Water PollutionWater Pollution

Water PollutionWater Pollution

Water pollutionWater pollution - when harmful waste or - when harmful waste or chemicals are exposed to the water.chemicals are exposed to the water.May be harmful to the organisms in the water May be harmful to the organisms in the water

or those that drink the wateror those that drink the water

The two underlying causes of water The two underlying causes of water pollution are industrialization and rapid pollution are industrialization and rapid human population growth.human population growth.

Developed countries have cleaned up many Developed countries have cleaned up many polluted water supplies, but some water is still polluted water supplies, but some water is still dangerously polluted.dangerously polluted.

In developing parts of the world, often the only In developing parts of the world, often the only water available for drinking is polluted with water available for drinking is polluted with sewage and agriculture runoff, which can spread sewage and agriculture runoff, which can spread waterborne diseases.waterborne diseases.

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

Give an example of a polluted Give an example of a polluted water source that you know. Do water source that you know. Do

you know of a local polluted you know of a local polluted water source?water source?

Point Source PollutionPoint Source Pollution

Point-source Point-source pollutionpollution - - pollution pollution that comes from a that comes from a specific site.specific site.

Although point-source Although point-source pollution can often be pollution can often be identified and traced identified and traced to a source, enforcing to a source, enforcing cleanup is sometimes cleanup is sometimes difficult.difficult.

Non-point Source PollutionNon-point Source Pollution

Non-point source pollutionNon-point source pollution - pollution that comes from - pollution that comes from many sources rather than many sources rather than from a single specific site. from a single specific site. Ex. Pollution washed off of Ex. Pollution washed off of

streetsstreets Controlling non-point source Controlling non-point source

pollution depends on public pollution depends on public awareness of the effects of awareness of the effects of activities such as spraying activities such as spraying lawn chemicals.lawn chemicals.

Name a local point source of Name a local point source of pollution and non-point source pollution and non-point source

of pollutionof pollution

WastewaterWastewater

After water flows down the drain in the sink, it After water flows down the drain in the sink, it flows through a series of sewage pipes that flows through a series of sewage pipes that carry it to a wastewater treatment plant.carry it to a wastewater treatment plant.

At a wastewater treatment plant, water is filtered At a wastewater treatment plant, water is filtered and treated to make the water clean enough to and treated to make the water clean enough to return to a river or lake.return to a river or lake.

Sewer SludgeSewer Sludge

Sewage sludgeSewage sludge is the solid material that is the solid material that remains after water treatment.remains after water treatment.

Sludge that contains dangerous toxic Sludge that contains dangerous toxic chemicals, it must be disposed of as chemicals, it must be disposed of as hazardous waste. hazardous waste.

The problem of sewage sludge disposal The problem of sewage sludge disposal has prompted creative uses for the waste has prompted creative uses for the waste If the toxicity of sludge can be reduced to safe If the toxicity of sludge can be reduced to safe

levels, it can be used as a fertilizer. levels, it can be used as a fertilizer. Sludge can be combined with clay to make Sludge can be combined with clay to make

bricks that can be used in buildings.bricks that can be used in buildings.

What kind of pollutants can you What kind of pollutants can you find in sewage sludge?find in sewage sludge?

Artificial EutrophicationArtificial Eutrophication

Artificial eutrophicationArtificial eutrophication - - an increase in an increase in the amount of nutrients in a body of water the amount of nutrients in a body of water through human activities, such as waste through human activities, such as waste disposal and land drainage.disposal and land drainage.

The major causes of eutrophication are The major causes of eutrophication are nitrates in fertilizer and phosphates in nitrates in fertilizer and phosphates in some laundry detergents.some laundry detergents.

Artificial EutrophicationArtificial Eutrophication

When extra nutrients enter the water, algae can When extra nutrients enter the water, algae can form large floating mats, called algal blooms.form large floating mats, called algal blooms.

As the algae die and decompose, most of the As the algae die and decompose, most of the dissolved oxygen is used and fish and other dissolved oxygen is used and fish and other organisms suffocateorganisms suffocate

How else can algae blooms How else can algae blooms reduce the amount of dissolved reduce the amount of dissolved

oxygen in a body of water? oxygen in a body of water?

