灰色聚类法对太湖地区农村地下水水质的评价

Application of grey clustering method to rural groundwater quality evaluation in Tai-Lake Region

以太湖流域典型水稻种植地区—宜兴、常熟王庄和辛庄9月份农村地下水水质为研究对象,分析了地下水样的硝态氮、铵态氮、亚硝态氮、总磷、高锰酸钾指数、硫酸盐、氯化物、总硬度等常规项目,确定硝态氮、铵态氮、亚硝态氮、总磷、高锰酸钾指数为该地区地下水的主要污染因子。运用灰色聚类法对地下水水质现状进行了评价。结果表明:太湖地区农村地下水普遍受到了污染,仅有10%的地下水水质勉强达到III类水标准;80%的地下水达到IV类或劣IV类水标准;10%的地下水达V类水标准,已不适合饮用。地下水中的主要超标项目是铵态氮、亚硝态氮和高锰酸钾指数,其中铵态氮和亚硝态氮超标十分严重。宜兴地区铵态氮和亚硝态氮污染最严重;个别监测点地下水中硝态氮含量较高,超过世界卫生组织规定的生活饮用水硝态氮质量浓度10 mg/L的上限。总硬度、硫酸盐、氯化物、砷和硒的含量较正常,但是发展趋势值得关注。

This paper has made an investigation and analysis of the rural groundwater quality of Yixing, Wangzhuang and Xinzhuang of Changshu City in Tai-Lake typical paddy growth region during the month of September. The analysis involved the water content of NO3^- -N, NH4^＋ -N, NO2^- -N, TP, CODMn, chloride, sulfate, as well as the total hardness and so on. AS the result of investigation, it turned out that NO3^- - N, NH4^＋ - N, NO2^- - N, and CODMn were the main polluting factors. To analyze and evaluate the groundwater quality more accurately, the grey clustering method was applied. The testing results indicated that the rural groundwater around the Tai- Lake region has been seriously and widely polluted. There was only ten percent of the groundwater quality just is near to the standard grade Ⅲ of drinking water. However, 80% of it hardly reached or overtook the standard grade IV. The 10 % of it came to the standard grade Ⅴ. Thus, it can be seen that it was not fit for drinking. The main pollutants proved to be NH4^＋ - N, NO2^- - N and CODMn, especially in Yixing. The contents of NO3^- - N in some areas in Wangzhuang and Xinzhuang proved to be quite high. And it went even beyond the limit value （10 mg/L） for drinking which was prescribed by WHO. In addition, although the contents of its total hardness, sulfate, chloride, arsenic and selenium were not high and did not go beyond the pollution standard, attention should be paid to seriously. Thus, it is the earnest wish of the authors of this paper to call for the departments concerned to take effective measures in protecting the groundwater safety of the Tai-Lake region.