Water Pollution Types and Sources of Water Pollution

Water Pollution

Types and Sources of Water Pollution Ø #1 problem - Eroded soils Ø Organic wastes, disease-causing agents Ø Chemicals, nutrients Ø Radioactive stuff, heat

Point and Nonpoint Sources NONPOINT SOURCES Rural homes Cropland Urban streets Animal feedlot Suburban development POINT SOURCES Wastewater treatment plant Factory

Major Problem: Drinking Water Ø 1/2 of world’s people drink polluted water Ø Safe Drinking Water Act Ø EPA: Maximum contaminant levels (municipal, but not rural and private)

Pollution of Surface Water: Streams Ø D. O. , B. O. D. , fecal coliform bacteria count

Pollution of Surface Water: Lakes Ø Cultural eutrophication Ø Slow turnover ØAccumulation of nutrients, excessive plant growth, algae blooms

Case Study: The Great Lakes

Mississippi River Basin Ohio River Missouri River LOUISIANA Mississippi River Depleted Dead Zone Oxygen Gulf of Mexico

Thermal Pollution Suffocated fish Altered food web Low dissolved oxygen Decreased fish population

Groundwater Pollution: Sources Ø Cold temperatures Ø Low flow rates Ø Few bacteria Hazardous waste injection well Coal strip mine runoff Pesticides De-icing road salt Pumping well Waste lagoon Buried gasoline and solvent tank Cesspool septic tank Gasoline station Water pumping well Landfill Accidental spills Sewer ifer aqu Leakage from faulty casing Discharge r ate r w e h uif res Confined aquifer q f a r ed e t n i a f con shw Groundwater e n r U df e flow n nfi o C

Groundwater Pollution Prevention Ø Monitoring aquifers - expensive Ø Leak detection systems Ø Strictly regulating hazardous waste disposal Ø Protecting recharge areas - aquifer classifications

Ocean Pollution: dumping and oil

Oil Spills Ø Sources: offshore wells, tankers, pipelines and storage tanks Ø Effects: death of organisms, loss of animal insulation and buoyancy, smothering Ø Significant economic impacts Ø Short-term cleanup problems - beaches, wildlife Ø Long-term cleanup problem - persistence (decades)

Case Study: Chesapeake Bay Ø Largest US estuary Ø Relatively shallow Ø Slow “flushing” action to Atlantic Ø Major problems with dissolved O 2

Solutions: Preventing and Reducing Surface Water Pollution Nonpoint Sources Ø Reduce runoff Ø Buffer zone vegetation Ø Reduce soil erosion Point Sources Ø Water Pollution Control Act (1972) Ø Clean Water Act (1977) - set effluent standards - secondary treatment

Technological Approach: Septic Systems Ø Require suitable soils and maintenance

Technological Approach: Sewage Treatment Ø Mechanical and biological treatment

Technological Approach: Advanced Sewage Treatment Ø Removes specific pollutants

Technological Approach: Using Wetlands to Treat Sewage