Aquatic Pollution and Coastal Zone Managememnt (2+1)

Unit 5 : Heavy metal pollution

5.3.Sources of Heavy Metals
Heavy metals are natural components of the earth's crust. They cannot be degraded or destroyed. Heavy metals enter the aquatic environment from both natural and anthropogenic sources.

• Natural sources: Volcanic activity -continental weathering (weathering of rocks) - forest fires, biodegradation of dead plants and animals
• Anthropogenic sources: Mining effluents,industrial effluents, domestic effluents and urban storm-water run off,leaching of metals from garbage and solid waste dumps,metals inputs from agricultural pesticides,atmospheric source (burning of fossil fuel, incineration of wastes and industrial emissions), petroleum industry activities.