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Freshwater Pollution Tuesday 2/4/2014
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Warm-up Define a point and nonpoint source of pollution. Label if the below examples are point or nonpoint sources of pollution. 1. Smokestack? 2. Urban runoff? 3. A leak from a septic tank? 4. People driving cars?
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Disease carrying agents Fecal coliform bacteria Ex: E. coli Ex: E. coli A fecal coliform bacteria test is used to indicate the likely presence of disease-causing bacteria in water. A fecal coliform bacteria test is used to indicate the likely presence of disease-causing bacteria in water. Ex: cholera, dysentery, giardasis, typhoid fever, etc. (see pg 495) Ex: cholera, dysentery, giardasis, typhoid fever, etc. (see pg 495)
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Dissolved oxygen Only a few fish species can survive in water less than 4ppm at 20°C.
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Pollution of Freshwater Steams Flowing streams can recover if they are not overloaded and their flows are not reduced
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“Dilution is the solution to pollution”
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Eutrophication the natural nutrient enrichment of a shallow lake, estuary or slow moving stream, mostly from runoff of plant nutrients from the surrounding land.
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Cultural Eutrophication human activities accelerate the input of plant nutrients (mostly nitrate and phosphate fertilizers) to a lake. 85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication 85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication
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Oxygen Depletion in the Northern Gulf of Mexico
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Chesapeake Bay Apoxia Hypoxia
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Groundwater pollution Groundwater cannot effectively cleanse itself and dilute and disperse pollutants. Moves very slowly Moves very slowly
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Groundwater pollutants Nondegradable wastes (toxic lead, arsenic, flouride) are there permanently. Slowly degradable wastes (such as DDT) are there for decades.
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Coastal and Marine Pollution
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Harmful Algal Blooms Caused by explosive growth of harmful algae from sewage and agricultural runoff.
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Red Tide: Specific type of algal bloom caused by red- pigmented algae
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Oil pollution Most ocean oil pollution comes from human activities on land takes about 3 years for many forms of marine life to recover from large amounts of crude oil (oil directly from ground). takes about 3 years for many forms of marine life to recover from large amounts of crude oil (oil directly from ground). Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover. Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover.
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Oil Spills: Case Studies Exxon Valdez Spill Prince William Sound, Alaska 1989 Prince William Sound, Alaska 1989 largest spill ever in the U.S. until… largest spill ever in the U.S. until… Deepwater Horizon Spill Gulf of Mexico, 2010 Gulf of Mexico, 2010
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Offshore drilling can be devastating to marine life
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Solution? The key to reducing nonpoint pollution – most of it from agriculture – is to prevent it from reaching bodies of water Farmers can reduce runoff by planting buffers and locating feedlots away from steeply sloped land, flood zones, and surface water. Farmers can reduce runoff by planting buffers and locating feedlots away from steeply sloped land, flood zones, and surface water.
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How Would You Vote? Should we greatly increase efforts to reduce water pollution from nonpoint sources even though this could be quite costly? a. No a. No b. Yes b. Yes Explain why some one might vote no, and some one might vote yes.
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How Would You Vote? Should we greatly increase efforts to reduce water pollution from nonpoint sources even though this could be quite costly? a. No. Most farmers and ranchers can't afford more regulations. a. No. Most farmers and ranchers can't afford more regulations. b. Yes. Nonpoint source water pollution is a serious environmental and human health threat. b. Yes. Nonpoint source water pollution is a serious environmental and human health threat.
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US Clean Water Act The U.S. Clean Water Act sets standards for allowed levels of key water pollutants and requires polluters to get permits
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