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• “Water and air, the two essential fluids on which all life depends, have become global garbage cans.”

• Jacques Cousteau

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Chapter 14Water Pollution

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Water Pollution

© Water pollution- the contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human activities and that negatively affect organisms.

© Point sources- distinct locations that pump waste into a waterway.

© Nonpoint sources- diffuse areas such as an entire farming region that pollutes a waterway.

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Human Wastewater

© Water produced by human activities such as human sewage from toilets and gray water from bathing and washing clothes or dishes.

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Three reasons scientists are concerned about human wastewater:

© Oxygen-demanding wastes like bacteria that put a large demand for oxygen in the water

© Nutrients that are released from wastewater decomposition can make the water more fertile causing eutrophication

© Wastewater can carry a wide variety of disease-causing organisms.

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Biochemical Oxygen Demand (BOD)

© BOD- the amount of oxygen a quantity of water uses over a period of time at a specific temperature.

© Lower BOD values indicate the water is less polluted and higher BOD values indicate it is more polluted by wastewater.

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Fig. 21-3, p. 496

WaterQuality

Below 4

Below 4.5

DO (ppm) at 20°C

4.5–6.7

6.7–8

8–9

Gravelypolluted

Heavilypolluted

Moderatelypolluted

Slightlypolluted

Good

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POLLUTION OF FRESHWATER STREAMS

ØFlowing streams can recover from a moderate level of degradable water pollutants if they are not overloaded and their flows are not reduced.l In a flowing stream, the breakdown of degradable

wastes by bacteria depletes DO and creates and oxygen sag curve.• This reduces or eliminates populations of organisms with high oxygen requirements.

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Fig. 21-4, p. 497

8 ppm

Biologicaloxygendemand

Dissolvedoxygen(ppm)

Types oforganisms

8 ppm

RecoveryZoneSeptic

ZoneDecomposition

ZoneClean Zone

Fish absent,fungi, sludgeworms,bacteria

(anaerobic)

Trash fish(carp, gar,leeches)Clean Normal clean

water organisms(Trout, perch, bass,

mayfly, stonefly)

Normal clean water organisms

(Trout, perch, bass,mayfly, stonefly)

Clean Zone

Trash fish(carp, gar,leeches)

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Eutrophication

© Eutrophication is an abundance of fertility to a body of water.

© Eutrophication is caused by an increase in nutrients, such as fertilizers.

© Eutrophication can cause a rapid growth of algae which eventually dies, causing the microbes to increase the BOD.

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Common Diseases from Human Wastewater

© Cholera

© Typhoid fever

© Stomach flu

© Diarrhea

© Cholera

© Hepatitis

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Table 21-2, p. 495Monday, May 16, 16

Treatments for Human and Animal Wastewater

© Septic systems- a large container that receives wastewater from the house.

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Fig. 21-15, p. 510

Distribution box

Manhole cover(for cleanout)

Vent pipePerforated pipe

Drain field(gravel orcrushed stone)

Septic tank

Sludge

Wastewater

Gas

Scum

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Treatments for Human and Animal Wastewater

© Sewage Treatment Plants- centralized plants in areas with large populations that receive wastewater via a network of underground pipes.

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Treatments for Human and Animal Wastewater

© 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.

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Heavy Metals and Other Substances that can threaten human Health and the Environment

© Lead

© Arsenic

© Mercury

© Acids

© Synthetic compounds (pesticides, pharmaceuticals, and hormones)

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Fig. 21-7, p. 501

Coal strip mine runoff

Polluted air

Deicing road salt

Pesticidesand fertilizers

Hazardous waste

injection well

Pumping well

Gasoline station

Water pumping well

LandfillSewer

Buried gasoline and solvent tanks

Cesspool, septic tank

Groundwater flow

Confined aquifer

Confined freshwater aquifer

Unconfined freshwater aquifer

Accidentalspills

Waste lagoonLeakage from faulty casing

Discharge

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Oil Pollution

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Ways to Remediate Oil Pollution

© Containment using booms to keep the floating oil from spreading.

© Chemicals that help break up the oil, making it disperse before it hits the shoreline.

© Bacteria that are genetically engineered to consume oil

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Other Water Pollutants

© Solid waste pollution (garbage)

© Sediment pollution (sand, silt and clay)

© Thermal pollution

© Noise pollution

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Water Laws

© Clean Water Act- (1972) supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water”.

© Issued water quality standards that defined acceptable limits of various pollutants in U.S. waterways.

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Water Laws

© Safe Drinking Water Act- (1974, 1986, 1996) sets the national standards for safe drinking water.

© It is responsible for establishing maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater.

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Is Bottled Water the Answer?

ØSome bottled water is not as pure as tap water and costs much more.l 1.4 million metric tons of plastic bottles are thrown

away.l 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.

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Fig. 21-18, p. 517

• Prevent groundwater contamination

Solutions

Water Pollution

• Reduce birth rates

• Reduce poverty

• Reduce air pollution

• Practice four R's of resource use (refuse, reduce, recycle, reuse)

• Work with nature to treat sewage

• Find substitutes for toxic pollutants

• Reuse treated wastewater for irrigation

• Reduce nonpoint runoff

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Fig. 21-19, p. 517

What Can You Do?

Water Pollution

• Fertilize garden and yard plants with manure or compost instead of commercial inorganic fertilizer.

• Minimize your use of pesticides.

• Do not apply fertilizer or pesticides near a body of water.

• Grow or buy organic foods.

• Do not drink bottled water unless tests show that your tap water is contaminated. Merely refill and reuse plastic bottles with tap water.

• Compost your food wastes.

• Do not use water fresheners in toilets.

• Do not flush unwanted medicines down the toilet.

• Do not pour pesticides, paints, solvents, oil, antifreeze, or other products containing harmful chemicals down the drain or onto the ground.

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