A man works in an aluminum smelter for 10 years. The drinking water in the smelter contains 0.070 mg/L arsenic and 0.560 mg/L methylene chloride. His only exposure to these chemicals in water is at work.
(a) What is the hazard index (HI) associated with this exposure?
(b) Does the HI indicate this is a safe level of exposure?
(c) What is the incremental lifetime cancer risk for the man due solely to the water he drinks at work and does it seem to be an acceptable risk according to USEPA and Health Canada?