Toxicity

Result of an action, more or less harmful to a living organism, which chemicals can exert when coming into contact with the latter. We talk about toxic substance when, after entering the organism, by any means whatsoever (at an appropriate dose given once or several times at very short intervals, or repeated small doses over a long time), it causes, immediately or after a more or less long latency period, transient or permanent disorders of one or more functions of the organism up to their complete removal and death of the organism (called lethal toxicity). Acute toxicity (causing death or serious physiological disorders immediately or shortly after exposure) should be distinguished from subacute (at lower doses, effects which occur in the short term on target organisms and which are sometimes reversible) or from chronic toxicity (causing long-term irreversible effects by continuous absorption of small doses of pollutants, or cumulative effects).