Endemic fluorosis surveillance in Qinan County of Gansu Province from 2004 to 2007: an outcome analysis

Abstract

Objective To investigate the prevalence of endemic fluorosis and the progress acchieved through control measures in Taian County of Gansu Province so as to provide basis and technique support for endemic fluorosis control. Methods The survey was carried out according to the National Surveillance Scheme of Endemic Fluorosis. Fulfillment of control measures and the quality of water improving projects were surveyed. Samples of household water and urine in children aged 8-12 years were collected and fluoride content was detected by iron selective electrode method. Children's dental fluorosis were examined with Dean method. Results In Qinan County, water was improved in a rate of 100%. In water-improving and defluoridation projects investigated, 81.15% (99/122) projects worked well, 18.85% (23/122) projects were closed or abandoned. The number of water improvement projects monitored were 24,81,9,8,respectively in the year through 2004 to 2007, revealing 13 projects having water fluorine content(>1.0-2.0 mg/L) in 2004, 15 and 5 projects having water fluorine content higher that 1.0-2.0 and 2.0-4.0 mg/L respectively in 2005, 2 projects having water fluorine content(>1.0-2.0 mg/L) in 2006, and no projects above 4.0 mg/L. In Anfu Village, the fluorine content of source and drinking water were all below 1.0 mg/L in 2006 and 2007. The urinary fluoride content of 8-12 years old children was equal and higher than 1.5 mg/L, dental fluorosis rate was 34.47% (354/1027), and dental fluorosis index was 0.65 in 2004-2007. Conclusions Projects running out of status and excessive levels of water fluorine are frequently seen, dental fluorosis is not controlled in Taian County of Gansu Province Key words: Drinking; Fluoride poisoning; Surveillance