Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses.
Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses.
复制标题
DOI：
10.1016/j.scitotenv.2015.06.080
复制
发表时间：
2015-11
期刊：
影响因子：
--
通讯作者：
Heejung Kim;D. Kaown;B. Mayer;Jin‐Yong Lee;Y. Hyun;K. Lee
中科院分区：
文献类型：
--
作者：
Heejung Kim;D. Kaown;B. Mayer;Jin‐Yong Lee;Y. Hyun;K. Lee
为阐明韩国某盆地不同季节和不同土地利用方式下地下水污染物的来源和控制地下水污染物的生物地球化学反应，对硝酸盐和硫酸盐进行了基于水文地球化学、微生物和双同位素方法的综合研究。研究区土地利用类型主要为林地（58.0%）、菜地（27.6%）、稻田（11.4%）和其他（3.0%）。菜地地下水中NO3-N和SO 42-的浓度最高，分别为4.2-15.2 mg L− 1和1.6-19.7 mg L− 1，而稻田地下水中NO3-N的浓度范围为0 - 10.7 mg L− 1，硫酸盐浓度约为15 mg L− 1。NO3-N浓度> 10 mg L− 1的地下水的δ 15 N-NO3 −值在5.2 ‰至5.9‰之间，硝酸盐的δ 18 O值在2.7 ‰至4.6‰之间，表明硝酸盐是由土壤有机质矿化而来的。菜地含水层中SO 42 −浓度升高，δ 34 S-SO 42 −值在1 ‰至6‰之间，表明来自大气沉降、土壤有机质矿化和合成肥料的硫酸盐混合物是地下水硫酸盐的来源。从稻田收集的样本中δ 18 O-NO3-和δ 18 O-SO 42-值升高表明反硝化和细菌硫酸盐还原正在活跃地发生，以去除地下水中的硫酸盐和硝酸盐。16 S rRNA焦磷酸测序分析表明，稻田地下水中存在大量的硫酸盐还原菌和反硝化菌。这项研究表明，双同位素技术与微生物数据相结合，可以成为一个强大的工具，用于识别影响NO3-和SO 42-的来源和微生物过程，在集约化农业土地利用地区的地下水。
An integrated study based on hydrogeochemical, microbiological and dual isotopic approaches for nitrate and sulfate was conducted to elucidate sources and biogeochemical reactions governing groundwater contaminants in different seasons and under different land use in a basin of Korea. The land use in the study area is comprised of forests (58.0%), vegetable fields (27.6%), rice paddy fields (11.4%) and others (3.0%). The concentrations of NO3–N and SO42 −in groundwater in vegetable fields were highest with 4.2–15.2 mg L− 1and 1.6–19.7 mg L− 1respectively, whereas under paddy fields NO3–N concentrations ranged from 0 to 10.7 mg L− 1and sulfate concentrations were ~ 15 mg L− 1. Groundwater with high NO3–N concentrations of > 10 mg L− 1had δ15N–NO3−values ranging from 5.2 to 5.9‰ and δ18O values of nitrate between 2.7 and 4.6‰ suggesting that the nitrate was mineralized from soil organic matter that was amended by fertilizer additions. Elevated concentrations of SO42 −with δ34S–SO42 −values between 1 and 6‰ in aquifers in vegetable fields indicated that a mixture of sulfate from atmospheric deposition, mineralization of soil organic matter and from synthetic fertilizers is the source of groundwater sulfate. Elevated δ18O–NO3−and δ18O–SO42 −values in samples collected from the paddy fields indicated that denitrification and bacterial sulfate reduction are actively occurring removing sulfate and nitrate from the groundwater. This was supported by high occurrences of denitrifying and sulfate reducing bacteria in groundwater of the paddy fields as evidenced by 16S rRNA pyrosequencing analysis. This study shows that dual isotope techniques combined with microbial data can be a powerful tool for identification of sources and microbial processes affecting NO3−and SO42 −in groundwater in areas with intensive agricultural land use.