Water Quality and Pollution

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Water Quality and Pollution
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Water Pollution

• Water Pollution is any chemical, biological, or
  physical change in water quality that has a
  harmful effect on living organisms and makes
  water unsuitable for desired uses
• Air and water pollution are closely related
  because they mix together

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Pollution Sources

• 1. Point Source Specific site of pollution
  dumping.
• Ex Pipes from factories and houses.
• 2. Nonpoint sources are not easily determined.
  No direct point of entry
• Ex runoff from a field or road, acid rain

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Point Pollution
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Non-point Pollution
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• 3. STORM RUNOFF
• - during heavy storms water mixes in the sewers
  and the sewage treatment plants can not handle
  the overload excess is released
• 4. Agricultural runoff Open fields are especially
  at risk because the excess water leaches down
  into the ground water carrying phosphates and
  nitrates. Farmers can reduce this by leaving a
  zone of undisturbed land at the end or near
  drains or streams.
• 5. Mining runoff moves iron, copper, sulfuric
  acid (from coal) sulfur and zinc acid mine
  drainage

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This is an add-in. Yes, I know its not in your
packet. Find a space.

• 1. 2FeS2 7O2 2H2O ? 2FeSO4 2H2SO4
• Iron Pyrite (Iron (II) Sulfide) reacts with
  water and oxygen to form Iron (II) Sulfate and
  Sulfuric acid
• 2. 2Fe2 1/2 O2 2H ? 2Fe3 H2O
• The Iron (II) ion dissociates and oxidizes to
  form Iron (III)
• 3. Fe3 3H2O ? Fe(OH)3 3H
• Iron (III) ion reacts with water to form the
  insoluble Iron (III) Hydroxide which is a yellow
  orange color. Precipitates out of solution and
  kills fish by clogging their gills. Also makes
  the water more acidic.

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Water Pollutants

• 1) Disease causing organisms
• a) Bacteria -
• i) Cholera - Vibrio cholerae - highly
  spreadable. One fish packer in Equador died of
  Cholera and before they could contain the fish
  that he packed, it went to 8 countries. 300,000
  cases and 3000 deaths came from that one person.
• ii) E. coli - Bacteria associated with
  sewage causes horrible stomach problems for many
  days.

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• Cholera E. coli

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• Good indicator for quality of drinking and
  swimming water is the number of coliform bacteria
  present in 100-mL sample
• WHO recommends 0 colonies for drinking
• EPA recommends max of 200 colonies for swimming
• Avg. person excretes 2 billion bacteria a day
• iii) Bacterial dysentery - diarrhea,
  vomiting, upset digestive tract for 4-5 days

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• b) Protozoans - Amoebic dysentery - vomiting,
  diarrhea, and colon perforation causing death

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• c) Giardiasis - a problem in high mountain
  springs. People think the water is safe and drink
  it only to have 3-4 days of diarrhea and
  vomiting. Dehydration is a problem as well as
  fatigue.
• Video

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• d) Parasitic worms
• Video

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• e) Viruses

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• 2) Oxygen Demanding Wastes organic wastes that
  can be decomposed by aerobic bacteria which
  depletes oxygen
• - sewage, animal manure and some industrial
  wastes.
• - decomposition uses available oxygen and
  releases excess phosphorous
• - cause high level algal growth which blocks the
  sunlight from other plants and they die more
  decomposition less oxygen fish death

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• Level of oxygen required for the break down of
  material is called
• Biological oxygen demand (BOD) amount of
  dissolved oxygen needed by aerobic decomposers to
  break down over 5 day period _at_ 20ºC (68ºF)
• Test Procedure
• 1. Take 2 samples of water
• 2. Record the DO (DISSOVLED OXYGEN) level
  (ppm) of one immediately using the method
  described in the dissolved oxygen test.
• 3. Place the second water sample in an
  incubator in complete darkness at 20 C for 5
  days.
• 4. After 5 days, take another dissolved oxygen
  reading (ppm) using the dissolved oxygen test
  kit.
• 5. Subtract the Day 5 reading from the Day 1
  reading to determine the BOD level. Record

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BOD Level (ppm) Water Quality Interpretation
1-2 Very Good Little waste
3-5 Fair Moderately Clean
6-9 Poor Bacterial decomposition of Organic Matter present
10-99 Polluted Higher amounts of waste
100 or greater Very Poor Very polluted
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• - High BODs indicate that too much organic
  materials are in the water.
• - oxygen is used and the anerobic bacteria begin
  to produce chemicals that smell and have a
  unpleasant taste.
• - Food wastes are not as bad as detergent
  wastes. Soap and detergent have phosphates in
  them, which creates a problem

