Cancer Risk Analysis in Untreated and Photocatalytic Treated Water Containing THM

In this study, cancer risk analysis was investigated in untreated trihalomethanes (THMs) containing water using synthetic THM solution and after photocatalytic treatment with TiO2 and ZnO of this water. Trace amounts of disinfection by-products remain in the water. In this study, cancer risk assessment was investigated water containing trihalomethanes (THMs) constituted with synthetic THM solution and after the photocatalytic treatment of this water, the cancer risk was determined depending on the presence of THM in the water. With the photocatalytic treatment method using ZnO and nano TiO2 particles, THM removal was studied with synthetic water with an initial concentration of 300 µg/L. In the ZnO-catalyzed process chloroform 25 µg/L, BDCM 2.4 µg/L and DBCM 35 µg/L were found. However, in the TiO2-catalyzed process, chloroform 49 µg/L and DBCM 28 µg/L were obtained. The cancer risk analysis and the hazard index of THMs through oral, dermal and inhalation ingestion from these waters were evaluated. Comparing the three different pathways, humans have a higher risk of cancer through oral ingestion than dermal and inhalation pathways. It has been determined that the cancer risk for ZnO treated water was reduced by 62% and for TiO2 treated water by 69% when THMs by oral ingestion have examined compared to untreated water in cancer risk analysis. The cancer risks of oral ingestion are determined as acceptable low risk, but the cancer risk of THMs through dermal ingestion from dibromochloromethane plays an essential role in this study.