How is the dose of a toxic pesticide calculated?

Question

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Answer 1

The lethal dose for a toxic substance depends on the substance.  It is defined as the quantity of a substance that is necessary to kill 50 percent of the animals in a test sample.  Lethal doses of poisons are expressed in milligrams of toxic substance per kilogram of body mass of the animal.  Usually the test animals are rats.  Generally the  smaller the value of LD50, the more toxic the substance. The toxicity of a substance varies from one animal to another.  While the lethal dose or LD50 provides an  indication of  the toxic  dose for a substances,   but it can vary from one species to another.  A substance with a relatively high lethal dose in rats may have a low lethal dose in humans.