Introduction
This topic explains how the toxic potential of a chemical is established experimentally and how a safe exposure level is derived for workers and for the general population. It links toxicological data to the hygiene standards that regulate air, water, food and consumer products.
Aim and basic concepts
Hygiene-toxicological evaluation determines the dose-effect and dose-response relationship of a substance, identifies the lowest dose that produces a harmful effect, and converts this into a legally fixed hygiene norm. Key terms the examiner expects you to define:
- Toxicity is the capacity of a substance to cause harm at a given dose, while hazard is the possibility of harm under real conditions of exposure.
- NOAEL (no-observed-adverse-effect level) is the highest dose at which no harmful effect is detected.
- LOAEL (lowest-observed-adverse-effect level) is the lowest dose at which a harmful effect is detected.
- LD50 and LC50 are the dose or concentration lethal to 50 percent of test animals, used to characterise acute toxicity.