Area IV: Pollution

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Area IV Pollution

• IVA3 Water Pollution

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20-1 Types, Effects, Sources of Water Pollution

• water is polluted by infectious bacteria,
  inorganic and organic chemicals, and excess heat
• water pollution any chemical, biological, or
  physical change in water quality that has a
  harmful effect on living organisms
• the WHO estimates that 3.4 million people/yr
  people die prematurely from waterborne diseases
• an estimated 1.5 million people/yr in U.S. become
  ill from infectious agents

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20-1 Types, Effects, Sources of Water Pollution

• scientists monitor water quality by using
  bacterial counts, chemical analysis, and
  indicator organisms
• number of colonies of fecal coliform bacteria
  present in a water sample
• drinking water 0 colonies/100 mL
• swimming water lt 200 colonies/100 mL
• bacterial source tracking (BST)
• biological oxygen demand (BOD) the amount of
  dissolved oxygen consumed by aquatic decomposers

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Fig. 20-2 Fecal coliform bacteria
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• In May 2000 the small community of Walkerton,
  Ontario was laid waste by a toxic strain of E.
  coli0157.
• The contamination came from the public water
  supply.
• Six people died in the first week including a two
  year old daughter of a local medical doctor.
• Four new cases surfaced in late July, all very
  young children.
• Over a thousand innocent people were infected.

bss.sfsu.edu/ehines/geog600/ Freshwater20and20oc
ean20Pollution.ppt
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Waterborne Bacteria

• Disease symptoms usually are explosive emissions
  from either end of the digestive tract

Escherichia coli
Vibrio sp.
Barbara E. Moore, Ph.D., Department of Biology,
University of Texas at San Antonio
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Indicator Tests
Total coliform Endo agar
Fecal coliform m-FC agar
Fecal streptococci M-enterococcus
Prescott et al., Microbiology
Barbara E. Moore, Ph.D., Department of Biology,
University of Texas at San Antonio
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20-1 Types, Effects, Sources of Water Pollution

• scientists monitor water quality, cont.
• chemical analysis inorganic and organic
  chemicals present, sediment content, and
  turbidity of water
• indicator species
• genetic techniques are being used to develop
  organisms that will glow in the presence of
  specific pollutants such as toxic heavy metals in
  the ocean and carcinogens in food

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Fig. 20-3 Water quality and dissolved oxygen
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20-1 Types, Effects, Sources of Water Pollution

• water pollution can come from a single source or
  variety of dispersed sources
• point sources discharge at specific locations
• examples drainpipes, sewer lines
• easy to identify, monitor, and regulate
• non-point sources are scattered and diffuse and
  cant be traced to any single site of discharge
• examples runoff from croplands, livestock
  feedlots
• difficult and expensive to identify and control
  these discharges

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Fig. 20-4 Point and nonpoint sources
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20-1 Types, Effects, Sources of Water Pollution

• sources of water pollution, cont.
• leading sources agriculture, industries, mining
• agricultural activities
• erosion
• overgrazing
• fertilizers
• pesticides
• excess salt from irrigated soils

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20-1 Types, Effects, Sources of Water Pollution

• too much rain and too little rain can increase
  water pollution
• increased moisture with more intense rains can
  flush harmful chemicals, plant nutrients, and
  microorganisms into waterways
• prolonged drought can reduce river flows so there
  is less dilution available
• warmer water contains less dissolved oxygen

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Causes of Acid Rain

• Sulfur dioxide (SO2) and nitrogen oxides (NOx)
  are the primary causes of acid rain.
• In the US, about 2/3 of all SO2 and 1/4 of all
  NOx comes from electric power generation that
  relies on burning fossil fuels like coal.

