Sources Of Nitrate Contamination Research Articles

Quantifying the environmental fate and source of nitrate contamination using dual-isotope tracing coupled with nitrogen cascade model on the basin scale.

Nitrate (NO3-) contamination in riverine networks has threatened the environment and human health. Clarifying the NO3- source and environmental fate within the basin under different underlying surfaces is essential for water body protection, especially China's two mother rivers. A series of combination methods were established i.e., field survey, index measurements, isotope-tracing techniques, and material flow analysis in four typical basins to investigate the spatiotemporal variation and source of NO3- pollution and nitrogen cascade characteristics. The dual-isotope coupled with MixSIAR model revealed that manure and sewage were the major NO3- source in the irrigation basin (WY, 76.7%), hilly mountainous basin (YC, 52.3%), and plateau lake basin (DC, 48.7%). However, for the plain-river network basin (CZ), soil leachate was the main source (55.5%). In terms of the N losses to water within agri-environment system, livestock-breeding system in three basins made the biggest contribution among the systems, WY (77.3%), YC (47.3%), and DC (41.8%). While in CZ, about 34.4% of N was delivered from the crop-production system. The N cascade model verified the results of isotope-tracing techniques for each basin. The study provides new insight into NO3--tracing combining hydrogeochemical indicators, isotopic-tracing techniques, and material flow analysis and guides strategies for mitigating the negative impacts of NO3- pollution on aquatic environments on basin scale.

Tracing nitrate contamination sources and dynamics in an unconfined alluvial aquifer system (Velika Gorica well field, Croatia).

Nitrate ions (NO3-) are one of the most common contaminants in the groundwater of the Zagreb alluvial aquifer, which hosts strategic groundwater reserves of the Republic of Croatia and supplies drinking water to one million inhabitants of the capital city. To better understand the origin and the dynamics of NO3- in the unsaturated and saturated zones, the stable isotopes of nitrogen (δ15N) and oxygen (δ18O) in dissolved nitrate, combined with physico-chemical, hydrogeochemical and water stable isotope data, were used in the current work, together with statistical tools and mixing models. The study involved monthly sampling of groundwater, surface water, precipitation and soil water samples. Additionally, the isotopic composition of total nitrogen (δ15Nbulk) was determined in solid samples representing the local nitrate sources. The combination of a nitrous oxide isotopic analyzer and the titanium(III) reduction method provides reliable measurements of δ15NNO3 and δ18ONO3, with optimal stability achieved under specific conditions. Nitrate in the study area predominantly originates from organic sources, with nitrification as the main biogeochemical process, while denitrification was identified at sampling sites under specific anaerobic conditions. Although statistical analysis can be a valuable tool, it should be applied with caution if NO3- originates from multiple sources. The isotopic composition of water showed that groundwater is predominantly recharged by the Sava River but its contribution varied spatially. The results also show the existence of a different recharge source in the southern part of the aquifer. Our findings highlighted the importance of employing a diverse range of analytical methods to obtain reliable and comprehensive understanding of nitrate contamination. By integrating multi-method approaches, stakeholders can better understand the complexities of groundwater contamination and implement more targeted measures to safeguard the water supplies for future generations.

Safeguarding Groundwater Nitrate within Regional Boundaries in China.

Groundwater, essential for irrigation, industry, and drinking, plays a crucial role in environmental health and human well-being. A major threat to groundwater quality is nitrate pollution, primarily stemming from human activities. Safeguarding nitrogen levels in groundwater within regional thresholds remains a global challenge. By integrating 3,134 groundwater samples and nitrogen budget modeling, we found that China's national average nitrate concentration has risen by 29% since the 2000s, reaching 14 mg N L-1. The main sources of nitrate contamination are cropland, landfills, and wastewater disposal, with average annual nitrogen leaching of 1.91 ± 0.16, 0.86 ± 0.18, and 0.63 ± 0.17 million tonnes, respectively; these sources collectively account for 73% of the total nitrate leakage during 2000-2020. Current robust mitigation practices could reduce nitrogen leaching into groundwater by 45% (1.93 million tonnes N), delivering a net societal benefit of US$83 billion in China. Nevertheless, this reduction remains insufficient to meet the safe nitrogen boundary for all provinces, underscoring a compelling necessity for additional measures and policy guidance tailored to protect groundwater resources on a site-specific basis.

