Chapter 20 Water Pollution. Chapter Overview Questions What pollutes water, where do these...

Chapter 20Chapter 20Water PollutionWater Pollution

Chapter Overview QuestionsChapter Overview Questions

What pollutes waterWhat pollutes water, where do these , where do these pollutants come from, and what effects do pollutants come from, and what effects do they have?they have?

What are the major water pollution problems What are the major water pollution problems in in streams and lakesstreams and lakes??

What causes What causes groundwater pollutiongroundwater pollution, and how , and how can it be prevented?can it be prevented?

Chapter Overview Questions (cont’d)Chapter Overview Questions (cont’d)

What are the major water pollution problems What are the major water pollution problems affecting affecting coastal waterscoastal waters & & oceansoceans??

How can we prevent and reduce How can we prevent and reduce surface surface waterwater pollution? pollution?

How safe is drinking water, and how can it be How safe is drinking water, and how can it be made safer?made safer?

Case Study: Using Nature to Purify Case Study: Using Nature to Purify SewageSewage

Ecological wastewater Ecological wastewater purification by a purification by a living living machinemachine.. Uses the sun and a series Uses the sun and a series

of tanks containing plants, of tanks containing plants, snails, zooplankton, snails, zooplankton, crayfish, and fish (that crayfish, and fish (that can be eaten or sold for can be eaten or sold for bait).bait).

Water can be purified with Water can be purified with UV or OUV or O33 and consumed! and consumed!

Figure 21-1Figure 21-1John Todd, Providence, RI

WATER POLLUTION: SOURCES, WATER POLLUTION: SOURCES, TYPES, AND EFFECTSTYPES, AND EFFECTS

Water pollutionWater pollution is any is any chemical, biological, chemical, biological, or physicalor physical change in water quality that has a change in water quality that has a harmful effect on living organisms or makes harmful effect on living organisms or makes water unsuitable for desired uses.water unsuitable for desired uses. Point sourcePoint source:: specific location (drain pipes, specific location (drain pipes,

ditches, sewer lines).ditches, sewer lines). Nonpoint sourceNonpoint source:: cannot be traced to a single cannot be traced to a single

site of discharge (atmospheric deposition; site of discharge (atmospheric deposition; agricultural / industrial / residential runoff) agricultural / industrial / residential runoff)

WATER POLLUTION: SOURCESWATER POLLUTION: SOURCES

Point sourcePoint source:: specific specific location (drain pipes, location (drain pipes, ditches, sewer lines).ditches, sewer lines).

WATER POLLUTION: SOURCESWATER POLLUTION: SOURCES Nonpoint sourceNonpoint source:: cannot be traced to a single site of cannot be traced to a single site of

discharge (atmospheric deposition; agricultural / discharge (atmospheric deposition; agricultural / industrial / residential runoff) industrial / residential runoff)

Table 21-2, p. 495

Biological Pollution: Pathogens in Water

Major Water Pollutants Major Water Pollutants and Their Effectsand Their Effects

A A fecal coliform fecal coliform bacteria test is used to bacteria test is used to indicate the likely indicate the likely presence of disease-presence of disease-causing bacteria in causing bacteria in water.water.

The standard for The standard for

drinking water is drinking water is zerozero fecal coliform colonies fecal coliform colonies per culture!per culture!

Figure 21-2Figure 21-2

DO: Reduced by Degradeable Wastes, DO: Reduced by Degradeable Wastes, Heat, and Algae Growth from Excess Heat, and Algae Growth from Excess

Inorganic NutrientsInorganic Nutrients Water quality and dissolved oxygen (DO) Water quality and dissolved oxygen (DO)

content in parts per million (ppm) at 20content in parts per million (ppm) at 20°C.°C. Only a few fish species can survive in water less Only a few fish species can survive in water less

than 4 ppm at than 4 ppm at 2020°C.°C.

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Dissolved OxygenDissolved Oxygen For most solutes (sugar, salt, etc):For most solutes (sugar, salt, etc):

solubility increases as temperature increasessolubility increases as temperature increases

For DO:For DO:

solubility decreases as temperature increasessolubility decreases as temperature increases

NextNext

Most solutes….Most solutes….

