaminants. Our study provides a method for other states and countries to conduct preliminary geospatial analysis between water contamination and health with open data. Maps and analysis from this research can inform the public, advocacy groups, and policy leaders of health-related concerns in relation to nitrate water contamination and environmental justice in California. DACs should be provided cost-effective drinking water monitoring and treatment, and governments should incentivize nitrate loading reductions in agriculture, industry, and wastewater. Future research is recommended with more localized, private health data on thyroid cancer incidence.
... Nitrate (NO − 3 ) is one of the most common contaminants in the world's aquifers (Shukla and Saxena 2018;Spalding and Exner 1993) and of particular concern in agricultural countries, such as Denmark, that use nitrogen fertilizers and have intensive animal production (Hansen et al. 2017;Burow et al. 2010;Nolan et al. 1997). Excess nitrogen on agricultural fields may leach as watersoluble nitrate into groundwater depending on local soil and hydrogeological and geochemical conditions. ...
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Background: High levels of nitrate (NO3-) in drinking water cause methemoglobinemia in infants; however, few studies have examined the potential effects of low-level exposure on fetal growth, and the results have been inconsistent. Objectives: We sought to assess the association between maternal exposure to nitrate in drinking water during pregnancy and offspring size at birth in a nationwide study of full-term (≥37 wk gestation) live-born singletons. Methods: We estimated maternal nitrate exposure for 898,206 births in Denmark during 1991-2011 by linkage of individual home address(es) with nitrate data from the national monitoring database. Maternal address during pregnancy, infant size at birth [i.e., birth weight, low birth weight (LBW), body length, and birth head circumference] and covariates were compiled from the Danish Civil Registration System, the Danish Medical Birth Register, and The Integrated Database for Longitudinal Labor Market Research. Linear and logistic models with generalized estimating equations were used to account for multiple births to an individual. Nitrate exposure was modeled using five categories and as a log-transformed continuous variable. Results: There was evidence of a decreasing trend in models for term birth weight using categorical or continuous measures of exposure. Modeling exposure continuously, a difference of -9.71 g (95% confidence interval: -14.60, -4.81) was predicted at 25 mg/L (half the value of the European Union drinking water standard) compared with 0 mg/L NO3-. Body length also decreased as nitrate concentrations increased in categorical and continuous models. There was little evidence of an association between NO3- and head circumference or LBW. Discussion: Although the estimated effects were small, our findings for live singleton births to Danish-born parents suggest that maternal intake of nitrate from drinking water may reduce term birth weight and length, which are markers of intrauterine growth. However, there was little evidence for an association between nitrate and head circumference or LBW. Future studies in other populations and with data on dietary sources of nitrate are encouraged to confirm or refute these findings. https://doi.org/10.1289/EHP7331.
... To develop management strategies, groundwater characteristics have been studied to establish hydrogeological settings. Studies have been conducted to evaluate fertilizers as a source for drinking water NO 3 contamination (Chen et al. 2017;Daud et al. 2017;Shukla et al. 2018), but the role of coal and coal mining practices as a nitrate source to groundwater is less well understood. ...
Article
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To assess the loading profiles of groundwater nitrate (NO3−) and fluoride (F−), their spatial distributions, geochemistry and associated health risks were determined for 131 groundwater samples from eastern (ESR), central (CSR) and Trans-Indus Salt Ranges (TSR) in Pakistan. Groundwater NO3− concentrations were 0.2–308 mg/L (mean 59 mg/L) in ESR, 2.7–203 mg/L (mean 73 mg/L) in CSR and 1.1–259 mg/L (mean 69 mg/L) in the TSR. Forty-one %, 57% and 36% of the ESR, CSR and TSR samples, respectively, exceeded the WHO and Pak-NEQs permissible limit of 50 mg/L NO3−. Likewise, groundwater F− concentrations ranged from 0.1–1.8 mg/L (mean 0.6 mg/L), 0.1–2.7 mg/L (mean 0.9 mg/L) and 0.3–2.5 mg/L (mean 1.6 mg/L) mg/L in the ESR, CSR and TSR sites, respectively. In this case, 3%, 17% and 27% of the ESR, CSR and TSR samples, respectively, exceeded the WHO and Pak-NEQs permissible limit of 1.5 mg/L F. Oxidation of coal and coal waste resulted in the release of NO3− to groundwater. By contrast, enrichment of F− in groundwater was due to dissolution and cation exchange processes. Elevated values of the Higher Pollution Index (PI) and Health Risk Index (HRI) reflect a non-acceptable carcinogenic risk for drinking water NO3− and F− which should be addressed on a priority basis to protect human health.
... Point sources of NO 3 À include leaks from septic systems, chemical and manure storage, and from sewer systems (Ako et al., 2014). Manure and fertilizers are widely used to raise the agricultural yield (Shukla and Saxena, 2018). The pollution of NO 3 À in agricultural lands is the major issue due to leaching of these plant nutrient sources into the groundwater. ...
Article
The present research was attempted to examine the human health risks due to nitrate contamination in the groundwater of Texvalley (Tiruppur region) of southern India. Groundwater samples (n ¼ 40) were picked up from open wells (shallow aquifer) and tube wells (deep aquifer) during January 2020, and laboratory examination was conducted for various major physicochemical constituents. Nitrate concentration varied from 10 to 290 mg/l with a mean of 83.45 mg/l. About 58% (n ¼ 23) of the wells exceeded the recommended limit (>45 mg/l) ofWorld Health Organisation, which spread over an area of 335.16 km2. Among this, 45% of the samples (n ¼ 18) represented shallow aquifers (depth < 15 m), and 13% of them (n ¼ 5) represented deep aquifers (depth > 15 m). Synthetic fertilizers, cow dung and sheep manure, industrial discharge, septic tank leakage and municipal solid waste disposal are the major sources of nitrate pollution in this region. The USEPA health risk assessment model was applied in this study to assess hazard quotients (HQ) according to the NO3 exposure in various age groups of inhabitants through two different pathways such as drinking (HQoral) and skin contact (HQdermal). Eventually, total hazard index (THI) was obtained for all the groundwater samples for different age groups. According to THI, 87%, 78%, 66%, 60%, 56% and 48% of the samples contain health risks (THI >1) for infants, kids, children, teens, adults and aged people, respectively. The study finally recommended seven environmental friendly actions for the groundwater quality improvements and for the sustainable health management.
... Furthermore, along with groundwater quantity depletion, deterioration of groundwater quality is another major global concern that impacts human health, ecosystem services, and sustainable economic development (Li et al. 2021). In recent years, groundwater pollution by arsenic, fluoride, and nitrate has become a serious issue worldwide, affecting aquifer health and human health (Shukla and Saxena 2019;Jha and Tripathi 2021). Unfortunately, this mismanagement of groundwater resources has raised concerns in terms of sustainability and has led to environmental problems affecting both the present and the future generations. ...
Article
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Groundwater plays a pivotal role in sustaining the water needs of the population of South and Southeast Asia. However, long-term overexploitation and unsustainable practices have caused groundwater depletion, and deterioration in many parts of the region, further impacting human health and ecosystem services. Thus, understanding the current groundwater research activities and identifying the issues are crucial for improving future studies. This study conducted a bibliometric analysis to evaluate the groundwater-related literature available for South and Southeast Asia from the Scopus database for the last 50 years (1970–2020). Of the total, this study identified 7895 documents, representing 13% of the total global research productivity. India was the most productive country, followed by Pakistan and Malaysia. National Geophysical Research Institute, Anna University, and Indian Institute of Technology, Kharagpur, were the top three institutions with the highest number of groundwater-related publications. In international research collaboration, the USA and Japan were the two most collaborated countries with the South and Southeast Asian countries. Environmental science, earth and planetary sciences, and agricultural and biological sciences were the top three disciplines. The Environmental Earth Sciences journal published the highest number of groundwater-related publications in the study period. Research topic trends were observed through keyword analysis revealing increased outputs for groundwater quality, availability and suitability, recharge, and management. Our results provide valuable insights on groundwater issues that have received the most attention in South and Southeast Asia and identify the potential research topics and opportunities for researchers working in the groundwater domain.
