Toxicity Test Type(ToxicityTestType) 1 Acute The acute toxicity tests generally involve exposure of any of 20 test organisms to each of five effluent concentrations and a control water. The test duration ranges from 24 to 96 hours. 2008-07-18T11:58:21 AMERICA/NEW_YORK Toxicity Test Type(ToxicityTestType) 2 Chronic A toxicity study designed to measure the (toxic) effects of chronic exposure to a chemical. Chronic Toxicity. Definition: The capacity of a substance to cause adverse human health effects as a result of chronic exposure. Chronic Toxicity Test is a short-term test in which sublethal effects (e.g., reduced growth or reproduction) are usually measured in addition to lethality 2008-07-18T11:58:21 AMERICA/NEW_YORK