Dissolved Oxygen (DO)Dissolved Oxygen (DO)

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

Water Pollution Problems in StreamsWater Pollution Problems in Streams

DilutionDilution and and decaydecay of of degradable, oxygen-degradable, oxygen-demanding wastesdemanding wastes and and heatheat in a stream. in a stream.

NextNext

NextNext

Oxygen Sag CurveOxygen Sag Curve

POLLUTION OF FRESHWATER POLLUTION OF FRESHWATER STREAMSSTREAMS

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

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

with high oxygen requirements.with high oxygen requirements.

POLLUTION OF FRESHWATER STREAMSPOLLUTION OF FRESHWATER STREAMS Most Most developed countriesdeveloped countries have sharply have sharply

reduced point-source pollution but toxic reduced point-source pollution but toxic chemicals and pollution from chemicals and pollution from nonpoint nonpoint sourcessources are still a problem. are still a problem.

Stream pollution from discharges of Stream pollution from discharges of untreated sewage and industrial wastes is a untreated sewage and industrial wastes is a major problem in major problem in developing countriesdeveloping countries..

80-90%80-90% of raw sewage directly discharged of raw sewage directly discharged

into rivers in developing countries into rivers in developing countries (!)(!)..

Stream Pollution in Developing CountriesStream Pollution in Developing Countries

Water in many of Water in many of central central China'sChina's rivers are greenish rivers are greenish black from uncontrolled black from uncontrolled pollution by thousands of pollution by thousands of factories.factories.

Stream Pollution in Developing CountriesStream Pollution in Developing Countries

Case Study: India’s Ganges River: Case Study: India’s Ganges River: Religion, Poverty, and HealthReligion, Poverty, and Health

Religious beliefs,Religious beliefs, cultural traditions, poverty,cultural traditions, poverty, and a and a large populationlarge population interact to cause severe interact to cause severe pollution of the pollution of the Ganges RiverGanges River in India. in India. Very little of the sewage is treated.Very little of the sewage is treated. Hindu believe in Hindu believe in cremating the deadcremating the dead to free the soul to free the soul

and throwing the ashes in the holy Ganges.and throwing the ashes in the holy Ganges.

• Some are Some are too poortoo poor to afford the wood to afford the wood to fully cremateto fully cremate..

• Decomposing bodiesDecomposing bodies promote promote disease disease and and depletes DOdepletes DO..


Hindu funeral pyre

Decorated Funeral Pyre

Incompletely burned bodies cause pollution.


Daily, more than 1 Daily, more than 1 million Hindus in million Hindus in India bathe, drink India bathe, drink from, or carry out from, or carry out religious ceremonies religious ceremonies in the highly polluted in the highly polluted Ganges River.Ganges River.


India’s Ganges RiverIndia’s Ganges River

LakesLakes

Lake George, NYLake George, NY

Overturn in LakesOverturn in Lakes

POLLUTION OF POLLUTION OF FRESHWATER LAKESFRESHWATER LAKES

Dilution of pollutants in Dilution of pollutants in lakeslakes is less effective is less effective than in most streams because most lake than in most streams because most lake water is water is not mixed wellnot mixed well and and has little flowhas little flow.. Lakes and reservoirs are often Lakes and reservoirs are often stratifiedstratified and and

undergo little mixing (Low DO in lower layers)undergo little mixing (Low DO in lower layers) Low flow makes them Low flow makes them susceptible to runoffsusceptible to runoff..

Various human activities can overload lakes Various human activities can overload lakes with with plant nutrientsplant nutrients, which decrease DO and , which decrease DO and kill some aquatic species.kill some aquatic species.

Cultural EutrophicationCultural Eutrophication EutrophicationEutrophication: the : the naturalnatural nutrient nutrient

enrichmentenrichment of a shallow lake, estuary or slow of a shallow lake, estuary or slow moving stream, mostly from runoff of plant moving stream, mostly from runoff of plant nutrients from the surrounding land.nutrients from the surrounding land.

Cultural eutrophicationCultural eutrophication: human activities : human activities accelerate the input of plant nutrientsaccelerate the input of plant nutrients (mostly (mostly nitrate- and phosphate-containing effluents) nitrate- and phosphate-containing effluents) to a lake.to a lake. 85% of large lakes near major population centers 85% of large lakes near major population centers

in the U.S. have some degree of cultural in the U.S. have some degree of cultural eutrophication.eutrophication.