... However, sporadic occurrence of nitrate in the study area also suggests the possible contribution of geogenic factors 27 . Consuming water with high nitrate content (>45 mg/l) might cause 'blue baby syndrome', cancer and thyroid problems 28,29 . ...
Article
The major problem of groundwater contamination primarily in the Indo-Gangetic alluvium is of fluoride, nitrate, arsenic, iron and salinity. One such area is Raebareli district, Uttar Pradesh, India representing the central Indo-Gangetic alluvium, where groundwater contamination through fluoride, nitrate and salinity has already been reported. However, a comprehensive picture pertaining to water quality as a whole has not been published yet. The present study deals with the changes in water quality parameters in groundwater samples of Raebareli district to present a wholesome picture. The results for water quality index (WQI) show that 7% samples in the study area are in the class of 'unsuitable for drinking' purposes, with WQI value as high as 411.5. Moreover, the results suggest that 57% and 43% of the samples in the pre-monsoon and post-monsoon period respectively, are under the category of 'poor' water. This study will enable the government authorities to suggest alternate drinking water sources in the affected area.
... Nitrites in freshwater ecosystems can be evidence of recent contamination (Gil et al. 2013). This inorganic compound in aquatic ecosystems arising from the biological degradation of organic matter affects the physiological processes of aquatic organisms (Alonso and Camargo 2013;Shukla and Saxena 2018). Nitrite causes alterations in the functional role of respiratory pigments and the capacity to uptake oxygen, with severe consequences for many aquatic organisms (Hannas et al. 2010;Alonso and Camargo 2013). ...
Article
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In river ecosystems, spatial complexity as well as anthropogenic factors operating at different temporal and spatial scales are shaping demography, connectivity and population genetic structure of species inhabiting these habitats. Chilina dombeiana is a freshwater gastropod with direct development (absence of a free larval phase) that inhabits the Biobío river basin in Chile (36°S). No studies have yet evaluated the spatial patterns of the genetic diversity of this species and the potential factors that influence these patterns. Consequently, in this study, we analyzed the population genetics of C. dombeiana based on 15 locations along the Biobío river. Eight microsatellite loci were genotyped. Also, at each sampling site, 40 environmental parameters were recorded to characterize them. Results showed that C. dombeiana has low genetic variability with high population structure. In addition, we detected signs of historical decreases in effective population sizes, unidirectional gene flow (upstream to downstream) and contemporary demographic bottleneck. Spatial subdivisions in populations showed a pattern of isolation by distance. The redundancy analysis and variance partitioning showed that spatial components and dissolved oxygen could explain 28% of the interpopulation genetic variation, while the Random Forest analysis identified significant effects of dissolved oxygen, nitrite and total coliforms on the genetic variability of populations (22%). Although C. dombeiana is widely distributed in Chilean rivers, its low dispersal and specific habitat requirements make this species very sensitive to the severe increase in anthropogenic disturbances affecting river ecosystems in recent decades. Long-term monitoring of genetic population conditions and environmental parameters are needed to implement robust management and conservation policies.
... In recent decades there has been increased interest in assessing the environmental impacts of broad scale sugarcane farming, particularly in relation to the transport of nitrate (NO 3 -) (Mitchell et al., 2009;Davis et al., 2013;Thorburn et al., 2011;Rasiah et al., 2003Rasiah et al., , 2013. NO 3 has been identified globally as a widespread contaminant in groundwater and surface waters, following the application of nitrogen-rich agricultural fertilisers (Appelo and Postma, 2010;Hiscock and Bense, 2014;Zhou et al., 2016;Shukla and Saxena, 2018;Reading et al., 2019). Although considered an essential plant nutrient in soils, NO 3 becomes a pollutant once it is leached below the root zone and occurs in undesirable concentrations (Tate, 2000;Zhou et al., 2016;Juntakut et al., 2019). ...
Article
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The transport of nitrogen (N) to groundwater and surface water in the form of nitrate (NO3⁻), as a by-product of the application of N-rich fertilisers, has been studied extensively. Yet, in the catchments adjacent to the Great Barrier Reef (GBR) in tropical north Queensland, Australia, NO3⁻ transport in groundwater is not regularly monitored. An assessment of groundwater chemistry in the Liverpool Creek catchment of Queensland's wet-tropics region was conducted by regular sampling and analysis of groundwater over 12 months, through wet and dry seasons. A distinct spatial variability in groundwater chemistry was observed; groundwater aquifers with very low dissolved oxygen (DO) and NO3⁻ consistently displayed relatively higher concentrations of sulphate (SO4²⁻), sulphur (S²⁻) and ferrous iron (Fe²⁺) and low concentrations of dissolved organic carbon (DOC) (<2 ppm). Combined with averaged measured redox potential (Eh) of <250 mV, this indicates certain regions of the catchment have conditions favourable for removal of NO3⁻ via autotrophic denitrification (DN), while other groundwater aquifers retained NO3 – concentrations just above the acceptable trigger limits defined in regional water quality guidelines. Observations indicate that the naturally heterogeneous structure of the coastal alluvium contributes to the distinct variability in groundwater chemistry over small distances, with NO3⁻ concentrations influenced by a combination of DN, lateral shallow drainage and potential adsorption to clay surfaces within the alluvial sediments.
... Nitrate is one of the most widespread contaminants of ground and surface water worldwide [1][2][3]. Excessive nitrate in drinking water has been associated primarily with methemoglobinemia. Nitrate intake at levels, below the permissible limit of 45 mg/L, has also been linked with thyroid diseases, colorectal cancer, and neural tube defects [4]. ...
Article
Removal of nitrate by Donnan dialysis was investigated in semi- and fully- continuous flow systems. The performance of the two different operating modes was compared. In the semi-continuous mode, a nitrate solution was continuously dosed into the feed compartment while the receiver compartment was operated in a batch mode. In the fully continuous system, both feed and receiver solutions were continuously dosed into the corresponding compartments. Similar removal efficiencies of nitrate were obtained in both modes of operation, with a maximum of 80% reached at residence time of 4 h based on the flow into the feed compartment. Differences between the two modes of operation were manifested by inhibition of nitrate transfer following a pseudo steady-state in the semi-batch system and by nitrate accumulation in the receiver solution. In the fully continuous-flow Donnan dialysis system, the nitrate concentration in the receiver reached a saturation level corresponding to the nitrate removed from the feed. As in the case of batch dialysis, nitrate was adsorbed by the ion exchange membrane also in continuous flow. The amount of adsorbed nitrate depended on both the concentration of the receiver solution as well as on the feed nitrate concentration. The mass transfer coefficients, obtained in the semi- and the fully- continuous systems, were found to be very close to the values obtained in batch operation.
... Otherwise, it is necessary to conduct further research to determine the source of the excessive nitrate content in the groundwater to prevent health fatality for the local people. The nitrate content consumed by the body can be harmful and cause health risks such as methemoglobinemia, cancer, diabetes, etc., in both humans and animals [17]. Therefore, groundwater in the contaminated residential area is not suitable for consumption. ...
Article
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This paper aims to determine the existence of groundwater contamination due to coal stockpile activity in shallow groundwater. The research area is located in a stockpile that has been operating since 1986. We conducted chemical content analysis at several points around the coal stockpile and outside the stockpile area to see the impact of pollution on the surrounding residents’ areas. This study also uses geoelectric methods and direct observations to identify shallow groundwater levels (water table). The research area has a groundwater depth of about 2 m from the surface, and groundwater flows from northeast to southwest (sea). The chemical content analysis results show that each sample taken around the stockpile is below the water quality standard threshold, so it can be concluded that coal stockpile activity does not contaminate the shallow groundwater. However, there is nitrate contamination from shallow groundwater located outside the stockpile area taken from dug wells and drilling wells with a depth of 8 m shows a value of 14.08-23.67 ppm (>10 ppm threshold). We suspect that this pollution is caused by the large number of mining activities carried out in the north of the study area.
