Health risk assessment of exposure to organic matter from the use of reclaimed water in toilets.

To estimate the carcinogenic and non-carcinogenic risks of six volatile organic compounds (VOCs) found in reclaimed water used for flushing toilets, a probabilistic health risk assessment based on Monte Carlo simulations was used. Before Monte Carlo simulations, the contaminant volatilization model was applied to estimate the concentration of the pollutants in air. Moreover, a questionnaire was used to acquire daily exposure time and the Batch Fit tool of Crystal Ball software was applied to find the best-fitting distribution of a part of the input parameters. The risk analysis indicated that the health risks from six VOCs were lower than the negligible risk level (1 × 10(-8)) in all cases, and the health risk for females was slightly higher than that for males. Overall, exposure to organic pollutants in reclaimed water during toilet flushing does not currently pose a significant carcinogenic risk to humans. In this study, we want to provide some information on the health risk from reclaimed water used for toilet flushing in China and hope that it will be useful to promote the application of reclaimed water in water-deficient areas.