Pollution Notes.ppt

7/29/2019 Pollution Notes.ppt

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POLLUTION

Water Pollution

Air Pollution


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Water Pollution Background

Sources Types

Eutrophication Sewage Management and Treatment


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Pollution=

The presence of a substance in the environment thatprevents the functioning of natural processes andproduces undesirable environmental and health effects

Pollutant=

Any material that causes pollution

Strategies to manage pollution

1. Identify materials causing the pollution

2. Identify source of the pollutants3. Develop control strategies to prevent pollution

4. Develop alternatives to avoid pollution altogether


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Sources of Pollution Point sources=

Source of pollution with specific points of discharge

Examples

Factories Sewage systems

Power plants

Coal mines

Oil wells

Nonpoint sources=

Sources of pollution that are harder to identify

Examples

Agricultural runoff

Stormwater drainage

Acid rain


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Types of Pollution

1. Chemical Pollutants

2. Pathogens

3. Organic Wastes

4. Sediments5. Nutrients


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1. Chemical Pollutants Inorganic chemicals

Heavy metals Acids from mine

drainage

Acid precipitation Road salts

Organic chemicals

Petroleum products Pesticides

Detergents

Biomagnification=

Pollutants become more concentrated bypassing through several levels of the food

web


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2. Pathogens Pathogens=

Disease-causing bacteria, viruses, and other parasiticorganisms If wastes from carriers contaminate water, pathogens

can infect others

Methods for controlling waterborne diseases:1. Purify and disinfect water

2. Sanitary collection and treatment of wastes3. Sanitary standards around food4. Public education in hygiene


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3. Organic Wastes

Detritus=

Dead organic matter, such as fallen leaves,

twigs, and other plant/animal wastes

As bacteria break down detritus, they useoxygen that is dissolved in water (DO)

Lots of detritus = lots of oxygen getting

used up This limits animal life


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4. Sediments Erosion leads to more sediment in the water

which disrupts the ecosystem

1. Muddy water reduces amount of lightpenetration and photosynthesis

2. Extra silt and sand removes attachedaquatic organisms from rocks

3. Hiding and resting places get buried insediment


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5. Nutrients

Agricultural runoff is a primary source of

nutrients Phosphorus

Nitrogen

Result:

Excessive plantgrowth


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Eutrophication

Different Kinds of Aquatic Plants

Phytoplankton=

Plants that live suspended in water Found wherever light and nutrients are available

Emergent vegetation=

Plants that are rooted in sediment, grow with lowerparts in water, but upper parts stick out of water

Submerged aquatic vegetation (SAV)=

Plants that grow totally underwater so they need clearwater that lets light through

Get nutrients from sediment

Not limited by water low in nutrients


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What happens when too many nutrients areadded to water?

Sequence of eutrophication

1. Phytoplankton grow2. Phytoplankton block light

3. SAV die

4. Phytoplankton die (competition)

5. Detritus builds up

6. Bacteria grow (break down detritus)7. Dissolved oxygen gets used up by bacteria

8. Animals suffocate and die


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Eutrophic =

Body of water that is nutrient rich Supports growth of lots of phytoplankton

Has little or no dissolved oxygen

Organisms end up dying!

Oligotrophic=

Body of water that is nutrient poor

Unable to support much phytoplankton

Light penetrates deeply

HEALTHY body of water! Note: Natural eutrophication is a normal process

but can become a problem when humans add too

many nutrients too quickly (pollution!)


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Combating Eutrophication

Attack symptoms Herbicides

Aeration

Harvesting aquatic weeds Drawing water down

Cut down on nitrogen and phosphorus in water

Ban sale of phosphate detergents

Issue and monitor permits for dischargingpollutants

Best management practices=

Farm management practices that serve

best to reduce soil and nutrient runoff


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Sewage Management and Treatment

Storm drains= Collect and drain runoff

from precipitation

Sanitary sewers=

Receive wastewater fromsinks, tubs, and toilets

Raw sewageor sludge= Untreated organic matter that is removed from

sewage water by letting it settle 99.9% water to 0.1% waste


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Removing Pollutants from Sewage

1. Preliminary Treatment= Removal of debris and grit from wastewater

using a course screen and grit-settling chamber

2. Primary Treatment= Water passes very slowly through large tank so

that clumps of organic material can settle out

3. Secondaryor biological treatment= Removes most of remaining organic matter Organisms feed on it and oxidize it through

respiration *Oxygen must be added to water*


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4. Biological Nutrient Removal (BNR)= Removes nitrogen and phosphorus

5. Final Cleansing and Disinfection Usually using chlorine gas

Note: Discharging this treated wastewater mayimprove water quality of the receiving body ofwater


