An analysis of monitoring data of drinking-water-borne endemic fluorosis in Shanxi Province in 2014

Objective To dynamically monitor the implementation progress and the quality of the water quality improvement project in drinking water type of endemic fluorosis areas, to learn the condition change tendency, and to evaluate the effect of control measures. Methods According to "The Plan of Surveillance on Drinking-water-borne Endemic Fluorosis in China", 18 villages in 6 counties were selected as monitoring sites in Yanggao, Dingxiang, Xiaodian, Taigu, Xiangfen, Linyi counties. Water fluoride content in residents' drinking water samples was determined in monitoring counties and villages, and the operation of water supply projects was investigated. The fluorine content in water samples was determined according to the standard testing methods for drinking water (GB/T 5750.5-2006). All children aged 8 to 12 of the survey villages were examined and determined dental fluorosis using "Diagnostic of Dental Fluorosis" (WS/T 208- 2011). People of over 25 years old in monitoring counties were selected to be examined skeletal fluorosis by X-ray and the content of urinary fluoride was determined, and they were examined by X- ray according to "Diagnostic Criteria of Endemic Skeletal Fluorosis" (WS 192- 2008), and the urinary fluoride content was determined by fluoride ion selective electrode method. Results A total of 18 villages were monitored, 16 had changed the water, 2 had not changed the water. In water changed villages, small water projects were 15, accounted for 93.75% (15/16); large water project was 1, accounted for 6.25% (1/16); all projects were in normal operation, 10 of the projects provided water with normal fluoride, the range of water fluoride content was 0.11 - 1.00 mg/L, the qualified rate of water fluoride content was 62.50% (10/16); 6 of the projects provided water with fluoride exceeded the standard, the range of water fluoride content was 1.69 - 2.91 mg/L, the rate of water fluoride content exceeded was 37.5% (6/16). Water fluoride content of the two villages which water had not changed were 2.59, 2.62 mg/L. The detectable rates of dental fluorosis of children were 20.00% (147/735), 44.89% (224/499) and 48.42% (46/95), respectively, in the monitored villages with qualified, excessive water fluoride content and not changed water villages, the differences were significant statistically (χ2 = 99.32,P < 0.01). The prevalence rates of skeletal fluorosis were 4.67% (21/450), 3.00% (9/300) and 9.00% (9/100), respectively, in the three groups. Determination of urinary fluoride in population were 450, 205 and 100 cases, and geometric means of urinary fluoride concentration of human were 1.57, 3.48 and 2.05 mg/L, respectively, in the three groups. Conclusions By reducing fluorine and improving drinking water quality, the disease in drinking water endemic fluorosis areas in Shanxi Province has been controlled to a certain degree. However, some areas are still threatened by high fluoride, the quality of water improvement project needs to be improved; prevention and control situation is still grim. Key words: Water; Fluorine; Outcome assessment