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ESC110 Chapter Ten Water: Resources and Pollution

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Tests for water quality are done for coliform bacteria (intestinal bacteria) ... Escherichia coli (E. coli) is the major coliform bacterium species ... – PowerPoint PPT presentation

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Title: ESC110 Chapter Ten Water: Resources and Pollution


1
ESC110 Chapter Ten Water Resources and Pollution
2
Part 6 Water Pollution
Nonpoint source pollution - runoff from farm
fields and feedlots, lawns and gardens, golf
courses, construction sites, atmospheric deposits
- no specific location so harder to monitor and
regulate
Point source pollution - source is from drain
pipes, ditches, sewer outfalls, factories and
power plants - easy to monitor and regulate
3
Types and Results of Water Pollution
  • Infectious agents - 25 million deaths a year
  • Organic materials - biological oxygen demand
    (BOD) increase resulting in oxygen sag
  • Plant nutrients - eutrophication, toxic tides
  • Metals - mercury and lead poisoning
  • Nonmetallic salts - poison seeps and springs
  • Acids and bases - ecosystem destabilization
  • Organic chemicals - birth defects, cancer
  • Sediments - clogged estuaries, death of coral
    reefs
  • Thermal pollution - thermal plume

4
Infectious Agents
  • Main source of waterborne pathogens is untreated
    and improperly treated human waste.
  • Animal wastes from feedlots and fields is also an
    important source of pathogens.
  • In developed countries, sewage treatment plants
    and pollution-control devices have greatly
    reduced pathogens.
  • Tests for water quality are done for coliform
    bacteria (intestinal bacteria). Such tests are
    easier and cheaper.
  • Escherichia coli (E. coli) is the major coliform
    bacterium species

5
Basics for Understanding Environmental
Implications of Oxygen-Demanding Wastes
  • Water with a Dissolved Oxygen Content (DOC)
    content gt 6 parts per million (ppm) will support
    desirable aquatic life, whereas water with lt 2
    ppm oxygen will support mainly detritivores and
    decomposers.
  • Oxygen is added to water by diffusion from wind
    and waves, and by photosynthesis from green
    plants, algae, and cyanobacteria. Oxygen is
    removed from water by respiration and
    oxygen-consuming processes.
  • Biochemical Oxygen Demand (BOD) is the amount of
    dissolved oxygen consumed by aquatic
    microorganisms in respiration.
  • When organic wastes are added to rivers,
    microorganisms demand oxygen for respiration used
    in consuming the increase in food resource. As a
    result, DOC levels decline downstream (oxygen
    sag) from a pollution source as decomposers
    metabolize organic waste materials.

6
Oxygen sag
7
Plant Nutrients and Cultural Eutrophication
  • Oligotrophic - Bodies of water that have clear
    water and low biological productivity.
  • Eutrophic - Bodies of water that are rich in
    organisms and organic material.
  • Eutrophication - Process of increasing nutrient
    levels and biological productivity.
  • Cultural Eutrophication - Increase in biological
    productivity and ecosystem succession caused by
    human activities.

8
Toxic Tides
  • Excessive nutrients support blooms of deadly
    aquatic microorganisms in polluted waters.
  • Increasingly common where nutrients and wastes
    wash down rivers.
  • Pfiesteria piscicida is a poisonous
    dinoflagellate recognized as killer of fish and
    shellfish.

9
Inorganic Pollutants
  • Metals
  • Many metals such as mercury, lead, cadmium, and
    nickel are highly toxic.
  • Highly persistent and tend to bioaccumulate in
    food chains.
  • Lead pipes are a serious source of drinking water
    pollution.
  • Mine drainage and leaching are serious sources of
    environmental contamination.
  • Nonmetallic Salts
  • Many salts that are non-toxic at low
    concentrations can be mobilized by irrigation and
    concentrated by evaporation, reaching levels
    toxic to plants and animals.
  • Leaching of road salts has had detrimental effect
    on many ecosystems.
  • Acids and Bases
  • Often released as by-products of industrial
    processes.

10
Organic Chemicals
  • Thousands of natural and synthetic organic
    chemicals are used to make pesticides, plastics,
    pharmaceuticals, pigments, etc.
  • Two most important sources of toxic organic
    chemicals in water are
  • Improper disposal of industrial and household
    wastes.
  • Runoff of pesticides from high-use areas.
  • Fields, roadsides, golf courses

11
Sediment
  • Human activities have accelerated erosion rates
    in many areas.
  • Cropland erosion contributes about 25 billion
    metric tons of suspended solids to world surfaces
    each year.
  • Sediment can either be beneficial (nourish
    floodplains) or harmful (smother aquatic life).

12
Thermal Pollution
  • Raising or lowering water temperatures from
    normal levels can adversely affect water quality
    and aquatic life.
  • Oxygen solubility in water decreases as
    temperatures increase.
  • Species requiring high oxygen levels are
    adversely affected by warming water.
  • Industrial cooling often uses heat-exchangers to
    extract excess heat, and discharge heated water
    back into original source.
  • Thermal Plume
  • Produce artificial environments which attract
    many forms of wildlife.

