Ecotoxicology is the study of toxic effects of chemicals on non-human organisms within an ecosystem at the individual, population, or community level (Suter 1993). In order to qualitatively and/or quantitatively evaluate risks posed by contaminants to ecological resources, ecological risk assessments rely heavily upon the field of ecotoxicology. Ecological evaluations of risks from contaminants can also be beneficial in identifying exposure pathways for human populations. Thus, it is important for risk managers to be familiar with basic terminology and concepts from the field of ecotoxicology.