Transcript Other Water Pollutants

Chapter 14
Water Pollution
Water Pollution
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Water pollution- the contamination of streams, rivers, lakes,
oceans, or groundwater with substances produced through
human activities and that negatively affect organisms.
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Point sources- distinct locations that pump waste into a
waterway. These are easily identified
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Nonpoint sources- diffuse areas such as an entire farming
region that pollutes a waterway. These are more expensive
and difficult to clean up.
Can you identify which
of these is point source
Pollution?
Categories of Water Pollution
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Sewage
disease-causing agents
sediment pollution
inorganic plant and algal nutrients
organic compounds
inorganic chemicals
radioactive substances
thermal pollution
Noise pollution
Water Pollution is a Problem
Worldwide
Half of the world’s major rivers are
seriously depleted and polluted
They poison surrounding ecosystems
Threaten the health and livelihood of
people
The invisible pollution of groundwater has
been called a “covert crisis”
Water Pollution
Over two-thirds of U.S. estuaries and bays are severely
degraded because of nitrogen and phosphorous pollution
Every year almost 25% of U.S. beaches are closed at least
once because of water pollution
Over 73 different kinds of pesticides have been found in the
groundwater that we eventually use to drink
1.2 trillion gallons of sewage, storm water and industrial waste
are discharged into U.S. waters every year
A large number of U.S. rivers are too polluted for aquatic life to
survive
Americans use over 2.2 billion pounds of pesticides every year,
which eventually washes into our rivers and lakes
Leading causes of water pollution
1.Agriculture activities
• Sediment eroded from the lands
• Fertilizers and pesticides-almost all waters
are polluted with pesticides
• Bacteria from livestock and food processing
wastes
2.Industrial facilities- heavy metals, corrosive
materials organic and non-organic chemicals
3.Mining- acid drainage pollutes water by
leeching out heavy metals
Agriculture major source of water
pollution
 Agriculture is leading source of water
pollution in US
 Animal wastes and plants residues
have high BOD
 Chemical pesticides can leach into
groundwater
 Almost all streams and rivers are
polluted with agricultural pesticides
Agricultural Runoff is the main cause of the
Dead Zone in the Gulf of Mexico; The U.N.
documented 250 dead zones worldwide in 2005
Sediment runoff from farmland is the highest
Pollution from agriculture by weight.
Eutrophication
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Eutrophication is an abundance of fertility to a body
of water.
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Eutrophication is caused by an increase in nutrients,
such as fertilizers.
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Eutrophication can cause a rapid growth of algae
which eventually dies, causing the microbes to
increase the BOD and oxygen levels to fall
eventually may cause a die-off of all organisms.
Solutions to Reduce
Eutrophication
• Phosphate-free detergents
• Planting vegetation to increase
nutrient uptake
• Treat wastewater
• Reduce fertilizer application
Different industries add different
pollutants
 Food processing plants- high BOD
 Paper mills- High BOD and toxic
compounds
 Textile industry-the World Bank
estimates that 17-20 percent of
industrial pollution comes from textile
industry with 72 toxic chemicals being
added to water
According to Greenpeace, the discharge from these factories includes
heavy metals and “hazardous and persistent chemicals with hormonedisrupting properties” were found being discharged from China’ s factories
Heavy Metals and Other Substances that can
threaten human Health and the Environment
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Lead
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Arsenic
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Mercury
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Acids
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Synthetic compounds (pesticides,
pharmaceuticals, and hormones)
More on heavy metals
Lead
Found in old paint, industrial
pollutants, leaded gasoline
Mercury
Mercury bioaccumulates in
the muscles of top predators of
the open ocean
Arsenic found naturally in rocks
and water
• When arsenic is found in water, it may
be from natural causes
• Highest levels of arsenic in U.S. found
in upper Midwest and West
• Individual wells dug in Southeast Asiamany are contaminated by arsenic
causing arsenic posioning
World Mercury Production from Human Activities
Pharmaceuticals and Hormones Found in Water
Industrial Compounds
• Chemicals used in manufacturing
• Local examples include PCBs in
Hudson River from General Electric Co.
