Question

Determine if exposure by oral ingestion to the chemicals xylene, toluene, arsenic and hexavalent chromium poses a noncarcinogenic health risk. The chemical specific reference doses (mg/kg-day) obtained from IRIS are xylene (0.2), toluene (0.8), arsenic (0.0003), and hexavalent chromium (0.003). Assume a 70 kg individual consumes 2 L of water per day with these chemicals at dissolved concentrations of 1 mg/L.

Answer 1

The chemical specific reference dose for xylene = 0.2 mg/Kg-day

(a) since the individual is 70 kg, therefore the reference dose for the individual for xylene would be 0.2 X 70 = 14 mg/day

(b) reference dose for the individual for toluene would be 0.8 X 70 = 56 mg/day

(c) reference dose for the individual for arsenic would be 0.0003 X 70 = 0.021 mg/day

(d) reference dose for the individual for hexavalent chromium would be 0.003 X 70 = 0.21 mg/day

Since the individual drinks 2L of water with concentration of each of the chemicals is 1mg/L, so the individual is consuming 1 X 2 = 2 mg of all the chemicals per day.

So any of the chemical, whose chemical reference is less than 2 mg per day for the individual, that chemical will poses a noncarcinogenic health risk. Thus the those chemicals are arsenic and hexavalent chromium