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3 Ways to Treat Sludge

1. Anaerobic Digestion= Breakdown of organic material by

microorganisms in the absence of oxygen

2. Composting=

Letting organic wastes decompose in thepresence of air

Product = nutrient rich humus

3. Pasteurization=

Heating organic material to kill pathogens

*All 3 result in material that can be used forfertilizer*


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Air Pollution

BackgroundTypes of PollutantsSmog

Acid PrecipitationImpact of Air PollutantsClimate Change

Ozone DestructionControl Strategies


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Background

Air pollutants=

Substances in the atmosphere that

have harmful effects

3 factors determine level of air pollution

1. Amount of pollutants entering the air2. Amount of space into which thepollutants can spread out

3. Mechanisms that remove pollutantsfrom the air


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Natural air pollutants=

From volcanoes, fires,dust storms, and othernatural processes

There are natural cleansing agents thatremove and recycle natural pollutants

Hydroxyl radicals, sea salts, microorganisms in soil

Nature cant remove all of the pollution

humans are creating fast enough


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Types of Pollutants

Primary pollutants=

Pollutants releaseddirectly into atmosphere

mainly as a result ofburning fuels and wastes

Examples

Carbon monoxide (CO) Nitrogen oxides (NOx)

Sulfur oxides (SOx)

Lead (Pb) Radon (Rn)

Secondary pollutants=

Pollutants resulting fromreactionsof primary air

pollutants in theatmosphere

Examples

Ozone (O3) Sulfuric acids

Nitric acids


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Smog Industrial smog=

Grayish mixture of moisture, soot, andsulfurous compounds

Occurs in industrial areas and where coal is a

primary energy source

Photochemical smog= Brownish haze that typically forms over largecities with lots of automobile traffic


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Impacts of smog

Pollutants can build up to dangerous levels

Can cause headaches, nausea, eye and

throat irritation Affects trees and other vegetation also


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Acid Precipitation Acid=

Has a pH less than 7

Base= Has a pH greater than 7

pH scale

0 (highly acidic ) 7 (neutral) 14 (highly basic)

In the absence of pollution, rainfall is normallyslightly acidic, with pH of 5.6

Acid precipitation= Acid rain, acid fog, acid snow, and other forms of

precipitation that is more acidic than normal

pH less than 5.6


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Buffer, the Acid Slayer

Buffer=

Substance that will neutralize the pH of asolution

Limestone is a natural buffer


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Impact of Air Pollutants

Effects on Human Health

Those most sensitive to air pollution are

Small children

Asthmatics People with chronic lung or

heart disease

The elderly


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Effects on Materials and Buildings Walls and windows turn gray

Paints and fabrics deteriorate more rapidly Rubber products become hard and crack

Metal corrosion increases

Limestone and marble buildings andmonuments erode quickly

Visibility decreases


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Effects on the Environment

Plants are even more sensitive togaseous air pollutants than are humans

Crop damage

Forest damage

Aquatic ecosystems become more acidic

Kills organisms Upsets balance


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Climate Change

Since 1855, global average temperature hasincreased 0.6C

Proxies=

Measurable records that provide data onfactors such as temperature, ice cover, and

precipitation

Used to observe climate changes

Examples Tree rings, ice cores


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The Ocean affects climate as wellConveyor system=

Giant pattern of oceanic currents that

moves water masses from the surface tothe depths and back again

Produces major effects on climate


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Heinrich events=

Melting icebergs from polar ice cap supplyhuge amounts of fresh water as they melt

Result of global warming

Effects:

Lowers density of water

Interrupts conveyor systemBlocks northward movement

of warmer, saltier water

Changes climate

The Greenhouse Effect


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The Greenhouse Effect

Greenhouse gases (GHGs)= Gases in atmosphere that absorb infrared

energy and contribute to air temperature

Create a heat blanket important in insulatingEarths surface

Keep the surface of Earth warm and livable!

Examples

1. CO22. Water vapor

3. Methane

4. Nitrous oxide

5. Ozone

6. Chlorofluorocarbons and other halocarbons

More about Carbon dioxide


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More about Carbon dioxide

Natural sources

When there is more respiration(late fall through spring)

CO2 levels rise

When there is more photosynthesis(late spring through early fall)

CO2 levels fall

Other sources Burning of fossil fuels

Burning of forest trees

Recent years, steady rise in CO2 levels Results in thicker insulating blanket

We need to be careful that pollution doesnt

make it too warm!


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Ozone Destruction

Importance of the Ozone Layer

Ozone in the stratosphere (higher layer ofthe atmosphere) absorbs over 99% of UV

radiation UV radiation damages protein and DNA

Causes sunburn and skin cancer


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The Hole in the Ozone Layer

Ozone is broken down by pollutants such as CFCs

Chlorofluorocarbons (CFCs)=

Act as transport agents that continuouslymove chlorine atoms, which destroy ozone,

into stratosphere

Increase UV radiation

Destruction of ozone layer is occurring worldwide

Layer is getting thinner

More UV radiation is getting through


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Note: Ozone in the stratosphere protects us from

harmful UV rays

Ozone in the troposphere is a greenhouse gas

Too much is considered pollution!

Think:

Good up high!

Bad near by!

Control Strategies


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1978 EPA banned use of CFCs in aerosolcans in US

Limiting pollutants from motor vehicles

Catalytic converter=

Reduces amount of CO and hydrocarbons ina cars exhaust

Control Strategies


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Legislation

Clean Air Act of 1970 (CAA)

Calls for identifying and controlling mostwide-spread pollutants

Setting ambient standards=

Determine certain levels of pollutants

that should not be exceeded in order tomaintain environmental and humanhealth

Title IV of Clean Air Act Amendments

1st law in US history to address acid-precipitation problem

Documents

Pollution Notes.ppt