When is biological monitoring indicated and what does it assess?

• A. When exposure has internal-dose implications; assesses internal dose via biomarkers in blood/urine.
• B. When exposure to chemicals has external dose implications.
• C. To measure temperature around the worker.
• D. To evaluate noise levels.

Answer: (A)

Biological monitoring focuses on the body's actual absorbed dose by measuring biomarkers in a biological sample such as blood or urine. It is indicated when the health risk is driven by the chemical after it has entered the body, and when there are validated biomarkers that reflect internal dose. This approach captures the total uptake from all routes (inhalation, dermal, ingestion) and accounts for individual differences in absorption and metabolism, giving a direct indication of the dose the body has received.

This is different from external exposure monitoring, which measures what's present in the environment (like air concentrations) and may not reflect how much actually gets into the body. It’s also not about measuring temperature or noise, which assess physical conditions rather than chemical dose.

Examples include measuring lead in blood, cadmium in urine, or metabolites of solvents in urine. Timing and interpretation matter, since many biomarkers have specific half-lives and may require particular sampling schedules.