Water Pollution

Any physical, chemical, or biological change in water quality that has a harmful effect on living organisms or that makes water unusable for desired uses.

Classes of water pollutants

1. Disease-causing agents2. Oxygen demanding wastes3. Water-soluble inorganic chemicals4. Inorganic plant nutrients5. Organic chemicals6. Sediments/suspended matter7. Water-soluble radioactive isotopes8. Thermal pollution

Pathogens• Coliform bacteria (fecal coliforms)• Standard drinking = 0 in 100mL• Standard swimming = 200 in 100mL

Oxygen demanding wastes• Organic wastes that can be decomposed by

aerobic bacteria• Measurement of oxygen required by bacteria is

called BOD = biological oxygen demand

Water-soluble inorganic chemicals

• Acids, salts, toxic metals (mercury & lead)

Inorganic plant nutrients(fertilizers)

Water-soluble nitrates and phosphates

– Result indirectly in depleted oxygen

– Consumption can lower oxygen carrying capacity of the blood

Organic chemicals (carbon chemistry)

Oil, gasoline, plastics, pesticides, cleaning agents, detergents, solvents and others

Silt, sediment, suspended matter

• Insoluble particles of soil and other• Cause cloudiness in water

– Reduces photosynthesis – buries fish eggs– clogs gills

• Silting also fills channels, harbors, and reservoirs• Measurement is called turbidity

Radioactive Isotopes

Oyster Creek Nuclear Plant

Thermal pollution

• Cool water is drawn in by industrial plants, used to cool machinery, and returned to river at warmer temperature

• This warmer water lowers D.O.• Fish can suffer thermal shock

Detecting water pollution

1. Water quality tests2. Indicator species

Classifying sources of water pollution

Two types:point and non-point

Point source = pipes, sewers, ditches

Non-point = runoff from watershed

EPA estimates that 33% of all contamination in lake and estuaries is caused by runoff

Pollution in streams

Moving waters allow streams to recover more quickly than lakes

Biodegradable wastes are broken down more quickly in streams and rivers than in lakes

Lake PollutionLess mixing in lakesThis makes lakes more vulnerable to pollutionFish can’t escape pollutants

Cultural Eutrophication

Aerobic bacteria that break down algae use up oxygen

Algae & duckweed grow in population

explosion

Fertilizers, animal wastes,

Run into lakeAlgal bloom

Which leads to …………

……. a “fish kill”

Prevention • Advanced waster water treatment• Bans or limits on phosphates in detergents• Soil conservation and land-use to reduce runoff

Cleanup • Dredging

• Removal of excess weeds

Noteworthy cases

• The Great Lakes-pollution(point/non-point)• The Hudson River-PCBs• Chesapeake Bay-pollution(point/non-p)• Colorado River-water rights• Hetch Hetchy Valley-to dam or undam• James Bay, Canada-water diversion• Mono Lake-water diversion, overuse• Aswan Dam

Ocean Pollution

• “The ocean is the ultimate sink”

                                         

               

We live on coasts

Most affected

• Coastal areas• Estuaries, wetlands, reefs, swamps• ½ of world population lives within 150

miles of coast• Bangladesh, Malaysia, Philippines,

Thailand, Indonesia• Mediterranean Sea 85% untreated

U.S. • 35% of raw sewage goes untreated• Santa Monica• Chesapeake Bay

– Drains six states– Only 1% of runoff goes out to ocean

Ocean Pollutants

• Dredge spoils – From harbor dredging

• Sewage sludge– From wastewater and sewage treatment plants– US banned in 1992– London Dumping Convention of 1972, 1983, 1994

• Oil (equal to more than 1,000 Exxon Valdez)

                                                                                                                                            

Protecting the Coasts

• Prevention– Separate pipes– Discourage dumping– Protect sensitive and

ecologically valuable areas

– Use eco land-use planning

– Double hulls on ships– Recycle oil

• Cleanup– Improve cleanup

technologies– Require secondary

treatment of coastal sewage

Clean Water Act (CWA)

• 1972 Clean Water Act!

• Main goal was to make all surface water safe for swimming and fishing by 1983

Clean Water Act

• Was first called Water Pollution Control Act, 1972

• 1977 was amended to the Clean Water Act• 1987 Water Quality Act• Main goal was to make all surface water

safe for swimming and fishing by 1983

More CWA

• Also sought to restore chemical integrity of the water

• Some gains have been made over point source pollution

• Little gains made in non point source • 1995 established discharges trading policy

And still more laws…

• Source Water Assessment Program (SWAP), 1996

• SWPP, 1996• Surface Water Treatment Rule, 1996

Clean Water Act Results

• Some gains have been made over point source pollution

• few gains made in non point source

Results of CWA!

197236%

199262%

% of US lakes And rivers

That are fishable and swimmable

Results of CWA

phosphorus DDT

Laws, Treaties, Legislation

• Safe Drinking Water Act, 1974

• Water Quality Act, 1965

• Clean Water Act, 1972

More Laws

• Emergency Wetlands Resources Act, 1986• Soil and Water Conservation Act, 1977• Wild and Scenic Rivers Act, 1968• Marine Plastic Pollution Research and Control Act,

1987• Ocean Dumping Ban Act, 1988• Oil Spill Prevention and Liability Act, 1990• Water Resources Development Act, 1974• National Estuary Program (NEP), 1987