PRINCIPLES OF ENVIRONMENTAL TOXICOLOGY AND CONTAMINATION (PART I)

Table of Contents

1. Index
2. UNIT 1 - General principles
3. UNIT 2 - Main sources of environmental contamination
   1. Introduction
   2. Main sources of contaminants in the environment
   3. Major types of pollution
4. UNIT 3 - Air Pollution
5. Unit 4 - Water and soil Pollution
6. Glossary of key terms associated with environmental toxicology

Introduction

Chemicals are everywhere in our environment. All matter on our planet consists of chemicals. For example, the great majority of highly toxic chemicals occur naturally in the environment, and/or are produced by animals and plants.

It is difficult to imagine a modern society without the benefits of the chemical industry. Pharmaceuticals, petrochemicals, agrochemical, industrial and consumer chemicals, all contribute to our modern lifestyles. A rapid growth of the chemical industry occurred after word war II, resulting in the manufacture of a large amount of chemicals. Additionally, a dramatic increase in food production, together with technology advancements and a rise in industrial output led to an increase in the release of chemicals in the environment. Many hazardous waste sites and industrial facilities have been contaminated for decades and continue to affect the environment. Thus, chemical contamination of the environment is a pervasive, insidious side effect of human population growth and technological development.

It is known that despite ecosystems are very robust and resilient to the natural forces of nature, such as flooding, fire, drought, etc., the effects of chemical pollution can overwhelm their dynamic stability causing significant adverse effects. Probably the most well-known examples of chemical pollution are the deleterious effects of air pollution on rain forests and the effects of DDT - a pesticide which has been banned in many parts of the world - on some species in the wild (e.g. bald eagles). Chemical pollution also causes health hazards to human beings.

Nowadays, the rise of chemical manufacture and use has increased public awareness and concern regarding the presence of chemicals in the environment. However and unlike many other environmental stressors, casual observers often become aware of chemical pollutants only after some catastrophic event, such as an oil or chemical spill that kills many living organisms. Typically, chemical discharges that can be seen or smelled - or barren mine spoils and fishless streams - draw attention to chemical pollutants.