Lect 28 Water Pollution PP outline

Lect 28 Water Pollution PP outline - Water Pollution WATER...

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Water Pollution WATER POLLUTION Any physical, biological, or chemical change in water quality that adversely affects living organisms can be considered pollution. Point Sources - Discharge pollution from specific locations. - Factories, Power plants Non-Point Sources - Scattered or diffuse, having no specific location of discharge. - Agricultural fields, Feedlots Water Pollution Atmospheric Deposition - Contaminants carried by air currents and precipitated into watersheds or directly onto surface waters. - Estimated 600,000 kg of the herbicide atrazine in the Great Lakes. Most thought to have been deposited from the atmosphere. Contaminants can also evaporate from lakes. TYPES AND EFFECTS OF WATER POLLUTION Infectious Agents Oxygen-Demanding Wastes Plant Nutrients and Cultural Eutrophication Inorganic Pollutants Metals Non-metallic salts Acids and bases Organic chemicals Sediments Thermal pollution TYPES AND EFFECTS OF WATER POLLUTION Infectious Agents Main source of waterborne pathogens is improperly treated human waste. - Animal wastes from feedlots and fields is also important source of pathogens. At least 2.5 billion people in less developed countries lack adequate sanitation, and about half of these lack access to clean drinking water. Infectious Agents In developed countries, sewage treatment plants and pollution-control devices have greatly reduced pathogens. Coliform bacteria - Intestinal bacteria. Drinking water generally disinfected via chlorination. Oxygen-Demanding Wastes Water with an oxygen content > 6 ppm will support desirable aquatic life. Water with < 2 ppm oxygen will support mainly detritivores and decomposers. Oxygen is added to water by diffusion from wind and waves, and by photosynthesis from green plants, algae, and cyanobacteria. Oxygen is removed from water by respiration and oxygen-consuming processes. Oxygen-Demanding Wastes Biochemical Oxygen Demand - Amount of dissolved oxygen consumed by aquatic microorganisms. Dissolved Oxygen Content - Measure of dissolved oxygen in the water. Effects of oxygen-demanding wastes on rivers depend on volume, flow, and temperature of river water. Oxygen Sag - Oxygen levels decline downstream from a pollution source as decomposers metabolize
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This note was uploaded on 04/26/2008 for the course BIOLOGY 118 taught by Professor Richardson during the Spring '08 term at Winona.

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Lect 28 Water Pollution PP outline - Water Pollution WATER...

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