Transcript Pollution 2015

Water Quality
What is water pollution?
Water pollution is any
chemical, physical or
biological change in the
quality of water that has a
harmful effect on any
living thing that drinks
or uses or lives in it.
WATER POLLUTION
• Ususally comes from:
– Human activities both intentional &
unintentional
2 categories of water pollution sources:
1. Point Source
2. Non-Point Source
1. Point sources
Point sources discharge pollutants at
specific locations into the water source.
Example…through pipelines or sewers into the surface water.
Examples of point
sources are:
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Leaking sewagge pipes,
Factories
sewage treatment plants
underground mines
oil wells
oil tankers
agriculture.
2. Nonpoint sources
Nonpoint sources are sources that cannot be traced to a
specific or single site of discharge.
*They are the result of wide spread runoff from large areas.
Examples of nonpoint sources
are:
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acid deposition from the air
Traffic; urban run off
chemical and pesticide runoff from
farmland
Storm sewers
pollutants that are spread through rivers
pollutants that enter the water through
groundwater.
There are many classes of water
pollution, here are a few…
1. Biodegradeable
Wastes
3. Sediment Pollution
– Eutrophication
4. Chemical Pollution
– Sewage
– Disease Causing
Agents
2. Heat, Thermal
Pollution
– Bioaccumulation
– Organic/inorganic
compounds
5. Ocean Dumping
I. Biodegradable Wastes
• This category includes such SOURCES as:
– Human / animal wastes
– Food scraps
– Organic materials
– Sources of Nutrient Pollution are sewage,
septic runoff, livestock waste, fertilizer runoff,
detergents, and industrial wastes
– Disease-causing agents
Effects of Biodegradable
Wastes for water pollution…
• If there are excessive nutrients,
oxygen consuming bacteria will
mulitpy too rapidly, consuming the
oxygen in a stream and making it
uninhabitable for some species of
fish and other aquatic life.
• If bacteria grow too fast, they
consume enough oxygen so that
virtually everything in the water
dies, leaving only anaerobic
bacteria creates foul smelling
gasses.
• Spreading of
disease-causing
bacteria
• Provides nutrients
for bacteria to
multiply fast
• Also can cause
Eutrophication…
What is Eutrophication?
(part of Biodegradeable wastes)
• Naturally-occurring
changes that take place
in a body of water
• Caused Lake Erie to age
nearly 15,000 years
between 1950 and 1975
• Nitrates and phosphates
from runoff cause the
process & From erosions
of surrounding lands
• Occurs slowly over
millions of years.
• Human activities can
accelerate this process
• Increasing the amounts of
runoff of nitrates and
phosphates will increase
the rate of eutrophication
Biodegradeable:
What is Sewage?
• Wastewater carried off by drains or sewers
(from toliets, washing machines, showers,
etc…)
Typically includes:
• Water containing human wastes, soaps,
detergents, and then is released into water
causing a number of pollution problems.
What Harm Does Sewage Cause?
--It carries disease causing agents, water
polluted with sewage poses a health threat to the
public.
• Causes 2 serious environmental
problems in the water:
1.Enrichment
2.Oxygen demand
ENRICHMENT…
• The fertilization of a body of water, caused by
the presence of high levels of plant nutrients
such as nitrogen and phosphorous
• This causes:
– Aquatic plants and algae grow faster
– May take over / clog waterways
– Excessive plants/algae cause a lack of
oxygen in the water, because the sewage
and other organic materials decomposes into
CO2, water, and other materials by the
microorganisms… cellular respiration….
What Harms Does Sewage
Cause?
2. Biological Oxygen Demand (BOD):
A. Sewage is measured in terms of its biological
oxygen demand (BOD).
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BOD is defined as:
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The amount of oxygen needed by microorganisms in the water
to decompose the waste
– Large amount of sewage = High BOD, which
robs the water of necessary amounts of
dissolved oxygen
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When dissolved oxygen levels are low, anaerobic microorganism
also produce compounds that have unpleasant odors, further
deteriorating the water quality.
BOD
• Dissolved oxygen is used by most aquatic
organisms
• When an aquatic ecosystem contains high levels
of sewage, the decomposing bacteria use up
most of the available oxygen and fish begin to
die off
Biodegradeable:
Disease-Causing Agents
• Municipal wastewater (from cities) usually contains many
bacteria, viruses, protozoa, parasitic worms, and other
infectious agents that cause human or animal diseases.
• Organisms that cause disease, like below, enter the
waterways from domestic sewage and untreated human and
animal wastes.
• Diseases caused by contaminated food and water include:
– Typhoid
– Cholera
– Bacterial dysentery(diarrhea)
– Polio
– Hepatitis A
Test for Contaminated Water?
• Contaminated water causes about 80%
of the diseases in developing countries
– Kills about 10 million people per year.
