Life-time cancer risk assessment of carbonaceous disinfection by-products through multiple pathways of exposure in drinking water: Isparta distribution system

Abstract

Disinfection by-products (DBPs) are mutagenic and carcinogenic compounds formed as a result of reactions between precursors and disinfectants in water sources. The aim of this study is to monitor the concentration and speciation of trihalomethanes (THMs) and haloacetic acids (HAAs) and in water samples taken monthly from 5 points of the Isparta water distribution system for 1 year. Also, the lifetime cancer risk of THMs and HAAS through oral ingestion, dermal absorption, and inhalation exposure from tap water in 5 districts in Isparta are estimated. The total concentrations of THMs and HAAs in tap water samples were ranged 24-57 mu g/L and 12-36 mu g/L, respectively. The estimated total carcinogenic risk levels of THMs for male and female through ingestion, dermal absorption, and inhalation were 8.3E-05 and 8.1E-05, respectively. Among the three pathways studied in THMs exposure, inhalation contributed 62% of the total risk followed by oral exposure (27%) and dermal contact (%11). In the Isparta water distribution system, the total cancer risk values estimated for THM are 81 times higher for women and 83 times higher for men than the negligible risk value (1E-06) determined by the United States Environmental Protection Agency (USEPA). The estimated total carcinogenic risk levels of THMs for male and female through multi -pathway were 3.3E-05 and 4.4E-05, respectively. For HAA, the mean total lifetime cancer risk values are 44 times higher for women and 33 times higher for men than the negligible risk value determined by the USEPA.