Analysis on endemic fluorosis of burning coal pollution in Chongqing

Objective To investigate the current situation of endemic fluorosis related to air pollution caused by burning coal in Chongqing and to evaluate the effectiveness of countermeasures against fluorosis. Methods Dental fluorosis and skeletal fluorosis Ⅲ° were investigated among children aged 8 to 12 in 13 counties. Urine fluoride content of children sampled from each age group was detected. Fluoride content of corn and pepper was detected in fluorosis endemic areas. The oven improvement and diet were investigated. At the same time the dental fluorosis of children, fluoride content of urine, corn and pepper, oven improvement were investigated in non-endemic areas by sampling as control. Results 74795 children were investigated in 626 villages in endemic areas. The detected rate of dental fluorosis was 45.86% and the fraying rate was 7.09%. 222 cases of skeletal fluorosis Ⅲ° were diagnosed in 4 counties. The median of urine fluoride content was 0.89 mg/L and it was higher than 1 mg/L in 5 counties. The median of fluoride content in corn and pepper was 1.70 mg/kg and 9.20 mg/kg respectively; the detected rate of oven improvement was 68.85% and the rate of proper oven using was 70.00%. The rice was the major diet for local residents. 206 villages reached the criterion of controlled endemic area. The detected rate of dental fluorosis was more than 30% in 12 villages in non-endemic area. Conclusions The endemic areas are have shrunk, the disease situation is improved. Remarkable progress has been made in controlling fluorosis. However, the situations in some endemic areas are still serious and new endemic areas have appeared. So it was important to strengthen the defluoridizing measures mostly aiming at oven improvement.