Transcript water pollution

WATER POLLUTION
Water pollution

What is it?
The contamination of water in lakes, rivers,
oceans, aquifers and groundwater.
Water pollution occurs when pollutants are
discharged directly or indirectly into water
bodies without adequate treatment to
remove harmful compounds.
Categories of water pollution
Point source refers to contaminants that enter
the water from a single, easy-to-identify source
like a pipe or a storm drain.
Categories of water pollution
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Non-point source pollution is pollution that
comes from a big area and not from a single,
easy-to-identify source like an agricultural
field or a shopping centre parking lot.
Point and Nonpoint Sources
NONPOINT SOURCES
Rural homes
Cropland
Urban streets
Animal feedlot
Suburban
development
POINT
SOURCES
Wastewater
treatment
plant
Factory
Type of water pollution
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Bacteria,Viruses,Protozoa, Parasitic worms
Oxygen demanding substances
Inorganic plant nutrients
Organic chemicals
Sediment or suspended matter
Thermal pollution
Genetic pollution
1. Bacteria & Co.
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Often comes from fecal (poop) material –
untreated or poorly treated sewage, farmers’
fields (animal poop) or septic tanks
Major cause of acute contamination of human
drinking water – can immediately make people
sick
Major issues: E. coli, giardia, cryptosporidium,
Norovirus
1. Bacteria & Co.
Health Impacts? – diarrhea, vomiting, etc.
Preventing contamination?
 Treated by water treatment plants – various
chemicals
 Filtering or boiling well water and water that
you are not sure about
Access to clean water
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Not everyone in the world has access to clean
water – we are lucky here in Canada!
Solutions?
Type of water pollution
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Bacteria,Viruses,Protozoa, Parasitic worms
Oxygen demanding substances
Inorganic plant nutrients
Organic chemicals
Sediment or suspended matter
Thermal pollution
Genetic pollution
Oxygen demanding substances
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Usually organic compounds that are broken
down by bacteria that need oxygen
Like what?
Green waste (leaves, grass cuttings, etc.), food
waste, garbage
Oxygen demanding substances
So what?
When there are many organic compounds
decomposing at the same time (and consuming
oxygen), they can reduce the amount of oxygen
available to suffocate organisms that need
oxygen to live.
Could kill plants and fish in the water!
What can happen? Fish kills….
Type of water pollution
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Bacteria,Viruses,Protozoa, Parasitic worms
Oxygen demanding substances
Inorganic plant nutrients
Organic chemicals
Sediment or suspended matter
Thermal pollution
Genetic pollution
Inorganic plant nutrients
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What is inorganic?
A chemical compound that does not have any
carbon (C) in it.
Examples: nitrate (NO3-), phosphate (PO43-),
sulfate
Inorganic plant nutrients
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Where do they come from ?
Agricultural fields (fertilizer or manure),
feedlots, septic tanks….
Inorganic plant nutrients
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Where do nitrates, phosphates and sulfates
end up?
In surface water (water we can see)
In ground water
Inorganic plant nutrients
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1.
2.
What is the problem?
Eutrophication of water bodies – too
many nutrients
Harmful health effects – blue baby
syndrome and cancer
1. Eutrophication
Eutrophication – also known as lots of nutrients,
more than necessary, released into a water
body
Eutrophication comes from too much nitrogen,
phosphorus and sulfate from fertilizers used in
agriculture, septic tanks and industry.
Problems with eutrophication
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Too many nutrients – more algae will
grow
Algae use up all the oxygen in the water
Low oxygen in the water means there is
none left for other organisms in the water
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That means that fish and insects could die
Too many algae on the surface of the
water could block the sunlight – no light
to water plants, they can die
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Some algae can produce toxins – red tide
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Toxins can move up the food chain
Eutrophication
Eutrophication cont’d….
