Combined microbial and isotopic signature approach to identify nitrate sources and transformation processes in groundwater
Combined microbial and isotopic signature approach to identify nitrate sources and transformation processes in groundwater
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结合微生物和同位素特征方法来识别地下水中的硝酸盐来源和转化过程
DOI：
10.1016/j.chemosphere.2019.04.163
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发表时间：
2019
期刊：
影响因子：
8.8
通讯作者：
Cao Lixiang
中科院分区：
文献类型：
--
作者：
Zhu Aiping;Chen Jianyao;Gao Lei;Shimizu Yuta;Liang Dongmei;Yi Ming;Cao Lixiang
硝酸盐（NO3-）污染是一个严重的全球性问题。确定NO3−的来源和含水层中的转化过程是有效控制和减轻NO3−污染的关键步骤。在这项研究中，水化学，微生物和双同位素方法相结合，以阐明在珠江三角洲，中国NO3−污染的来源和影响过程。结果显示，NO3−污染严重，75%的样本NO3−-N浓度高于WHO标准10 mg L−1。δ 15 N单键NO3-和δ 18 O单键NO3-值以及水化学数据的多元统计分析都表明，粪便和污水是NO3−污染的主要原因。生物指标进一步表明，粪肥和污水在雨季对地下水质量的影响大于旱季。根据δ 15 N单键NO3-和δ 18 O单键NO3-与对数NO3−浓度（Ln（NO3−））的显著相关性，证实了雨季排放区存在反硝化作用，其中变形菌门、拟杆菌门和浮游菌门为优势类群，脱氯单胞菌属、黄杆菌属和硝化螺旋菌属为优势类群.雨季反硝化细菌丰度与δ 15 N单键NO3-和NO2−-N呈显著正相关，进一步证实了雨季反硝化作用的发生。这项研究表明，双同位素技术结合微生物数据可以成为确定影响地下水中NO3−的来源和微生物过程的有力工具。此外，研究结果可以为环境管理人员提供有用的见解，以验证地下水污染和更好地应用修复解决方案。
Nitrate (NO3−) pollution is a serious problem worldwide. Identification of NO3−sources and transformation processes in aquifers is a key step in effectively controlling and mitigating NO3−contamination. In this study, hydrochemical, microbial, and dual isotopic approaches were integrated to elucidate the sources and processes influencing NO3−contamination in the Pearl River Delta, China. The results showed a severe NO3−contamination, with 75% of the samples having NO3−-N concentrations above the WHO standard of 10 mg L−1. The δ15Nsingle bondNO3-and δ18Osingle bondNO3-values and a multivariate statistical analysis of hydrochemical data both revealed that manure and sewage were mainly responsible for NO3−contamination. Biological indicators further demonstrated that, manure and sewage had greater impacts on groundwater quality during the rainy season than during the dry season. Based on the significant relationships of δ15Nsingle bondNO3-and δ18Osingle bondNO3-with the logarithmic NO3−concentration (Ln(NO3−)), denitrification was confirmed to occur in the discharge zone during the rainy season.Proteobacteria,Bacteroidetes, andPlanctomyceteswere identified as the dominant phyla, andDechloromonas,Flavobacterium, andNitrospirawere dominant among the denitrifying bacteria in groundwater. The abundance of denitrifying bacteria had significant positive correlations with δ15Nsingle bondNO3-and NO2−-N during the rainy season, further confirming the occurrence of denitrification during the rainy season. This study showed that dual isotope techniques combined with microbial data can be a powerful tool for identifying the sources and microbial processes affecting NO3−in groundwater. Moreover, the results can provide useful insights for environmental managers to verify groundwater pollution and better apply remediation solutions.