... The global water situation involves significant contamination of water sources with nitrate pollutants as a consequence of increasing industrial activities, the use of nitrogen-based fertilizers in agricultural activities, and inappropriate disposal of wastewater. 1 The elimination of nitrate compounds from water sources has become an important challenge among researchers and experts due to their harmful effects on the environment and human health. 2,3 In particular, they are a potential precursor of several types of cancer and they reduce the blood capacity to carry oxygen (called "blue baby syndrome") 4 At the same time, excessive nitrate ions in the environment produce anoxic or hypoxic conditions due to the massive growth of algae, destroying ecosystems, and having a negative impact on human well-being. ...
Article
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The reverse osmosis concentrate generated during the water reuse process contains a high concentration of nitrate but a low amount of biodegradable organic carbon for heterotrophic denitrification. Catalytic reduction of nitrates using Pd-Cu is one of the most promising technologies to achieve complete removal of nitrate; however, the effect of a range of experimental factors on the nitrate removal rate and N 2 selectivity is still an ongoing concern. Two kinds of supporting materials, alumina and activated carbon felt, were used to immobilize the Pd-Cu catalyst. The alumina-based catalyst was used to establish reference conditions for further experiments, and the effect of pH control was evaluated for both supporting materials. It was observed that pH has a direct influence on the nitrate reduction rate as well as the N 2 selectivity. Nitrate reduction efficiency was low at acidic conditions while the highest N 2 selectivity was obtained at the acidic conditions. The optimal pH condition for Pd-Cu/activated carbon felt was determined as pH 4, showing the highest total nitrogen removal as N 2 gas. Finally, the feasibility of catalytic nitrate reduction for reverse osmosis concentrate was evaluated by investigating the effects of organic and inorganic components commonly present in reverse osmosis concentrate. The organic and inorganic components did not show a significant inhibitory effect on catalytic nitrate reduction, while a high concentration of salt significantly decreased the nitrate reduction rate as well as the N 2 selectivity. The filter type morphology of the Pd-Cu/activated carbon felt would be beneficial for field application compared to the conventional catalyst with powder form.
... Zum einen ist der Einsatz von Düngemitteln für das Pflanzenwachstum essentiell für wirtschaftliche Erträge in der Landwirtschaft, zum anderen müssen die Vorgaben und Grenzwerte zum Schutz unserer Umwelt eingehalten werden. Daraus ergibt sich die Notwendigkeit, den Nitratgehalt in Boden und Wasser zu überwachen [1,2]. Mit mobilen Systemen, die eine Messung vor Ort erlauben, kann beispielsweise den Landwirten ein Instrument zur Verfügung gestellt werden, mit dem sie eine bedarfsgerechte Düngung ihrer Anbauflächen durchführen und gleichzeitig auf die Belange des Umweltschutzes achten können. ...
... In India, total extracted Groundwater shares 89% for irrigationand 9% for domestic use.Also, rural domestic water requirements are fulfilled by groundwater (Suhag, 2019), but many people are drinking water, having contamination level beyond the BIS limits (Rao, 1998;Khandare, 2013;Shukla & Saxena, 2019). About 297 districts of 24 States are affected by geogenic contaminants (Suhag, 2019). ...
Conference Paper
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The Ganga River basin (GRB) is a highly populated region in the world due to the availability of fertile alluvial soil and industrialization. The farmers have been developing different livelihood practices to resist and sustain the climate change vulnerability in the industrial region (IR) and non-industrial region (NIR) of GRB. Hence, an attempt is being made to compare the livelihood vulnerability index (LVI) of farmers residing in the IR and NIR of GRB. The farmer communities living in the IR showed greater vulnerability in terms of socio-demographic profile, livelihood strategies, health, food, water, social network, and natural disaster and climate variability. Trends revealed that the major components that are highly contributing factors in the LVI of IR become less contributing in the LVI of NIR. The LVI–IPCC contributing factors (i.e. adaptive capacity, sensitivity and exposure) were found to be high in the IR, which resulted in demographic instability as well as low resistance and resilience of the farmers, consequently they were highly vulnerable to natural disasters and climate change in the industrial region.
... Since, the area is mostly agriculture dominated, excessive fertilizer usage might be the reason behind elevated level of nitrate in groundwater. Nitrate beyond permissible limits may cause 'blue baby syndrome', thyroid problems etc. (Shukla and Saxena, 2018). Sulfate and nitrate levels in an aquifer are also affected by the microbial degradation of organic matter Bhattacharya et al., 2004). ...
Article
Groundwater is a primary drinking water source in various parts of Indo-Gangetic plain. Many rural agglomerations in this alluvial plain face scarcity of safe drinking water. Yet, there is a lack of public awareness and scientific studies in these areas, and Raebareli district is one of them. Groundwater samples collected from handpumps, dugwells, and tubewells were analysed for various physico-chemical parameters and compared with drinking standards for drinking suitability. The elevated concentrations of nitrate can be attributed towards heavy fertilizer application and irrigation practices, whereas rock-water interaction can be a cause for higher fluoride concentrations in groundwater. The ionic abundance was in order of HCO3⁻ > Na⁺>Cl− > SO42− > Mg²⁺>Ca²⁺>NO3⁻ > K⁺>F⁻, and HCO3⁻ > Na⁺>Cl− > SO42− > Ca²⁺>Mg²⁺>NO3⁻ > K⁺>F⁻ during the pre-monsoon and post-monsoon seasons respectively. Irrigation suitability of groundwater was also assessed using Sodium Absorption Ratio, Wilcox diagram, Doneen's plot, Kelley's index, Magnesium Hazard, and other suitable indices. The analysis suggested that there is a medium to high salinity hazard in the area. As per Kelley's index, approximately 57% of the samples were found unsuitable for irrigation practices. Non-carcinogenic health hazards associated with nitrate and fluoride and their impacts on adult men and children were also assessed. The ‘Total Hazard Index’ values ranged from 0.4 to 14.5 in children, and 0.3 to 10.8 in adult men. The results also suggested that more than 82% of the samples for children and 77% for adult men could possibly impart non-carcinogenic health hazards.
... Some research studies have shown that the health risks of NO − 3 pollution and the dramatic increase in NO − 3 content in groundwater are mainly due to the impact of intense agricultural activity on the aquifer system, especially in arid and semi-arid areas, in many areas in the world (Barzegar et al. 2016;Serio et al. 2018;Soldatova et al. 2018;Wang et al. 2018; Barakat et al. 2019;Barakat 2020). In addition, it is the most commonly occurring ion in groundwater due to the irrigation-return-flows, untreated household wastes, sewage and septic tank leaks, nitrogen-rich soils, and animal waste Shukla and Saxena 2018;Zhang et al. 2018;Karunanidhi et al. 2019;Subba Rao et al. 2021a, b, c). With the high solubility of NO − 3 in water and the low retention capacity of NO − 3 through soils, NO − 3 reaches the groundwater body, when it is not used properly by plants and leaches to subsurface soils (Barakat 2020). ...