Human health risk and water quality assessment due to fluoride and nitrate around Cauvery River basin, southern India.

Good quality water for human consumption, irrigation, and industrial use is very important. Today, around the world, water is contaminated by natural processes and human activities. This study aimed to evaluate the suitability of groundwater for drinking and irrigation, identifythe source of fluoride and nitrate contamination, and assess thehuman health risks around the Cauvery River basin in southern India. A total of 30 groundwater samples were collected and analyzed for hydrochemical parameters, including EC, TDS, pH, Ca, Mg, Na, K, HCO3, Cl, SO4, NO3, and F-. The majority of groundwater samples in the study area are used for drinking and irrigation. The pH of groundwater in the study area was observed to be dominantly alkaline. The levels of TDS, Ca, Na, K, F, and TH exceeded the permissible limits recommended by BIS and WHO. Fluoride and nitrate levels in groundwater exceeded the permissible limits for drinking purposes in 43% and 50% of the samples, respectively. The excessive concentration of fluoride and nitrate in groundwater could pose serious human health problems. Fluoride and nitrate concentrations in groundwater vary between 0.1 and 2mg/l and 12 and 95mg/l, respectively. Based on the computation of the drinking water quality index, about 73% of groundwater samples were classified asexcellent to good. Health risk was assessed for infants, children, and adults using non-carcinogenic risk indices such as hazard quotients (HQ), hazard indexes (HI), total hazard indices (THI), and carcinogenic risk indices (CR). Infants, children, and adults have different total hazards indexes ranging from 1.508 to 5.733, 1.579 to 6.003, and 0.011 to 0.046, respectively. Health risk assessment results indicatedthat the hazard index and hazard quotient were above the recommended limit of > 1 in most of the samples for infants and children. Non-carcinogenic risk and carcinogenic risks were more likely to affect infants and children rather than adults through ingestion of contaminated water.

Tracing Nitrate Contamination Sources and Apportionment in North-Western Volta River Basin of Ghana Using a Multi-Isotopic Approach

Tracing Nitrate Contamination Sources and Apportionment in North-Western Volta River Basin of Ghana Using a Multi-Isotopic Approach

Correction to: Evaluation of Hydrogeochemical Processes for Irrigation Use and Potential Nitrate Contamination Sources in Groundwater Using Nitrogen Stable Isotopes in Southwest Delhi, India: A Case Study

Correction to: Evaluation of Hydrogeochemical Processes for Irrigation Use and Potential Nitrate Contamination Sources in Groundwater Using Nitrogen Stable Isotopes in Southwest Delhi, India: A Case Study

High‐Resolution Forensic Evaluation of Nitrate‐Contaminated Groundwater

AbstractDetermining the source(s) of nitrate contamination in agricultural areas is complicated; doing this as a forensic evaluation for litigation in one field week is especially challenging. The objective of this 2021 investigation, conducted for an agricultural producer who began applying animal waste in 2007, was to determine whether animal waste was the source of nitrate reported at downgradient residential wells. The test Site was a 180 acre, irrigated field that overlies a thick sand aquifer with the water table at about 20 ft below ground level (fbgl). We used multiple lines of evidence to resolve the source(s) of nitrate at three test locations at the Site using continuous vertical testing for hydraulic conductivity and high‐resolution vertical testing of selected chemical and isotopic parameters in water at 5‐ft depth intervals between 5 and 80 fbgl. We found that beneath the Site at the depth interval of most of the impacted residential wells: (1) groundwater travel time indicates nitrate at the impacted residential wells could not have originated from the Site, (2) the groundwater age based on tritium (3H) pre‐dates the establishment of manure spreading, and (3) the nitrogen‐15 concentrations (δ15N) in nitrate indicate the nitrate is not all, if in any part, due to animal waste. This high‐resolution investigation clearly indicated that the agricultural producer was not responsible for the impacted residential wells and was completed in only 1 week.

