What are biomarkers in environmental toxicology and provide two examples?

Biomarkers in environmental toxicology are measurable biological changes in an organism that indicate exposure to, or the effects of, environmental contaminants. They serve as early warning signals of potential harm before overt disease or population-level effects become apparent.

Their role includes:

• Exposure Assessment: Identifying if an organism has been exposed to a specific toxicant.
• Effect Assessment: Indicating a biological response or damage caused by the toxicant.
• Risk Prediction: Helping to predict future health outcomes or ecological impacts.

Two examples of biomarkers are:

1. DNA Adducts: These are structural changes in DNA resulting from covalent binding of a chemical (e.g., from polycyclic aromatic hydrocarbons or heavy metals) to DNA. Their presence indicates exposure to genotoxic substances and potential for mutations or cancer.
2. Acetylcholinesterase (AChE) Inhibition: AChE is an enzyme crucial for nerve function. Exposure to certain pesticides (organophosphates and carbamates) inhibits AChE activity. Measuring reduced AChE levels in blood or brain tissue indicates exposure to these neurotoxic chemicals and predicts neurological effects.