• A good indicator of the quality of water for
drinking or swimming is the number of
colonies of coliform bacteria present in a
100-milliliter sample of water.
– Coliform bacteria are excreted by the
billions from humans and animals.
• Fecal Coliform Test
– A reliable test to indicate if the water is
contaminated with sewage or with disease
causing agents in the water
– Obtain a sample of water
• Filter the bacteria and incubate
• Count the # of greenish colonies (E. coli)
• Safe drinking water should contain no more
than 1 coliform bacterium per 100 ml of
water (about ½ a cup).
• Safe swimming water should have no more
than 200 per 100 ml.
Sewage in Cities
• Today wastewater is usually
treated before being released into
the environment
• However some viruses and
parasites are able to resist
chlorine and other water
treatment processes.
• During heavy rains and floods,
sanitary sewers sometimes
overflow and run into storm sewers
that lead to surface water.
Sewage in Rural Areas
• People have to be careful
where they locate septic
tanks. If a tank is too near a
stream or on a hill, wastewater
can leak into the stream or
flow into a well downhill.
•Wastes from cattle, pigs, & chickens can
also be a problem
•They contribute disease-causing
bacteria and other kinds of pollution
II. Thermal Pollution
• Heat can be a deadly water pollutant
• An important relationship exists between the amount
of dissolved oxygen in water and its temperature.
– The warmer the water, the less dissolved oxygen
• Caused by the dumping of hot water into a body of
water
– Natural causes:
• Hot springs
• Shallow ponds in summer
– Human causes:
• Water used to cool industrial or power plants is discharged into
streams, etc…
Effects of Thermal Pollution
• Raises the temperature of the body of water
• Reduces the amount of dissolved oxygen; which
affects the life the water can support
• Affects/reduces the diversity of species that can
survive in that body of water, which can impact the
environmental health of a stream
– Some sport fish, such as trout, need cold water with high
levels of dissolved oxygen and cannot live in warm water.
– Other fish, like carp and suckers, thrive in warm water
and can take over habitats from other fish if waters
become too warm.
III. Sediment Pollution
• Sediment is one of our most destructive water
pollutants.
• Sediments are particles suspended in a body of water
from erosion and surface run off, that eventually
settle out and accumulate on the bottom.
– America’s water is polluted by more than one billion tons of
sediment annually.
• It comes from agricultural lands, forest soils exposed
by logging, over grazed rangelands, strip mines, and
construction.
• The damage from sediment pollution is cumulative.
As plants and fish die, the waterway loses its ability to break down
wastes and materials that are naturally washed into it.
These materials begin to accumulate and form another source of
pollution
Sediment Pollution affects:
• Makes the water cloudy (turbidity) and reduces light penetration
– reduces photosynthesis and disrupts aquatic food webs by reducing the number
of photosynthesizing organisms (such as plankton and plants). This, in turn,
reduces the number of aquatic organisms that feed on those organisms.
– As sediments darken the water, it causes the absorption of more solar radiation,
raising the water temperature even further.
• Disrupts food chains
– Sediments can also clog the gills and feeding structures of many
aquatic animals,
– whether they are benthic organisms (ones that live on the
bottom), or swimmers.
• Sediments can also carry pesticides, bacteria, and other
harmful substances.
– Sediment that settles out destroys feeding and spawning grounds
of fish.
• Can block or clog water flows; fills lakes, artificial reservoirs,
stream channels, and harbors.
IV. Chemical Pollution
• Usually human-caused
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Modern nations rely on thousands of organic and inorganic chemicals in industry,
agriculture, and the home. They provide many benefits and improve existing
processes.
But improperly used or disposed of, reasonable safe chemical compounds cause
toxic reactions. The effects of such toxics can be short term or long term and are
regarded as a major national and international health concern.
Includes organic and inorganic chemicals:
– Household cleaners
– Industrial wastes/discharge
– Fertilizers and pesticides
that have surface run off
– Toxic metals
• (mercury, lead, cadmium)
– Oil spills
Chemical Pollution
• Sources of chemical pollution include:
– industrial discharges or accidents in the transport of chemicals (such as
oil spills). It can also come from surface runoff from both urban and rural
areas, and transport through the atmosphere.
– Roads and parking lots collect toxics such as lead, oil, cadmium (from
tires) and other pollutants, which can be washed into streams through
storm drains.
• These can cause immediate toxic effects as well as long-term effects by
accumulating in sediment or in living organisms (remember
bioaccumulation).
– In agricultural areas, pesticides containing toxic compounds are applied
to crops to improve crop quality and increase yields.
• Improper application of pesticides, however, creates serious water
pollution problems.
• Runoff from fields can introduce large amounts of toxics into
waterways.
– Pesticides can also cause groundwater contamination.
Chemical Pollution
• The cost of disposing of toxic chemicals created by industry is
high.
