Module 3: Toxicology - Section 4: Biological Monitoring

TOX 4.4: Lecture: Biological Monitoring and Biological Effect Monitoring - (Continued)

EXAMPLE OF BIOLOGICAL MONITORING - INORGANIC LEAD:

1. Legislated schedule including medical removal. (See OHSA- Regulations: Lead Regulations, 2001.)
2. Four compartment kinetics: blood, soft tissues, trabecular bone, cortical bone.
3. Interpretation of a given blood lead is different in new as vs long service workers.
4. Interlaboratory differences may be substantial (See the graph).

EXAMPLE OF BIOLOGICAL EFFECT MONITORING:

• Red cell cholinesterase
• Plasma cholinesterase

1. Use individual baseline as reference!
2. Normal variation, i.e. in absence of exposure: 10-15%.
3. 2-3 month recovery, i.e. return to baseline in absence of exposure.

BIOLOGICAL EFFECT MONITORING OF EXPOSURE TO POSSIBLE CARCINOGENS:

These tests are not used routinely but rather in toxicologic or epidemiologic research.

1. Urinary mutagens (Ames test)
   
   • non-specific test of genotoxicity;
   • smoking a confounder
     .
2. Haemoglobin and DNA-adducts e.g. benzo(a)pyrene
   (Adduct = chemical bond)
   • Specific but expensive. Doesn’t necessarily mean disease.
   
   
3. Chromosomal abnormalities ("clastogenic"),
   e.g. for ethylene oxide
   
   • chromosomal aberrations;
   • sister chromatid exchanges.
   • Oncogene activation.

Postgraduate Diploma in Occupational Health (DOH) - Modules 3: Occupational Medicine & Toxicology (Basic) by Profs Mohamed Jeebhay and Rodney Ehrlich, Health Sciences UCT is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 South Africa License. Major contributors: Mohamed Jeebhay, Rodney Ehrlich, Jonny Myers, Leslie London, Sophie Kisting, Rajen Naidoo, Saloshni Naidoo. Source available from here. For any updates to the material, or more permissions beyond the scope of this license, please email healthoer@uct.ac.za or visit www.healthedu.uct.ac.za. Last updated Jan 2007.
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