Environmental Toxicology

Environmental Toxicology
It refers to the study of poisons/pollutants and their action on the environment.

pollutant may be defined as a substance or effect which adversely alters the environment by changing the growth rate of species, interferes with health, comfort, facilities or property values of the people.
In general pollution causes degradation and/or damage to the natural functioning of the biosphere which may involve vegetation, animals and all other species, crops, soil, water and ultimately altering the food chains.

The presence of these compounds in the environment may lead to:
•air pollution
•water pollution
•soil pollution
AIR POLLUTANTS
Air pollution is a reality of the twenty-first-century lifestyle. It can be classified into:
1. Outdoor Air Pollution
The ambient air is contaminated with mixture of gases including: Sulfur dioxide, carbon monoxide, ozone, nitrogen dioxide, lead and particulate matter.

Sulfur Dioxide
Sulfur dioxide is a water-soluble irritant gas that is absorbed predominantly in the upper airways and stimulates bronchoconstriction and mucus secretion in a number of species, including humans.
The penetration of SO2 into the lungs is greater during mouth as opposed to nose breathing. An increase in the airflow rate further augments penetration of the gas into the deeper lung. As noted with asthmatics, are likely to experience greater irritation. Once deposited along the airway, SO2 dissolves into surface-lining fluid as sulfite or bisulfite and is distributed readily throughout the body. It is thought that the sulfite interacts with sensory receptors in the airways to initiate local and centrally mediated bronchoconstriction and narrowing of the airways.
The conversion of SO2 to sulfuric acid is favored in the environment.