Nitrogen Isotope Study on Nitrate-Contaminated Groundwater in the Sichuan Basin, China
Nitrogen Isotope Study on Nitrate-Contaminated Groundwater in the Sichuan Basin, China
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DOI：
10.1007/s11270-006-9186-y
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发表时间：
2007-01
期刊：
影响因子：
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通讯作者：
Xiao-dong Li;H. Masuda;K. Koba;Hai-Ao Zeng
中科院分区：
文献类型：
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作者：
Xiao-dong Li;H. Masuda;K. Koba;Hai-Ao Zeng
我们调查了中国四川盆地NO3−污染地下水的扩展。为了评价该流域氮污染的来源，对该流域4个地区的地下水和雨水中的氮含量和NH 4+、NO3-同位素比值进行了分析。雨水中的NH 4+，其δ 15 N值为强负值至略正值−13.4至+2.3 ‰，似乎来自肥料和排泄物。雨水中的NO3−（δ 15 N：−10.2至−4.4‰）来自汽车尾气中的NOx。研究区井水中δ 15 NNO 3最高，平均值为+9.7 ± 4.7‰，表明受生活污水的污染。在泉水中发现的最低δ 15 NNO 3（−0.2 ± 3.7‰）表明，所研究的地下水样品受到燃料燃烧产生的空气污染物（主要是氮氧化物）的广泛影响。来自农田的井水的δ 15 NNO 3（+3.7 ± 2.1‰）值介于这两个水平之间，表明NO3−污染主要来自使用氮肥的耕作，尽管不能排除动物粪便的贡献。这些结果表明，所研究的地下水被广泛污染的本地来源的氮源。
We investigated the expansion of NO3−-contaminated groundwater in the Sichuan Basin, China. Nitrogen concentrations and isotopic ratios of NH4+and NO3−were analyzed in groundwater and rain collected from four areas in this basin in order to evaluate the sources of nitrogen pollution. NH4+in rain, for which δ15N values are strongly negative to slightly positive −13.4 to + 2.3‰, appears to originate from fertilizers and excretory waste. NO3−in rain (δ15N: −10.2 to −4.4‰) was attributed to NOxfrom automobile exhaust gas. In the studied area, well water sampled from farmyards was found to have the highest δ15NNO3(average: +9.7 ± 4.7‰), indicating contamination by domestic sewage as animal excrement. The lowest δ15NNO3(−0.2 ± 3.7‰), found in spring water, indicates that the studied groundwater samples are widely affected by air contaminants (mainly as nitrogen oxides) resulted from fuel combustions. The δ15NNO3(+3.7 ± 2.1‰) values of well water from farmland are between these levels, suggesting that NO3−contamination results primarily from cultivation using nitrogen fertilizers, although the contribution from animal excrement cannot be excluded. These results demonstrate that the studied groundwater is widely polluted by locally derived nitrogen sources.