Thermal PollutionThermal Pollution

Thermal pollutionThermal pollution is a temperature is a temperature increase in a body of water that is caused increase in a body of water that is caused by human activityby human activity

Thermal pollution can occur when power Thermal pollution can occur when power plants and other industries discharge plants and other industries discharge warm water into a lake or river.warm water into a lake or river.

If the flow of warm water into a lake or If the flow of warm water into a lake or stream is constant, it may cause the total stream is constant, it may cause the total disruption of an aquatic ecosystem.disruption of an aquatic ecosystem.

Groundwater PollutionGroundwater Pollution

Pollutants usually enter groundwater when Pollutants usually enter groundwater when polluted surface water percolates down polluted surface water percolates down from the Earth’s surface.from the Earth’s surface.

Pesticides, herbicides, chemical fertilizer, Pesticides, herbicides, chemical fertilizer, and petroleum products are common and petroleum products are common groundwater pollutants. Other sources of groundwater pollutants. Other sources of pollution include septic tanks, unlined pollution include septic tanks, unlined landfills, and industrial wastewater landfills, and industrial wastewater lagoons.lagoons.

Cleaning up Groundwater PollutionCleaning up Groundwater Pollution

Groundwater pollution is one of the most Groundwater pollution is one of the most challenging environmental problems in the challenging environmental problems in the world.world.

Groundwater recharges very slowly, so the Groundwater recharges very slowly, so the process for some aquifers to recycle water and process for some aquifers to recycle water and purge contaminants can take hundreds of years.purge contaminants can take hundreds of years.

Pollution can cling to the materials that make up Pollution can cling to the materials that make up an aquifer, so even if all of the water in aquifer an aquifer, so even if all of the water in aquifer were pumped out and replaced with clean water, were pumped out and replaced with clean water, the groundwater could still become polluted.the groundwater could still become polluted.

Do you think that having a Do you think that having a polluted river or a polluted polluted river or a polluted

aquifer is a bigger problem?aquifer is a bigger problem?

Ocean PollutionOcean Pollution

At least 85 percent of ocean pollution, At least 85 percent of ocean pollution, including pollutants such as oil, toxic including pollutants such as oil, toxic wastes, and medical wastes, comes from wastes, and medical wastes, comes from activities on land, near the coasts.activities on land, near the coasts.

Sensitive coastal ecosystems, such as Sensitive coastal ecosystems, such as coral reefs, are the most effected by coral reefs, are the most effected by pollution.pollution.

Oil SpillsOil Spills Each year, about 37 million gallons of oil from Each year, about 37 million gallons of oil from

tanker accidents are spilled into the ocean.tanker accidents are spilled into the ocean.

Such oil spills have dramatic effects, but they Such oil spills have dramatic effects, but they are responsible for only about 5 percent of oil are responsible for only about 5 percent of oil pollution in the oceans. Most of the oil that pollution in the oceans. Most of the oil that pollutes the oceans comes from cities and pollutes the oceans comes from cities and towns.towns.

Limiting these nonpoint-sources of pollution Limiting these nonpoint-sources of pollution would go a long way toward keeping the oceans would go a long way toward keeping the oceans clean.clean.

Why is pollution from the land Why is pollution from the land so much worse than pollution so much worse than pollution

from an oil tanker?from an oil tanker?

Cleaning Up Water PollutionCleaning Up Water Pollution

The Clean Water Act of 1972 was to designed to The Clean Water Act of 1972 was to designed to “restore and maintain the chemical, physical, “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.”and biological integrity of the nation’s waters.”

The Marine, Protection, Research, and The Marine, Protection, Research, and Sanctuaries Act of 1972 strengthened the laws Sanctuaries Act of 1972 strengthened the laws against ocean dumping.against ocean dumping.

The Oil Pollution Act of 1990 requires all oil The Oil Pollution Act of 1990 requires all oil tankers traveling in U.S. waters to have double tankers traveling in U.S. waters to have double hulls by 2015 as an added protection against oil hulls by 2015 as an added protection against oil spillsspills

Which do you think is the larger Which do you think is the larger problem – freshwater pollution problem – freshwater pollution

or ocean pollution?or ocean pollution?