Biological Monitoring

• It can measure the actual exposure of workers to chemicals, taking into account all routes of exposure (inhalation, ingestion, skin absorption, etc.).
• It can reflect the individual variability in metabolism, excretion, and susceptibility to chemicals.
• It can provide information on the cumulative exposure and the internal dose of chemicals in the body.
• It can indicate the potential health effects of exposure, such as biochemical or physiological changes before they become clinically evident.

Not all chemicals are suitable for biological monitoring. Some of the criteria for selecting chemicals for biological monitoring are:

• The chemical should have a significant potential for occupational exposure and health effects and should be regulated by an occupational exposure limit or a biological exposure limit.
• The chemical should have a specific and reliable biological marker, which can be measured in a biological sample with sufficient sensitivity, specificity, and accuracy.
• The biological marker should have a known relationship with the exposure level, the internal dose, and/or the health effect of the chemical.
• The biological marker should have a suitable sampling time and biological half-life, which reflect the exposure pattern and the kinetics of the chemical in the body.
• The biological sample should be easy to collect, store, transport, and analyse, with minimal discomfort and risk to the worker and the analyst.

The results of biological monitoring should be interpreted and communicated in a clear and understandable way, taking into account the purpose and the context of the monitoring, the characteristics of the biological marker, the sources of variability and uncertainty, and the ethical and legal implications.

Some of the steps for interpreting and communicating the results of biological monitoring are:

• Compare the results with the relevant reference values, such as biological exposure limits, biological guidance values, or background levels, which indicate the acceptable or normal range of exposure or effect.
• Evaluate the significance and the implications of the results, considering the exposure scenario, the health risk, and the preventive measures.
• Provide feedback and advice to the workers, the employers, and the occupational health professionals, explaining the meaning and the limitations of the results and the actions to be taken, if any.
• Record and report the results in a confidential and anonymous manner, respecting data protection and the workers’ rights.