Toxicology is the study of the adverse effects of chemicals on living
organisms. A toxicologist is trained to examine the nature of
those effects (including their cellular, biochemical, and molecular
mechanisms of action) and assess the probability of their occurrence.
Thus, the principles of toxicology are integral to the proper
use of science in the process commonly called risk assessment,
where quantitative estimates are made of the potential effects on
human health and environmental significance of various types of
chemical exposures (e.g., pesticide residues on food, contaminants
in drinking water). The variety of potential adverse effects and the
diversity of chemicals in the environment make toxicology a very
broad science. Therefore, toxicologists often specialize in one area
of toxicology.