Question

7. Carbon tetrachloride is a relatively common halogenated hydrocarbon that is moderately toxic. A long-term study using rats shows that below 0.311 mg per day of ingested carbon tetrachloride there was no evidence of toxic response. a. Assuming the average rat weighs 439 g, calculate the NOEL and ADI (RfD) values that would correspond to the data found in this study. Calculate the maximum recommended daily dose for a 22 kg child. Why might the ADI (or RfD) value be set at an even lower value for young children b. c. than for adults?

Answer 1

a.

In the study of toxicity of carbon tetrachloride on humans and rats

With the given level of 0.311 mg /days level limit

NOEL should be below 0.311 mg per day

Acceptable daily dose would be therefore, lower than 0.311 mg.

b.

For a child of weight 22 kg

maximum recommended daily dose would be = 22 x 0.311 = 6.842 mg per day

c.

For the children's exposure rate special attention should be paid, in fact, they are always higher in compare with the adults, because in spite of almost equal consumption values, their bw (body weight ) is considerable lower. Because of this ADI values should be set as lower for children in compare to adults.