3. Impact assessment phase

Any chemical compound is potentially toxic to an organism, and this applies to any substance, according to Paracelsus' (1493-1541) famous phrase: "everything is poison, nothing is poison, only the dose makes the poison and thus distinguishes the remedy from the poison". In order to measure this toxicity, we first need to define what constitutes a toxic effect. The most obvious toxic effect for an individual is death. However, interest is increasingly focused on other types of effect, in order to limit losses to organisms and to discern more discreet consequences. Effects at biochemical, physiological, reproductive or behavioral levels can provide measures of toxicity, and the influence of dose is obvious on the nature and degree of toxicity. Many experiments are conducted in such a way as to link a selected effect to a dose of the chemical compound. This relationship...