Analysis of surveillance results of drinking-water-born endemic fluorosis in Shaanxi Province from 2009 to 2013 / 中华地方病学杂志

ABSTRACT

Objective To investigate the operating situation of water-improvement projects,fluoride content in drinking water and the tendency of drinking-water-born fluorosis in Shaanxi Province.Methods In the areas of drinking-water-born endemic fluorosis,15 villages in 5 counties were randomly selected as monitoring sites,by random number table method.Ten water-improvement projects in each county were randomly selected to investigate the operating situation and 1 water sample from the tap water of each water-improvement project was collected to determine the fluoride level in 2009-2011.For water-improvement villages,the operating situation of the water-improvement projects was monitored and 1 water sample from the tap water of each water-improvement project was collected to determine the fluoride level,and for water-unimprovement villages,1 water sample from each direction of the east,west,south,north and middle of the villages was collected,respectively,to determine fluoride level in 2009-2013.Dental fluorosis of 8-12 years old children and X-ray skeletal fluorosis of adults 25 years old were examined in each village.Water fluoride was tested according to the Standard Testing Methods for Drinking Water (GB/T 5750.5-2006).Diagnosis of dental fluorosis was based on the Dean's Standard (2009 to 2011 edition) and WS/T 208-2011 (2012 to 2013 edition) and that of the adults X-ray skeletal fluorosis was based on WS 192-2008.Results The number of investigated water-improvement projects was 146 in survey counties and 68 in survey villages.The normal operation rates were 97.95％ (143/146) and 98.53％ (67/68),respectively.The qualified rates of water fluoride were 53.42％ (73/146) and 61.67％ (42/68),respectively.The populations covered by the qualified water-improvement projects were 18.93％ and 8.70％ of the total water-improvement projects.And,78.95％ (15/19) of the water-unimproved villages had a water fluoride level of over 1.2 mg/L in the drinking water.In the water-improved villages,children dental fluorosis rate reached an average of 41.62％ (1 061/2 549) and decreased year by year from 2009 to 2013 (except 2012) (x2 =46.818,P ＜ 0.01),but in the water-unimproved villages,the rate was 64.73％(1 167/1 803) on average and did not go down year by year,and the difference was statistically significant (x2 =225.557,P ＜ 0.01).Adults X-ray skeletal fluorosis rate was 22.55％(124/550) in the water-improved villages and 30.00％ (60/200) in the water-unimproved villages in 2009,and the difference was statistically significant (x2 =4.402,P ＜ 0.05).In 2013,adults X-ray skeletal fluorosis rate was 34.17％(219/641) in the water-improved villages and 24.67％(37/150) in the water-unimproved villages,and the difference was statistically significant (x2 =5.010,P ＜ 0.05).Conclusions The measures of water improvement against fluoride have showed definitely control effects,but excess fluoride in drinking water is still a health problem,and the prevalence of fluorosis is not controlled completely.The control work remains to be further strengthened and deepened.