and cadmium from foundry in Cold
Spring
• PCBs cause brain damage, are lethal
and carcinogenic
Oil Pollution
Marine pollution threatens resources
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Even into the mid-20th century, coastal U.S. cities
dumped trash and untreated sewage along their shores
Oil, plastic, chemicals, excess nutrients make their way
from land into oceans
Raw sewage and trash from cruise ships
Abandoned fishing gear from fishing boats
In 2006, 359,000 Ocean Conservancy volunteers from 66
nations picked up 3.2 million kg (7 million lbs.) of trash
Ways to Remediate Oil Pollution
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Containment using booms to keep the floating oil
from spreading.
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Chemicals that help break up the oil, making it
disperse before it hits the shoreline.
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Bacteria that are genetically engineered to consume
oil
Water Pollution from Mining
• Acid Mine Drainage-low pH of water
causes iron to precipitate from pyrite
and cause a rusty red color
• Heavy metal contamination and
leeching
• Mine waste and tailings
• Processing chemicals pollution
• Sedimentation of waters and erosion
Mining often pollutes waters
Other Water Pollutants
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Solid waste pollution (garbage)
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Sediment pollution (sand, silt and clay)
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Thermal pollution
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Radioactive pollution
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Noise pollution
Solid Waste Pollution
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Much solid waste is garbage
North Pacific Gyre-Great Pacific Garbage
Patch
Plastic waste is dangerous to marine
animals and humans
Found in the stomachs of dead baby sea
birds as parent birds think the small
pieces of plastic is phytoplankton.
Plastic rubbish deposits
Plastic Pollution of Water
• Plastics can release harmful chemicals
into the water
• Plastic is a synthesized organic
compound (carbon-hydrogen bonds)
that does not decompose
• Plastic breaks up into extremely tiny
pieces that is mistaken for food by many
organisms.
Sediment Pollution
Excessive amounts of suspended soil
particles
Originates from erosion of agricultural lands,
forest soils exposed by logging, degraded
stream banks, overgrazed rangelands, strip
mines, and construction
Problems
Limits light penetration
Covers aquatic animals and plants
Brings insoluble toxins into waterways
Land disturbance results in
poor water quality
Clear-cutting, mining, poor cultivation
practices
Dramatically changes aquatic habitats, and
fish may not survive
Solutions: better management of farms and
forests; avoid large-scale disturbance of
vegetation
Radioactive Substances
 Contain atoms of unstable isotopes that
spontaneously emit radiation
 Sources
 Mining
 Processing radioactive materials
 Nuclear power plants
 Natural sources
Thermal Pollution
Occurs when heated water produced during
industrial processes is released into
waterways
Temperature affects digestive rates, heart
rates, and respiration rates
Warmer water holds less dissolved oxygen
Removing streamside cover also raises
water temperature
Noise Pollution
• Sounds from ships and submarines
• Sonar equipment could negatively affect
whales, causing them to be beached
• U. S. Military exempt from
environmental laws related to sonar use
Organic Compounds found in Polluted Water
Human Wastewater
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Water produced by human activities such as human
sewage from toilets and gray water from bathing
and washing clothes or dishes.
Why human and animal waste
water needs to be treated
Pathogens and toxins enter water supply via
inadequately treated human waste and
animal waste via feedlots
Causes more human health problems than any
other type of water pollution
Three reasons scientists are concerned about
human wastewater:
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Oxygen-demanding wastes like bacteria that put a
large demand for oxygen in the water
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Nutrients that are released from wastewater
decomposition can make the water more fertile
causing eutrophication
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Wastewater can carry a wide variety of diseasecausing organisms.
Biochemical Oxygen Demand (BOD)
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BOD- the amount of oxygen a quantity of water uses
over a period of time at a specific temperature.
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As BOD increases Dissolved Oxygen (DO) decreases
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Lower BOD values indicate the water is less
polluted and higher BOD values indicate it is more
polluted by wastewater.