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Buffering Capacity

• Acid rain primarily affects sensitive bodies of
  water, which are located in watersheds whose
  soils have a limited buffering capacity
• Lakes and streams become acidic when the water
  itself and its surrounding soil cannot buffer the
  acid rain enough to neutralize it
• Some lakes now have a pH value of less than 5

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Effects on Wildlife

• Generally, the young of most species are more
  sensitive to environmental conditions than adults
• At pH 5, most fish eggs cannot hatch
• At lower pH levels, some adult fish die
• Some acid lakes
• have no fish

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20-2 Pollution of Freshwater Streams

• streams can recover from moderate levels of
  degradable water pollutants if the flows are not
  reduced
• dilution and biodegradation can allow recovery of
  stream pollution if
• they are not overloaded
• do not have reduced flow due to damming,
  agricultural diversion, or drought

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20-2 Pollution of Freshwater Streams

• stream recovery, cont.
• breakdown of pollutants by bacteria creates an
  oxygen sag curve
• organisms with a high oxygen demand cant survive
  in the curve
• factors in size of curve
• volume of the stream
• volume of wastes entering
• flow rate
• temperature
• pH levels

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Fig. 20-5 Dilution and decay of wastes
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Investigating BOD Amount of dissolved oxygen
needed by aerobic decomposers to break down the
organic materials in a given volume of water at a
certain temperature over a specified time period
Distilled water
Pollutant (milk)
yeast
Color Indicator
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Investigating BOD Amount of dissolved oxygen
needed by aerobic decomposers to break down the
organic materials in a given volume of water at a
certain temperature
Initial Demonstration Both started Dark Blue-
Picture taken after 10 min at 28deg Celcius-(84
F)
Test Tube B contains 10ml milk, yeast and
methylene Blue
Test Tube A the control contains distilled water,
yeast and methylene Blue
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Initial Demonstration Both started Dark Blue-
Picture taken after 20 min at 28deg Celcius-(84
F)
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8AM Initial setup with series of dilutions
containing degrees of pollutants Level of O2
high-indicated by blue color
(BOD)Control 1/16 1/8 ¼ ½ full
concentration
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(No Transcript)
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After about 1 hr the tubes began to change
color. Why are those to the left darker?
(BOD) Control 1/16 1/8 ¼ ½ full
concentrationm milk
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(No Transcript)
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Ultimate results BOD level obvious G Greater
the BOD stronger the reattion More white the
more oxygen present
(BOD) Control 1/16 1/8 ¼
½ full concentration milk
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20-2 Pollution of Freshwater Streams

• most developed countries have reduced point
  source pollution, but toxic chemicals and
  pollution from non-point sources are still
  problems
• the U.S. has avoided increases in pollution from
  point sources in most streams
• cleanup of rivers Cuyahoga River in Ohio and the
  Thames River in Great Britain
• there are sometimes large fish kills, and
  contamination of drinking water from industry,
  mining, and non-point runoff of fertilizers and
  pesticides

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20-2 Pollution of Freshwater Streams

• stream pollution in most developing countries is
  a serious and growing problem
• half of the worlds 500 major rivers are heavily
  polluted
• many run through developing countries where waste
  treatment is minimal or nonexistent

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20-2 Pollution of Freshwater Streams

• the Ganges River in India is severally polluted
• 350 million people live in the Ganges River
  basin with little treatment of sewage
• Hindu beliefs compound problem
• air pollution from cremated bodies
• water pollution from bodies thrown in river
• government solutions
• waste treatment plants in the 29 large cities
  along the Ganges
• electric crematoriums on its banks
• introduction of snapping turtles as body
  scavengers

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20-3 Pollution of Freshwater Lakes

• lakes are less effective at diluting pollutants
  that enter them
• often stratified with little vertical mixing
• very little flow occurring
• may take from 1100 years to flush and change
  water in lakes and reservoirs
• much more vulnerable to runoff contamination of
  all kinds of materials
• chemical concentrations build up as they pass
  through the food webs in lakes

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Fig. 20-6 Biomagnification of PCBs
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20-3 Pollution of Freshwater Lakes

• human activities can reduce dissolved oxygen and
  kill some aquatic species
• natural eutrophication nutrient enrichment of
  lakes from runoff
• depends on composition of the surrounding
  drainage basin
• can enrich abundance of desirable organisms
• cultural eutrophication occurs due to runoff
• usually near urban or agricultural areas and in
  coastal water, enclosed estuaries, and bays
• can lead to serious pollution problems