Article
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Evaluation of groundwater quality and related health hazards is a prerequisite for taking preventive measures. The rural region of Telangana, India, has been selected for the present study to assess the sources and origins of inferior groundwater quality and to understand the human health risk zones for adults and children due to the consumption of nitrate (NO3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{NO}}_{3}^{-}$$\end{document})- and fluoride (F⁻)-contaminated groundwater for drinking purposes. Groundwater samples collected from the study region were determined for various chemical parameters. Groundwater quality was dominated by Na⁺ and HCO3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{HCO}}_{3}^{-}$$\end{document} ions. Piper’s diagram and bivariate plots indicated the carbonate water type and silicate weathering as a main factor and man-made contamination as a secondary factor controlling groundwater chemistry; hence, the groundwater quality in the study region is low. According to the Groundwater Quality Index (GQI) classification, 48.3% and 51.7% of the total study region are excellent (GQI: < 50) and good (GQI: 50 to 100) water quality types, respectively, for drinking purposes. However, NO3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{NO}}_{3}^{-}$$\end{document} ranged from 0.04 to 585 mg/L, exceeding the drinking water quality limit of 45 mg/L in 34% of the groundwater samples due to the effects of nitrogen fertilizers. This was supported by the relationship of NO3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{NO}}_{3}^{-}$$\end{document} with TDS, Na⁺, and Cl⁻. The F⁻ content was from 0.22 to 5.41 mg/L, which exceeds the standard drinking water quality limit of 1.5 mg/L in 25% of the groundwater samples. The relationship of F⁻ with pH, Ca²⁺, Na⁺, and HCO3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{HCO}}_{3}^{-}$$\end{document} supports the weathering and dissolution of fluoride-rich minerals for high F⁻ content in groundwater. They were further supported by a principal component analysis. The Health Risk Index (HRI) values ranged from 0.20 to 20.10 and 0.36 to 30.90 with a mean of 2.82 and 4.34 for adults and children, respectively. The mean intensity of HRI (> 1.0) was 1.37 times higher in children (5.70) than in adults (4.16) due to the differences in weight size and exposure time. With an acceptable limit of more than 1.0, the study divided the region into Northern Safe Health Zone (33.3% for adults and 28.1% for children) and Southern Unsafe Health Zone (66.7% for adults and 71.9% for children) based on the intensity of agricultural activity. Therefore, effective strategic measures such as safe drinking water, denitrification, defluoridation, rainwater harvesting techniques, sanitary facilities, and chemical fertilizer restrictions are recommended to improve human health and protect groundwater resources.
... Fertilizer's use in agriculture is reported to be the highest anthropogenic source of nitrate contamination in groundwater (Shukla and Saxena 2018). In fact, it is known that nitrogen is one of the major components of fertilizers, whose usage in agriculture has increased in time to escalate the crop yield. ...
Chapter
In environmental sciences, the risk assessment methods focus on the most reliable techniques to quantify vulnerability and hazard, being the former defined as functionally related to the latter independent variables. With regard to groundwater systems, this chapter explores the possibility of assessing directly the environmental risk as a probability, avoiding to evaluate each of its components. Environmental risk is intended here as the probability of groundwater (i.e., the vulnerable natural system) quality degradation due to the uncontrolled spreading of nutrients on soils in agriculture (i.e., the hazardous event). Risk is formally defined as the probability of exceeding given thresholds of nitrate concentration, conditioned by values sampled within the considered groundwater system. Then, a probabilistic methodology is proposed, based on geostatistical, non-parametric, stochastic simulation, to estimate and spatialize such a risk. Finally, the methodology has been applied to the shallow aquifer of the “Tavoliere di Puglia” plain, located in Apulia, Southern Italy, and characterized by intense agricultural activities and civil facilities.
... In China, nearly 50 million people were estimated to be exposed to high-fluoride groundwater (>1 mg/L) (Wen et al., 2013). With increasing agricultural fertilizer application and emissions from numerous septic tanks, nitrate has become the most alarming and widespread groundwater contaminant globally (Shukla and Saxena, 2018). Shaanxi province in western China was reported to have the highest mean nitrate concentration in groundwater among all 31 provinces in China Zhai et al., 2017). ...
Article
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Intense anthropogenic activities have led to deterioration of groundwater quality worldwide. Scientific assessments of groundwater quality and human health risks are the premise to ensure water safety and residents’ health. Based on 321 groundwater samples collected from the Guanzhong Basin (GB), this study comprehensively assessed the groundwater quality and potential risks of As, F⁻, NO3–N, and Cr⁶⁺ to human health for the first time in GB. With differences in hydrogeological settings and human activities, the chemical composition of groundwater in GB exhibited wide spatial variability. Results of the integrated-weight water quality index (IWQI) showed that Cr⁶⁺, As, NO3–N, and F⁻ have stronger effects on groundwater quality than other ions. Except for As, other pollutants (Cr⁶⁺, NO3–N, and F⁻) distributed mainly in the north of the Wei River, with northeast part of GB had much poorer groundwater quality than other areas. The human health risk assessment showed that carcinogenic risks associated with As and Cr⁶⁺ were higher for adults than for children, whereas non-carcinogenic risks posed by As, F⁻, NO3–N, and Cr⁶⁺ were higher for children. The primary exposure pathway for both carcinogenic and non-carcinogenic risks was daily oral ingestion. According to the spatial distribution of total carcinogenic and non-carcinogenic hazard indices, both adults and children living in the north of GB are at high risk. Monte Carlo simulations were used to assess model uncertainty and to determine pollutant treatment priority. The probability of non-carcinogenic risk for children is up to 92.25%. Sensitivity analysis results indicated that the main threat to residents' health is the high concentrations of F⁻ and Cr⁶⁺ in groundwater. Hydrogeochemical analyses revealed that the poor quality of groundwater in the northeast of GB is mainly controlled by the geological background and extensive evaporation due to long-term irrigation activities. The findings of this study laid the foundation for the rational development and utilization of groundwater resources and the protection of residents' health in GB. It can also be used as references for the study of groundwater environment and human health risks in other similar areas.
... Nitrate pollution of water is a major issue worldwide [4][5][6][7], and inefficient management of treated/untreated wastewater (Minnig et al. 2018) [8] and solid waste disposal (Wakida and Lerner 2005) [9]. Focusing on groundwater, nitrate contamination is a worldwide problem ( [10][11][12][13]. In Europe, policies to reduce NH4 + and NO3 − losses have been in place since nearly 30 years following the issue of the Nitrates Directive (ND; EC 1991) [14]. ...
Article
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Nitrogen-nitrate, while being fundamental for crop production, is of particular concern in the agricultural sector, as it can easily leach to the water table, worsening groundwater quality. Numerical models and Geographic Information System may support the estimation of nitrate leaching rates in space and time, to support sustainable agricultural management practices. In this paper, we present a module for the simulation of the processes involved in the nitrogen cycle in the unsaturated zone, including nitrate leaching. This module was developed taking steps from the ANIMO and EPIC model frameworks and coupled to the hydrological models integrated within the FREEWAT platform. As such, the nitrogen cycle module was then included in the FREEWAT platform. The developed module and the coupling approach were tested using a simple synthetic application, where we simulated nitrate leaching through the unsaturated zone for a sunflower crop irrigated district during a dry year. The results of the simulation allow the estimation of daily nitrate concentration values at the water table. These spatially distributed values may then be further used as input concentration in models for simulating solute transport in aquifers.
Article
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Depletion and pollution of groundwater, Earth's largest and most accessible freshwater stock, is a global sustainability concern. A changing climate, marked by more frequent and intense hydrologic extremes, poses threats to groundwater recharge and amplifies groundwater use. However, widespread human development and contamination of groundwater reservoirs pose an immediate threat of resource extinction with impacts in many regions with dense population or intensive agriculture. A rapid increase in global groundwater studies has emerged, but this has also highlighted the extreme paucity of data for substantive trend analyses and assessment of the state of the global resource. Noting the difficulty in seeing and measuring this typically invisible resource, we discuss factors that determine the current state of global groundwater, including the uncertainties accompanying data and modeling, with an eye to identifying emerging issues and the prospects for informing local to global resource management in critical regions. We comment on some prospective management strategies. Expected final online publication date for the Annual Review of Environment and Resources, Volume 45 is October 19, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Nas áreas rurais do Brasil 75% da população não tem acesso ao sistema de coleta de esgoto. Nestes locais, o efluente doméstico é despejado em fossas sem impermeabilização, o que permite a infiltração e percolação da porção líquida do efluente no solo e contaminação da água subterrânea. Por esta razão, as fossas são uma das principais fonte de contaminação por nitrato em aquíferos rasos em muitas regiões com carência de serviços de saneamento básico. Além da contaminação por nitrato, pressupõe-se que as características hidroquímicas de aquíferos rasos em áreas rurais são influenciadas pelo influxo de efluentes. Para testar esta premissa, foram coletadas e analisadas amostras de água subterrâneas de nascentes e poços rasos na porção norte do munícipio de Paulínia/SP, realizadas simulações geoquímicas e realizadas simulações numéricas de fluxo e transporte para avaliação da migração da pluma de efluentes na área de estudo. Constatou-se que a águas subterrâneas sem ação antrópica à montante dos poços ou nascentes amostrados possuem reduzida possuem concentração de sólidos totais dissolvidos abaixo de 16 mg/L, sugerindo reduzida influência antrópica. Nascentes situadas à jusante de indústrias apresentaram algum tipo de influência antrópica. As nascentes situadas à jusante de residências rurais e poços rasos próximos destas residências apresentaram características que indicam a influência das fossas sépticas, caracterizadas por concentrações elevadas de STD, NO3-, Cl-, SO4 2-e Na +. Embora representem fontes pontuais, as simulações numéricas de fluxo e transporte demonstram que fossas podem gerar plumas de NO3-, Cl-e Na + com grandes dimensões. O conjunto de resultados obtidos sugere que a influência do ingresso de efluentes domésticos se manifesta pelos incrementos de STD, NO3-, Cl-, SO4 2-e Na +. Deste modo, conclui-se que as fossas são importante agentes atuante na composição química de aquíferos rasos em áreas rurais.
