ABSTRACT
Toxicity tests are controlled laboratory experiments in which organisms are exposed to a contaminant (or contaminant mixture) for a specified duration, in order to evaluate potential toxic effects. The type of toxic effect measured depends upon the test organism exposed, the contaminant concentration, and the mechanism(s) of action. Acute lethality in test organisms is a commonly-measured response, since it is relatively straightforward to measure and is biologically meaningful. Examples 326of acute tests are fathead minnow acute lethality (aquatic) and earthworm survival (terrestrial). Measurement of sublethal test responses are becoming more widely used and generally provide a more sensitive response. Sublethal test responses include changes in growth, reproduction, and behavior. Examples of sublethal tests are daphnid reproduction (aquatic) and radish seedling germination (terrestrial).
