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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 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
Urban streets
Suburban development
Wastewater treatment plant
Rural homes
Cropland
Factory
Animal feedlot
POINT SOURCES
Type of water pollution
Bacteria,Viruses,Protozoa, Parasitic worms
Oxygen demanding substances Inorganic plant nutrients Organic chemicals Sediment or suspended matter Thermal pollution Genetic pollution
1. Bacteria & Co.
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
Not everyone in the world has access to clean water – we are lucky here in Canada!
Solutions?
Type of water pollution
Bacteria,Viruses,Protozoa, Parasitic worms
Oxygen demanding substances Inorganic plant nutrients Organic chemicals Sediment or suspended matter Thermal pollution Genetic pollution
Oxygen demanding substances 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 substancesSo 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
Bacteria,Viruses,Protozoa, Parasitic worms
Oxygen demanding substances Inorganic plant nutrients Organic chemicals Sediment or suspended matter Thermal pollution Genetic pollution
Inorganic plant nutrients
What is inorganic? A chemical compound that does not
have any carbon (C) in it.
Examples: nitrate (NO3-), phosphate (PO43-), sulfate
Inorganic plant nutrients
Where do they come from ?
Agricultural fields (fertilizer or manure), feedlots, septic tanks….
Inorganic plant nutrients
Where do nitrates, phosphates and sulfates end up?
In surface water (water we can see) In ground water
Inorganic plant nutrients
What is the problem?
1.Eutrophication of water bodies – too many nutrients
2.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 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
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
Some algae can produce toxins – red tide
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
- 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
Rainbow smelt1.04 ppm
Zooplankton0.123 ppm
Phytoplankton0.0025 ppm
Water0.000002 ppm
Herring gull124 ppm
Lake trout4.83 ppm
Herring gull eggs124 ppm
Biological Magnification
Biological Magnification
Pollution of Lakes
Eutrophication Eutrophication Discharge of untreated
municipal sewage(nitrates and phosphates)
Nitrogen compoundsproduced by cars
and factories
Discharge of treatedmunicipal sewage
(primary and secondarytreatment:
nitrates and phosphates)
Discharge of detergents
( phosphates)
Natural runoff(nitrates andphosphates
Manure runoffFrom feedlots(nitrates andPhosphates,
ammonia)
Dissolving of nitrogen oxides
(from internal combustionengines and furnaces)
Runoff and erosion(from from cultivation,mining, construction,
and poor land use)
Runoff from streets,lawns, and construction
lots (nitrates andphosphates)
Lake ecosystemnutrient overload
and breakdown of chemical cycling
Fig .22.7, p. 499
Fig. 20-12
Aquifer
Water well
Migrating vapor phase
Contaminant plume moveswith the groundwater
Free gasolinedissolves ingroundwater(dissolved phase)
Groundwaterflow
Watertable
Gasolineleakage plume(liquid phase)
Leakingtank
Bedrock
Groundwater Pollution: Causes
Coal strip mine runoff
Pumping well
Waste lagoon
Accidental spills
Groundwater flow
Confined aquifer
Discharge
Leakage from faulty casing
Hazardous waste injection well
Pesticides
Gasoline station
Buried gasoline and solvent tank
Sewer
Cesspool septic tank
De-icing road salt
Unconfined freshwater aquifer
Confined freshwater aquifer
Water pumping well Landfill
Fig. 20-11
Fig. 21-10, p. 505
Healthy zoneClear, oxygen-richwaters promote growthof plankton and sea grasses,and support fish.
Oxygen-depleted zoneSedimentation and algaeovergrowth reduce sunlight,kill beneficial sea grasses, useup oxygen, and degrade habitat.
Red tidesExcess nitrogen causesexplosive growth of toxicmicroscopic algae,poisoning fish andmarine mammals.
FarmsRunoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus.
Toxic sedimentsChemicals and toxic metals contaminate shellfish beds, kill spawning fish, andaccumulate in the tissues of bottom feeders.
Construction sitesSediments are washed intowaterways, choking fish and plants, clouding waters, and blocking sunlight.
Urban sprawlBacteria and viruses fromsewers and septic tanks contaminate shellfish beds
Oxygen-depletedzone
Closedbeach
CitiesToxic metals and oil from streets and parking lots pollute waters;
IndustryNitrogen oxidesfrom autos andsmokestacks,toxic chemicals,and heavy metals in effluents flow into bays and estuaries.
Closedshellfish beds
Global Outlook: Stream Pollution in Developing Countries
Water in many of central China's rivers are greenish black from uncontrolled pollution by thousands of factories.
Figure 20-7Figure 20-7
Case Study: India’s Ganges River: Religion, Poverty, and Health
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
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? 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.