Using dual isotopes to evaluate sources and transformations of nitrate in the West Lake watershed, eastern China

Jin, Zanfang; Qin, Xue; Chen, Lingxiao; Jin, Ming; Li, Feili

doi:10.1016/j.jconhyd.2015.02.008

Cited by 56 publications

(16 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The approach may also serve as a valuable tool to understand N transformation processes (Sun et al 2011). This approach has been successfully applied during the past several decades to streams and rivers (Mayer et al 2002;Kaushal et al 2011;Ma et al 2015), groundwater (Li et al 2007; Barnes and Raymond 2010;Jin et al 2015), and coastal and estuarine systems (Wankel et al 2009;Korth et al 2013Korth et al , 2014Wong et al 2015). The approach is based on the realization that NO 3 − originating from different sources will exhibit differing isotopic compositions.…”

Section: Introductionmentioning

confidence: 99%

“…In shallow groundwater, NO 3 − distributions are also influenced by land use. In the West Lake watershed, eastern China (Jin et al 2015), nitrogen and oxygen isotopic data indicated that nitrate sources in groundwater were soil N from forest, chemical fertilizers and manure in the tea garden, and domestic sewage from the old residential area in forest and urban area. In deep groundwater, Murgulet and Tick (2013) found that δ 18 O-NO 3 − and δ 15 N-NO 3 − values in the coastal aquifer of the Alabama, USA, indicated that the mixing ratios of sewage and fertilizer were consistent with the study area's land use.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A stable isotope approach and its application for identifying nitrate source and transformation process in water

Kang

Sun

2015

Environ Sci Pollut Res

View full text Add to dashboard Cite

Nitrate contamination of water is a worldwide environmental problem. Recent studies have demonstrated that the nitrogen (N) and oxygen (O) isotopes of nitrate (NO3(-)) can be used to trace nitrogen dynamics including identifying nitrate sources and nitrogen transformation processes. This paper analyzes the current state of identifying nitrate sources and nitrogen transformation processes using N and O isotopes of nitrate. With regard to nitrate sources, δ(15)N-NO3(-) and δ(18)O-NO3(-) values typically vary between sources, allowing the sources to be isotopically fingerprinted. δ(15)N-NO3(-) is often effective at tracing NO(-)3 sources from areas with different land use. δ(18)O-NO3(-) is more useful to identify NO3(-) from atmospheric sources. Isotopic data can be combined with statistical mixing models to quantify the relative contributions of NO3(-) from multiple delineated sources. With regard to N transformation processes, N and O isotopes of nitrate can be used to decipher the degree of nitrogen transformation by such processes as nitrification, assimilation, and denitrification. In some cases, however, isotopic fractionation may alter the isotopic fingerprint associated with the delineated NO3(-) source(s). This problem may be addressed by combining the N and O isotopic data with other types of, including the concentration of selected conservative elements, e.g., chloride (Cl(-)), boron isotope (δ(11)B), and sulfur isotope (δ(35)S) data. Future studies should focus on improving stable isotope mixing models and furthering our understanding of isotopic fractionation by conducting laboratory and field experiments in different environments.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A stable isotope approach and its application for identifying nitrate source and transformation process in water

Kang

Sun

2015

Environ Sci Pollut Res

View full text Add to dashboard Cite

show abstract

“…Therefore, it is difficult for fertilizer to seep into the groundwater. Chloride may originate from domestic sewage, chemical fertilizers, manure, road salt and the natural dissolution of minerals [32,33]. In the study area, the chemical fertilizers and road salt were possibly not the main pollution sources of Cl − .…”

Section: Identifying the Main Groundwater Pollution Sources Via Pcamentioning

confidence: 87%

“…In addition, the higher concentration of TH, Ca 2+ , K + , SO 4 2− , Na + and Mg 2+ may be related to the a large discharge of domestic sewage [33]. Due to the untreated discharge of domestic sewage, a large amount of K + and Na + ions enters the soil layer along with the liquid medium, thereby displacing Ca 2+ and Mg 2+ ions into the groundwater [19].…”

Section: Identifying the Main Groundwater Pollution Sources Via Pcamentioning

confidence: 99%

Spatio-Temporal Variation of Groundwater Quality and Source Apportionment Using Multivariate Statistical Techniques for the Hutuo River Alluvial-Pluvial Fan, China

