Human health risk from trihalomethanes in drinking water evaluation with fuzzy aggregation

The human body is most likely to ingest microbes or disinfection by-products (DBPs) in drinking water. More than 80% of water treatment plants use chlorine as a disinfectant. Approximately 14-16% of the bladder cancers in Ontario, Canada, are attributable to the drinking waters containing relatively high levels of chlorinated by-products (CBPs). In recent studies, in addition to the chronic cancer risk from CBPs, several acute effects including cardiac anomalies, stillbirth, miscarriage and pre-term delivery have been reported. In DBPs, the formation of trihalomethanes (THMs) is highest (60-70%); thus the health risk of THMs is likely to be the maximum. In this study, a framework for evaluating human health risk from THMs using fuzzy aggregation is presented. The triangular fuzzy membership functions (TFNs) are used to capture the associated uncertainties. The analytic hierarchical process (AHP) has been employed for weighting schemes of different level attributes. A sensitivity analysis has been performed to verify the importance of different weighting schemes.