Water Pollution G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 19 G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 19

What is water pollution? Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses.

Major categories of water pollutants 1.Infectious Agents 2.Oxygen-Demanding Wastes 3.Inorganic Chemicals 4.Organic Chemicals 5.Plant Nutrients 6.Sediment 7.Radioactive Material 8.Heat (Thermal Pollution) Review Table 19.1!!

Common Diseases Transmitted Through Contaminated Drinking Water Type of OrganismDisease BacteriaTyphoid fever Cholera Bacterial Dysentery Enteritis VirusesInfectious hepatitis Parasitic ProtozoaAmoebic Dysentery Giardiasis Parasitic WormsShistosomiasis

Effects Premature death of 3.4 million people worldwide each year Diarrhea alone kills 2.1 million people

How do we measure water quality? Fecal Coliform Test Drinking water 0 colonies per 100 ml Swimming water 200 colonies per 100 ml 200 colonies per 100 ml

How do we measure water quality? Measuring the level of Dissolved Oxygen (DO)Measuring the level of Dissolved Oxygen (DO) Fig p. 485

Biological Oxygen Demand (BOD): the amount of dissolved oxygen needed by aerobic decomposers to break down organic matter.the amount of dissolved oxygen needed by aerobic decomposers to break down organic matter.

How do we measure water quality? Using chemical analysisUsing chemical analysis –Presence and concentration Using indicator speciesUsing indicator species –Filter feeding mussels, macroinvertebrates

Sources of Water Pollution Point SourcesPoint Sources –Discharge of pollutants at specific locations through pipes, ditches, or sewers into bodies of surface water. Easier to control Non-Point SourcesNon-Point Sources – pollutants cannot be traced to any single source of discharge Difficult to controlDifficult to control

Point and Nonpoint Sources NONPOINT SOURCES Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES Fig p. 486

Pollution of Streams  Can recover rapidly from oxygen-demanding waste Fig p. 488

Oxygen Sag

Pollution of Lakes Slow turnover –Flushing and changing of water Thermal stratification –Little vertical mixing Biological Magnification Increase in the concentration of chemicals in organisms at successively higher trophic levels of a food chain Eutrophication Natural nutrient enrichment of lakes

Water ppm Phytoplankton ppm Zooplankton ppm Rainbow smelt 1.04 ppm Lake trout 4.83 ppm Herring gull 124 ppm Herring gull eggs 124 ppm Biomagnification

Pollution of Lakes  Cultural Eutrophication Fig p. 491

Solutions: Preventing and Reducing Surface Water Pollution Nonpoint Sources Point Sources  Reduce runoff  Buffer zone vegetation  Reduce soil erosion  Clean Water Act  Water Quality Act

Fig. 21-8, p. 502 Aquifer Water well Migrating vapor phase Contaminant plume moves with the groundwater Free gasoline dissolves in groundwater (dissolved phase) Groundwater flow Water table Gasoline leakage plume (liquid phase) Leaking tank Bedrock

Groundwater Pollution Prevention Monitoring aquifers Leak detection systems Strictly regulating hazardous waste disposal Storing hazardous waste materials above ground

Case Study: Chesapeake Bay  Largest US estuary  Relatively shallow  Slow “flushing” action to Atlantic  Major problems with dissolved O 2 Fig p. 500

OCEAN OIL POLLUTION Most ocean oil pollution comes from human activities on land. –Studies have shown it 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 years for marine life to recover.

OCEAN OIL POLLUTION Tanker accidents and blowouts at offshore drilling rigs can be extremely devastating to marine life (especially diving birds, left).

Water Break

Reducing Water Pollution through Sewage Treatment Septic tanks and various levels of sewage treatment can reduce point- source water pollution.

Reducing Water Pollution through Sewage Treatment Raw sewage reaching a municipal sewage treatment plant typically undergoes: –Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling. –Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes.

Reducing Water Pollution Through Sewage Treatment Primary and Secondary sewage treatment.

Fig , p. 511 Raw sewage from sewers Activated sludge Disposed of in landfill or ocean or applied to cropland, pasture, or rangeland PrimarySecondary Grit chamberBar screenSettling tankAeration tankSettling tank Chlorine disinfection tank Sludge drying bed Sludge digester Air pump To river, lake, or ocean (kills bacteria) Sludge

Reducing Water Pollution Through Sewage Treatment Advanced or tertiary sewage treatment: –Uses series of chemical and physical processes to remove specific pollutants left (especially nitrates and phosphates). Water is chlorinated to remove coloration and to kill disease-carrying bacteria and some viruses (disinfect).

Technological Approach: Advanced Sewage Treatment  Removes specific pollutants Fig p. 505

2 million plastic bottles, dumped every 5 minutes. Is Bottled Water the Answer?

Some bottled water is not as pure as tap water and costs much more. 1.4 million metric tons of plastic bottles are thrown away. Fossil fuels are used to make plastic bottles. –The oil used to produce plastic bottles in the U.S. each year would fuel 100,000 cars.