Certified in Public Health (CPH) Practice Exam

Which method provides the most accurate exposure assessment for workers?

1. Determination of the chemical in the air

2. Biomonitoring determination of metabolites of the chemicals in blood and urine

3. Determination of the chemical on the skin

4. Estimation of the exposure by taking an occupational history

The correct answer is: Biomonitoring determination of metabolites of the chemicals in blood and urine

Biomonitoring, which involves assessing metabolites of chemicals in blood and urine, offers the most accurate exposure assessment for workers. This method directly measures the body's response to exposure by analyzing biological samples, providing a comprehensive view of how much of a substance has been absorbed and its potential effects on health. Unlike environmental measures, biomonitoring accounts for all pathways of exposure, including inhalation, ingestion, and dermal contact. Additionally, it reflects the actual internal dose that can impact biological systems, making it a preferred choice when precision is crucial. In contrast, determining chemicals in the air, on the skin, or through occupational history may not capture the full scope of exposure. Air sampling may miss short-term spikes or variations in exposure levels. Skin assessments can be influenced by various factors such as clothing or the specific activities of an individual and may not provide a complete measure of internal exposure. Estimating exposure through occupational history relies on recall and may introduce bias or inaccuracies, as individuals may not accurately report their exposure levels or history. Thus, biomonitoring stands out as the most reliable method for assessing worker exposure to harmful substances.