Investigation on status of endemic fluorosis control in Gansu province in 2006

Objective To understand distribution of the endemic fluorosis areas and running status of water-improving defuoridation projects in Gausu province. Methods In 2006, Gansu province endemic fluorosis areas, the content of fluoride in drinking water was measured in villages where water was not improved, running status of delluoridation projects was investigated and the content of fluoride in drinking water were determined in villages where water was improved. Dental fluorosis and skeletal fluorosis prevalence were examined in children in identified high-fluorlde villages. The fluorine content in drinking water was determined by F-ion selective electrode, dental fluorosis of children was diagnosed using Dean method, and adults skeletal fluorosis was diagnosed according to "National Standard for Clinical Diagnosis of Endemic Skeletal Fhiorosis" (GB 16396-1996). Results Water samples were examined in 1997 villages of 26 countries, among which water fluoride content was higher than 1.0 mg/L in 598 villages, accounting for 29.94%(598/1997). All 1215 water-improving and defluoridation projects had been investigated, among which 94.90%(1153/1215) of the projects were functioning well, and intermittent and abandoned projects accounted for 2.96%(36/1215) and 2.14%(26/1215). Mean fluoride of treated water of 1084 water-improving and defluoridation projects had water fluoride content ≤ 1.0 mg/L, accounted for 90.79%(1084/1194) ; mean fluoride of water from 1068 water-improving and defluoridation projects had water fuoride content ≤ 1.0 mg/L, accounting for 91.75%(1068/1164). Total 86 390 children of 8 to 12 year-old were examined, the detectable rate of dental fluorosis was 22.47%(19 414/86 390) and 142 211 adults above 16 year-old were examined, the detectable rate of skeletal fluorosis was 4.20%(5967/142 211). Conclusions Some villages yet have water fluoride content exceeding the standard. Some projects are abandoned and running badly, leading to fluoride content exceeding the standard. In a few areas, the prevalence of children dental fluorosis and adult skeletal fluorosis still exists in Gansu province, the task of prevention and control for endemic fluorosis is still arduous. We must raise the effect of prevention and treatment of this disease. Key words: Drinking;  Fluorides;  Fluorosis, dental;  Ostcofluorosis;  Data collection