Transcript groundwater pollution11_12

WATER POLLUTION
Two main types of freshwater pollution
1. Point Source: Pollution that comes from a known and specific location
EX) Factory pipes, tail pipe, leaking land fill, leaking storage tank
2. Non-Point: does not have a specific point of origin
EX) 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
Hypoxia_in_the_Delta.asf
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
"Clean Water 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
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
Disease
organisms
Sewage
Organic
Chemicals
Inorganic
chemicals
EXAMPLES
SOURCES
EFFECTS
INFORMATION
Waste from
animals
Typhoid, cholera,
dysentery
Chicago 1885- 90,000 deaths
Direct dumping banned in US
Animal/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
Oil spills,
plastics,
pesticides,
fertilizers
Oil spills,
leakage from
ships, runoff
from roads,
improper
disposal
Bacteria,
viruses
Acids, toxic
metals
Industrial
effluent, urban
runoff,
household
cleaners
Deplete oxygen,
animal contamination
Poisons fresh alter
and sicken those who
drink it
-largest Spill: Persian Gulf
War ‘91
hundreds of thousands of
metrics tons of oil spilled
intentionally
- Exxon Valdez – 42,000
metric tons of crude
-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
Plant
Fertilizers
Water
soluble
compounds
with nitrate,
phosphorous
ions
Sewage,
manure,
farm/garden
runoff
Sediment
Soil
Erosion
Radioactive
substances
Radon,
uranium
Nuclear power
plants, ore
mining &
processing
Thermal
pollution
Spurs rapid growth
of algae that decay
and deplete water’s
oxygen…fish die
Largest source of runoff
pollution
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
Cancers, birth
defects, genetic
mutations
1973 & 1950 radioactive
spills from sites- thousands
exposed to high level
radiation
Increase in fish
Large
Power
-Nuclear power plants pull
metabolism
increase in plants/industry
in cold water and release
requiring them to
water
water 10-15 degrees higher.
consume more
temperature
- Industrial use
oxygen- water holds
less dissolved oxygen
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