13
Three "waters" I have measured
  • Water mg/liter
  • --------------------------------------------------
    -----
  •  1) 205
  •  2) 73,000
  •  3) 89,000

14
Which one would you rather drink?
  • Water mg/liter number of class
  • --------------------------------------------------
    --------
  •  1) 205 gt200
  •  2) 73,000 0
  •  3) 89,000 1

15
Three "waters" I have measured
  • Water mg/liter what is it?
  • --------------------------------------------------
    -----------------
  •  1) 205 Snoqualmie Pass
    Sewage
  •  2) 73,000 Coca Cola Classic
  •  3) 89,000 Whole milk

16
Part 7 Water Quality Today
17
Percentage of impaired river miles in the U.S. by
source of damage
18
  • Areas of Progress
  • Clean Water Act (1972) established a National
    Pollution Discharge System which requires a
    permit for any entity dumping wastes in surface
    waters.
  • In 1999, EPA reported 91.4 of all monitored
    river miles and 87.5 of all accessed lake acres
    are suitable for their designated uses.
  • Most progress due to municipal sewage treatment
    facilities.
  • Watershed Approach Is Also an Improvement
  • 1998, EPA switched regulatory approaches.
    Rather than issue standards on a site by site
    approach, the focus is now on watershed-level
    monitoring and protection.
  • States are required to identify waters not
    meeting water quality goals and develop total
    maximum daily loads (TMDL) for each pollutant and
    each listed water body.
  • Persistent Environmental Problems That Remain
  • Greatest impediments to achieving national goals
    in water quality are sediment, nutrients, and
    pathogens, especially from non-point discharges.
  • About three-quarters of water pollution in the US
    comes from soil erosion, air pollution fallout,
    and agricultural and urban runoff.
  • Single cow produces 30 kg manure/day.
  • Some feedlots have 100,000 animals.

19
Groundwater and Drinking water Pollution
  • About half the US population, and 95 of rural
    residents, depend on underground aquifers for
    drinking water.
  • For decades, groundwater was assumed impervious
    to pollution. It was considered the gold
    standard for water quality.
  • An estimated 1.5 million Americans fall ill from
    fecal contamination annually.
  • Cryptosporidium outbreaks

20
Groundwater Pollution
21
Progress and Problems in Other Countries
  • Sewage treatment in wealthier countries of Europe
    generally equal or surpass the US.
  • In Russia, only about half of the tap water
    supply is safe to drink.
  • In urban areas of South America, Africa, and
    Asia, 95 of all sewage is discharged untreated
    into rivers.
  • Two-thirds of India's surface waters are
    contaminated sufficiently to be considered
    dangerous to human health.

22
Location of Oil Pollution in the Oceans
23
Part 8 Pollution Control
  • Nonpoint Pollution Sources and Land Management
  • Reduce nutrient loading thru land use regulations
  • Source reduction is cheapest and most effective
    way to reduce pollution. To work society must
    get public and business leaders to avoid
    producing or releasing substances into the
    environment.
  • Studies show as much as 90 less road salt can be
    used without significantly affecting winter road
    safety.
  • Soil Conservation
  • Banning phosphate detergents
  • Sewage Treatment
  • Remediation

24
Sewage Treatment
  • Rationale
  • More than 500 pathogenic bacteria, viruses, and
    parasites can travel from human or animal
    excrement through water.
  • Natural Processes
  • In many areas, outdoor urination and defecation
    is the norm.
  • When population densities are low, natural
    processes can quickly eliminate waste.
  • Artificial Wetlands Are a Low Cost Method
  • Natural water purification
  • Effluent can be used to irrigate crops or raise
    fish for human consumption.

25
Municipal Sewage Treatment
  • Primary Treatment - Physical separation of large
    solids from the waste stream.
  • Secondary Treatment - Biological degradation of
    dissolved organic compounds.
  • Effluent from primary treatment transferred into
    trickling bed, or aeration tank
  • Effluent from secondary treatment is usually
    disinfected (chlorinated) before release into
    nearby waterway.
  • Tertiary Treatment - Removal of plant nutrients
    (nitrates and phosphates) from secondary
    effluent.
  • Chemicals, or natural wetlands.
  • In many US cities, sanitary sewers are connected
    to storm sewers.
  • Heavy storms can overload the system, causing
    by-pass dumping of raw sewage and toxic runoff
    directly into watercourses.

26
Sewage Treatment
27
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28
Water Remediation
  • Containment methods confine liquid wastes in
    place, or cap surface with impermeable layer to
    divert water away from the site.
  • Extraction techniques are used to pump out
    polluted water for treatment.
  • Oxidation, reduction, neutralization, or
    precipitation.
  • Living organisms can also be used effectively to
    break down polluted waters.

29
Part 9 WATER LEGISLATION
  • Clean Water Act (1972)
  • Goal was to return all U.S. surface waters to
    "fishable and swimmable" conditions.
  • For Point Sources, Discharge Permits and Best
    Practicable Control Technology are required.
  • Set zero discharge for 126 priority toxic
    pollutants.
  • Areas of Contention
  • Draining or Filling of Wetlands
  • Many consider this taking of private land.
  • Un-funded Mandates
  • State or local governments must spend monies not
    repaid by Congress.
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