An Intervention Trial on Short Term Exposure to Inorganic Arsenic in Drinking Water

There is still considerable debate surrounding the proposed reduction of current drinking water guidelines for arsenic to 10 L and how low is low enough. One of the main issues is the estimation of potential health impacts of low doses of arsenic and the ability to assess exposure at these lower arsenic levels in drinking water. There has been little investigation of whether reducing the concentration of arsenic in drinking water at low arsenic concentrations in drinking water (greater than the current WHO drinking water guideline of 10 g/L, but less than 50 g/L), to levels below the guidelines, is associated with a significant reduction in urinary arsenic concentrations. We investigated the effect of removing a contaminated drinking water source and replacing it with uncontaminated bottled water on the urinary inorganic arsenic concentrations of 23 exposed individuals. The average drinking water arsenic concentration was 17.5 g/L (range 2.7-27.0 g/L). The results of this study showed that changing from usual drinking water to bottled water decreased urinary inorganic arsenic concentrations, but not significantly. The trial had low power and a larger sample size would be required in addition to more information on other routes of exposure. The results of this small study suggest that factors other than drinking water arsenic concentrations may play an important role in short term exposure to drinking water with below 20 g/L inorganic arsenic.