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Oligotrophic lake
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Eutrophic lake
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Fig. 20-7 Cultural eutrophication
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20-3 Pollution of Freshwater Lakes

• human activities, cont.
• cultural eutrophication, cont.
• the EPA states that 85 of large lakes near major
  population centers in U.S. have some amount of
  cultural eutrophication
• can be reduced or prevented by
• banning or limiting phosphates in detergents
• advanced treatment methods to remove nitrates and
  phosphates from wastewater
• use of soil conservation to reduce runoff

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20-3 Pollution of Freshwater Lakes

• human activities, cont.
• hot weather or drought -gt blooms of organisms
  -gt reduction in lake productivity
• reduced sunlight decomposition -gt increase in
  bacteria populations -gt decrease in DO -gt fish
  kills -gt anaerobic bacteria take over
• cleanup of lakes includes removing excess weeds,
  controlling plant growth, and pumping air through
  lakes and reservoirs to avoid oxygen depletion
• pollution prevention is cheaper than cleanup

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20-3 Pollution of Freshwater Lakes

• Case Study in lake recovery Lake Washington,
  Seattle
• sewage diverted from the lake to Puget Sound,
  where rapid water exchange dilutes sewage
• recovery took 4 years
• lake had not filled with weeds and sediment
• concern about Puget Sound due to increased urban
  runoff and growing population
• What is the best way to deal with pollution?

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Lake Washington
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Lake Washington
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20-3 Pollution of Freshwater Lakes

• Case Study pollution of the Great Lakes has
  dropped but is still a problem
• the Great Lakes contain about 95 of the fresh
  surface water in the United States, and 20 of
  the worlds fresh surface water
• gt 38 million people obtain drinking water from
  the lakes
• vulnerable due to less than 1 outflow to the St.
  Lawrence River but lots of inputs
• Lake Erie shallowest was the most polluted
  high concentration of people and industry

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Fig. 20-8 Great Lakes basin
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Western Lake Eerie
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20-3 Pollution of Freshwater Lakes

• Case Study Great Lakes pollution, cont.
• since 1972, the U.S. and Canada have worked
  together to reduce pollution
• there is still a large area of depleted oxygen
  that occurs in the center of the lake each August
  for unknown reasons
• a 2000 survey by the EPA stated that more than ¾
  of the shoreline is not clean enough for swimming
  or use as drinking water
• non-point land runoff is now a greater problem
  than industrial pollution

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20-3 Pollution of Freshwater Lakes

• Case Study Great Lakes pollution, cont.
• biomagnification of the depositions from
  atmospheric contaminants means that one fish in
  four is unsafe for human consumption
• EPA funding for cleanup has also dropped by 80
  since 1992
• environmentalists call for banning the use of
  bleach, building new incinerators, and stopping
  the discharge into the lakes of 70 toxic chemicals

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20-4 Pollution of Groundwater

• groundwater is vulnerable to pollution
• spilling gasoline, oil, paint thinners, etc. onto
  the ground can contaminate groundwater
• low-risk ecological problem
• high-risk health problem
• contaminated water in the aquifer will slowly
  flow, creating a plume of contaminated water
• contaminants in groundwater are not diluted or
  dispersed because this water moves usually less
  than 0.3 meter per day

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20-4 Pollution of Groundwater

• groundwater vulnerability, cont.
• cleansing is slow factors
• lower oxygen content
• colder temperature of the water
• smaller populations of decomposing bacteria
• it can take hundreds of years to cleanse
  degradable wastes nondegradable wastes are there
  permanently

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20-4 Pollution of Groundwater

• the extent of groundwater contamination is
  generally unknown
• EPA and U.S. Geological Survey figures state that
  one or more organic chemicals contaminate about
  45 of municipal groundwater supplies in the U.S.
• 26,000 industrial waste ponds and lagoons in
  U.S. do not have a liner to prevent seepage
• many underground storage tanks have leaks
• determining the extent of a leak is costly, and
  the cost of cleanup is more costly yet

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Fig. 20-9 Groundwater contamination
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20-4 Pollution of Groundwater