Evaluation of Hydrogeochemical Processes for Irrigation Use and Potential Nitrate Contamination Sources in Groundwater Using Nitrogen Stable Isotopes in Southwest, India: A Case Study

Evaluation of Hydrogeochemical Processes for Irrigation Use and Potential Nitrate Contamination Sources in Groundwater Using Nitrogen Stable Isotopes in Southwest, India: A Case Study

Source-oriented health risk assessment of groundwater nitrate by using EMMTE coupled with HHRA model

Conventional concentration-oriented approaches for nitrate risk diagnosis only provide overall risk levels without identifying risk values of individual sources or sources accountable for potential health risks. Therefore, a hybrid model combining the end-member mixing model tool on Excel™ (EMMTE) with human health risk assessment (HHRA) was developed to assess the source-oriented health risks for groundwater nitrate, particularly in the Poyang Lake Plain (PLP) region. The results indicated that the EMMTE and the Bayesian stable isotope mixing model (MixSIAR) exhibited remarkable consistency in source apportionment of groundwater nitrate. The source contribution of groundwater nitrate in PLP was related to land use types, hydrogeological conditions, and soil properties. Notably, manure and sewage sources, contributing up to 53.4 %, represented the largest nitrate pollution sources, with a significant contribution of soil nitrogen and nitrogen fertilizers. The non-carcinogenic risk for four potential sources was below the acceptable threshold of 1. Given the factors including rainfall dilution and economic development, attention should be directed towards mitigating the health risks posed by manure and sewage. This study can verify the efficacy of EMMTE in source apportionment and offer valuable insights for decision-makers to regulate the largest sources of nitrate contamination and enhance groundwater management efficiency.

Multiple stable isotopic approaches for tracing nitrate contamination sources: Implications for nitrogen management in complex watersheds

Nitrate (NO3–) contamination of surface water is a global environmental problem that has serious consequences for watershed ecosystems and endangers human health. It is crucial to identify influences of different sources of NO3−, especially the incoming water from upper reaches. A combination of hydrochemistry and multi-isotope tracers (δ11B, δ15N-NO3−, and δ18O-NO3–) were used to determine NO3– sources and their transformation the North Jiulong River (NJLR), Southeast China. The findings revealed that NO3–, which accounted for an average of 87.1% of dissolved inorganic nitrogen (DIN), was the main chemical form of nitrogen species. The integration of dual stable isotopes of NO3−, δ11B, and hydrochemistry showed that NO3– was primarily contributed by sewage, soil nitrogen (SN), and ammonium (NH4+) via precipitation or fertilizers. The contributions from the sewage and soil nitrate source were almost equivalent and much higher than those from other sources in the NJLR watershed. The contributions from diverse sources varied seasonally and spatially. Manure and sewage (M&S) were the leading sources in the summer and autumn, accounting for 60.9 ± 8.5% and 47.3 ± 7.9%, respectively. However, NO3− fertilizers were the predominant source in the spring and winter. The NO3− inflow from upper reaches was proposed as an additional end-member to identify its contribution in the midstream and downstream in this study. The contributions of NO3− from the upper reaches were significant sources in the midstream and downstream, accounting for 27.2 ± 17.8% and 42.9 ± 21.9%, respectively. The obvious decline in local NO3−contribution shares from midstream to downstream implied structural changes in pollutant sources and regional environmental responsibility. Therefore, tracing nitrate sources and quantifying their contributions is critical for clarifying environmental responsibilities for precise local nitrogen management in watersheds.

