烟台市农村地区集中式生活饮用水硝酸盐污染现状

Nitrate pollution of centralized drinking water system in rural areas of Yantai City

[目的]调查烟台市农村地区集中式生活饮用水中硝酸盐污染现状,分析污染来源。[方法]2014—2016年按照GB/T 5750—2006《生活饮用水标准检验方法》对烟台市12个涉农县、市、区3 705个农村小型集中式供水单位的出厂水和末梢水在枯、丰水期进行采样和检测,采集水样10 644份,运用Excel 2003和SPSS 11.5对硝酸盐的监测结果进行统计分析。[结果]烟台市农村集中式生活饮用水中硝酸盐质量浓度均值为26.31 mg/L。按GB 5749—2006《生活饮用水卫生标准》中规定限值(≤20 mg/L)进行评价,硝酸盐超标率为46.91%。水中硝酸盐的超标率在枯水期(46.93%)、丰水期(46.89%)的差别无统计学意义(P>0.05);出厂水(46.92%)和末梢水(46.89%)硝酸盐超标率的差别也无统计学意义(P>0.05)。饮用水中硝酸盐含量及超标率较高地区均分布在烟台的中西部。[结论]烟台市农村集中式生活饮用水硝酸盐污染严重,分布呈现一定的区域性。

[Objective] To investigate nitrate pollution of drinking water distributed by centralized treatment systems in rural areas of Yantai City, and analyze pollution sources. [Methods] According to Standard sampling and testing methods for drinking water （GB/T 5750-2006）, 10 644 samples of finished water and tap water from 3 705 small centralized water supplies in 12 agricultural counties/county-level cities/districts of Yantai City were collected in all dry seasons and wet seasons during the period of 2014-2016. Excel 2003 and SPSS 11.5 were used for statistical analysis on the monitoring results of nitrate. [Results] The average concentration of nitrate in drinking water in selected rural areas of Yantai was 26.31 mg/L. According to the limits of nitrate ≤ 20mg/L in Drinking water health standards （GB 5749-2006）, the unqualified rate of nitrate was 46.91%. There was no difference in the qualified rates of nitrate between dry season （46.93%） and wet season （46.89%） （χ2=0.0015, P〉 0.05）, nor between finished water （46.92%） and tap water （46.89%） （χ2=0.0008, P 〉 0.05）. The rural areas with high unqualified rates of nitrate were concentrated in midwest of Yantai. [Conclusion] A heavy nitrate pollution of drinking water is identified in rural areas of Yantai city, showing a regional distribution.