Metabolic Aspects of Pesticide Toxicology

Abstract

At least 1500 organic and inorganic chemicals are used in a manner such that they can be called pesticides (1). These chemicals are indispensable in the management of a seemingly endless variety of pest organisms, including insects, weeds, fungi, bacteria, pest birds and mammals, and others.Pesticides are intentionally applied to many components of the environment, and they or their degradation products often move quite freely through the environment by mechanisms such as runoff, leaching, and volatilization. The production and use of pesticides on a world scale exceeds 3 billion pounds annually (1), and it can safely be said that residues of various pesticides interact at some level with virtually all components of the environment.Pesticides by design are meant to be toxic! Although a major goal of the discipline of modern pesticide chemistry is to develop pesticides and consequent use patterns that confine pesticide toxicity to pest organisms, such a goal is seldom attained easily. All living organisms have much in common biochemically, and successful exploitation of the often relatively minor biochemical differences between pest and non-pest species is almost always difficult and is, in fact, sometimes impossible.Thus, it is often necessary to use pesticides that are toxic not only to the pest species but to other organisms as well. Even when we succeed in developing what appear to be highly efficacious yet selective pesticides, we are always concerned that interactions of these chemicals or their transformation products with non-target species, particularly man, may result in some unforeseen toxic consequences.From the human perspective, the direct toxicological implications of pesticide use to our own species merit the most thorough and serious consideration. Most would agree that the judicious use of pesticides contributes in a positive way to many aspects of human welfare, but we also recognize that these chemicals have genuine potential for adverse human effects.Therefore, if the proposed use patterns of a pesticide create a substantial likelihood that interactions with man may occur, it is prudent to