Cultural EutrophicationCultural Eutrophication Cultural EutrophicationCultural Eutrophication of lakes causes of lakes causes

sudden sudden fish kills fish kills when DO drops due towhen DO drops due to

1.1. Overpopulated algae respiring at night Overpopulated algae respiring at night without producing any Owithout producing any O22 via photosynthesis via photosynthesis

and/orand/or

2.2. Bacteria respiring as they decompose dead Bacteria respiring as they decompose dead overpopulated algaeoverpopulated algae

Acid Rain in Acid Rain in Freshwater LakesFreshwater Lakes

POLLUTION OF GROUNDWATERPOLLUTION OF GROUNDWATER

GroundwaterGroundwater can become contaminated with can become contaminated with a variety of chemicals because it a variety of chemicals because it cannot cannot effectively cleanseeffectively cleanse itself and itself and dilutedilute and and dispersedisperse pollutants. pollutants.

The drinking water for about The drinking water for about half of the half of the U.SU.S. population and . population and 95% of those in rural95% of those in rural areasareas comes from groundwater. comes from groundwater.

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

POLLUTION OF GROUNDWATERPOLLUTION OF GROUNDWATER

One way to think about waste: One way to think about waste: degradabilitydegradability Degradable wastes Degradable wastes (urine & fecal matter, dead (urine & fecal matter, dead

leaves, food waste)leaves, food waste) Nondegradable wastesNondegradable wastes (lead, mercury, arsenic, (lead, mercury, arsenic,

flouride) are there permanently.flouride) are there permanently. Slowly degradable wastesSlowly degradable wastes (such as DDT and (such as DDT and

PCBs) are there for decades.PCBs) are there for decades. It can take hundreds to thousands of years for It can take hundreds to thousands of years for

contaminated groundwater to cleanse itself of contaminated groundwater to cleanse itself of degradable wastes.degradable wastes.

Fig. 21-8, p. 502

Aquifer

Water well

Migrating vapor phase

Contaminant plume moveswith the groundwater

Free gasolinedissolves ingroundwater(dissolved phase)

Groundwaterflow

Watertable

Gasolineleakage plume(liquid phase)

Leakingtank

Bedrock

POLLUTION OF GROUNDWATERPOLLUTION OF GROUNDWATER Over the 21Over the 21stst century, scientists expect to find century, scientists expect to find

many millions of many millions of leaking underground storage leaking underground storage tankstanks to become a major global health problem. to become a major global health problem.

POLLUTION OF GROUNDWATERPOLLUTION OF GROUNDWATER Leaks from a number of sources have Leaks from a number of sources have

contaminated groundwater in parts of the contaminated groundwater in parts of the world.world. According the the EPA, one or more organic According the the EPA, one or more organic

chemicals contaminate about chemicals contaminate about 45%45% of of municipalmunicipal groundwater supplies.groundwater supplies.

By 2003, the EPA had completed the cleanup of By 2003, the EPA had completed the cleanup of 297,000 of 436,000 underground tanks leaking 297,000 of 436,000 underground tanks leaking gasoline, diesel fuel, home heating oil, or toxic gasoline, diesel fuel, home heating oil, or toxic solvents.solvents.

Case Study: Arsenic in Groundwater - Case Study: Arsenic in Groundwater - a Natural Threata Natural Threat

Toxic Arsenic (Toxic Arsenic (AsAs) can ) can naturally occurnaturally occur at high at high levels in soil and rocks.levels in soil and rocks.

Drilling Drilling into aquifers can release into aquifers can release AsAs into into drinking water supplies.drinking water supplies.

According to WHO, more than 112 million According to WHO, more than 112 million people are drinking water with people are drinking water with AsAs levels 5- levels 5-100 times the 10 ppb standard.100 times the 10 ppb standard. Mostly in Bangladesh, China, and West Bengal, Mostly in Bangladesh, China, and West Bengal,

India.India.

Fig. 21-9, p. 504

Solutions

Groundwater Pollution

CleanupPrevention

Find substitutes for toxic chemicals

Install monitoring wells near landfills and underground tanksRequire leak detectors on underground tanks

Ban hazardous waste disposal in landfills and injection wells

Store harmful liquids in aboveground tanks with leak detection and collection systems

Pump to surface, clean, and return to aquifer (very expensive)

Pump nanoparticles of inorganic compounds to remove pollutants (may be the cheapest, easiest, and most effective method but is still being developed)

Keep toxic chemicals out of the environment

Inject microorganisms to clean up contamination (less expensive but still costly)

OCEAN POLLUTIONOCEAN POLLUTION The abyssal/benthic zones of open oceans, if they The abyssal/benthic zones of open oceans, if they

are not overloaded, can are not overloaded, can disperse and breakdisperse and break down down large quantities of large quantities of degradable pollutantsdegradable pollutants..

