3. Toxicity and regulations

3.1 Indices

• Acute toxicity is defined by the lethal dose 50 (LD 50): this is the dose expressed in mg of active substance per kg of body weight (sometimes given in ppm, parts per million) that kills 50% of a batch of laboratory animals to which it is administered in a single dose.

  The animal species to be tested and the route of administration (oral (ingestion), dermal (contact), inhalation or injection) must be specified. The LD50 of clopyralid, for example, is over 5,000 mg/kg for rats by ingestion. The results of studies on rats by ingestion are generally available. The transposition of this active substance to a preparation depends on its dosage and formulation.

• Chronic...