Environmental Toxicology

Pollution

The presence or introduction of substances to the environment which are harmful or have a poisonous effect is called environmental pollution. These harmful materials are called pollutants. Pollutants can be naturally occurring substances or can also be created by human activity, but they are considered contaminants when in excess of natural levels. Many things that are necessary to human beings produce pollution. Cars spew pollutants from their exhaust pipes. Burning coal to produce energy pollutes the air. Industries and homes generate garbage and sewage that can pollute the land and water. Pesticides used to kill weeds and insects seep into waterways and harm wild and aquatic life.