ABSTRACT
Acute, subchronic, and chronic toxicity of a chemical compound can be evaluated by ve basic approaches:
• Epidemiological studies of human or other populations exposed to the toxic compound
• Animal tests with higher organisms (in vivo) • Tests with lower organisms (in vivo) • Tests with cell cultures (in vitro) • Computer calculations (in silico)
5.1 EPIDEMIOLOGICAL STUDIES
Human exposure to a xenobiotic can be
• Incidental via the environment, occupation, or diet • Intentional, for example, with a drug or a food additive
Well-documented accidents with xenobiotics can provide essential information about the human toxicity of the respective compound(s). e same kind of information can be obtained from the occupational exposure of workers to a substance, in case that monitoring as well as recording has been on a required level. Monitoring must include the estimation of the concentration of the potentially toxic substance and its metabolites in the body liquids and the use of biochemical indicators of pathological alterations. As an example, the inhibition rate of cholinesterase in the blood samples of agricultural workers handling organophosphorous pesticides can be presented. However, these data are rather complicated to obtain and are, unfortunately, seldom complete.
