云南省2017—2020年农村学校饮用水毒理学指标监测结果分析

  目的  了解云南省2017—2020年农村学校饮用水毒理学指标达标情况和影响因素, 为保障农村学校饮用水卫生安全和采取针对性的干预措施提供科学依据。  方法  2017—2020年在云南省129个县采用方便抽样法选取456, 399, 391和387所农村中小学校作为监测点, 采用学校饮水供水工程的末梢水, 对水样的11项毒理学指标进行检测和分析评价。  结果  云南省农村中小学校供水工程毒理学指标总达标率为99.33%, 达标率最低的是硝酸盐氮、三氯甲烷、镉, 超标率分别为0.31%, 0.15%和0.09%;不同年份达标率差异有统计学意义(χ2=11.04, P < 0.05);枯、丰水期达标率差异无统计学意义(χ2=0.05, P>0.05);地表水达标率高于地下水(χ2=9.62, P < 0.05);工程经过处理与未处理达标率差异无统计学意义(χ2=1.55, P>0.05);日供水规模≤500 m3达标率低于日供水规模>500 m3(χ2=4.27, P < 0.05)。  结论  云南农村中小学饮用水毒理学指标超标率均较低, 硝酸盐氮、三氯甲烷、镉应被作为云南农村学校饮水优先治理的污染物。

Analysis on monitoring results of toxicological indexes of drinking water in rural schools of Yunnan Province from 2017 to 2020

  Objective  To understand the toxicological indexes and indexes factors of drinking water in rural schools in Yunnan Province during 2017-2020, so as to provide scientific basis for ensuring drinking water safety, and targeted intervention in rural schools.  Methods  The end water of 456, 399, 391, 387 rural primary and secondary school drinking water supply projects in 129 counties in Yunnan Province was collected from 2017 to 2020, 11 toxicological indexes were analyzed and evaluated.  Results  The overall compliance rate of drinking water toxicological indexes in rural primary and secondary schools in Yunnan Province was 99.32%; The top three indexes exceeding the standard were nitrate nitrogen(0.31%), chloroform (0.15%) and cadmium(0.09%). The difference of compliance rate by year was statistically significant(χ2=11.04, P < 0.05); No difference in compliance rate was found between dry and wet seasons(χ2=0.05, P>0.05); The rate of the surface water meeting the standard was higher than that of the groundwater(χ2=9.62, P < 0.05). There was no significant difference in the compliance rate between the treated and untreated projects(χ2=1.55, P>0.05); The daily water supply scale was less than 500 m3, and the rate of reaching the standard was lower than that of daily water supply is greater than 500 m3(χ2=4.27, P < 0.05).  Conclusion  The overall percentage of the toxicological indexes in drinking water exceeding the standard in rural primary and secondary schools in Yunnan Province is low. Nitrate nitrogen, chloroform and cadmium should be considered as the prioritirized pollutants of drinking water in rural schools of Yunnan Province.