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• 3) Water-Soluble Inorganic Materials
  water-soluble nitrates and phosphates
• - excessive growth of algae and other aquatic
  plants that die and deplete the O2 content (kills
  fish)
• EX acids
• Salts phosphate (X3PO4), nitrates (XNO3) and
  sulfur (X2SO4)
• Toxins/toxicants -- lead , arsenic salts
• Can lead to Eutrophication

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Eutrophication

• Eutrophication natural enrichment of lakes
• Cultural Eutrophication process of human
  activities accelerating the input of nutrients
  farming, golf courses
• Prevention of cultural eutrophication advanced
  waste water treatment which bans/ limits the
  amount of phosphates in detergents, soil
  conservation, and land use control
• Cleanup methods dredging bottom sediments,
  removing excess weeds, controlling plant growth
  with herbicides and algaecides, pumping air
  thorough lakes and reservoirs

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• 4) Organic Chemicals threatens human, animal and
  aquatic plant life
• EX oil, gas, plastic, pesticides, detergents,
  ext.
• a) Synthetic organic chemicals plastics,
  detergents, oil, solvents and pesticides
• Most of it comes from runoff.
• Oil is highly toxic because it destroys the
  organisms ability to swim, stay afloat and to
  feed. It is poisonous in small amounts. It coats
  the water with a fine film to not allow O2or CO2
  movement to the air. It coats corals and other
  underwater species with film so the air exchange
  is impossible.

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Oil

• Tanker spills and blowouts, offshore drilling rig
  accidents,
• Almost ½ of the oil reaching the oceans is waste
  oil dumped, spilled, or leaked onto the land or
  into sewers by cities, individuals and industries
  
• The effects of oil on ocean depend on
• The type of oil (crude or refined)
• amount released
• distance of release from shore
• time of year
• weather conditions
• average water temperature
• ocean currents

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Oil

• Research shows that most (but not all) forms of
  marine life recover from exposure to large
  amounts of crude oil within 3 years Recovery
  from exposure to refined oil take gt10 yrs
• Moderate oil spills can be cleaned up by
  mechanical, chemical, fire, and natural methods

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Oil

• Mechanical methods include
• Floating booms to contain the oil spill or keep
  it from reaching sensitive areas
• Skimmer boats to vacuum up some of the oil into
  collection barges
• Absorbent pads or large feathered filled pillows
  to soak up oil on beaches or in waters to shallow
  for skimmer boats

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Oil

• Chemical methods include
• Coagulating agents to cause floating oil to clump
  together for easier pick up or sink to the bottom
  where is usually does less harm
• Dispersing agents to break up oil slicks
• Natural Methods
• Oil digesting bacteria spray on slick

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• 5) Sediments or Suspended Matter particles of
  soil/solid that stay suspended in water and made
  the water cloudy, reduces photosynthesis and
  disrupts food webs and clogs harbors, reservoirs,
  channels and artificial lakes
• sediments - Sediments are not an immediate
  problem.
• take time to pollute
• block the sunlight.
• May have small amounts of toxins in them that
  build up
• clog fish gills
• cover and destroy the natural plants of a lake
  or reservoir.
• remove nesting sites of fishes.

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• 6) Water-Soluble Radioactive Isotopes could lead
  to cancer
• 7) Thermal Pollution rise in water temp because
  water used to cool power plants
• - occurs when water is removed from a source,
  heated to a high heat, driving off the oxygen and
  placing the water back into the source
• Ex cooling electric generator and steam.

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• Thermal Pollution Prevention
• 1) large pond that is not attached to any other
  water
• - hot water is placed into one end and the
  cooled water is used from the other.
• 2) cooling towers water is sprayed in and
  cooled by evaporation
• 3) cooling tower in which the water is moved
  into the tower inside tubes and the heat is
  released, not the water
• 4) Discharging the heated water into shallow
  ponds or canals, and reusing it as cooling water

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• Problems with Thermal Pollution
• Affects fish spawns
• Thermal shock the effect of sharp changes in
  water temperature (kills fish that cant adapt)
• Thermal enrichment beneficial uses of heated
  water
• - Lengthens the commercial fishing season,
  reduces winter ice cover in cold areas, can
  extend the growing seasons, help heat nearby
  buildings and greenhouses

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• 8) Genetic Pollution deliberate or accidental
  addition of non-native species disrupts aquatic
  systems and crowd out natives reduces
  biodiversity principal way they are introduced
  intake and ballast from ships
• Ex Zebra mussels

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• 9) GROUNDWATER POLLUTION
• - due to percolation of pollutants to the water
  table
• - Typical Pollutants
• 1. Pesticides
• 2. Fertilizers farming and septic tanks
• 3. Gasoline leaking underground tanks
• MTBE methyl-tert butyl ether oxygenate
  enhance octane rating of gasoline
• 4. Toxins/toxicants landfills

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• 10) SALINIZATION
• - Increasing salt in the soils creates salt in
  the water.