Operational state of drinking water defluorination project and situation of fluorosis in children aged 8 to 12 in Dagang district of Tianjin in 2009

Objective To investigate the state of drinking water defluorination project in Dagang district and study urinary fluoride levels and detect dental fluorosis of children aged 8 to 12, and to provide scientific basis for prevention and control of fluorosis. Methods Five defluorination projects in rural streets (towns) with highfluoride water and 2 urban water supply projects were choosen to investigate the running status in Dagang district Tianjin in 2009. Five rural and 2 urban schools were choosen to select 100 children aged 8 to 12 (for gender, age matched) in each primary school to study urinary fluoride levels and detection of dental fluorosis. Results A total of 66 defluorination projects in 73 villages were surveyed, among which 61 projects actually worked normally with using rate 92.4%(61/66). Water qualification of all projects could not be ensured due to direct project managers'lack of necessary expertise. In 2009, water qualification rate were 39.3%(24/61 )among the project normally used,with highlighted problem of biological pollution. A total of 490 children aged 8 - 12 in 5 rural towns were surveyed,dental fluorosis rate were 90%(441/490), and dental fluorosis index were 1.82. A total of 207 children aged 8 - 12in 2 urban areas were surveyed, the detection rate of dental fluorosis was 49.8%(103/207), and dental fluorosis index were 0.86. The urinary fluoride level of 230 children aged 8 - 12 in the 5 villages were surveyed. The Range of geometric mean of urinary fluoride were 1.82 - 2.70 mg/L. The urinary fluoride of 102 children aged 8 - 12 in the 2 urban area were surveyed. The Range of geometric mean of urinary fluoride were 1.53 - 1.72 mg/L. Conclusions There was phenomenon of high coverage, low utilization rate and less water consumption in the villages of Dagang district, Tianjin drinking water defluoridation projects, thus the health effects of the projects was minimum.Significant health effects is found in the defluorination projects in the urban areas with high coverage and high utilization rate. Studying new water improvment methods and new forms of water supply system is urgent for solving the problems met in the ineffective water defluorination project. Key words: Drinking water; Fluorosis, dental; Engineering; Data collection