Basics of Environmental Toxicology

Environmental toxicology is defined as the study of the fate and effects of chemicals in the environment. Although this definition would encompass toxic chemicals naturally found in the environment (i.e., animal venom, microbial and plant toxins), environmental toxicology is typically associated with the study of environmental chemicals of anthropogenic origin. Environmental toxicology can be divided into two subcategories  

A Textbook of Modern Toxicology, Third Edition, edited by Ernest Hodgson ISBN 0-471-26508-X Copyright 2004 John Wiley Sons, Inc. 

Historically chemicals that have posed major environmental hazards tend to share three insidious characteristics environmental persistence, the propensity to accumulate in living things, and high toxicity. 

---

The components of environmental toxicology. The field borrows heavily from a variety of scientific disciplines. The very nature of the field is multidisciplinary, making a basic knowledge of biology, chemistry, mathematics, and physics essential. 

There are many types of interactions that make up the field of environmental toxicology (Figure 1.2). Some are typical to fields of basic research but because of the use of the information in decision making there is a broad regulatory interest. Each type of interaction is described below. 

Unlike much of basic research, environmental toxicology has been often defined by and instigated by public policy as written in legislation. Many of these laws in the U.S., Canada, and Europe mandate toxicity testing or require an assessment of toxicity. In the U.S., federal law can often be... 

The three functions of environmental toxicology. Only three basic functions need to be described after the introduction of a xenobiotic into the environment. The first describes the fate and distribution of the material in the biosphere and the organism after the initial release to the environment [f(f)]. The second function describes the interaction of the material with the site of action [f(s)]. The third function describes the impact of this molecular interaction upon the function of an ecosystem [f(e)]. 

As its title implies, this is a general reference covering the basics of environmental chemistry. Contents indude general chemistry (matter, atoms, elements), chemical reactions and equations, water pollution and treatment, geochemistry, agricultural chemistry, treatment and disposal of hazardous substances, toxicology and occupational health, and nuclear chemistry. 

Environmental toxicology is based on the premise that the amount of chemical reaching an active site in, or on the surface of, an organism determines whether a compound will exert a specific beneficial or adverse effect or pose an ecological or health risk. This basic toxicological principle is embodied in the expression attributed to Paracelsus that it is "the dose that makes the poison."... 

ERA applies methods of systems analysis to integrate ecology, environmental chemistry, environmental toxicology, geochemistry, hydrology, and other fundamental sciences in estimating the probabilities of undesired ecological impacts. In theory, ERA applies to both human-induced and natural disturbances. ERA can be viewed as a subset of basic... 

---