Spatial trends of nitrate pollution and groundwater chemistry in Shimabara, Nagasaki, Japan
Spatial trends of nitrate pollution and groundwater chemistry in Shimabara, Nagasaki, Japan
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DOI：
10.1007/s12665-015-4971-9
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发表时间：
2016-02-01
影响因子：
2.8
通讯作者：
Berndtsson, Ronny
中科院分区：
文献类型：
--
作者：
Nakagawa, Kei;Amano, Hiroki;Berndtsson, Ronny
硝酸盐污染地下水是世界许多地区的一个常见问题。日本长崎的重要农业区岛原地区正在经历这个问题。研究区饮用水的主要来源是地下水，因此硝酸盐污染是一个重要问题。为此，我们于2011年8月至2013年11月期间对住宅区、公共供水井、泉水和河流等40个地点进行了地下水调查并采集了水样。结果显示，有15个地点的硝酸盐氮（NO3-N）浓度超过了日本饮用水质量标准（10 mg L-1）。 NO3-N 最大浓度为 26.6 mg L-1。硝酸盐 (NO3-) 分别与 Cl- (r = 0.96)、K+ (r = 0.68)、SO42- (r = 0.66) 和 Ca2+ (r = 0.59) 密切相关。与 Cl- 和 K+ 的高度相关性与牲畜粪便有关。 SO42- 与化肥相关，Ca2+ 与钙质物质相关，以中和酸性土壤。主成分分析中的第一和第二成分均反映了地下水沿山坡流向冲积扇下游时含水层基质中离子的溶解。利用层次聚类分析，地下水的化学特征被分为四类。其中一个簇与硝酸盐污染的地下水密切相关，其他簇反映了地下水中主要离子的来源。
Groundwater contamination by nitrate is a common problem in many parts of the world. The agriculturally important Shimabara district in Nagasaki, Japan, is experiencing this problem. The general source of drinking water of the study area is groundwater and consequently the nitrate contamination is a significant problem. For this reason, a groundwater investigation was performed and water samples were collected at 40 locations including residential areas, public water supply wells, springs, and rivers from August 2011 to November 2013. Results showed that nitrate nitrogen (NO3-N) concentration is exceeding the Japanese drinking water quality standards (10 mg L-1) at 15 locations. Maximum NO3-N concentration was 26.6 mg L-1. Nitrate (NO3-) was strongly correlated with Cl- (r = 0.96), K+ (r = 0.68), SO42- (r = 0.66), and Ca2+ (r = 0.59), respectively. The high correlations with Cl- and K+ are related to livestock waste. Corresponding correlation with SO42- is related to chemical fertilizers and Ca2+ to calcareous material to neutralize acidic soil. Both the first and second components in principal component analysis reflect ion dissolution from aquifer matrix during groundwater flow along the mountain side towards the lower reaches of the alluvial fan. Using hierarchical cluster analysis, chemical characteristics of groundwater were classified into four clusters. One cluster is strongly related to the nitrate contaminated groundwater and the other clusters reflect the origin of the major ions in the groundwater.