Analysis of surveillance results of drinking water type of endemic fluorosis in Qinghai province in 2009

Abstract

Objective To investigate the development trend of drinking water type of endemic fluorosis in Qinghai province, and to provide the basis for the prevention and treatment of the disease. Methods In 2009, six monitoring counties were chosen by using simple random sampling methods, all diseased villages of the six monitoring counties were classified into light, moderate and severe disease types according to water fluorine content on the historical data, and 1 village was respectively chosen from each type. In monitoring villages with improved water, 3 tap water and one source water samples were collected, respectively. Five water samples were collected randomly in water unimproved monitoring villages according to water well locations of east, west, south, north and center. The fluorine content in water and urine was determined according to the "Standard Testing Methods for Drinking Water" (GB/T 5750-2006). Children aged 8 to 12 were examined for dental fluorosis by Dean method.Clinical osteofluorosis of all the resident over the age of 16 was examined, 2 village of these counties were randomly selected, and clinically diagnosed patients with skeletal fluorosis were examined again by X-ray using "Diagnostic Criteria of Endemic Skeletal Fluorosis" (WS 192-2008). Urine sample of 30 children aged 8 to 12 and of 20 adults over the age of 16 were randomly collected and urinary fluoride was determined by F-ion selective electrode method (WS/T 89-2006). Results Improving water projects had been implemented in 14 monitoring villages of the 18 villages in 6 counties, the rate of improved-water was 77.78％(14/18). Among the 14 projects, 5 improved-water projects ran normally, and 9 projects ran with intermittently water supply. Seventy-five water samples were tested, themean of water fluoride was 0.48 mg/L. The prevalence of dental fluorosis was 31.95％ (285/892), that of clinical skeletal fluorosis was 36.55％(1570/4295) and the X-ray detection rate of skeletal fluorosis was 25.64％ (20/78).Five hundred and seventy-one urine samples of children were determined, and geometric mean of urinary fluorine was 1.04 mg/L; 370 adult urine samples were determined, and geometric mean of urinary fluorine was 1.52 mg/L Conclusion Epidemic of drinking water type of endemic fluorosis is still serious in Qinghai province, and drinking water defluoride measures should be further strengthened and improved. Key words: Fluoride poisoning;  Fluorosis, dental;  Osteofluorosis;  Data collection