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Background There is limited evidence that nitrate, a common contaminant in drinking water, increases the risk of childhood cancers. Our objective was to examine this association in Denmark. Methods We conducted a nationwide case-control study based on all singletons liveborn to Danish-born parents from 1991 to 2015 (N = 1,219,140) that included 596 leukemias, 180 lymphomas, and 310 central nervous system cancers (CNC) who were ≤15 years of age at diagnosis and were identified from the Danish Cancer Registry. Approximately 100 controls were randomly selected and matched to each case on date of birth and sex. Nitrate measurements in public water systems were linked with an address registry to estimate individual average nitrate concentrations during preconception, prenatal, and postnatal periods. Odd ratios (OR) and 95% confidence intervals (95%CI) were estimated using conditional logistic regression controlling for the matching variables, and birth order, birthweight, urbanicity, maternal education, employment, income and smoking, and parental age. Results There was no evidence of an association of nitrate with leukemia or lymphoma. An association between CNC and the highest category of nitrate exposure (>25 mg/L nitrate) was observed for preconception (OR = 1.82, 95%CI:1.09 to 3.04), prenatal (OR = 1.65, 95%CI:0.97 to 2.81), and postnatal exposure (OR = 1.48, 95%CI:0.82 to 2.68) in fully-adjusted models. There was also some evidence of an exposure–response in models of continuous nitrate exposure and CNC. Conclusions Our findings provide some evidence that exposure to nitrate from drinking water may increase the risk of childhood CNC cancer, but not leukemia or lymphoma.
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Nitrate nitrogen is one of the vital issues needed to be addressed in the water purification process utilizing groundwater as a drinking water source. In this study, a sandwich-type polyoxometalate Na [α-SiW9O34] has been synthesized and SiW9/TiO2/Cu composite has been prepared by sol-gel method. Samples have been characterized by XRD, BET, FTIR, SEM, ED-Mapping, UV-Vis, XPS. The catalytic reduction of nitrate was performed in the presence of SiW9/TiO2/Cu composite as photocatalyst. The effects of catalyst loading, initial nitrate concentration, sandwich-type polyoxometalate loading, dissolved O2, and concentration of formic acid on nitrate removal have been investigated. The results showed that the prepared composite catalyst had better photocatalytic activity than the TiO2. 76.53% of nitrate removal with 82.09% of N2 selectivity was obtained under the following conditions: catalyst dosage 0.8 g/L, initial nitrate concentration of 30 mg/L, SiW9/Cu loading percentage of 10%, 30 mmol/L of formic acid, in presence of N2, and 6 h reaction time.
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The EU Nitrate Directive has been ruling for almost 30 years, nevertheless nitrate concentration in the Lombardy Plain did not decrease. Together with failures of management implementation, a possible cause for such field observations is that management actions were taken without adequately considering the actual hydrogeological dynamics. To consider this aspect, the paper presents a groundwater flow and transport numerical model of a specific area of the Lombardy Plain. The aim of this model is to demonstrate how modelling, as a management tool, can be useful in the governance process. The groundwater model, using well-known MODFLOW-MT3D codes, is based on existing hydrogeological information, while a nitrogen mass balance has been performed at municipal scale to determine the agricultural N surplus to the subsurface. The model adequately reproduces head levels and nitrate concentrations in observation wells for a 10-year simulation period, showing that 4.5% of the N annual input remains stored in the system. The model indicates the efficiency of rivers and springs to export N out from the system at an estimated rate of 77.5% of the annual N inputs. Back to governance, the model shows that management data at municipal level (e.g. irrigation rates, groundwater withdrawal, N net recharge) provide a satisfactory scale for successfully reproducing nitrate evolution. Hence those variables that can be object of debate during a governance process can be treated as input data to the numerical model. Therefore, backcasting exercises can be conducted to check whether the model outcome fits with the expected results of specific management actions. The model highlights how the N mass balance evolves, providing clues on which factors can be managed to reduce nitrate concentrations and meet the Directive’s requirements. Numerical groundwater models, as an option to address water management issues, ultimately contribute to solve the information and capacity governance gaps.
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Diabetes mellitus is one of the leading chronic and degenerative diseases in the world. It is caused by a myriad of established risk factors such as unhealthy diet, alcohol intake, tobacco use, and physical inactivity among others. Groundwater contamination, though not as prominent as the others, has surfaced as a possible predisposing risk factor of DM. Three major contaminants of groundwater, which have strong link to DM are arsenic, nitrate and fluoride.This paper reviews the findings of previous ecological studies on the nature of the relationship between DM and groundwater contaminants and highlights inconsistencies and contradictions in the findings. Therefore, it is too early to conclude on the effects of the groundwater contaminants on DM based on these early studies. It is still difficult to tell which DM type is more responsive to which groundwater contaminant. Finally, most of the existing studies have been carried out in Asia and Europe/North America regions while very little presently comes from Africa where there is very limited access to public water supply and most private water supplies depend on groundwater sources.
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A pressurized hydrogenotrophic denitrification reactor to remove nitrate from groundwater was recently presented. To enable treatment of nitrate-concentrated brines, we demonstrate here the removal of high nitrate concentrations without nitrogen gas accumulation in the reactor’s headspace over time. In order to eliminate nitrogen gas build up in the pressurized reactor’s headspace, the main unsaturated flow pressurized reactor was connected to an external degassing unit via liquid recirculation. Pressurized liquid from the main reactor was intermittently discharged to the degassing unit where dissolved N2 gas effervesced and escaped to the atmosphere. The degassed effluent water was continuously recirculated back to the main reactor to maintain steady-state nitrogen and hydrogen gas partial pressures. Denitrifying rates of up to 6 g N/L-reactor/d were achieved in the reactor system under freshwater and brine conditions. Nitrate removal was over 97 %, with nitrate effluent concentrations lower than 10 mg N/L for influent concentrations of about 400 mg N/L. The reactor system maintained steady-state nitrogen and hydrogen gas partial pressures using low external recirculation rates at low reactor total pressures (< 5 atm). At high denitrification rates, dissolved nitrogen concentrations in the reactor were super saturated (125–150%) while on the other hand, dissolved hydrogen was undersaturated (30–60%) due to intense bacteria uptake from the water. These dynamic conditions reduced the external recirculation flow requirement for degassing and resulted in much better hydrogen utilization than expected (greater than 93 %).
