云南省大理州高砷水源筛查结果报告

Screening of high-arsenic water resources in Dali Prefecture, Yunnan

目的了解云南省大理州高砷水分布和当地居民高砷暴露状况。方法在大理州12个县（市），采取筛查和抽样调查相结合的方法抽取自然村，以村为单位采集居民饮水水样，半定量方法检测水砷；对水砷≥0．03mg／L的水样，采用二乙氨基二硫代甲酸银比色法或原子荧光光度法进行复检；统计大理州高砷暴露总人口和儿童人口数。结果共对2639个自然村进行了水砷筛查，检测水样15180份，检出水砷〈0．01mg／L的水样14976份，占98．66％（14976／15180）；≥0．05mg／L水样110份，占0．72％（110／15180）；有超标水源（≥10．05mg／L）的自然村29个，占筛查自然村的1．10％（29／2639）。在检测的水样中，井水10399份（水井深度均在10m以内）、山泉水3903份、河水93份、温泉水69份、水库水26份、地表水690份。在≥0．05mg／L的水样中．井水89份，占0．86％（89／10399）；山泉水15份，占0．38％（15／3903）；温泉水6份，占8．70％（6／69）。共筛查人口1561553人，占总人口数的67．83％（1561553／2302157），其中儿童420513人，占筛查总人数的26．93％（420513／1561553）；高砷暴露人1527865人，占总筛查人口的1．78％（27865／1561553）；儿童暴露人口8993人，占筛查儿童数的2．14％（8993／420513）。结论云南省大理州存在高砷饮用水源，当地居民暴露在高砷危害中，应尽快开展砷中毒病情调查，预防和控制砷中毒的发生。

Objective To find out the distribution characteristics of drinking water with high arsenic in Dali Prefecture, Yunnan. Methods General investigation plus sampling survey was adopted in the city of Dali and 11 counties. The arsenic content in water was tested by half-quantitative fast reagent-box method. The water samples exceeding the standard（≥0.03 mg/L） were re-tested by silver diethyldithiocarbamate colorimetric method or mercury- atomic fluorescence spectrometric method. Population and children exposed by high-arsenic were statistically analyzed. Results Arsenic content in 15 180 samples from 2639 villages are screened, of which 14 976 samples were less than 0.01 mg/L, reaching 98.66% （14 976/15 180）; 110 samples was no less than 0.05 mg/L, only accounting for 0.72% （110/15 180）. Water sources with excessive arsenic was found in 29 villages, in a percentage of 1.1% of all covered villages（29/2639）. The samples were constituted of 10 399 portions of well water （well was less than 10 m deep）, 3903 from spring, 93 from fiver water, 69 from hot spring water, 26 from reservoir water and 690 from surface water. And for the samples which arsenic content were ≥0.05 mg/L, 89 samples（0.86%, 89/10 399） were from well water, 15 from spring water（0.38%, 15/3903） and 6 from spring water（8.70%, 6/69）. A total of 1 561 553 individuals were investigated, in a percentage of 67.83%（ 1 561 553/2 302 156） of the whole population, among those 420 513 were children, rating 26.93% of the investigated population（420 513/ 1 561 553）; 27 865 were exposed to arsenic, accounting for 1.78% of the investigated population 27 865/1 561 553; 8993 children were exposed, rating 2.14% of the investigated population（8993/420 513）. Conclusions There exists high-arsenic water resources in Dali Prefecture, Yunan, so the local inhabitants are in the danger of high-arsenic exposure. Urgent attention shall be paid for the endemic arsenic including investigation, prevention and control.