Introduction to the Textbook

The purpose of this volume is to provide the background knowledge so that the short- and long-term effects of chemical pollution can be evaluated and the risks understood. There are 11 more chapters, each a specific building block towards the understanding of the status of the field of environmental 

Chapter 2, A Framework for Environmental Toxicology, provides an overview of the field of environmental toxicology and introduces the progression from the initial introduction of the toxicant to the environment, its effect upon the site of action, and finally the impacts upon an ecosystem. Many of the terms used throughout this book are introduced in this section. After an introduction to toxicity testing, the remainder of the book is organized from the molecular chemistry of receptors to the ecological effects seen at the system level. 

Chapter 5 is an analysis of the routes of exposure allowing a toxicant to enter an organism and the modes of action at the molecular level that cause 

A developing area of research has been endocrine disruption. Apparently, a wide variety of materials can interfere with or mimic endocrine function. Estrogen mimics and the possible modes of action of these materials are discussed with particular emphasis on dioxins and the polychlorinated biphenyls (PCBs). Other classes of compounds and modes of action are also summarized in this section. 

In addition to the biochemistry introduced in this chapter, a great deal of emphasis is placed on the determination of the activity of a compound by an analysis of its structure. Quantitative structure-activity relationships (QSAR), used judiciously, have the ability to help set testing priorities and identify potentially toxic materials in mixtures. Heavily reliant upon the quality of the toxicity data discussed in Chapter 4, these methods use sophisticated statistical techniques or analysis of interaction of a toxicant with the receptor to estimate toxicity. A method that uses structure-activity relationships coupled with availability and an assumed additive model for toxicity is presented to estimate the risk due to polyaromatic hydrocarbons (PAHs). 

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I. A general introduction to the textbook chapter as u whole in the context of previously covered material. 

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