Question

Agricultural chemicals such as 2,4-d may be ingested by routes other than food. Compare the CDIs for ingestion of a soil contaminated with 10mg kg-1 of 2,4-d by a 3-year-old child and an adult. Assume both the child and the adult have an equivalent exposure of 1 day per week for 20 weeks in 1 year, and the fraction of 2,4-d ingested is 0.10, and that the averaging time equals the exposure time.

a) The CDI for the child is greater than the CDI for the adult.
b) The CDI for the child is equal to the CDI for the adult.
c) The CDI for the child is less than the CDI for the adult.
d) The CDI for the child is not affected by exposure time.

Answer 1

The CDI for ingestion of soil contaminated with 2,4-D is likely greater for a 3-year-old child compared to an adult, due to the child's lower body weight and proportionately higher soil ingestion.

Step-by-step explanation:

When comparing the Chronic Daily Intake (CDI) for ingestion of soil contaminated with 10 mg kg-1 of 2,4-dichlorophenoxyacetic acid (2,4-D) by a 3-year-old child and an adult, we need to consider the body weight and the amount of soil ingested. The fraction of the chemical assumed to be ingested is 0.10, and both individuals are exposed for the same duration: 1 day per week for 20 weeks. Additionally, the averaging time is equal to the exposure time.
Given that children tend to have lower body weights and may ingest more soil relative to their size compared to adults, the CDI for a 3-year-old child would likely be greater than that for an adult.

In conclusion, option (a) is correct: The CDI for the child is greater than the CDI for the adult. This conclusion considers the proportion of 2,4-D ingested relative to body weight, which is typically higher in children due to their smaller size.