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Groundwater quality was investigated for fluoride and nitrate contamination in the mica mining areas of Jharkhand with special emphasis on seasonal fluctuation, source apportionment and human health risk assessment. Samples were collected from thirty-seven locations on a seasonal basis. The results indicated 31% and 32% samples of groundwater to exceed the Indian drinking water quality standards for F– and NO3–, respectively. Marked seasonal variation was observed in the concentration of NO3– with highest levels in monsoon season; however, the seasonal fluctuation was insignificant for F–. The NO3– contamination can be attributed to agricultural activities while F– can be related to geogenic sources. For the evaluation of non-carcinogenic risk, Hazard Quotient (HQ) and Hazard Indices (HI) were calculated as per United States Environmental Protection Agency methodology. The results suggested the child population to be most vulnerable to health risks due to ingestion of F– and NO3–. The HI values for men (0.34–18.4), women (0.29–15.8) and children (0.55–29.3) suggested considerable health risk related to F– and NO3– to all the population groups. As high as 95% of the groundwater samples were likely to cause non cancer health effects in the child populace advocating upgraded water management plan for the residents.
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The extensively accumulation of nitrate in different water resources is currently regarded as one of the most predominant threats facing aquatic organisms on worldwide scale. In recent years, a growing body of evidences have been attempting to uncover the influences of nitrate on fish growth and health, thereby evaluating its environment security. However, the systematic assessment and intrinsic mechanism of such influences are apparently devoid. Hence, this investigation employed systematic analysis, meta-analysis and bioinformatic analysis to evaluate the nitrate biotoxicity. We first speculated two levels of nitrate concentration according to forty-four published bibliographies. Systematic analysis indicated that the broad variations of fish sensitivity to chronic and acute nitrate exposures were found in juvenile and larval stage, respectively, comparing to egg. Meta-analysis further revealed that survival rate, CF and SGR were significantly improved in low nitrate concentration during chronic exposure. Such improvements were reflected by Total mean differences (TMD) and 95% CIs (Confidence Intervals): Survival rate (-4.06 [-7.67, -0.45]), Fulton's condition factor (CF) (-0.03 [-0.03, -0.02]) and Specific growth rate (SGR) (-0.10 [-0.16, -0.04]). To trace the impact, the alternations of molecular expression and histology in brain, gill, liver, intestine, and blood suggested that the chronic and acute nitrate exposures could result in abnormal tissue structures and molecular dynamics. Moreover, omics analysis via integrating intestinal microbiome (microbial composition; %) and liver transcriptome (Gene Ontology: biological processes) revealed that the low concentration exposure induced a weakly immune response in fish liver and it matched to the intestinal immune response. Overall, current study has filled the gaps in the field of nitrate toxicity. It could also provide a novel insight for the evaluation of pollutant toxicity on aquatic species.
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The present investigation carried out from a rural part of Nalgonda district, Telangana, India was to know the general groundwater quality and also to measure the vulnerable zones of non-cancer-causing health risks with respect to infants, children, and adults due to consumption of nitrate and fluoride contaminated groundwater. Groundwater samples were collected from the study area and analyzed for major physicochemical parameters. Nitrate and fluoride contents ranged from 2 to 700 mg/L and 0.3–5 mg/L, in which 86% and 32% of the groundwater samples exceed the safe drinking water limits of 45 mg/L and 1.5 mg/L, which spread over an area of 77.59% and 25.41%, respectively. Domestic wastes, septic tank spillages, animal wastes, and nitrate composts are the prime sources of nitrate, while the fluoride-bearing minerals and phosphate fertilizers are the main sources of fluoride in the aquifer regime. Individual non-cancer-causing health index obviously suggested the nitrate as the higher health risk than fluoride. The total non-cancer-causing health index was observed to be more than the acceptable limit of 1.0 in 95.5% of the total groundwater samples concerning infants, children, and adults. The vulnerable intensity of this index appeared to be higher in infants than in children and adults due to differences in their body weights. The spatial coverage area of very health risk is more in infants (37.45%) than that of children (36.78%) and adults (30.34%). Thus, the present study suggested suitable measures for the improvement of groundwater quality and consequently the health conditions of the locals.
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Climate warming is a threat of imminent concern that may exacerbate the impact of nitrate pollution on fish fitness. These stressors can individually affect the aerobic capacity and stress tolerance of fish. In combination, they may interact in unexpected ways where exposure to one stressor may heighten or reduce the resilience to another stressor and their interactive effects may not be uniform across species. Here, we examined how nitrate pollution under a warming scenario affects the aerobic scope (AS), and the hypoxia and heat stress susceptibility of a generally tolerant fish species, common carp Cyprinus carpio. We used a 3 × 2 factorial design, where fish were exposed to one of three ecologically relevant levels of nitrate (0, 50, or 200 mg NO 3-L − 1) and one of two temperatures (18 • C or 26 • C) for 5 weeks. Warm acclimation increased the AS by 11% due to the maintained standard metabolic rate and increased maximum metabolic rate at higher temperature, and the AS improvement seemed greater at higher nitrate concentration. Warm-acclimated fish exposed to 200 mg NO 3-L − 1 were less susceptible to acute hypoxia, and fish acclimated at higher temperature exhibited improved heat tolerance (critical thermal maxima, CTMax) by 5 • C. This cross-tolerance can be attributed to the hematological results including maintained haemoglobin and increased haematocrit levels that may have compensated for the initial surge in methaemoglobin at higher nitrate exposure.
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Provision of safe drinking water sources is one of the most important agenda of the governing bodies in developing countries across the globe. Hence, the current study was taken up to assess the overall groundwater quality and the spatial distribution of the physico-chemical parameters governing the groundwater quality in Raebareli district (North India). In general, the groundwater was found to be slightly alkaline, with the order of ionic abundance being F − < K + < Ca 2+ < NO 3 − < Mg 2+ < SO 4 2− < Na + < HCO 3 −. The results of 'Pollution Index of Groundwater' (PIG) suggest that around 50% of the samples were in the category of 'insignificant pollution', with 1 sample each under 'high' and 'very high' pollution categories. The dominant water type in the study area was found to be 'mixed CaNaHCO 3 type' through hydrochemical facies assessment. The spatial distribution suggests that the north and central parts were the most affected areas with respect to PIG. The non-carcinogenic effects of consuming water contaminated with F − and NO 3 − were assessed through Hazard Quotient (HQ) and Total Hazard Index (THI) values. The HQ Fluoride varies between 0.16-6.34, 0.12-4.69, and 0.14-5.54 for the children, male, and female, respectively. The HQ Nitrate varies between 0.03-4.96, 0.02-3.67, and 0.02-4.33 in the case of children, male, and female, respectively. The spatial distribution of THI suggested that central parts of the study area were under high risk. The potential health risks to the residents in the study area should cause immediate attention from the society, governing authorities, and the research community.
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Diabetes mellitus is one of the leading chronic and degenerative diseases in the world. It is caused by a myriad of established risk factors such as unhealthy diet, alcohol intake, tobacco use, and physical inactivity among others. Groundwater contamination, though not as prominent as the others, has surfaced as a possible predisposing risk factor of DM. Three major contaminants of groundwater, which have strong link to DM are arsenic, nitrate and fluoride. This paper reviews the findings of previous ecological studies on the nature of the relationship between DM and groundwater contaminants and highlights inconsistencies and contradictions in the findings. Therefore, it is too early to conclude on the effects of the groundwater contaminants on DM based on these early studies. It is still difficult to tell which DM type is more responsive to which groundwater contaminant. Finally, most of the existing studies have been carried out in Asia and Europe/North America regions while very little presently comes from Africa where there is very limited access to public water supply and most private water supplies depend on groundwater sources. Keywords: Diabetes, Groundwater, Geogenic, Arsenic, Safe water
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Fresh and pure water has an important role to play for healthy life. Currently, in many studies higher concentrations of contaminants like calcium, sodium, nitrate, lead, chromium, arsenic, fluoride etc. have been reported that makes the water unfit for its direct consumption. Sources and release mechanism of many such pollutants is still not known. These sources can be anthropogenic or geogenic. This paper deals with one of such contaminants namely fluoride and emphasizes on its release from various minerals viz. Gypsum, fluorite, tourmaline, actinolite, plagioclase, biotite, quartz, kayanite, epidote and orthoclase under different pH environment. It has been noted that maximum fluoride has been released from the fluorite at all pH environment (acidic, normal and alkaline) of water while minimal fluoride was released from kayanite. However, orthoclase, tourmaline and biotite can release fluoride in considerable amount. The attempts were also made to compare the release of fluoride from modern sand (Ganga sediments) with ancient sand (from sandy aquifer) under different pH condition. Outcome of studies shows that maximum fluoride released from the sand at the pH range of 6.1 to 8.2.
