Investigation and distribution of higher fluorides water in different ecotypic areas in Gansu Province from 2006 to 2008

Abstract

Objective To master the status of the distribution of high-fluorine water and ecological districts endemic areas of fluorosis in Gansu Province so as to provide a scientific basis for control strategy. Methods The information on ecology and drinking water sources was surveyed in rural residential areas of the project counties (district). Five samples of source water were collected from five azimuths of east, west, north, south and center in every endemic village to detect fluoride content and calculate the mean. Water fluoride content was detected by means of fluorides ion selective electrode. Results In 41 counties of the total 45 counties, fluoride contents in 7174 water samples were screened out to be more than 1.0 mg/L and accounted for 29.84%(7174/24 041), which were distributed in 1524 villages, accounting for 31.64% (1524/4819) in water samples. It was found that fluoride contents in water samples in 28 counties were more than 2.0 mg/L and in 30 villages of 9 counties were more than 4.0 mg/L, which were distributed in the hills and valleys of Loess Plateau or the Loess Plateau-gully region. The results showed that the fluoride levels of different areas presented such a sequence as(from low to high): the grassland meadow area of Gannan plateau < the desert region < the gobi region of Hexi Corridor < the hills and valleys region of Loess Plateau < the Loess Plateau-gully region. Conclusions Residents in different ecotypic areas of Gansu Province face different drinking water problems, and reasonable planning and guidance should be adopted to prevent and control the endemic fluorosis. Key words: Drinking; Flouride poisoning; Endemic diseases; Data collection