Blood: Provides a measure of the chemical or its metabolite in the circulatory system.
Urine: Often used for its non-invasive collection and the ability to measure metabolites.
Breath: Useful for volatile organic compounds (VOCs).
Other specimens like
hair,
nails, and
saliva can also be used depending on the chemical and exposure scenario.
How is Biological Monitoring Conducted?
Biological monitoring involves the collection of biological samples from individuals who may be exposed to toxic chemicals. The samples are then analyzed using various
analytical techniques such as gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), or inductively coupled plasma mass spectrometry (ICP-MS) to quantify the levels of chemicals or their metabolites.
What are Biological Exposure Indices (BEIs)?
Biological Exposure Indices (BEIs) are reference values established by organizations like the American Conference of Governmental Industrial Hygienists (ACGIH). They represent the levels of chemicals or their metabolites in biological specimens that are likely to be observed in individuals exposed to chemicals at the threshold limit values (TLVs). BEIs are used to interpret biological monitoring results and assess whether exposures are within acceptable limits.
It may not be able to differentiate between exposures from different routes or sources.
Inter-individual variability in metabolism and excretion can affect results.
Some chemicals have very short biological half-lives, making it challenging to capture exposure accurately.
Ethical and privacy concerns related to the collection and analysis of biological specimens.
Applications of Biological Monitoring
Biological monitoring is used in various applications, including: Occupational health: To monitor worker exposure to hazardous substances and ensure compliance with occupational exposure limits (OELs).
Environmental health: To assess community exposure to environmental contaminants such as lead, mercury, and pesticides.
Clinical toxicology: To diagnose and manage poisoning cases by measuring toxic substances in biological samples.
Conclusion
Biological monitoring is an essential component of toxicology, providing valuable insights into the internal dose of hazardous substances and helping to protect human health. Despite its limitations, it remains a critical tool for assessing exposure, implementing safety measures, and guiding regulatory decisions.
