Evaluation of the control effect on coal-burning endemic fluorosis in Wulong County of Chongqing

Objective To evaluate the effects of prevention and control measures on coal-burning endemic fluorosis in Wulong County of Chongqing.Methods At a county level investigation,seven of the disease affected villages were investigated to evaluate the effectiveness of prevention and control measures on coal-burning endemic fluorosis in Wulong County from October 2012 to April 2013.Dental fluorosis of all children aged 8-12 was examined in every selected village.Urine samples of 50 children were collected and urinary iodine level was determined.The installed improved stoves,the drying of corn and pepper were investigated in every household surveyed.Ten samples of corn and pepper were collected and iodine level was determined.At a city level survey,seven of the disease affected villages were investigated to evaluate the effectiveness of prevention and control measures on coal-burning endemic fluorosis in April 2013.Dental fluorosis of all children aged 8-12 was examined in all villages.Ten households were selected for investigation of the installation of improved stoves,drying of corn and pepper.Children dental fluorosis was diagnosed based on the standard for ＂Diagnosis of Dental FIuorosis＂ （WS/T 208-2011）.The fluoride concentration of children＇s urine was measured according to the standard for ＂Urine-determination of Fluoride-ion Specific Electrode Method＂ （WS/T 89-1996）.The fluoride concentration of corn and pepper was measured by the method of fluoride-ion selective electrode.Results The field survey results at the county level showed that the prevalence rate of dental fluorosis of children aged 8-12 was 8.01% （44/549）.The qualified rate of installed improved stoves was 99.56%（3 186/3 200） and the rate of correct usage of improved stoves was 99.78%（3 179/3 186）.The correct drying rates of corn and pepper were all 100.00%（2 390/2 390）.Three hundred and fourteen urine samples were collected and the fluoride content was 0.25 mg/L.Fifty-eight corn and 58 pepper samples were collected.The fluoride contents of corn and pepper were 0.70,2.09 mg/kg,respectively.At the field survey at city level,seven of the disease affected villages were investigated,the prevalence rate of dental fluorosis of children was 11.28% （38/337）.Seventy households were surveyed for the improved stoves.The qualified rate of installation of improved stoves and the rate of correct usage of improved stoves were all 100.00%（70/70,70/70）.The drying of 56 corn and 58 pepper samples was surveyed.The correct drying rates of corn and pepper were all 100.00%（56/56,58/58）.Conchsion All villages have reached the elimination criteria of coal-burning endemic fluorosis areas in Wulong County. Key words: Coal; Fluoride poisoning; Effect; Evaluate