Objective To investigate the distribution of water-borne fluoride and the current situation of endemic fluorosis in Yan'an city in 2006, and to evaluate the effect of water defluoridation project by improving driking water quality. Method In 2006 in Yan'an city, 5 samples from water source were collected in each selected village that was chosen according to 5 directions of East, West, South, North, and Central. Meanwhile, 1 sample from water source, 1 sample from water processing factory and 2 tap water samples were collected from each water defluoridation project. Water fluoride was determined by spectrophotometric method, teeth and skeletal fluorosis examination were performed by Dean method and "national criteria of endemic skeletal fluorosis diagnosis of China" in children aged 8-12 year and adults, respectively if water fluoride level > 1.00 mg/L Results Of 726 water samples from 293 villages tested, samples from 25 villages had higher fluoride( > 1.00 mg/L), and these villages covered a population of 11 610 people and most of these people were in Wuqi and Yanchuan counties. Water fluoride ranged from 0.10 mg/L to 3.50 mg/L, with median being 0.59 mg/L. Of 100 water samples from 25 water defluoridation projects, only 1 sample exceeded the national criteria in Yanchuan, and Wuqi counties, respectively,with fluoride level being 1.85 mg/L and 1.60 mg/L, respectively, and population exposed was 3083 and 708, respectively, with water fluoride ranged 0.30 - 2.00 mg/L In the examination of 1281 children aged 8 - 12, we detected 238 cases of dental fluorosis, and the detection rate reached 18.58%; 13 900 adults were checked, and 375 cases were confirmed of skeletal fluorosis, a detection rate reached 2.70%. Conclusions Yan'an has a wide range of water with high fluoride and severe fluorosis people. The water defluoridation projects need to be further improved. The task of prevention of endemic fluorosis is still arduous, and we should speed up the implementation of comprehensive water defluoridation measures.%目的 掌握延安市高氟水的分布和地方性氟中毒(简称地氟病)病情现状,评价降氟改水工程效果.方法 2006年,在延安市以村为调查点,每村按东、西、南、北、中5个方位共采集5份水源水样,同时采集每个改水工程1份水源水样、1份出厂水水样和2份末梢水水样,采用氟试剂分光光度法检测水氟;在水氟>1.00 mg/L的村中采用Dean法对所有8～12岁儿童进行氟斑牙检查,根据<地方性氟骨症临床分度诊断>法对所有成人进行氟骨症检查.结果 筛查293个村的水源水样726份,水氟中位数为0.59 mg/L,范围为0.10～3.50 mg/L;有25个村水氟超标(>1.00 mg/L),暴露人口为11 610人,高氟村主要在吴起、延川县.筛查25个改水工程,100份水样,水氟中位数为0.58 mg/L,范围为0.30～2.00 mg/L;其中延川、吴起县各有1个工程水氟超标,水氟分别为1.85、1.60 mg/L,暴露人口分别为3083、708人.对1281名8～12岁儿童进行氟斑牙检查,检出238例患者,检出率为18.58%;对13 900名成人进行氟骨症检查,检出375例Ⅱ度以上氟骨症患者,检出率为2.70%.结论 延安市高氟水分布范围广,水氟超标情况和病情比较严重,改水工程有待进一步提高,防治任务依然艰巨,必须加快落实降氟改水等综合防治措施.
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