• groundwater contamination, cont.
• nitrates can contaminate groundwater, esp. in
  agricultural areas form nitrites in the body
• arsenic is released into drinking water when a
  well is drilled into arsenic-rich soils and rock
• WHO estimates that more than 112 million people
  drink water containing 5100 times the
  recommended level of 10 parts/billion
• Bangladesh has a serious problem with arsenic,
  but the UN and several NGOs have begun to assess
  wells and tag them

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20-4 Pollution of Groundwater

• prevention is the most effective and affordable
  way to protect groundwater from pollutants
• underground tanks in the U.S. and some other
  developed countries are now strictly regulated
• old, leaky tanks are being removed, and the
  surrounding soils are being treated

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Fig. 20-10 Groundwater pollution
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20-6 Preventing Surface Water Pollution

• reduce non-point pollution by preventing it from
  reaching bodies of surface water
• agricultural non-point pollution can be reduced
  by
• reducing soil erosion
• reducing fertilizer use slow-release fertilizer
• reforestation of watersheds
• keeping cover crops on farmland
• planting buffer zones between farmland and
  surface water nearby
• relying more on bio controls than pesticides
• EPA required to require 15,500 of the largest
  feedlots to apply for EPA permits

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20-6 Preventing Surface Water Pollution

• most developing countries do not have laws to set
  water pollution standards
• most cities in developing countries discharge
  8090 of untreated sewage water used for
  drinking, bathing, and washing clothes
• in U.S., the Clean Water Act sets standards for
  allowed levels of key water pollutants and
  requires polluters to obtain permits to discharge
  pollutants into aquatic systems
• EPA is experimenting with a discharge trading
  policy using credits

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20-6 Preventing Surface Water Pollution

• septic tanks and sewage treatment can reduce
  point-source water pollution
• 1/4 of homes in U.S. served by septic tanks
• most urban areas served by sewage treatment
  plants
• some 1,200 cities have combined storm runoff and
  sewer lines because it is cheaper can overflow
• sewer systems in the U.S. are estimated to cost
  10 billion a year for 10 years to install,
  expand, and repair the aging sewer network

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Fig. 20-15 Septic tank system
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20-6 Preventing Surface Water Pollution

• septic tanks and sewage treatment, cont.
• raw sewage generally undergoes one or two levels
  of treatment
• primary sewage treatment removes grit, floating
  objects, and suspended solids
• removes 60 of suspended solids and 3040 of
  organic wastes
• secondary sewage treatment is a biological
  process where aerobic bacteria remove up to 90
  of O2-demanding organic wastes
• tertiary sewage treatment removing specific
  pollutants

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Fig. 20-16 Primary and secondary treatment
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20-6 Preventing Surface Water Pollution

• septic tanks and sewage treatment, cont.
• raw sewage treatment, cont.
• a combination of primary and secondary treatment
  removes
• 9597 of the suspended solids and
  oxygen-demanding organic wastes
• 70 of most toxic metal compounds
• 70 of P, 50 of N, 5 of dissolved salts
• most U.S. cities have combined plants
• 34 East Coast cities screen out floating objects
  and discharge sewage into coastal waters

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20-6 Preventing Surface Water Pollution

• septic tanks and sewage treatment, cont.
• water is bleached to remove colors and then
  disinfected (usually chlorination) to kill
  disease-causing bacteria and some viruses
• ozonation and use of ultraviolet light are
  increasing as methods of disinfection

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20-6 Preventing Surface Water Pollution

• sewage sludge
• sludge is a thick, gooey mixture of bacteria,
  solids, chemicals, and metals when industrial and
  household wastes are combined
• some sludge undergoes anaerobic digestion to
  decompose organics and produce compost
• 36 of these biosolids are used as fertilizer
  rest is added to landfills or incinerated
• removing infectious bacteria, toxins, and metals
  is expensive, seldom done in the U.S.
• health problems?

