2014—2019年广西桂东南某村井水铊监测

Monitoring on thallium in well water of a village in southeastern Guangxi,2014-2019

目的了解广西桂东南某村井水铊浓度及其变化趋势。方法于2014—2019年平水期(5—6月)、丰水期(7—9月)、枯水期(11—12月),在广西桂东南某村选择3个自然屯作为监测区,同时以其邻近地区的1个行政村作为对照区,采集居民家中井水进行铊的动态监测,并与2014—2018年广西城市市政供水出厂水以及监测区所在县农村集中式供水出厂水铊监测结果进行比较。结果在监测区共采集井水样456件,铊浓度为未检出~2.66μg/L,中位数为0.28μg/L,检出率为89.91%(410/456),超标率为77.41%;在对照区采集检测井水样137件,铊浓度为未检出~0.09μg/L,检出率为4.38%(6/137),均未超标;2013年曾发生过突发环境事件的某河流水样(n=16)铊浓度为未检出~0.07μg/L,检出率为18.75%(3/16);广西14个城市市政供水出厂水(n=170)铊浓度为未检出~0.10μg/L,检出率为9.41%(16/170);2017年监测区所在县农村集中式供水出厂水水样(n=35)铊浓度为未检出~0.10μg/L,检出率为2.86%(1/35)。监测区井水中铊的检出率高于城市市政供水出厂水及监测区所在县农村集中式供水出厂水(P<0.01);与对照区比较,监测区井水中铊浓度和超标率均较高(P<0.01);不同年度监测区井水中铊浓度和超标率间差异均无统计学意义(P>0.05);不同水期井水中的铊浓度、检出率及超标率差异均无统计学意义(P>0.05)。D屯井水中均检出铊,超标率达97.17%,H屯、L屯检出率分别为88.00%和84.80%,超标率分别为53.42%和76.44%。不同自然屯井水铊浓度、检出率和超标率均为D屯>L屯>H屯(P<0.05)。结论广西桂东南某村井水存在铊污染或天然本底值较高,亟需进行改水并开展有关环境铊暴露与人群健康效应研究。

Objective To understand the level of thallium in well water and its variation trend in a village in southeastern Guangxi. Methods During the normal water season(May-June),wet season(July-September),and dry season(NovemberDecember) from 2014 to 2019,three natural villages were selected as the monitoring areas in a village in southeastern Guangxi,an administrative village in its neighboring area served as the control area. The levels of thallium in well water collected from households was dynamically monitored and compared with those in urban municipal water supply in Guangxi from 2014 to 2018 and the rural centralized water supply in local county. Results The levels of thallium ranged from not detectable level(NDL) to 2.66 μg/L,with a median of 0.28 μg/L,the detection rate of 89.91%(410/456) and the over-standard rate of 77.41% for 456 water samples collected in monitoring area,and were NDL-0.09 μg/L with detection rate of4.38%(6/137) for 137 qualified water samples in control area,NDL-0.07 μg/L with detection rate of 18.75%(3/16) for 16 water samples collected from a river where an environmental emergency had occurred in 2013,NDL-0.10 μg/L with detection rate of 9.41%(16/170) for 170 water samples collected from the municipal water supply of 14 cities in Guangxi,as well as NDL-0.10 μg/L with detection rate of 2.86%(1/35) for 35 finished water samples from rural centralized water supply in local county in 2017. Higher detection rates of thallium were found in monitoring area compared with those in finished water samples from urban municipal water supply in Guangxi and the rural centralized water supply in local county(P<0.01),higher levels and over standard rates were found in monitoring area compared with those in control area(P<0.01). No statistically significant differences were found in concentrations and over standard rates of thallium in well water among various years as well as in concentrations,detection rates and over standard rates of thallium in well water among various water periods in monitoring area(P>0.05). The detection rates and over standard rates of thallium in well water were 100% and 97.17% in natural village D,88.00% and 53.42% in natural village H,84.80% and 76.44% in natural village L,respectively.The concentrations,detection rates and over standard rates of thallium in well water all ranked as natural village D >L>T(P<0.05). Conclusion Thallium showes contamination or higher natural background value in well water of the investigated village in southeastern Guangxi,it is urgent to improve the water quality and carry out the research on health effects of environmental thallium exposure among population.