WATER POLLUTION

Water Pollution

The introduction of chemical, physical or biological agents into water that degrade water quality and adversely affect the organisms that depend on the water.

Developing countries – mostly polluted by sewage and agricultural runoff – waterborne diseases

Water pollution comes from two types of sources- point and non-point solutions

Point-source pollution

Comes from a single source like a factory, wastewater treatment plant or a leaking oil tanker Septic-tank leaking Leaking storage lagoons Unlined landfills Leaking underground

storage tanks for fuel or chemicals

Abandoned and active mines Discharge from industries Public and Industrial water

treatment plants

Nonpoint-source pollution From many different

sources – often difficult to identify Runoff from any of the land

surface in a watershed polluted by Chemicals or other debris on

road surfaces – salt, oil, gas, animal feces, litter

Pesticides, herbicides and fertilizers

Precipitation containing air pollutants – acid rain

Soil runoff from farms or construction sites

Oil and gasoline from personal watercraft

Wastewater Water that

contains waste from homes or industry

Typically carried to treatment plants through pipes Sewage Sludge – product

of waste water – the solid material that remains after treatment

May contain highly concentrated levels of toxic chemicals so it has to be disposed of as hazardous material Incinerated and ash buried in

a secure landfill Expensive to dispose of

and running out of places - communities are looking for new uses for the toxic sludge

Eutrophication Nutrients in an ecosystem can be good in the right

amount, but destructive in high or low amounts Natural process when organic matter builds up and

decomposes in a body of water Decomposition process uses oxygen, with oxygen used

more in the water the type of organisms that live there is changed

Organic matter continues to build up in water Plants root in water in organic matter and more organic

matter build up until it becomes a swamp or marsh

Artificial Eutrophication Eutrophication caused by humans Can be caused by runoff from farms,

lawns and gardens Runoff that has an excess of nutrients –

phosphorus and nitrogen Causes excess plant and algae growth

Thermal Pollution

Temperature of a lake or stream increases Can be caused by industries that release

cooling water that is now warmer into the lake or stream Rapid- can cause a fish kill Slowly – can slowly suffocate organisms and

change the ecosystem

Groundwater Pollution When polluted surface water

percolates down Pesticides, herbicides, fertilizers,

petroleum products, and underground tanks are common sources

Clean up is very difficult

http://www.pbs.org/wgbh/pages/frontline/poisonedwaters/view/