2. Blue-baby syndrome
- infants under 4 months of age who drink
well water with nitrates
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Nitrates turn into other chemicals in the
body and make it difficult for the body to
take up oxygen
Blue-baby syndrome can lead to fatigue,
coma, convulsions, asphyxia and death
Biological
Magnification
Water
0.000002 ppm
Herring gull
124 ppm
Phytoplankton
0.0025 ppm
Herring gull eggs
124 ppm
Lake trout
4.83 ppm
Zooplankton
0.123 ppm
Rainbow smelt
1.04 ppm
Pollution of Lakes
 Eutrophication
Discharge of untreated
municipal sewage
(nitrates and phosphates)
Nitrogen compounds
produced by cars
and factories
Discharge of
detergents
( phosphates)
Discharge of treated
municipal sewage
(primary and secondary
treatment:
nitrates and phosphates)
Natural runoff
(nitrates and
phosphates
Manure runoff
From feedlots
(nitrates and
Phosphates,
ammonia)
Runoff from streets,
lawns, and construction
Lake ecosystem lots (nitrates and
nutrient overload
phosphates)
and breakdown of
chemical cycling
Runoff and erosion
Dissolving of
(from from cultivation,
nitrogen oxides
mining, construction,
(from internal combustion
and poor land use)
engines and furnaces)
Fig .22.7, p. 499
Leaking
tank
Water
table
Groundwater
flow
Free gasoline
dissolves in
Gasoline
groundwater
leakage plume
(dissolved
(liquid phase)
phase)
Migrating
vapor phase
Contaminant plume moves
with the groundwater
Water well
Fig. 20-12
Groundwater Pollution: Causes
Hazardous waste injection well
Pesticides
Coal strip
mine runoff
De-icing
road salt
Pumping
well
Waste lagoon
Gasoline
station
Water pumping
well Landfill
Buried gasoline
and solvent tank
Cesspool
septic tank
Sewer
Leakage from faulty
casing
Accidental
spills
Discharge
Confined aquifer
Groundwater
flow
Fig. 20-11
Industry
Nitrogen oxides
from autos and
smokestacks,
toxic chemicals,
and heavy metals in
effluents flow into
bays and estuaries.
Cities
Toxic metals
and oil from
streets and
parking lots
pollute waters;
Urban sprawl
Bacteria and viruses
from
sewers and septic
tanks contaminate
shellfish beds
Construction sites
Sediments are washed into
waterways, choking fish and plants,
clouding waters, and blocking
sunlight.
Farms
Runoff of pesticides, manure, and
fertilizers adds toxins and excess
nitrogen and phosphorus.
Closed
shellfish beds
Closed
beach
Oxygen-depleted
zone
Red tides
Excess nitrogen causes
explosive growth of
toxicmicroscopic algae,
poisoning fish and
marine mammals.
Toxic sediments
Chemicals and toxic
metals contaminate
shellfish beds, kill
spawning fish, and
accumulate in the tissues
of bottom feeders.
Oxygen-depleted zone
Sedimentation and algae
overgrowth reduce sunlight,
kill beneficial sea grasses, use
up oxygen, and degrade habitat.
Healthy zone
Clear, oxygen-rich
waters promote growth
of plankton and sea grasses,
and support fish.
Fig. 21-10, p. 505
Global Outlook: Stream Pollution in
Developing Countries
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Water in many of
central China's rivers
are greenish black from
uncontrolled pollution
by thousands of
factories.
Figure 20-7
Case Study: India’s Ganges River: Religion,
Poverty, and Health
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Religious beliefs, cultural traditions, poverty, and
a large population interact to cause severe
pollution of the Ganges River in India.
 Very
little of the sewage is treated.
 Hindu believe in cremating the dead to free the soul
and throwing the ashes in the holy Ganges.
 Some
are too poor to afford the wood to fully cremate.
 Decomposing bodies promote disease and depletes DO.
Case Study: India’s Ganges River: Religion,
Poverty, and Health
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Daily, more than 1
million Hindus in India
bathe, drink from, or
carry out religious
ceremonies in the
highly polluted Ganges
River.
Is Bottled Water the Answer?
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Some bottled water is not as pure as tap water
and costs much more.
 1.4
million metric tons of plastic bottles are
thrown away.
 Fossil fuels are used to make plastic bottles.
 The
oil used to produce plastic bottles in the U.S. each
year would fuel 100,000 cars.