Determination of Nitrate Migration and Distribution through Eutric Cambisols in an Area without Anthropogenic Sources of Nitrate (Velika Gorica Well Field, Croatia)

Natural potential sources of nitrate contamination involve decaying of organic matter, bacterial production, atmospheric deposition, and soil N. The study presents the first results of nitrate distribution and migration through soil horizons of the Eutric Cambisols, one of the most common soils developed in the area of the Zagreb aquifer and situated in an area without potential anthropogenic sources of nitrate (first sanitary protection zone of the Velika Gorica well field). A total of 16 parameters of soil water and 16 parameters of soil were used to conduct statistical techniques and analyse associated factors within the soil zone. The results indicate that in the deepest soil horizon, nitrogen is present mostly as nitrate due to nitrification under aerobic conditions which promote stability and the potential for nitrate transport. It was found that nitrate concentrations are the result of soil N nitrification, caused by a NO3−/Cl− molar ratio higher than 1 and the absence of precipitation isotopic signature. The results also show that within the coarse-grained Eutric Cambisols N primarily migrates to deeper parts of unsaturated zone in the form of nitrate and nitrite.

Quantification of nitrate contamination sources in groundwater from the Anayari catchment using major ions, stable isotopes, and Bayesian mixing model, Ghana

Quantification of nitrate contamination sources in groundwater from the Anayari catchment using major ions, stable isotopes, and Bayesian mixing model, Ghana

Human health risk assessment of nitrate in private well waters of shallow quaternary alluvial aquifer.

Excessive nitrate intake via ingestion pathway and dermal absorption exposures has adverse health impacts on human health. This study evaluated groundwater (GW) nitrate concentrations and health risks which focused on ingestion and dermal exposures to residents in Bachok District, Kelantan, Malaysia. Three hundred (300) samples of private wells were collected and it is found that the nitrate concentrations ranging between 0.11 and 64.01mg/L NO3-N with a mean value of 10.45 ± 12.67mg/L NO3-N. The possible health hazards of nitrate by ingestion and dermal contact were assessed using USEPA human health risk assessment model for adult males and females. It is observed that the mean Hazard Quotient (HQ) values of adult males and females were 0.305 ± 0.364 and 0.261 ± 0.330, respectively. About 7.3% (n = 10) and 4.9% (n = 8) of adult males and females had HQ values more than 1, respectively. It was also observed that the mean of HQderm was lesser than HQoral for males and females. The spatial distribution of HQ by interpolation method showed high nitrate concentrations (> 10mg/L NO3-N) were distributed from the centre to the southern part of the study location, which identified as an agricultural area, indicating the used of nitrogenous fertilizers as the main source of GW nitrate contamination in this area. The findings of this study are valuable for establishing private well water protection measures to stop further deterioration of GW quality caused by nitrate.

Geochemistry and sources of fluoride and nitrate contamination of groundwater in six districts of the Dodoma region in Tanzania.

Fluoride (F−) and nitrate (NO3−) are common groundwater contaminants. In high concentrations, F− and NO3− cause skeletal fluorosis and methemoglobinemia in children respectively. Therefore protection of public health necessitates the evaluation of groundwater for F− and NO3− contamination. The goal of this study was to assess the geochemistry and spatial distribution of F− and NO3− in six districts in the Dodoma region. Results show that greater than 98% of samples were found to contain F− below 1.50 mgl−1 (WHO 2017). F− Levels exist in the gradient and concentrated to the north of the region. The highest and lowest levels of F− were found in Chemba district, and Mpwapwa district. In the Chemba district, values for F− are (max= 7.30 mgl−1, min = 0.11 mgl−1, mean and SD = 0.87±1.67). In the Mpwapwa district, values for F− are (max= 0.80 mgl−1, min = 0.06 mgl−1, mean and SD= 0.36±0.23). Positive correlation between F− and HCO3− / Ca2+ +Mg+2 and negative correlation between F− and TH, F− and Ca2++Mg2+, and F− and Ca2++Mg2+/Na++K+ suggests HCO3− promote dissolution of F containing rocks while Ca2++Mg2+ removes F− through precipitation reactions. Elevated levels of NO3− were found throughout the districts. The order of districts with NO3− levels above 45.0 mgl−1 was found to be Kongwa (94.74%) > Chemba (69.23%) > Dodoma urban (34.80%) > Chamwino (28.57%) > Mpwapwa (6.60%) and Kondoa (0.00%). Kongwa and Kondoa districts are located south and north of the region. The values in Kongwa are; (max= 196.8 mgl−1, min = 12.5 mgl−1, mean and SD= 137.02±48.47). Values in Kondoa are; (max= 28.00 mgl−1, min = 12.00 mgl−1, mean and SD= 19.97±4.61). Conclusions; groundwater in the Dodoma region safe for drinking with respect to F− and unsafe for drinking with respect to NO3− without remediation.

