Objective To evaluate the relationship between the urinary fluoride concentrations of residents around an electrolytic aluminum factory and their daily intake of fluorine, and the dose-effect relationship between the dental fluorosis of children and their cumulative intake of fluorine.
Methods Three villages at 0.3km and two villages at 1.3 km away from an electrolytic aluminum factory in Jiangxi were selected as monitoring site 1 and 2, and another village at 3.5 km away as control site (monitoring site 3). A total of 388 local residents without fluoride exposure (at least 50 residents from each site) were randomly selected to fill a questionnaire on dietary intake and collect their morning urine samples. A dental fluorosis check was performed by specialists to children aged between 6 and 12 years. Fluorine contents in air, drinking water, crops, vegetables, and meat at each monitoring site were also detected to calculate the respondents' daily fluorine intake. The relationship between children's cumulative fluorine intake and the prevalence rate of dental fluorosis were evaluated.
Results The daily fluorine intakes of residents at monitoring site 1, 2, and 3 were (0.73& #177;0.13), (0.70& #177;0.11), and (0.39& #177;0.03) mg/d, respectively, and there were significant differences (P < 0.05). The urinary fluoride concentrations were (1.80& #177;0.84), (1.44& #177;0.86), and (0.71& #177;0.39) mg/L, respectively, and there were also significant differences among the residents of the three monitoring sites (P < 0.05). After adjusting for age, the correlation coefficient between urinary fluoride concentration and daily fluorine intake was 0.441 (P < 0.05). The benchmark dose (BMD) and benchmark dose lower confidence limit (BMDL) of children's cumulative fluorine intake were calculated as 1 371.11 mg and 572.98 mg respectively.
Conclusion The fluoride released into surrounding area by the electrolytic aluminum factory might be associated with increased urinary fluoride concentration of local population and elevated dental fluorosis among children.
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