OCEAN POLLUTIONOCEAN POLLUTION

But pollution of But pollution of coastal waterscoastal waters near heavily near heavily populated areas is a serious problem.populated areas is a serious problem. About About 40%40% of the world’s population lives within of the world’s population lives within

160 miles of the coast.160 miles of the coast. The EPA has classified The EPA has classified 4 of 5 estuaries4 of 5 estuaries as as

threatened or impaired.threatened or impaired.

Fig. 21-10, p. 505

HEALTHY ZONESClear, oxygen-richwaters promote growthof plankton and sea grasses,and support fish.

O2 DEPLETION 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

OCEAN POLLUTIONOCEAN POLLUTION Harmful algal blooms (HAB) are caused by Harmful algal blooms (HAB) are caused by

explosive growth of harmful algae from sewage and explosive growth of harmful algae from sewage and agricultural runoff.agricultural runoff.


HABs Harmful Algae BloomsHABs Harmful Algae Blooms

““Red tide”Red tide”


Oxygen Depletion in the Northern Oxygen Depletion in the Northern Gulf of MexicoGulf of Mexico

A large zone of A large zone of oxygen-oxygen-depleted waterdepleted water (“dead zone”) (“dead zone”) forms for half of forms for half of the year in the the year in the Gulf of Mexico Gulf of Mexico as a result of as a result of HAB.HAB.

NextNext

Fig. 21-A, p. 507

Mississippi River

MississippiRiver Basin

Gulf of Mexico

Ohio River

Mississippi River

Missouri River

TX

MSLA

Depleted oxygen

LOUISIANA

Gulf of Mexico


Chesapeake Bay

Case Study: The Chesapeake Bay – Case Study: The Chesapeake Bay – An Estuary in TroubleAn Estuary in Trouble

Pollutants from Pollutants from six six statesstates contaminate contaminate the shallow the shallow estuary, but estuary, but cooperative effortscooperative efforts have reduced have reduced some of the some of the pollution inputs.pollution inputs.


OCEAN OIL POLLUTIONOCEAN OIL POLLUTION Most ocean oil pollutionMost ocean oil pollution comes from comes from

human activities on human activities on landland..

Studies have shown it takes about Studies have shown it takes about 3 years3 years for for many forms of marine life to recover from large many forms of marine life to recover from large amounts of amounts of crude oilcrude oil (oil directly from ground).(oil directly from ground).

Recovery from exposure to Recovery from exposure to refined oilrefined oil (fuel oil, (fuel oil, gasoline, etc…) can take gasoline, etc…) can take 10-20 years10-20 years for marine for marine life to recover.life to recover.

OCEAN OIL POLLUTIONOCEAN OIL POLLUTION Tanker accidentsTanker accidents

and and blowouts at blowouts at offshore drilling offshore drilling rigsrigs can be can be extremely extremely devastating to devastating to marine life marine life (especially diving (especially diving birds, left).birds, left).


OCEAN OIL POLLUTIONOCEAN OIL POLLUTIONExxon Exxon ValdezValdez oil spill:oil spill:

March 24, 1989March 24, 1989 Prince William Sound, AlaskaPrince William Sound, Alaska Single-wall oil tanker runs agroundSingle-wall oil tanker runs aground 10.8 million gallons of crude oil spilled10.8 million gallons of crude oil spilled Captain was drunkCaptain was drunk One of the worst single environmental One of the worst single environmental

disasters in US historydisasters in US history

Exxon ValdezExxon Valdez

Exxon ValdezExxon ValdezIn 1994, a jury awarded plaintiffs $287 million in compensatory damages and $5 billion in punitive damages.

Exxon appealed and the Ninth Circuit court reduced the punitive damages to $2.5 billion. Exxon then appealed the punitive damages to the Supreme Court which capped the damages to $507.5 million in June, 2008.

