Multipathways human health risk assessment of trihalomethane exposure through drinking water

• This study provides probable risk categorization for trihalomehtane in a mega city.
• Concentration of total trihalomethanes (TTHMs) exceeded USEPA and WHO guidelines.
• Cancer risk through ingestion and dermal routes were in “acceptable-low risk” range.
• Cancer risk through inhalation route was estimated under “acceptable-high risk” range.
• At some industrial-urban areas cancer risk for CHCl3 were under “unacceptable risk”.

Life-time human health risk of cancer attributed to trihalomethanes in drinking water in an urban-industrialized area of Karachi (Pakistan) was conducted through multiple pathways of exposure. The extent of cancer risk was compared with USEPA guidelines. Human health cancer risk for total trihalomethanes (TTHMs) through ingestion and dermal routes were estimated in “acceptable-low risk” (≥1.0E−06; ≤5.10E−05), whereas through inhalation route it was estimated under “acceptable-high risk” (≥5.10E−05; ≤1.0E−04) category. However, at some industrial–urban areas cancer risk for CHCl3 were estimated under “unacceptable risk” (≥1.0E−04) through inhalation route.