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Woodchip denitrification walls offer a potentially useful way for passive in situ remediation of groundwater nitrate pollution, yet because of the low redox state they induce on the subsurface environment there is an inherent risk they can promote pollution-swapping phenomena. We evaluated pollution-swapping phenomena associated with the first two operational years of a woodchip denitrification wall that is being trialled in a fast-flowing shallow gravel aquifer of quartzo-feldspathic mineralogy. Following burial of woodchip below the water table there was immediate export of dissolved organic carbon (DOC), phosphorus and ammonium into the groundwater. Under the low redox state sustained by labile DOC, the wall initially provided 100% nitrate removal at the expense of acute and localised pollution that occurred in the form of a plume of dissolved iron, manganese and arsenic that were mobilised from the aquifer sediments, in conjunction with methane gas emission. Within one year however, the reactivity of the woodchip wall subsided to support a steady state condition in which nitrate reduction was the terminal electron acceptor process with no measurable methane emission. Having initially functioned as a sink for the potent greenhouse gas nitrous oxide (N2O), evidence is that the woodchip wall is now exporting N2O, albeit at rates less than those associated with productive agricultural land.
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Efficient and sustainable removal of both organic and inorganic pollutants from contaminated water is an important but difficult task. Here, a novel chemical-biological coupling concept, namely simultaneous coupling of memory photocatalysts and microbial communities (SCMPMC), is proposed for the first time that alternates the removal of organic and inorganic pollutants under successive light/dark cycles. We established this novel coupling system with WO3/g-C3N4 memory photocatalysts and river sediment microbial communities, and applied it to alternately remove dimethyl phthalate (DMP) and nitrate under light/dark cycles. The performance of SCMPMC under the light/dark cycles (12/12 h) showed that ~84.90% of the DMP was removed mainly via robust photocatalytic oxidation during the light phase, and ~86.80% of the nitrate was removed via microbial reduction enhanced by photogenerated electrons stored in the WO3/g-C3N4 memory photocatalysts during the dark phase within one cycle. The microbial communities were positively affected by adding WO3/g-C3N4, as evidenced by increased enzyme activities, cellular antigen metabolism, and relative abundance of typical denitrifiers, including Proteobacteria and Bacteroidetes. These results will contribute to the development of promising decontamination methods and mechanisms to control water pollution driven by the natural day/night cycle.
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Catalytic denitrification is a promising technology for the removal of nitrate through its reduction by a reducing agent with the assistance of a catalyst. In this work, the modification of the silica catalyst support surface with amino groups was found to effectively enhance both nitrate reduction activity and nitrogen selectivity of PdxCuy alloy bimetallic nanocatalyst on it during the catalytic denitrification process. The underlying mechanism was determined to be the in-situ buffering effect from these amino groups to neutralize hydroxyl groups because they could effectively adsorb CO2 to react with hydroxyl groups to avoid their accumulation near the active PdxCuy alloy bimetallic catalyst. Thus, the nitrate reduction activity could be improved and the N2 selectivity could be enhanced. By modulating the Pd/Cu ratio to 4:1, 100 mg/L nitrate was reduced completely within just 50 min and the nitrate reduction rate constant reached 0.07 min⁻¹. After the complete nitrate reduction (100 mg/L), an elevated N2 selectivity of ∼ 97.8% was achieved by modulating the Pd/Cu ratio to 2:1. By hindering the copper oxidation to reduce the metal leakage during the recycle process, the recycle performance of the PdxCuy/NH2-SiO2 catalyst could be largely enhanced, beneficial for its potential applications.
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Significant nitrate contamination of groundwater has been observed in various parts of the world; intensive livestock farming is one of the major causes. This paper reviews various guidelines/regulations, which have been developed in advanced countries such as USA, Canada, Australia, and Europe to combat this problem by designing effective monitoring and management programs. Monitoring programs deal mainly with selection of sites, number of monitoring wells, specific parameters, and sampling frequency, which are helpful for identifying the source and extend of the contamination. Management programs deal with selection of suitable location, site characterization, proximity of livestock facilities and drinking wells, and proper storage, maintenance of the facilities, and limits of manures application in order to minimize nitrate leaching into groundwater. The main aim of this paper is to help states/countries, which do not have any guideline, and consulting engineers/consultants/owners of livestock operation in the design of effective strategies for point source nitrate management.
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The use of ammonium nitrate and fuel oil (ANFO) results in low cost blasting. Such costs may be further reduced by replacing fuel oil with alternative fuels such as biomass (biodiesel, rice straw, corn cob, sugar cane bagasse) and tires residue. This paper investigates the use of other fuels instead of fuel oil by measuring the detonation velocity (VOD) and verifying the importance of these fuels in an explosive mixture. Except for biodiesel, all the tests conducted for the mixture of ammonium nitrate and alternative fuels showed poor performance when compared with ANFO. The achieved percentage of detonation velocity (VOD) of the mixtures in relation to the ANFO were 55.4% for ammonium nitrate + rice straw, 64.9% for ammonium nitrate + corn cob, 70.1% for ammonium nitrate + sugar cane bagasse, 74.4% for ammonium nitrate + tires residue and 93.7% for ammonium nitrate + biodiesel. This study indicates that the methodology proposed can be applied as a reference for determination and preparation of explosive mixtures of fuel and oxidizing agents since in all the tests conducted the detonation of the charges occurred.
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This book presnts a unique and up-to-date summary of what is known about groundwater on our planet, from a global perspective and in trems of area-specific factual information. See: https://www.crcpress.com/Groundwater-around-the-World-A-Geographic-Synopsis/Margat-Gun/9781138000346
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Water pollution is one of the biggest environmental problems and nitrate is among the most common and widespread pollutants in groundwater. There has been an increasing demand for fresh water in the last two decades due to a progressive increase in population. In addition, people face serious water shortages, because groundwater has been used faster than it is naturally replenished.At the same time an increasing amount of wastes and chemicals causes contamination of water resources, especially of groundwater. Although the movement of groundwater through the aquifer has often the effect of removing a lot of impurities from the water by filtering it through the porous rocks, so that groundwater is generally much cleaner than surface water, there are many contaminants which are not easily degraded in the subsurface. Such is the case for nitrate which is impounded into the groundwater by agricultural activities, namely fertilizers and livestock manure. Since nitrate is soluble and negatively charged, it has high mobility and is thus easily leached from the unsaturated zone. In this research work, an attempt has been made to estimate nitrate leaching to groundwater at six different places around the village of Srirangapatnataluk where organic manure and inorganic fertilizers, together with irrigation water and cesspools are the major sources of nitrate in the area. Existing models and Arc-GIS have been used for the analysis. The results indicate that, except for Belagola village, the groundwater nitrate concentrations underneath the irrigated lands are still within the permissible limit, which means that the water of these villages can be used for both drinking and irrigation purposes. The average leached nitrate amounts in the sampled areas supplied from irrigated land have been estimated to range between 51.23 and 74.93 kg/ha/year. For the groundwater nitrate concentrations underneath the cesspools, the results of the analysis show that they are all within the permissible limit, except for the villages of Karekura and Bommuragrahara. Nitrate leaching amounts supplied from the cesspools lie between 87.81 and 381.96 kg/year. The reasons for this wide margin are likely losses due to denitrification and volatilisation processes.
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The paper presents a compilation of various autotrophic and heterotrophic ways of solid-phase denitrification. It covers a complete understanding of various pathways followed during denitrification process. The paper gives a brief review on various governing factors on which the process depends. It focuses mainly on the solid-phase denitrification process, its applicability, efficiency, and disadvantages associated. It presents a critical review on various methodologies associated with denitrification process reported in past years. A comparative study has also been carried out to have a better understanding of advantages and disadvantages of a particular method. We summarize the various organic and inorganic substances and various techniques that have been used for enhancing denitrification process and suggest possible gaps in the research areas whi'ch are worthy of future research.