On August 27, 2008, Exxon Mobil agreed to pay 75% of the $507.5 million damages ruling to settle the 1989 Exxon Valdez oil spill off Alaska

In June 2009, a federal ruling ordered Exxon to pay an additional $480 million in interest on their delayed punitive damage awards

http://en.wikipedia.org/wiki/August_27

http://en.wikipedia.org/wiki/2008

But Remember…But Remember…Most ocean oil pollution comes Most ocean oil pollution comes from human activitiesfrom human activities on on landland..

Oceanic oil pollution has been considered a low-risk environmental problem…

Until April of 2010…

BP’s Deepwater Horizon Oil SpillBP’s Deepwater Horizon Oil Spill

BP’s Deepwater Horizon Oil SpillBP’s Deepwater Horizon Oil SpillApril 20, 2010, explosion of Deepwater Horizon11 killed, 17 others injuredJuly 15, 2010, the leak was partially capped 4.9 million barrels (780,000 m3) of crude oil released = 205.8 million gallons of crude (almost 30x the Exxon Valdez)On September 19, 2010, the relief well process was successfully completed

http://en.wikipedia.org/wiki/Deepwater_Horizon_explosion

http://en.wikipedia.org/wiki/Deepwater_Horizon_explosion

http://en.wikipedia.org/wiki/Crude_oil

BP’s Deepwater Horizon Oil SpillBP’s Deepwater Horizon Oil Spill

Fig. 21-14, p. 509

Reduce input of toxic pollutants

Solutions

Coastal Water Pollution

PREVENTION CLEANUP

Use wetlands, solar-aquatic, or other methods to treat sewage

Require at least secondary treatment of coastal sewage

Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful by-products(still under development)

Improve oil-spill cleanup capabilities

Recycle used oil

Regulate coastal development

Protect sensitive areas from development, oil drilling, and oil shipping

Ban ocean dumping of sludge and hazardous dredged material

Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters

Separate sewage and storm lines

Require double hulls for oil tankers

The key to reducing nonpoint pollution – most The key to reducing nonpoint pollution – most

of it from agriculture – is to of it from agriculture – is to preventprevent it from it from reaching bodies of water. Farmers can reaching bodies of water. Farmers can reduce runoffreduce runoff by by Planting buffers Planting buffers Using low-till & no-till techniquesUsing low-till & no-till techniques Keeping cropland covered with vegetationKeeping cropland covered with vegetation Using no fertilizer on steep landUsing no fertilizer on steep land Locate feedlots well away from waterLocate feedlots well away from water

USA: Successful on Point Sources, USA: Successful on Point Sources, Working on Non-point SourcesWorking on Non-point Sources

PREVENTING AND REDUCING PREVENTING AND REDUCING SURFACE WATER POLLUTIONSURFACE WATER POLLUTION

Most Most developed countries use lawsdeveloped countries use laws to set to set water pollution standards, but such laws water pollution standards, but such laws rarely exist in developing countriesrarely exist in developing countries..

The The U.S. Clean Water ActU.S. Clean Water Act (1972)(1972) sets standards sets standards for allowed levels of key water pollutants and for allowed levels of key water pollutants and requires polluters to get permits.requires polluters to get permits.

EPAEPA is experimenting with a is experimenting with a discharge trading discharge trading policypolicy similar to “cap & trade” for air pollution similar to “cap & trade” for air pollution control.control.

Reducing Water Pollution through Reducing Water Pollution through Sewage TreatmentSewage Treatment

Septic tanksSeptic tanks and various levels of sewage and various levels of sewage treatment can reduce point-source water treatment can reduce point-source water pollution.pollution.


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


Primary and SecondaryPrimary and Secondary sewage treatment. sewage treatment.Figure 21-16Figure 21-16

Fig. 21-16, p. 511

Raw sewagefrom sewers

Activated sludge

Disposed of in landfill or ocean or applied to cropland,pasture, or rangeland

Primary Treatment Secondary Treatment

Grit chamberBar screen Settling tank Aeration tank Settling tankChlorinedisinfection tank

Sludge drying bed

Sludge digester

Air pump

To river, lake,or ocean

(kills bacteria)

Sludge

Physical Processes Biological Processes


Raw sewageRaw sewage reaching a municipal sewage reaching a municipal sewage treatment plant typically undergoes:treatment plant typically undergoes:

Primary sewage treatmentPrimary sewage treatment: a : a physical processphysical process that uses screens and a grit tank to that uses screens and a grit tank to remove large remove large floating objectsfloating objects and and allows settlingallows settling (sludge!) (sludge!)

