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Two main types of freshwater pollution
1. Point Source: Pollution that comes from a known and specific locationEX) Factory pipes, tail pipe, leaking land fill, leaking storage tank
2. Non-Point: does not have a specific point of originEX) Runoff - water that flows over the land rater
than seeping into the ground.
Eutrophication- Nutrients enter surface water & too many nutrients cause
environmental problems-Large amounts of phosphates & nitrates promote
runaway growth of algae and plants- Open water is choked with plant growth. - Plants die – increase in the # of decomposing bacteria
- Oxygen in water decreases
WATER POLLUTION
Hypoxia_in_the_Delta.asfPackage
Sources of Water Pollution
1. Agriculture Discussed in chapter 13
2. Municipal:Contains salts, asbestos, chlorides, copper, cyanides, grease, lead, zinc, hydrocarbons, motor oil, organic wastes, phosphates, sulfuric acid
3. Industrial - High BOD, toxic
compounds, sludge - Some industries are
cleaning water before they discharge it
Riparian buffers- the area on both sides of a creek or stream that acts as a habitat for immature organisms and
helps catch & filter pollutants
RESOURCE DEGRADATION = pollution!
Controlling Water Pollution- 1898 Rivers and Harbors Act - First legislation to address water pollution
- Individual states were responsible for enforcing laws on water pollution
- Studies not accurate- People not held accountable for pollution
Rachel Carson- wrote the book Silent Spring- Brought water pollution problems to the
common man in terms they could understand- Helped lead to water pollution control act
1972 FEDERAL WATER POLLUTION CONTROL ACT
- Set water-quality standards for all 50 states- Provides a vision of water quality standards and a means of
measuring improvement - Does not set laws for enforcement
Cuyahoga River notes later….
- Many states have improved their water quality, but there are still problems- Sewage treatment, soil erosion, removal of toxic chemicals, and
heavy metals- Cancer causing agents identified in drinking water
- Mississippi River is still dangerously polluted - by the time the water of the Mississippi reaches the ocean, it is estimated that the water has moved through 5 humans and 5 different treatment plants as well as many industrial sites
"Clean Water Act"
1969 Cuyahoga River Cleveland Ohio The Cuyahoga River was so polluted that the river actually caught fire and burned for several days. The incident was a major factor
behind the passage of the Clean Water Act of '72
Other Countries don't have the same regulations we have:
TYPE EXAMPLES SOURCES EFFECTS INFORMATION
Disease organisms
Bacteria, viruses
Waste from animals
Typhoid, cholera, dysentery
Chicago 1885- 90,000 deathsDirect dumping banned in US
SewageAnimal/human
manure and plant debris that bacteria decompose
Sewage, animal feedlots, water
treatment plants or the lack of them
Great amounts of bacteria can remove oxygen from water killing fish. Also
causes algal blooms and possible
eutrophication
-Industrialized societies have sewage treatment plants-Many unindustrialized
societies dump waste directly into water sources.
-encourages the growth of disease organisms
Organic Chemicals
Oil spills, plastics,
pesticides, fertilizers
Oil spills, leakage from ships, runoff from roads, improper disposal
Deplete oxygen, animal contamination
-largest Spill: Persian Gulf War ‘91
hundreds of thousands of metrics tons of oil spilled
intentionally- Exxon Valdez – 42,000
metric tons of crude
Inorganic chemicals
Acids, toxic metals
Industrial effluent, urban
runoff, household cleaners
Poisons fresh alter and sicken those who
drink it
-Lead & mercury levels in fresh water ecosystems enter human food web easily and cause brain, liver & kidney
damage-Acid rain
-Japan 1950- mercury poisoning- 8,000 people
paralyzed or brain damaged
PlantFertilizers
Water soluble
compounds with nitrate, phosphorous
ions
Sewage, manure,
farm/garden runoff
Spurs rapid growth of algae that decay and deplete water’s
oxygen…fish die
Largest source of runoff pollution
Sediment Soil Erosion
Disrupts aquatic food webs, clogs
lakes & reservoirs, reduces
photosynthesis of aquatic plants
- over time the water may fill with sediment causing fresh water ecosystems to
fill with sediment and become a meadow over
time
Radioactive substances
Radon, uranium
Nuclear power plants, ore mining & processing
Cancers, birth defects, genetic
mutations
1973 & 1950 radioactive spills from sites- thousands
exposed to high level radiation
Thermal pollution
Large increase in
water temperature
Power plants/industry
Increase in fish metabolism
requiring them to consume more
oxygen- water holds less dissolved oxygen
-Nuclear power plants pull in cold water and release
water 10-15 degrees higher.
- Industrial use
Groundwater Pollution
Municipal Sewage Treatment Waste water undergoes several treatments at a
sewage treatment plant to prevent environmental and public health problems. The treated water is then discharged into rivers, lakes or the ocean.
Process:
1. Primary Treatment
A. Removes suspended & floating particles
B. Screening & gravitational settling
1. Solid material that settles out is known as primary sludge
2. Does not eliminate the inorganic & organic compounds remaining in the wastewater.
2. Secondary Treatment
A. Uses microorganisms to decompose the suspended organic material
1. Trickling filters: wastewater trickles through rock beds containing bacterial which degrade the organic material
2. Activated sludge process: Wastewater is aerated and circulated through bacteria rich particles.
3. Particles and microorganisms are allowed to settle out forming Secondary Sludge
** Water is clear and free of organic wastes such as sewage**
Primary and Secondary Treatment
Individual Septic Systems
• Many private residences use individual septic systems instead of municipal sewage treatment.– Household sewage is piped into the septic tank – Particles settle to the bottom– Grease and oils form a scummy layer where bacteria
decomposes it– Waste water containing suspended organic and inorganic
material flows into the drain field through a network of perforated pipes set in trenches of crushed stone
• Purified wastewater then percolates into
the groundwater or evaporates from the soil
Do you see how there could be a contamination problem here?
Septic Systems
The septic tank works much like primary treatment in municipal sewage treatment- sewage from the house is piped to the septic tank, where particles settle to the bottom
Wastewater containing
suspended organic and inorganic
material flows into the drain field and
gradually seeps into the soil