Fluoride levels in different drinking water sources in Bangladesh

The fluoride levels in 304 water samples from different sources in Bangladesh were determined using the proton induced gamma emission (PIGE) method. Concentrations vary from 0.02 to 2.32 mg/L with a mean of 0.43 +/- 0.40 mg/L. In tube well water the concentrations range from 0.02 to 2.32 mg/L for 163 samples with a mean of 0.56 +/- 0.48 mg/L. Surface waters contain the lowest amount of fluoride with a mean of 0.14 +/- 0.10 mg/L for 23 samples. In rain water the mean fluoride content is 0.26 +/- 0.13 mg/L, slightly higher than in surface water. The concentration of fluoride in 102 city water supplies ranges from 0.03 to 1.10 mg/L with the mean of 0.33 +/- 0.21 mg/L. These results indicate that the fluoride level in groundwater is, in general, lower than the maximum official permissible limit of 1 mg/L in drinking water set for Bangladesh.