Secondary sewage treatmentSecondary sewage treatment: a : a biological biological processprocess in which in which aerobic bacteriaaerobic bacteria remove as remove as much as 90% of much as 90% of dissolved and biodegradable, dissolved and biodegradable, oxygen demanding organic wastesoxygen demanding organic wastes..


Advanced or Advanced or tertiarytertiary sewage treatment: sewage treatment: Uses series of chemical and physical processes to Uses series of chemical and physical processes to

remove specific pollutants left over (especially remove specific pollutants left over (especially nitrates and phosphatesnitrates and phosphates).).

Water is Water is chlorinatedchlorinated to remove coloration and to to remove coloration and to kill disease-carrying bacteria and some viruses kill disease-carrying bacteria and some viruses (disinfect). (disinfect).

OzoneOzone or or UV lightUV light may also be used to sanitize may also be used to sanitize sewage treatment effluentsewage treatment effluent


Sewage Sewage sludgesludge can be used as a can be used as a soil soil conditionerconditioner but this can cause health but this can cause health problems if it contains problems if it contains infectious bacteriainfectious bacteria and/or and/or toxic chemicalstoxic chemicals..

Preventing toxic chemicalsPreventing toxic chemicals from reaching from reaching sewage treatment plants would eliminate sewage treatment plants would eliminate such chemicals from the sludge and water such chemicals from the sludge and water discharged from such plants.discharged from such plants.

Fig. 21-17, p. 513

Sludge

Groundwater ContaminationHarmful chemicals and pathogens may leach into groundwater and shallow wells.

OdorsOdors may cause illness or indicate presence of harmful gases.

Livestock PoisoningCows may die after grazing on sludge-treated fields.

Dust ParticlesParticles of dried sludge carry viruses and harmful bacteria that can be inhaled, infect cuts or enter homes.

Surface RunoffHarmful chemicals and pathogens may pollute nearby streams,lakes, ponds, and wetlands.

ExposureChildren may walk or play in fertilized fields.

BUFFER ZONE

Humboldt County, California decided to treat wastewater as a resource rather than a problem, and built the Arcata Marsh and Wildlife Sanctuary. The marsh relies on natural systems to filter the city’s sewage.


Natural and artificial wetlandsNatural and artificial wetlands and other and other ecological systems can be used to treat ecological systems can be used to treat sewage.sewage.

California created a 65 hectare wetland near California created a 65 hectare wetland near Humboldt Bay that acts as a natural wastewater Humboldt Bay that acts as a natural wastewater treatment plant for the town of 16,000 people.treatment plant for the town of 16,000 people.

The project The project cost less than halfcost less than half of the estimated of the estimated price of a conventional treatment plant.price of a conventional treatment plant.


Water pollution lawsWater pollution laws have significantly have significantly improved water qualityimproved water quality in many U.S. streams in many U.S. streams and lakes but there is a long way to go.and lakes but there is a long way to go.

Some want to strengthenSome want to strengthen the U.S. Clean the U.S. Clean

Water Act (CWA) to Water Act (CWA) to preventprevent rather than rather than focusing on focusing on end-of-the-pipe removalend-of-the-pipe removal..

Many farmers and developersMany farmers and developers see the CWA see the CWA as as limiting their rightslimiting their rights as property owners to as property owners to fill in wetlands.fill in wetlands.

DRINKING WATER QUALITYDRINKING WATER QUALITY Centralized water treatment plantsCentralized water treatment plants and… and…

watershed protectionwatershed protection can provide safe can provide safe drinking water for drinking water for city dwellers in developed city dwellers in developed countries.countries.

Watering the Big Apple (NYC)Watering the Big Apple (NYC)

90% of NYC water comes from the Catskill 90% of NYC water comes from the Catskill Mountains in upstate New YorkMountains in upstate New York

Water for NYCWater for NYC 1997- NYC faced a 1997- NYC faced a $6 billion$6 billion upgrade to build upgrade to build

water purification facilitieswater purification facilities

Instead, NYC negotiated a Instead, NYC negotiated a $1.5 $1.5 billion, 10 yr billion, 10 yr agreement with towns, farmers, & NY state to agreement with towns, farmers, & NY state to protect & restore forests, wetlands, & streams protect & restore forests, wetlands, & streams in the Catskills watershed.in the Catskills watershed.

