What is the difference between biomonitoring and environmental monitoring in exposure assessment?

• A. Biomonitoring measures chemicals or metabolites in biological samples reflecting internal dose; environmental monitoring measures concentrations in air, water, or soil reflecting external exposure.
• B. Biomonitoring measures external exposure; environmental monitoring measures internal dose.
• C. Biomonitoring and environmental monitoring are identical.
• D. Environmental monitoring measures only biological samples.

Answer: (A)

Biomonitoring and environmental monitoring address different parts of exposure assessment. Biomonitoring measures the chemical or its metabolites in a biological specimen such as blood or urine, which reflects the internal dose that has actually entered and been processed by the body. It captures absorption from all routes (inhalation, ingestion, dermal) and the body’s metabolism and elimination, giving a picture of what the individual’s tissues are truly exposed to. Environmental monitoring, by contrast, measures the presence and concentrations of chemicals in environmental media like air, water, or soil. This shows what is available in the environment and indicates potential external exposure, but it does not directly measure how much actually enters the body or what dose results after uptake and metabolism.

So the best answer aligns with biomonitoring as measuring chemicals or metabolites in biological samples reflecting internal dose, while environmental monitoring measures concentrations in environmental media reflecting external exposure. The other statements mix up internal versus external measurements, claim they are identical, or suggest environmental monitoring only involves biological samples, which is not correct.