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