2 Water PollutionWater pollution is the introduction of chemical, physical, or biological agents into water that degrade water quality and adversely affect the organisms that depend on the waterThe two biggest causes of water pollution are industrialization and human population growthTo prevent pollution, people must know from where water pollution comes
3 Point-Source Pollution Point-source pollution is pollution discharged from a single sourceExamples are a factory, waste water treatment plant, leaking oil tankerPoint-source pollution can often be identified and traced to a source, but enforcing cleanup can be difficult
4 Sources of Point Pollution Leaking septic-tank systemsLeaking storage lagoons for polluted wasteUnlined landfillsLeaking underground storage tanks that contain chemicals or fuels such as gasolinePolluted water from abandoned and active minesWater discharges by industriesPublic industrial waste water treatment plants
5 Nonpoint-Source Pollution Nonpoint-source pollution comes from many different sources that are often difficult to identifyBecause nonpoint-source pollutants can enter bodies of water in many different ways, they are extremely difficult to regulate and control96% of polluted bodies of water in the U.S. come from non point-sourcesControlling nonpoint-source pollution depends on public awareness of the effects of activities such as using lawn chemicals and using storm drains to dispose of used motor oil
7 Nonpoint-source Pollution Chemicals added to road surfaces (salt and other de- icing agents)Water runoff from city and suburban streets that may contain oil, gasoline, animal feces, and litterPesticides, herbicides, and fertilizer from residential lawns, golf courses, and farmlandFeces and agricultural chemicals from livestock feedlotsPrecipitation containing air pollutantsSoil runoff from farms and construction sitesOil and gasoline from personal watercraft
8 WastewaterWater goes down the drain through a series of sewage pipes that carry it to a waste water treatment plantWastewater is water that contains waste from homes and industryWastewater treatment plants filter the water until it is clean enough to return to a river or lake
9 Wastewater Treatment Process Filtration: Wastewater is passed through a large screen to remove solid objects.First settling tank: Wastewater is sent into a large tank, where smaller particles sink to the bottom and form sewer sludge. The sludge is removed from the water.Aeration tank: Wastewater is mixed with oxygen and bacteria. The bacteria use the oxygen and feed on the wastes.Second settling tank: Bacteria grown in the aeration tank, as well as other solid wastes, are removed in the form of sludge.Chlorination: chlorine is added to disinfect the water before it is released into a stream, lake, or ocean.
10 Treating WastewaterMost of the water used in homes contains biodegradable material that can be broken down by living organismsWastewater from toilets and kitchen sinks contain animal and plant waste, paper, and soap all of which re biodegradableWastewater treatment plants may not remove all of the harmful substances in water
11 Sewage SludgeOne of the products of wastewater treatment is sewage sludge, the solid material that remains after treatmentIf sludge contains toxic chemicals, it must be disposed of as hazardous wasteSludge is often incinerated and the ash buried in a landfillThe problem of sludge disposal has led many communities to look for new uses for this waste such as fertilizer or mixing with clay to make bricks
12 Artificial Eutrophication Most nutrients in water come from organic matter, such as leaves, that is broken down into mineral nutrientsNutrients are essential, but an over abundance can disrupt an ecosystemWhen slow moving water contains an abundance of nutrients it is eutrophicThe natural process of eutrophication is accelerated when inorganic plant nutrients enter the water from sewage and fertilizer runoffEutrophication caused by humans is called artificial eutrophication
13 Thermal PollutionWhen the temperature of a body of water increases, thermal pollution can happenIt can occur when power plants and other industries use water in their cooling systems and then discharge the warm water into a lake or riverThe warm water reduces the amount of available oxygen causing aquatic organisms to suffer
14 Groundwater Pollution Pollutants usually enter groundwater when polluted surface water percolates down from Earth's surfacePesticides, herbicides, chemical fertilizers, and petroleum products are common groundwater pollutantsThe U.S. has millions of underground storage tanks and leakage from those is another source of groundwater pollutionMore modern underground storage tanks are encased in concrete and have features to prevent leaks
15 Cleaning up Groundwater Pollution One of the most challenging environmental problems faced because even if it stopped today, it would still be polluted for generationsReasons for this are it takes a long time for groundwater to recharge and pollution can cling to the materials that make up an aquifer
16 Ocean Pollution Pollutants are often dumped directly into the oceans 85% of ocean pollution comes from activities on landSensitive coastal ecosystems, such as coral reefs, estuaries, and coastal marshes, are the most affected by pollution
17 Oil SpillsEach year approximately 37 million gallons of oil from tanker accidents are spilled into the oceansOil spills have dramatic effects, but they only account for 5% of oil pollution in the ocean. Most comes from cities and towns million gallons enter the ocean from nonpoint-sources on land
18 Water Pollution and Ecosystems Water pollution can cause immediate damage to an ecosystem, and the effects can be far reaching.Many pollutants accumulate because they do not decompose quickly.Polluted soil settles at the bottom of a river where it is eaten by insect larvae which are eaten by fish which are eaten by birds...This buildup of pollutants at higher levels of the food chain is called biomagnification. Biomagnification has alarming consequences for organisms at the top of the food chain. Many states limit the amount of fish that can be eaten from certain bodies of water because of biomagnification.
19 Cleaning Up Water Pollution In 1969, the Cuyahoga River in Cleveland, OH, was so polluted it caught on fire and burned for days.This led to the passing of the Clean Water Act of It's purpose was to restore and maintain the chemical, physical, and biological integrity of the nation's waters. The goal was to make surface water clean enough for fishing and swimming by 1983.Although the goal was not achieved, much progress was made.
20 Federal Laws to Improve Water Quality 1972--Clean Water Act--surface water fit for swimming and fishing by 1983 and banned pollutant discharge into surface water after Metals are to be removes from wastewater.1972--Marine Protection Research and Sanctuaries Act--empowered EPA to control the dumping of sewage wastes and toxic chemicals in U.S. waters.1975--Safe Drinking Water Act--introduced programs to protect groundwater and surface water from pollution. Emphasized sound science and risk-based standards for water quality.1980--Comprehensive Environmental Response Compensation and Liability Act-- Superfund Act--makes owners, operators, and customers of hazardous waste sites responsible for the cleanup of the sites. This act has reduced the pollution of groundwater by toxic substances leaching from hazardous waste dumps.1987--Water Quality Act--supports state and local efforts to clean polluted runoff.1990--Oil Pollution Act--attempts to protect U.S. waterways from oil pollution by requiring that oil tankers in U.S. waters be double-hulled by 2015.
21 Copy now, answer laterExplain why point-source pollution is easier to control than nonpoint-source pollution.List the major types of water pollutants. Suggest ways to reduce the leVels of each type of pollutant in a water supply.Describe the unique problems of cleaning up groundwater pollution.Describe the source of most ocean pollution. Is it point-source or nonpoint-source pollution?Draw a diagram that shows the biomagnification of a pollutant in an ecosystem.