Quality and Health Risk Assessment of Groundwater for Drinking and Irrigation Purpose in Semi-Arid Region of India Using Entropy Water Quality and Statistical Techniques

The continuous intake of contaminated drinking water causes serious issues for human health. In order to estimate the suitability of groundwater for drinking and irrigation, and also conduct human risk assessments of various groups of people, a total of 43 sample locations in the semi-arid southern part of India were selected based on population density, and we collected and analyzed groundwater from the locations for major anions and cations. The present study’s novelty is integrating hydrochemical analysis with the entropy water quality index (EWQI), nitrate pollution index (NPI) and human health risk assessment. The results of the EWQI revealed that 44.19% of the sample locations need to be treated before consumption. About 37.20% of the study region has a high concentration of nitrate in the groundwater. NPI revealed that 41.86% of the samples had moderate or significant pollution levels. The non-carcinogenic risk evaluation showed that 6–12-year-old children are at a higher risk than teenagers, adults and elderly people in the study area. The natural sources of nitrate and other contamination of groundwater are rock–water interaction, weathering of rock, dissolution of carbonate minerals and evaporation processes, and the anthropogenic sources are the decomposition of organic substances in dumping yards, uncovered septic tanks and human and animal waste. The results suggest taking mitigation measures to reduce the contamination and improve the sustainable planning of groundwater management.

Application of Membrane Processes for Nitrate (NO3-) Removal

Background: The primary sources of nitrate contamination in groundwater resources are excessive fertilizer use and unregulated land discharges of treated wastewater. Due to its harmful nature to human health and its contribution to eutrophication, the removal of nitrate from water has been of great interest in the last decades. Various techniques, such as adsorption, ion exchange, catalytic and biological denitrification, and membrane processes, have been applied for NO3 - removal. Objective: In this review study, the removal of NO3 - by membrane processes, including electrodialysis (ED), electrodeionization (EDI), reverse osmosis (RO), and ultrafiltration, has been reviewed. Method: The pressure-driven membrane and electro-membrane processes applications to NO3 - removal have been reviewed. Results: The effects of process parameters, interferences, and limitations of membrane processes have been summarized. Conclusion: Membrane processes could be a promising alternative for NO3 - removal. After suitable membrane preparation/modification, the nitrate removal rate could reach >99%.

A national isotope survey to define the sources of nitrate contamination in New Zealand freshwaters

A national survey identifies the extent and origin of nitrates in New Zealand’s freshwater resources using nitrogen (δ15N) and oxygen (δ18O) isotopes. A comprehensive database with 1042 samples investigates freshwater type, land-use, geology, soil type and geographic effects on nitrate isotopes across New Zealand. Nitrate contamination is the biggest threat to New Zealand’s drinking water resources with almost 60 % of samples in the study having above-baseline nitrate (NO3-N) concentrations >0.9 mg/L, a threshold noted for higher colorectal cancer risk. Groundwater (2.89 mg/L) had higher median NO3-N concentration than surface water (0.65 mg/L). Traditional nitrate isotope biplots based on the Haber-Bosch cycle (which integrates synthetic fertilizers into the food chain), are reinterpreted to place New Zealand’s unique farming nitrogen contributions from urea and ammonia into context. The majority of New Zealand’s freshwater nitrate isotopes lie in a Normal-Nitrogen-Retention (NNR) zone which also acts as a Mixed Urea-Urine-Fertilizer (Mixed UUF) zone, transitioning nitrified fertilizers and animal waste via redox reactions, microbial action and/or dissipation towards a denitrification zone. Nitrogen ‘hot spots’ with strong urea/urine input can be differentiated from natural N cycling in the NNR/Mixed UUF transition zone by a combined NO3-N concentration and dual isotope approach to identify high-risk sites.

