Why are LD50 and LC50 values a measure of acute toxicity?
Acute toxicity is the ability of a chemical to cause ill effects relatively soon after one oral administration or a 4-hour exposure to a chemical in air. “Relatively soon” is usually defined as a period of minutes, hours (up to 24) or days (up to about 2 weeks) but rarely longer. How are LD/LC50 tests done? In nearly all cases, LD50 tests are performed using a pure form of the chemical. Mixtures are rarely studied. The chemical may be given to the animals by mouth (oral); by applying on the skin (dermal); by injection at sites such as the blood veins (i.v.- intravenous), muscles (i.m. – intramuscular) or into the abdominal cavity (i.p. – intraperitoneal). The LD50 value obtained at the end of the experiment is identified as the LD50 (oral), LD50 (skin), LD50 (i.v.), etc., as appropriate. Researchers can do the test with any animal species but they use rats or mice most often. Other species include dogs, hamsters, cats, guinea-pigs, rabbits, and monkeys. In each case, the LD50 value is