Sewage and pollutants in drinking water
Currently, 1.1 billion people are without safe
drinking water
2.4 billion have no sewer or sanitary facilities
Mostly rural Asians and Africans
An estimated 1.6 to 5 million people die per
year from unsafe drinking water
Common Diseases from Human
Wastewater
Major Water Pollutants and Their
Sources
Table 20-1, p. 532
Solutions
• Treat sewage
• Disinfect drinking water
• Public education to encourage
personal hygiene
• Government enforcement of
regulations
Treatments for Human and Animal
Wastewater
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Septic systems- a large container that receives
wastewater from the house.
Treatments for Human and Animal
Wastewater
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Sewage Treatment Plants- centralized plants in
areas with large populations that receive
wastewater via a network of underground
pipes.
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Test for human and animal waste using fecal
coliform bacteria test
Levels of Treatment and Success
Primary treatment: Some pathogenic bacteria and some
solids removed
Secondary treatment: some viruses, more waste solids,
more pathogenic bacteria, and some dissolved
organics removed, BOD lowered
Tertiary treatment: Phosphorous and nitrogen levels
lowered, dissolved organics and pathogenic bacteria
lowered, waste solids completely removed
Chlorination treatment: Pathogenic bacteria completely
removed, nitrogen amounts lowered further, viruses
lowered further
Tertiary treatment of waste water often
includes Chlorine treatment
Chlorine Dilemma
Chlorine byproducts are linked to
numerous cancers, miscarriages and birth
defects
Peru stopped using chlorine
1991: huge cholera epidemic that
infected 300,000 people
Fluoridation
Prevents tooth decay
Linked to cancer, kidney disease
Treatments for Human and Animal
Wastewater
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Manure lagoons- large, human-made ponds line with
rubber to prevent the manure from leaking into the
groundwater. After the manure is broken down by
bacteria, it is spread onto fields as fertilizers.
Problems with Manure Lagoons
Containment of lagoons may burst if containment walls
break.
During high precipitation events lagoons may overflow
bringing pathogenic bacteria to water supply
We have better methods- We can
improve traditional sewage
treatment
Use of natural wetlands
Remove toxic wastes before sewage
enters treatment plants
Use composting toilets
Reduce use of toxic materials
Using Nature to Purify our waste
water and sewage water
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Natural water purification system
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Sewage flows into anaerobic digester
Cleaner water then passes through artificial
marsh to remove some nutrients
water flows into a passive greenhouse
Solar energy and natural processes remove
and recycle nutrients
Diversity of organisms used
Use of a Living Machine to purify waste
water Omega Center in Rhinebeck NY
Water Laws
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Clean Water Act- (1972) supports the “protection
and propagation of fish, shellfish, and wildlife and
recreation in and on the water”.
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Issued water quality standards that defined
acceptable limits of various pollutants in U.S.
waterways.
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Effectively improved water quality from point
sources
Water Laws
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Safe Drinking Water Act- (1974, 1986, 1996) sets the
national standards for safe drinking water.
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It is responsible for establishing maximum
contaminant levels (MCL) for 77 different elements
or substances in both surface water and
groundwater.
Indicators of
water quality
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Scientists measure properties of water to
characterize its quality
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Biological indicators: presence of fecal coliform
bacteria and other disease-causing organisms
Chemical indicators: pH, nutrient concentration,
taste, odor, hardness, dissolved oxygen
Physical indicators: turbidity, color, temperature
Streams Can Cleanse
Themselves If We Do Not
Overload Them
• Dilution of pollutants does help
• Biodegrading of wastes by bacteria
(takes time) Some substances are not
biodegradable
• Higher human population stresses
natural system of cleansing
• Prevention is less costly and more
effective and cleanup
Dilution and Decay of Degradable,
Oxygen-Demanding Wastes in a
Stream
Fig. 20-7, p. 534
Solutions: Methods for Preventing
and Reducing Water Pollution
What Can You Do?
Reducing Water Pollution