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Fig. 20-17 Problems with sludge
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20-6 Preventing Surface Water Pollution

• preventing toxic chemicals from reaching
  treatment plants would eliminate these from
  sludge and water that is discharged
• require industries and businesses to remove toxic
  and hazardous wastes from water sent to sewage
  treatment plants
• encourage reduction or elimination of toxic
  chemical use and waste
• have households switch to waterless composting
  toilet systems maintained by professionals

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20-6 Preventing Surface Water Pollution

• wetlands can be used to treat sewage
• low-tech, low-cost alternative to expensive waste
  treatment plants
• sewage -gt sedimentation tanks -gt oxidation ponds
  -gt (1 month) artificial marsh
• genetic engineering is developing a bioreactor
  where modified bacteria will consume pesticides
• without large investments in building adequate
  sanitation facilities, more people will have
  inadequate sanitation

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Fig. 20-18 Wastewater garden
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20-6 Preventing Surface Water Pollution

• water pollution laws have significantly improved
  water quality in U.S.
• improvements
• 1992 to 2002, communities served by water systems
  meeting federal guidelines increased from 79 to
  94
• fishable and swimmable streams increased from 36
  to 60 of those tested
• topsoil loss through runoff was cut by 111
  billion metric tons annually (?)
• annual wetland losses decreased by 80

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20-6 Preventing Surface Water Pollution

• water pollution laws have significantly improved
  water quality in U.S., cont.
• problem areas
• in 2000, 40 of streams and 45 of lakes surveyed
  were too polluted for swimming or fishing
• animal waste and waste lagoons
• fish unsafe to eat (pesticides, Hg, etc.)
• in 2003, the EPA found that gt50 of the 6,000
  largest industrial facilities have been illegally
  discharging wastes into waterways

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20-6 Preventing Surface Water Pollution

• a 2001 report by EPAs inspector general calls
  for strengthening the Clean Water Act
• increased funding, increased authority to control
  non-point pollution, modernizing monitoring
  system, increasing compliance with the law
• integrating watershed and airshed planning to
  protect ground and surface water sources
• halt the loss of wetlands increase standards for
  wetland restoration and create new wetlands
  before filling existing ones
• farmers feel they should be compensated for
  property value losses that result from federal
  regulations protecting wetlands

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20-7 Drinking Water Quality

• 20 of people lack safe drinking water
• 95 of people in developed countries and 74 of
  people in developing countries have access to
  clean drinking water
• the UN estimates 23 billion/yr for 810 yr to
  bring clean drinking water to those lacking it
• centralized water treatment plants can provide
  safe drinking water water is settled, filtered,
  and chlorinated

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20-7 Drinking Water Quality

• the U.S. is upgrading water purification and
  delivery systems
• hard to secure
• also difficult to adequately poison
• both chemical and biological indicators are being
  developed to indicate contamination

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20-7 Drinking Water Quality

• several simple, inexpensive ways for individuals
  and villages to purify drinking water have been
  developed
• exposure of contaminated water to intense
  sunlight in a clear plastic bottle kills bacteria
• filtering water through cloth reduces risk of
  cholera
• a small amount of chlorine in a plastic or clay
  storage vessel cuts the rate of diarrheal disease
  in half

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20-7 Drinking Water Quality

• about 54 countries have standards for safe
  drinking water
• levels have been established called maximum
  contaminant levels for any pollutants that may
  adversely affect human health
• privately owned wells dont have to meet these
  standards
• some want the standards to be strengthened
• certain industries want to weaken the Safe
  Drinking Water Act (which industries?)

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20-7 Drinking Water Quality

• some bottled water is not as pure as tap water
  and costs much more
• bottled water is vastly more expensive than tap
  water
• 1/4 is tap water
• 1/3 is contaminated with bacteria
• 1/5 is contaminated with organic chemicals
• creates lots of waste
• manufacture releases toxic gases and liquids
• have home water tested
• be wary of companies claiming EPA approval

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20-7 Drinking Water Quality

• we need to shift priorities to preventing and
  reducing water pollution
• bottom-up political pressure on elected officials
  has reduced point-source water pollution
• a shift needs to be made to how we can prevent
  water pollution in the first place
• prevention of water pollution will take action
  from individuals and groups to pressure elected
  officials

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Fig. 20-19 Solutions
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Fig. 20-20 What can you do?