2016—2018年陕西省农村生活饮用水毒理学指标监测

目的了解陕西省2016-2018年农村生活饮用水水质毒理学指标达标情况和变化趋势。方法 2016-2018年在陕西省全部102个涉农县(区)辖区设置农村饮用水监测点。每个乡镇选择1~2处农村集中式供水工程的出厂水和末梢水及分散式供水的末梢水作为监测点,共设置18 284个监测点。于每年4-6月枯水期和7-9月丰水期分别采集水样,按照《生活饮用水标准检验方法》(GB/T 5750. 5-2006、GB/T 5750. 6-2006、GB/T 5750. 8-2006)进行实验分析,通过"全国饮用水水质卫生监测信息系统"收集整理水质监测信息。参照《生活饮用水卫生标准》(GB5749-2006)按照不同年份、水期、水源类型、水处理方式和地域对常规指标中的11项毒理学指标进行分析评价。结果 2016-2018年陕西省农村生活饮用水毒理学指标整体达标率为81. 02%,超标较严重的前4位指标依次为氟化物(9. 74%)、硝酸盐氮(6. 09%)、六价铬(4. 50%)和砷(1. 44%),其余超标指标的超标范围为0. 01%~0. 32%;镉、硒、氰化物、氟化物和硝酸盐氮在不同年份的水质达标率差异有统计学意义(P<0. 05),其中硒、氰化物、氟化物、硝酸盐氮达标率随着年份的递增呈上升趋势(P<0. 05);镉、硒在丰水期达标率高于枯水期,硝酸盐氮在枯水期达标率高于丰水期,差异有统计学意义(P<0. 05);砷、镉、六价铬、铅、硒、氟化物和硝酸盐氮在地表水中的达标率高于地下水(P<0. 05);集中式供水工程不同供水方式水质毒理学整体达标率差异有统计学意义(P<0. 001),常规处理水质达标率最高,其次为沉淀、过滤方式;关中、陕北和陕南地区超标指标种类数分别为10种、10种和4种,砷、镉、六价铬、铅、硒、氟化物和硝酸盐氮等7项指标的区域差异有统计学意义(P<0. 05)。结论陕西省农村生活饮用水毒理学指标整体达标率较低,氟化物、硝酸盐氮、六价铬和砷超标严重且存在明显的地域特征。今后应重点关注超标毒理学指标,从水源供给和处理技术等方面保障饮水安全卫生。

Analysis on monitoring results of toxicological indicators of rural drinking water in Shaanxi Province from 2016 to 2018

OBJECTIVE To understand the toxicological indexes of rural drinking water quality in 2016-2018 in Shaanxi Province. METHODS From 2016 to2018,rural drinking water monitoring points were set up in all( 102) agriculture-related counties( districts) in Shaanxi Province. Each township selected 1-2 rural water supply systems for terminal water supply and terminal water and waste water for distributed water supply as monitoring points. A total of 18 284 monitoring points were set. Water samples were collected during the dry season from April to June and from July to September,according to the Standard Test Method for Drinking Water( GB/T 5750. 5-2006,GB/T5750. 6-2006,GB/T 5750. 8-2006). Carried out experimental analysis and collected water quality monitoring information through the "National Drinking Water Quality Monitoring Information System ". Experimental analysis according to the Standard Test Method for Drinking Water( GB/T 5750. 5-2006, GB/T 5750. 6-2006, GB/T5750. 8-2006);11 toxicological indicators of the routine indicators were analyzed and evaluated according to the Standard of Drinking Water Hygiene( GB 5749-2006).RESULTS From 2016 to 2018,the overall compliance rate of drinking water toxicology indicators in rural areas of Shaanxi Province was 81. 02%. The top four indicators exceeding the standard were fluoride( 9. 74%),nitrate nitrogen( 6. 09%) and hexavalent chromium.( 4. 50%) and arsenic( 1. 44%),the other indicators exceeding the standard exceeds the range of 0. 01%-0. 32%. The difference of water quality compliance rates of cadmium, selenium, cyanide, fluoride and nitrate nitrogen in different years was statistically significant( P<0. 05),and the compliance rate of selenium,cyanide,fluoride and nitrate nitrogen increased with the year. Increasing trend( P<0. 05). The compliance rate of cadmium and selenium in the wet season was higher than that in the dry season,and the compliance rate of nitrate nitrogen in the dry season was higher than that in the wet season,the difference was statistically significant( P<0. 05). The compliance rate of arsenic,cadmium,hexavalent chromium,lead,selenium,fluoride and nitrate nitrogen in surface water were higher than that of groundwater( P < 0. 05). There was a statistically significant difference in the overall compliance rate of water toxicology between different water supply method in centralized water supply projects( P < 0. 001). The highest standard rate of water quality was observed in conventional water treatment,followed by sedimentation and filtration. There were 10,10 and 4 types of over-standard indicators in Guanzhong,northern Shaanxi and southern Shaanxi,and the regional differences of 7 indicators including arsenic,cadmium,hexavalent chromium,lead,selenium,fluoride and nitrate nitrogen had statistics significance( P<0. 05). CONCLUSION The overall compliance rate of toxicological indicators of drinking water in rural areas of Shaanxi Province is low,fluoride,nitrate nitrogen,hexavalent chromium and arsenic are serious and have obvious regional characteristics. In the future,we should focus on the excessive toxicological indicators,and ensure the safety and hygiene of drinking water from the aspects of water supply and treatment technology.