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It is commonly presumed that organic agriculture causes only minimal environmental pollution. In this study, we measured the quality of percolating water in the vadose zone, underlying both organic and conventional intensive greenhouses. Our study was conducted in newly established farms where the subsurface underlying the greenhouses has been monitored continuously from their establishment. Surprisingly, intensive organic agriculture relying on solid organic matter, such as composted manure that is implemented in the soil prior to planting as the sole fertilizer, resulted in significant down leaching of nitrate through the vadose zone to the groundwater. On the other hand, similar intensive agriculture that implemented liquid fertilizer through drip irrigation, as commonly practiced in conventional agriculture, resulted in much lower rates of pollution of the vadose zone and groundwater. It has been shown that accurate fertilization methods that distribute the fertilizers through the irrigation system, according to plant demand, during the growing season dramatically reduce the potential for groundwater contamination.
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The objective of this study is to remove the nitrate from aqueous solution by using the original and activated red mud in batch adsorption technique. The effects of pH, adsorbent dosage and contact time on the adsorption were investigated. The nitrate adsorption capacity of activated red mud was found to be higher than that of the original form and decreased above pH 7. Adsorption process was expressed by using Langmuir and Freundlich isotherms. Langmuir isotherm curves was found to be significant compared to Freundlich isotherm. Adsorption capacity of the original and activated red mud was found to be 1.859 and 5.858mmol nitrate/g red mud, respectively. It was found that sufficient time for adsorption equilibrium of nitrate ions is 60min. The mechanism for nitrate removal was explained by considering of chemical nature of red mud and interaction between metal oxides surface and nitrate ions.
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The objective of our study was to determine the current status of alluvial aquifer in the Souss-Massa basin, where the nitrate pollution of groundwater is being increasing along the last decades. A multi-approach methodology using hydrogeology, nitrate concentrations, irrigation type and oxygen-18 and deuterium data, was carried out to identify the sources of this pollution. According to the spatial distribution of nitrate contents, nitrate pollution occurs mainly in Chtouka-Massa plain. More than 36% of the sampled wells exceed the value of 50 mg/L as NO 3-. Groundwater in Souss plain is less polluted comparing it to Chtouka-Massa; only 7% of wells exceed the permitted level. Agricultural practices in the study sites are the main cause of serious nitrate pollution given the superimposition of high nitrate concentrations with the distribution of irrigated perimeters. High nitrate levels are associated with high δ 18 O values, clearly indicating that significant quantities of evaporated irrigation waters infiltrate along with fertilizer nitrate to groundwater system. Different δ 18 O-NO 3-trends suggest isotopically distinct, non-point source origins which vary spatially and temporally, due to different degrees of evaporation/recharge and amounts of fertilizer applied.
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Nitrate leaching is a global phenomenon. Nitrate contamination of drinking water leads to a number of health problems to human beings and animals. In the context of the challenge of increasing food production with decreasing cultivable lands demanding heavy application of nitrogen leading to increased nitrate leaching, strategies for reducing it are discussed. The need for measuring nitrates, and methods of measurement of nitrates are discussed. The need for modelling and for long term studies is emphasized. Management options to reduce nitrate leaching from agricultural lands, remedial measures available for removing the nitrates after contamination has occurred and nitrate leaching from organic farming, and finally, some special studies aimed at guiding policy makers are discussed. The status of nitrate contamination in the country is briefly described.
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1] Soil denitrification is an ecologically important nitrogen removal mechanism that releases to the atmosphere the greenhouse gas N 2 O, an intermediate product from the reduction of NO 3 À to N 2 . In this study we evaluate the relationship between soil carbon and denitrification potential in watersheds with bedrock acting as a nonpoint source of nitrogen, testing the hypothesis that nitrate leaching to stream water is in part regulated by denitrification. Two sites, one in a Mediterranean climate and the other in an arid climate, were investigated to understand the interplay between carbon and denitrification potential. Both sites included carbonaceous bedrock with relatively high nitrogen concentrations (>1,000 mg N kg À1) and had low background nitrogen concentrations in surface and groundwater. There was a net accumulation of carbon and nitrogen in soil relative to the corresponding bedrock, with the exception of carbonaceous shale from the arid site. There the concentration of carbon in the soil (15,620 mg C kg À1) was less than the shale parent (22,460 mg C kg À1), consistent with the bedrock being a source of soil carbon. Rates of denitrification potential (0.5–83 mg N kg À1 hr À1) derived from laboratory incubations appeared to be related to the ratio of dissolved organic carbon and nitrate extracted from soils. These data indicate that microbial processes such as denitrification can help maintain background nitrogen concentrations to tens of mM N in relatively undisturbed ecosystems when nitrogen inputs from weathering bedrock are accompanied by sufficient organic carbon concentrations to promote microbial nitrogen transformations.
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Inorganic nitrate and nitrite from endogenous or dietary sources are metabolized in vivo to nitric oxide (NO) and other bioactive nitrogen oxides. The nitrate-nitrite-NO pathway is emerging as an important mediator of blood flow regulation, cell signaling, energetics and tissue responses to hypoxia. The latest advances in our understanding of the biochemistry, physiology and therapeutics of nitrate, nitrite and NO were discussed during a recent 2-day meeting at the Nobel Forum, Karolinska Institutet in Stockholm.
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Nitrate contamination in groundwater is a worldwide problem especially in agricultural countries. Environmental factors, such as land-use pattern, type of aquifer, and soil-drainage capacity, affect the level of contamination. Exposure to high levels of nitrate in groundwater may contribute to adverse health effects among residents who use groundwater for consumption. This study aimed to determine the relationship between nitrate levels in groundwater with land-use pattern, type of aquifer, and soil-drainage capacity, in Photharam District, Ratchaburi Province, lower Mae Klong basin, Thailand. Health risk maps were created based on hazard quotient to quantify the potential health risk of the residents using US Environmental Protection Agency (U.S. EPA) health risk assessment model. The results showed the influence of land-use patterns, type of aquifer, and soil-drainage capacity on nitrate contamination. It was found that most of the residents in the studied area were not at risk; however, a groundwater nitrate monitoring system should be implemented.
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For hydro-chemical evolution and classification of ground water in southern part of Sikar city, 15 ground water samples have collected and analyzed for different water quality parameters, such as pH, EC, TDS, TH, TA, DO, calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, nitrate, sulfate and fluoride with the help of standard methods recommended by American Public Health Association. The analysis indicated that nitrate and fluoride concentrations in some samples are at alarming state as compared to the WHO standards for drinking purposes, thereby suggesting the need for treatment and precautionary measures for use of the particular ground water. On the basis of graphical and statistical analysis, various dimension of improving water quality for drinking and irrigation purposes have also been suggested.
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The nitrate of groundwater in the Gimpo agricultural area, South Korea, was characterized by means of nitrate concentration, nitrogen-isotope analysis, and the risk assessment of nitrogen. The groundwaters belonging to Ca–(Cl + NO3) and Na–(Cl + NO3) types displayed a higher average NO3− concentration (79.4 mg/L), exceeding the Korean drinking water standard (<44.3 mg/L NO3−). The relationship between δ18O–NO3− values and δ15N–NO3− values revealed that nearly all groundwater samples with δ15N–NO3− of +7.57 to +13.5‰ were affected by nitrate from manure/sewage as well as microbial nitrification and negligible denitrification. The risk assessment of nitrate for groundwater in the study area was carried out using the risk-based corrective action model since it was recognized that there is a necessity of a quantitative assessment of health hazard, as well as a simple estimation of nitrate concentration. All the groundwaters of higher nitrate concentration than the Korean drinking water standard (<44.3 mg/L NO3−) belonged to the domain of the hazard index <1, indicating no health hazard by nitrate in groundwater in the study area. Further, the human exposure to the nitrate-contaminated soil was below the critical limit of non-carcinogenic risk.