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论文类型：期刊论文

发表时间：2016-01-01

发表刊物：2nd Contaminated Land, Ecological Assessment and Remediation (CLEAR 2014) Conference - Environmental Pollution and Remediation

收录刊物：SCIE、CPCI-S、PubMed、Scopus

卷号：23

期号：2

页面范围：1133-1148

ISSN号：0944-1344

关键字：Stable isotopes; Nitrate sources; Isotope mixing models; N transformation processes

摘要：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, delta N-15-NO3 (-) and delta O-18-NO3 (-) values typically vary between sources, allowing the sources to be isotopically fingerprinted. delta N-15-NO3 (-) is often effective at tracing NO- (3) sources from areas with different land use. delta O-18-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 (delta B-11), and sulfur isotope (delta S-35) 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.