ABSTRACT
Risk is defined as the possibility of loss or injury. Within the context of environmental toxicology this broad definition can be restated as the possibility of an undesirable biological response (toxicity) that results from exposure to a toxicant. Risk may be expressed as a probability (e.g., P=0.00001) or incidence (e.g., 1 in 100,000) of a particular response for a given exposure. Risk (probability or incidence) is based on statistical estimates from sample populations studied during toxicity testing and on other observations, such as those from epidemiological studies. Risk statements, when properly interpreted, provide a valuable means for comparing the relative, but not necessarily absolute, possibility of a response occurring on exposure to a toxicant.