Zhang

Wang

et al. 2020

IJERPH

View full text Add to dashboard Cite

Groundwater quality deterioration has become an environmental problem of widespread concern. In this study, we used a water quality index (WQI) and multivariate statistical techniques to assess groundwater quality and to trace pollution sources in the Hutuo River alluvial-pluvial fan, China. Measurement data of 17 variables in 27 monitoring sites from three field surveys were obtained and pretreated. Results showed that there were 53.09% of NO3−, 18.52% of SO42− and 83.95% of total hardness (TH) in samples that exceeded the Grade III standard for groundwater quality in China (GB/T 14848-2017). Based on WQI results, sampling sites were divided into three types: high-polluted sites, medium-polluted sites and low-polluted sites. The spatial variation in groundwater quality revealed that concentrations of total dissolved solids (TDS), Cl−, TH and NO3− were the highest in high-polluted sites, followed by medium-polluted and low-polluted sites. The temporal variation in groundwater quality was controlled by the dilution of rainwater. A principal component analysis (PCA) revealed that the primary pollution sources of groundwater were domestic sewage, industrial sewage and water–rock interactions in the dry season. However, in the rainy and transition seasons, the main pollution sources shifted to domestic sewage and water–rock interactions, nonpoint pollution and industrial sewage. According to the absolute principal component scores-multivariate linear regression (APCS-MLR), most water quality parameters were primarily influenced by domestic sewage. Therefore, in order to prevent the continuous deterioration of groundwater quality, the discharge of domestic sewage in the Hutuo River alluvial-pluvial fan region should be controlled.

show abstract

“…While atmospheric molecular oxygen and oxygen in water have different isotopic compositions, microbial nitrification and denitrification are processes that fractionate isotopic composition. Measurement of coupled N and O isotopes in nitrate has been a starting point for source identification of nitrate in groundwater in many recent studies [8][9][10][11]. Analysis of oxygen isotopes in nitrate (δ 18 O-NO 3 − ) was used to help mitigate the inherent uncertainty of relying solely on δ 15 N-NO 3 − , since not only is the oxygen isotope variation greater between some sources than the nitrogen isotopic composition, but the systematic variation of oxygen isotopic compositions with nitrogen isotopic composition can be used to constrain nitrate sources and processes [12,13].…”

Section: Introductionmentioning

confidence: 99%

Nitrogen Cycle Dynamics Revealed Through δ18O-NO3− Analysis in California Groundwater

et al. 2019

View full text Add to dashboard Cite

Nitrate is a significant water-quality issue in California, the United States as a whole, and the world. Critical to addressing nitrate contamination is understanding the presence and extent of denitrification, and further refining the techniques used to identify nitrate sources. The use and understanding of nitrate isotopic signatures to identify nitrate sources have advanced tremendously; however, knowledge gaps remain concerning specific fractionation pathways and the role of denitrification in altering source values. Using a large unique database of California groundwater nitrate isotopic compositions, we explored the utility of nitrate–oxygen isotope ratios in determining specific nitrate origins. Lawrence Livermore National Lab (LLNL) samples were supplemented by United States Geological Society (USGS) data to create a dataset of over 1200 dual-isotope results. Methods used at LLNL allowed for the determination of δ15N-NO3−, δ18O-NO3−, δ18O-H2O, δ2H-H2O, excess air, major dissolved gases, and excess N2. Results were examined for the degree to which δ18O-NO3− conforms to the model of nitrification in which two atoms of oxygen are sourced from ambient water and one from the atmosphere. Almost 80% of the results fall within one standard deviation of predicted values. However, 19% of samples had significantly higher values, suggesting the preservation of a synthetic nitrate source signature, mixing of sources, or widespread denitrification. Results were examined with respect to general land-use classifications and, while nitrate concentrations followed the expected pattern of being higher in agricultural settings, δ18O-NO3−patterns are complicated by application of N-fertilizer in various forms, and subsequent N cycling in the soil zone. We found that the current understanding of oxygen isotope-fractionation mechanisms cannot yet explain the prevalence of oxygen-isotope compositions with higher than predicted δ18O values, but when paired with related data such as land use and indicators of denitrification, oxygen-isotope compositions of nitrate can help to assess nitrogen cycle dynamics.

show abstract

Using dual isotopes to evaluate sources and transformations of nitrate in the West Lake watershed, eastern China

Cited by 56 publications

References 36 publications

A stable isotope approach and its application for identifying nitrate source and transformation process in water

A stable isotope approach and its application for identifying nitrate source and transformation process in water

Spatio-Temporal Variation of Groundwater Quality and Source Apportionment Using Multivariate Statistical Techniques for the Hutuo River Alluvial-Pluvial Fan, China

Nitrogen Cycle Dynamics Revealed Through δ18O-NO3− Analysis in California Groundwater

Contact Info

Product

Resources

About