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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 usage.
What is water pollution?WHO[WORLD HEALTHORGANIZATION]
survey:3.4 million premature
deaths each year from waterborne diseases
1.9 million from diarrhea
U.S. 1.5 million illnesses1993 Milwaukee
370,000 sick
Major Sources of Water PollutionAgriculture: by far the
leaderSediment, fertilizers,
bacteria from livestock, food processing, salt from soil irrigation
Industrial: factories and powerplants
Mining: surface mining toxics, acids, sediment
TopicFreshwater pollution: What are major
problems in streams?Developed versus Developing CountriesLake Pollution: Why are lakes and reservoirs
more vulnerable?What is Eutrophication?
Freshwater Stream PollutionFlowing streams can
recover from moderate level of degradable water pollution if their flows are not reduced.
Natural biodegradation process
Does not work if overloaded or stream flow reduced
Does not work against non biodegradable pollutants
Two WorldsDeveloped CountriesU.S. and other developed
countries sharply reduced point sources even with population and economic growth
Nonpoint still a problemToxic chemicals still
problemSuccess Cuyahoga River,
Thames River
Two WorldsDeveloping Countries:Serious and growing
problemHalf of world’s 500 major
rivers heavily pollutedSewage treatment
minimal $$$Law enforcement
difficult10% of sewage in China
treatedEconomic growth with
little $$$ to clean up
India’s Ganges RiverHoly River (1 million
take daily holy dip)350 million (1/3rd of
pop) live in watershedLittle sewage treatmentUsed for bathing,
drinking etc.Bodies (cremated or
not) thrown in riverGood news is the Indian
government is beginning to work on problem
Freshwater Lake PollutionDilution as a solution in
lakes less effectiveLittle vertical mixingLittle water flow
(flushing)Makes them more
vulnerableToxins settleKill bottom lifeAtmospheric depositionFood chain disruptions
Eutrophication of LakesEutrophication: nutrient
enrichment of lakes mostly from runoff of plant nutrients (nitrates and phosphates)
During hot dry weather can lead to algae blooms
Decrease of photosynthesis
Dying algae then drops DO levels
Fish kills, bad odor
Eutrophication in LakesSolutions:Advanced sewage
treatment (N, P)Household detergentsSoil conservationRemove excess weed
build upPump in oxygen or
freshwater
Case Study: The Great Lakes•Pollution levels dropped, but long way to go
•95% of U.S. freshwater
•30% Canadian pop, 14% U.S.
•38 million drink
•1% flow out St. Lawrence
•Toxic fish
GroundwaterGroundwater can
become contaminatedNo way to cleanse itselfLittle dilution and
dispersion Out of sight pollutionPrime source for
irrigation and drinkingREMOVAL of pollutant
difficult
Groundwater Pollution: Causes Low flow rates Low flow rates Few bacteria Few bacteria
Cold temperatures
Cold temperatures
Coal strip mine runoff
Pumping well
Waste lagoon
Accidental spills
Groundwater flow
Confined aquifer
Discharge
Leakage from faulty casing
Hazardous waste injection well
Pesticides
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
Low oxygen
Low oxygen
Fig. 22-9 p. 502
Section 5 Ocean PollutionHow much pollution can the oceans tolerate?Coastal zones: How does pollution affect
coastal zones?What are major sources of ocean pollution
and what is being done?
Ocean PollutionOceans can disperse and
break down large quantities of degradable pollution if they are not overloaded.
Pollution worst near heavily populated coastal zones
Wetlands, estuaries, coral reefs, mangrove swamps
40% of world’s pop. Live within 62 miles of coast
Ocean PollutionLarge amounts of
untreated raw sewage (viruses)
Leaking septic tanksRunoffAlgae blooms from
nutrientsDead zones NO DOAirborne toxinsOil spills
Case Study: Chesapeake Bay
Largest US estuary
Largest US estuary
Relatively shallow Relatively shallow
Slow “flushing” action to Atlantic
Slow “flushing” action to Atlantic
Major problems with dissolved O2 Major problems with dissolved O2
Fig. 22-13 p. 506