Problem: Suppose drinking water contains 1.0 mg/L of toluene and 0.01 mg/L of tetrachloroethylene (C2Cl4). A 70 kg adult drinks 2 L per day of this water for 10 years.
1. Does the hazard index suggest that this was a safe level of exposures?
2. Tetrachloroethylene is a B2 carcinogen. What is the carcinogenic risk faced by someone drinking this water? Is it less than a goal of 10-6?
RfD for toluene is 0.02 mg/kg-day
RfD for tetrachloroethylene is 0.01 mg/kg-day
Hazard Quotient = daily dose/RfD