– There are many federal and state laws that require careful monitoring,
storage, and disposal of toxic chemicals. Legislation adopted since the
late 1970’s has imposed large fines and jail sentences for people caught
illegally dumping toxic wastes.
• Household chemicals, such as cleaners, dyes, paints,
pesticides, and solvents are a large source of toxic water
pollution, especially in urban areas.
– Many of these materials are simply poured down drains or flushed down
toilets with no regard to their consequences.
• A single quart of used motor oil can pollute a quarter of a
million gallons of water!
• Homeowners may use ten times the amount of pesticides per
acre as farmers do.
What is Bioaccumulation?
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The amount of these toxic chemicals increases
and accumulates in the tissues of organisms
each step up the food chain. (EX… DDT)
There were large amounts of pesticides that were
used during the 1960's and 1970's and these
chemicals still remain in places like the Lake
Superior environment.
Although sale of these persistent pesticides is
banned, there are still supplies of these poisons on
the back shelf in home garages, on farms, in
schools, and other community locations.
Even though these toxic chemicals are banned in
the US and Canada, they are still used in other
countries around the world.
If they enter the atmosphere when they are
sprayed or when they are burned, they can be
carried on the wind and deposited in our
environments.
If we eat food that comes from other countries
where these pesticides are still used, we can be
exposed to them.
Organic Compounds
• Organic compounds are ones that contain carbon (such as oil).
• Most of the organic compounds found in water are synthetic chemicals that
are created for human activities.
• These include pesticides, solvents, industrial chemicals, and plastics.
• These commonly have unusual shapes that are not easily broken down by
normal processes.
• As a result, they remain in waterways for very long periods of time, and can
cause issues in the metabolism and health of aquatic life.
– Ex. Oil and plastics
Inorganic Compounds
• These include acids, salts, and toxic
metals such as mercury and lead.
• A large number of inorganic
chemicals come from industrial plants,
mines, irrigation runoff, oil drilling, and
storm runoff from cities.
– Some of these pollutants are toxic to
organisms.
– High levels of these chemicals can
make water unfit to drink,
– harm or kill aquatic life,
– lower crop yields,
– and accelerate corrosion of metals
exposed to such water.
• Mercury and lead are known to cause
cancer and death in organisms.
Organic and Inorganic Compounds
Another class of water
pollutants is water-soluble
inorganic pollutants, such as
acids, salts and toxic metals.
Large quantities of these
compounds will make water
unfit to drink and will cause
the death of aquatic life.
Water can also be polluted
by a number of organic
compounds such as oil,
plastics and pesticides,
which are harmful to humans
and all plants and animals in
the water.
Industrial Wastes: Chemicals
• Some factories still release toxic
chemicals directly into nearby
rivers and lakes
• In the past: Industries stored
toxic wastes in barrels or other
containers and buried
underground. Over time these
containers leaked out, polluting
both the soil and the
groundwater.
Industrial Wastes: Acid Deposition
• When coal, oil, and gasoline are
burned, molecules of the gases
sulfur dioxide and nitrogen oxide
are released into the atmosphere.
• This reacts with rain forming acid
rain.
• Acid rain can change the pH level
of a lake killing fish and other
wildlife
Inorganic Plant Nutrients
• The rich supply of nutrients from
fertilizers encourages the
growth of plants and algae in and
around nearby bodies of water.
– This can “choke out” animal
life and the build up of dead
plant material can make the
water shallower and warmer
• Runoff & irrigation water also
carry away other pollutants
(pesticides) from farm fields.
Industrial Wastes: Thermal Pollution
• Occurs when heated water from industrial
processes is released into waterways
• Much of the water in factories is used to cool
machinery or metal objects.
• Even if it contains no chemicals, the warm
water alone can act as a pollutant.
• Many water organisms can live in only a narrow
range of temperatures.
V. Ocean Dumping
• Ocean dumping is the dumping or placing of
materials in designated places in the ocean,
often on the continental shelf.
• This includes:
– garbage, construction and demolition
debris, sewage sludge, dredge material,
and waste chemicals.
• In some cases, ocean dumping is regulated
and controlled, while some dumping occurs
“accidentally” by ships and tankers at sea, or
illegally within coastal waters.
– Incineration at sea of organic wastes has
been allowed at one time or another both in
the United States and in Europe.
• An important, but little recognized source of
ocean dumping is the elimination of bilge
water from ships.
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(water
that does not drain off the sides of the
ship decks drains into the bilge)
Ocean Dumping
California 1958
• Between 1946 and 1970, the US
dumped ~107,000 drums of
radioactive wastes
• including some 47,800 in the ocean
west of San Francisco
• However drums actually litter an area
of at least 1,400 square kilometers/540
square miles,
– known as the Farallon Island
Radioactive Waste Dump,
– which now falls almost entirely within
the boundaries of the Gulf of the
Farallones National Marine Sanctuary.
– The exact location of most drums is
unknown.
– At least some are corroding.