Objective To investigate the distribution of water fluoride and the present status of water-improving defuoridation projects in the endmie fluorosis areas in Gansu Province in 2006. Methods The content of fluoride in drinking water in 18 endemic disease counties was screened, and the defluoridation projects built after the 1980s were supervised and inspected. The content of fluoride in drinking water was assessed by F-ion selective electrode. Results Fluoride content was determined in water of 6260 sources in 1252 fluorosis villages in 18 counties, with 63.50% (3975/6260)≤1.0 mg/L and 36.50%(2285/6260)>1.0 mg/L. Nine hundred and ninty-seven water-improving and clefluoridation projects had been investigated in 16 counties, among which 95.49% (952/997) were function well, and projects intermittently running or abandoned respectively accounted for 3.11% (31/997) and 1.40%(14/997). Nine hundred and eighty-three sources of water treated by the water-improving and defluoridation projects had been determined for fluoride content, it turned out that 91.76% (902/983) were within the standard, only 8.24% (81/983) were not; as for outlet and leftover water of 934 water-improving and defluoridatian projects determined for water fluoride content, qualified projects accounted for 92.08% (860/934) and 91.97%(859/934), leaving 7.92%(74/934) and 8.03%(75/934) disqualified, respectively. Water-improving and defluoridation projects mostly relied on drilling a well in gaining under-ground water or collecting surface-ground water, so under-ground water and surface-ground water are the majority. Conclusions Water fluoride content exceeds the standard in some of the villages. A few projects do not function well. Fluorosis damage still exists in Gansu Province, therefore countermeasures for endemic fluorosis must be carried out as promptly as possible and surveillance on water-improving and defluoridation projects must be strengthened and managed.%目的 了解2006年甘肃省地方性氟中毒病区水氟分布和降氟改水工程现状.方法 在18个病区县(市、区)对未改水病区村进行高氟水源筛查,对20世纪80年代以来各县(市、区)所建设的全部改水工程进行监督、检测,用氟离子选择电极法测定水氟.结果 共筛查18个县(市、区)、1252个村的不同类型饮用水水源6260处,水氟≤1.0 mg/L的占63.50%(3975/6260),水氟>1.0 mg/L的占36.50%(2285/6260).调查16个县(市、区)的各类改水工程997处,正常供水工程占95.49%(952/997).间歇供水工程和已报废工程分别占3.11%(31/997)和1.40%(14/997).检测983处工程水源水,水氟均值合格工程占91.76%(902/983),水氟均值超标工程占8.24%(81/983);检测934处工程的出厂水和末梢水,水氟均值合格工程分别占92.08%(860/934)和91.97%(859/934),水氟均值超标工程分别占7.92%(74/934)和8.03%(75/934).降氟改水工程以打井和集流水窖为主,水源类型主要以地表水和地下水为主.结论 在调查的县(市、区)中,仍有部分村水源水氟超标,少部分改水工程报废或间歇运行,少部分改水工程不符合防病要求,氟危害依然存在,须尽快落实降氟改水措施和加强降氟改水工程的维护和管理.
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