Carbon tetrachloride (CCl4) used to be a relatively common household solvent (to
ID: 533186 • Letter: C
Question
Carbon tetrachloride (CCl4) used to be a relatively common household solvent (to remove nail polish), even though it is moderately toxic. A long term study on rats showed that there was no evidence of a toxic response below 0.311 mg per day of ingested CCl4.
a. The average lab rat in the study weighted 492 g. Calculate the “No Observable Effects Level” (NOEL) and “Acceptable Daily Intake” (ADI; also called toxicity reference dose, or RfD) values based on this study.
b. Calculate the maximum recommended daily dose for a 75 kg adult.
Explanation / Answer
For the study of toxicity of carbon tetrachloride on rats and humans
a. With the given level of 0.311 mg /days level limit
NOEL = below 0.311 mg per day
Acceptable daily does would be thus, lower than 0.311 mg.
b. For an adult of weight 75 kg
maximum recommended daily dose would be = 75 x 0.311 = 23.325 mg per day