FOUNTAINE WATER POTABILITY ASSESSMENT IN THE SUCEAVA COUNTY

Due to the qualitative changes of groundwater, produced by pollution with substances that alter the physical, chemical and biological qualities of water, at the level of individual water sources (wells), there are frequently recorded exceedances of the maximum permissible concentration for chemical parameters such as ammonium, nitrates, nitrites, hardness, etc.
 The quality of water in wells is influenced by the soil structure and various sources of pollution and the excessive use of fertilizer for fertilization and also by rain washing of agricultural soils (especially in winter). The presence of severe storms can be important sources of nitrate contamination for surface waters. Even the natural structure of the soil can alter the quality of the water.
 Increased concentrations of nitrate in drinking water can be produced by several sources already mentioned, but also by the non-compliance with hygienic-sanitary conditions and location of wells. The goal of this study is to increase the awareness of the importance of monitoring the quality of the water that people consumes. Systematic monitoring of the quality of drinking water is essential, considering the negative influence of the exceedence of maximum admissible values for some parameters, especially on the organisms of children and infants for whom can even lead to death. The results show that the maximum admissible limit values for nitrate and ammonium concentrations in the fountaine water from the Suceava district are exceeded in some cases, while the other parameters under investigation are in general within the permissible limits.

Anthropogenic nitrate contamination of water resources in Ethiopia: an overview

Abstract Nitrate is one of the water contaminants that mainly results from anthropogenic activities. The major causes of nitrate contamination of water resources are anthropogenic activities such as animal or human waste, septic or sewage systems, fertilizer application, concentrated animal farming, industrial waste, and landfill leachates. These man-made activities are the primary sources of nitrate contamination in water resources. Nitrate contamination of water is a global issue that has been increasing over time. According to previous research, exposure to nitrate in water above the World Health Organization (WHO) guideline limit (50 mg of NO3/L) has been found to induce major health effects such as methemoglobinemia in humans, with the severity depending on the amount consumed. This problem has become a major threat to humans and the environment. Thus, this article presented an overview of nitrate contamination of water resources in Ethiopia, emphasizing anthropogenic activities to indicate the current nitrate water contamination status for the necessary remedial actions.

Delineation of Hydrochemical Characteristics and Tracing Nitrate Contamination of Groundwater Based on Hydrochemical Methods and Isotope Techniques in the Northern Huangqihai Basin, China

Hydrochemical research and identification of nitrate contamination are of great significant for the endorheic basin, and the Northern Huangqihai Basin (a typical endorheic basin) was comprehensively researched. The results showed that the main hydrochemical facies were HCO3–Mg·Ca and HCO3–Ca·Mg. Spatial variation coefficients of most indices were greater than 60%, which was probably caused by human activities. The hydrochemical evolution was mainly affected by rock weathering and also by cation exchange. The D–18O relationship of groundwater was δD = 5.93δ18O − 19.18, and the d–excess range was −1.60–+6.01‰, indicating that groundwater was mainly derived from precipitation and that contaminants were very likely to enter groundwater along with precipitation infiltration. The NO3(N) contents in groundwater exceeded the standard. Hydrochemical analyses indicated that precipitation, industrial activities and synthetic NO3 were unlikely to be the main sources of nitrate contamination in the study area. No obvious denitrification occurred in the transformation process of nitrate. The δ15N(NO3) values ranged from +0.29‰ to +14.39‰, and the δ18O(NO3) values ranged from −6.47‰ to +1.24‰. Based on the δ15N(NO3) – δ18O(NO3) dual isotope technique and hydrochemical methods, manure, sewage and NH4 fertilizers were identified to be the main sources of nitrate contamination. This study highlights the effectiveness of the integration of hydrochemical and isotopic data for nitrate source identification, and is significant for fully understanding groundwater hydrochemistry in endorheic basins and scientifically managing and protecting groundwater.