SavingsSavings realized by relying on natural realized by relying on natural purification: purification: $4.5 billion$4.5 billion, PLUS $, PLUS $300 million per 300 million per yearyear saved in filtration costs saved in filtration costs

DRINKING WATER QUALITYDRINKING WATER QUALITY Simpler and cheaperSimpler and cheaper ways can be used to ways can be used to

purify drinking water for developing countries.purify drinking water for developing countries. Exposing water to heat and the sun’s UV rays Exposing water to heat and the sun’s UV rays

in a plastic bottle for 3 hours can kill infectious in a plastic bottle for 3 hours can kill infectious microbes.microbes. 30%-40% reduction in dangerous childhood 30%-40% reduction in dangerous childhood

diarrhea.diarrhea. ““Lifestraws”Lifestraws” Inexpensive Inexpensive UV exposureUV exposure facilities (per FLOW facilities (per FLOW

video)video) In the worksIn the works: handheld carbon nanotube filters: handheld carbon nanotube filters

Lifestraws in ActionLifestraws in Action

LifeStraw Personal filters a minimum of 700 litres of water, enough for one person for one year.

LifeStraw Family filters a minimum of 18,000 litres of water, providing safe drinking water for a family for more than two years.

It removes 99.9999% of waterborne bacteria, 99.99% of viruses, and 99.9% of parasites.

http://en.wikipedia.org/wiki/Bacteria

http://en.wikipedia.org/wiki/Virus

http://en.wikipedia.org/wiki/Parasite

Using Laws to Protect Drinking WaterUsing Laws to Protect Drinking Water

While most developed countries have While most developed countries have drinking water quality standardsdrinking water quality standards and laws, and laws, most developing countries do notmost developing countries do not..

The The U.S Safe Drinking Water ActU.S Safe Drinking Water Act requires the requires the EPAEPA to establish national drinking water to establish national drinking water standards (standards (maximum contaminant levelsmaximum contaminant levels) ) for any pollutant that may have adverse for any pollutant that may have adverse effects on human health.effects on human health.

Using Laws to Protect Drinking WaterUsing Laws to Protect Drinking Water The U.N. estimates that The U.N. estimates that 5.6 million 5.6 million

AmericansAmericans drink water that drink water that does not meetdoes not meet EPA standards.EPA standards.

1 in 51 in 5 Americans Americans drinks water from a drinks water from a treatment plant that violated one or more treatment plant that violated one or more safety standard.safety standard.

Industry pressuresIndustry pressures to weaken the Safe to weaken the Safe Drinking Act:Drinking Act: Eliminate national tests and public notification of Eliminate national tests and public notification of

violations. violations. Allow rights to pollute if provider cannot afford to Allow rights to pollute if provider cannot afford to

comply.comply.

Is Bottled Water the Answer?Is Bottled Water the Answer? Some Some bottled waterbottled water is often not as pure as is often not as pure as

tap water and costs much more.tap water and costs much more.

40%40% of bottled water is contaminated with of bottled water is contaminated with bacteria and/or fungibacteria and/or fungi 1.4 million metric tons of plastic bottles are 1.4 million metric tons of plastic bottles are

thrown away per year.thrown away per year. Fossil fuelsFossil fuels are used to make plastic are used to make plastic

bottles.bottles.• The oil used to produce plastic bottles in the The oil used to produce plastic bottles in the

U.S. each year would fuel 100,000 cars.U.S. each year would fuel 100,000 cars.

Fig. 21-18, p. 517

• Prevent groundwater contamination

Solutions

Water Pollution

• Reduce birth rates

• Reduce poverty

• Reduce air pollution

• Practice 5 R's of resource use (refuse, reduce, recycle, reuse, repurpose)

• Work with nature to treat sewage

• Find substitutes for toxic pollutants

• Reuse treated wastewater for irrigation (“purple pipe”)

• Reduce nonpoint runoff

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 or stainless steel 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.

Chapter 20 Water Pollution. Chapter Overview Questions What pollutes water, where do these...

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Transcript of Chapter 20 Water Pollution. Chapter Overview Questions What pollutes water, where do these...