Water Pollution

Chapter 19

“Today everybody is downwind or downstream from somebody else.”

William Ruckelshaus

Key ConceptsTypes, sources and effects of water pollution

Major pollution problems of surface water

Major pollution problems of groundwater

Reduction and prevention of water pollution

Drinking water quality

Types and Sources of Water Pollution

Fig. 19-3 p. 485

Point and Nonpoint SourcesNONPOINT SOURCES

Urban streets

Suburban development

Wastewater treatment plant

Rural homes

Cropland

Factory

Animal feedlot

POINT SOURCES

Pollution of StreamsOxygen sag curve Factors influencing recovery

Pollution of Lakes

Fig. 19-7 p. 491

Eutrophication

Slow turnover

Thermal stratification

Case Study: The Great Lakes

Low flow ratesFew bacteria

Groundwater Pollution: SourcesCold temperatures

Fig. 19-10 p. 494

Coal strip mine runoff

Pumping well

Waste lagoon

Accidental spills

Groundwater flow

Confined aquifer

Discharge

Leakage from faulty casing

Hazardous waste injection wellPesticides

Gasoline station

Buried gasoline and solvent tank

Sewer

Cesspool septic tank

De-icing road salt

Unconfined freshwater aquifer

Confined freshwater aquifer

Water pumping well Landfill

Groundwater Pollution Prevention

Monitoring aquifersLeak detection systemsStrictly regulating hazardous waste disposalStoring hazardous materials above ground

Ocean Pollution

Case Study: Chesapeake Bay

Fig. 19-14 p. 500

Largest US estuaryRelatively shallowSlow “flushing” action to AtlanticMajor problems with dissolved O2

Oil SpillsSources: offshore wells, tankers, pipelines and storage tanksEffects: death of organisms, loss of animal insulation and buoyancy, smotheringSignificant economic impactsMechanical cleanup methods: skimmers and blottersChemical cleanup methods: coagulants and dispersing agents

Solutions: Preventing and Reducing Surface Water Pollution

Reduce runoffBuffer zone vegetationReduce soil erosion

Clean Water ActWater Quality Act

Nonpoint sources Point sources

Technological Approach: Septic Systems

Require suitable soils and maintenance

Technological Approach: Sewage Treatment

Mechanical and biological treatment

Technological Approach: Advanced Sewage Treatment

Removes specific pollutants

Technological Approach: Using Wetlands to Treat Sewage

Drinking Water Quality

Fig. 19-11 p. 495

Bottled water

Safe Drinking Water Act

Maximum contaminant levels