Biomonitoring

Biomonitoring is the measurement of chemicals or their biological effects in human tissues or fluids to assess environmental exposures and the resulting body burden. It provides an integrated estimate of exposure from all sources and routes, including air, water, food, consumer products, and occupation. Common matrices include blood and urine; others such as hair, nails, saliva, breath, or breast milk may be used for specific substances. The concentration of a chemical or its metabolite in these matrices is compared with reference values, population distributions, or regulatory guidelines to interpret exposure levels and time trends.

Biomonitoring is used in public health surveillance, occupational health, regulatory risk assessment, and research. It helps identify at-risk populations, track progress of exposure-reduction measures, and evaluate the effectiveness of policies. Biomarkers vary in specificity and temporal sensitivity: some indicate recent exposure (hours to days), others reflect longer-term body burden. Accurate interpretation requires understanding of pharmacokinetics, co-exposures, and individual factors such as age, sex, genetics, health status, and sampling conditions.

Limitations include that biomonitoring measures internal dose rather than health outcomes, and results do not establish causation. Ethical considerations include informed consent, privacy, data protection, and proper use of results. Quality assurance, standardized methods, and reference values are essential for comparability across studies and programs.