RESUMO
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.
RESUMO
Objective To investigate the distribution of water fluoride and the present status of water- improving delluoridation projects in the endemic fluorosis areas in Gansu Province. Methods According to "The National Technical Scheme for Endemic Disease Control in 2004" for the water improving projects, water fluoride content was determined from fluorosis villages in 34 counties of 11 cities in Gansu Province. The fluoride content in drinking water was assessed by F-ion selective electrode. Results Water fluoride content was determined in 1576 fluorosis villages of 34 counties. Water fluoride content of 7829 water samples was determined, and the fluoride content of 1891 samples was over standard. Water fluoride content was ≤ 1.00 mg/L(accounting for 75.19%) in 1185 villages and 1.00 mg/L(accounting for 24.81%) in 391 villages; the highest water fluoride content was 6.78 mg/L Nine hundred and ninety three water-improving and defluoridation projects were determined. Water fluoride content of 867 water-improving and defluoridation projects was determined; 768 projects had water fluoride content ≤1.00 mg/L(accounting for 87.67%) and water fluoride content of 108 projects was 1.00 mg/L(accounting for 12.33%),with the highest water fluoride content being 5.27 mg/L. Water-improving and delluoridation projects mostly relied on drilling a well to obtain under-grand water. Abandoned projects accounted for 30%. Conclusions In 34 counties of 11 cites(prefecture), nearly 30% of the villages had water fluoride content exceeding the standard. The situation of endemic fluorosis control is still serious in Gausu Province, countermeasures for endemic fluorosis must be carried out as soon as possible and surveillance of water-improving and defluoridation projects must be strengthened.