U. B. Section 2 Monitoring Chemicals in the Environment

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U. B. Section 2 Monitoring Chemicals in the
Environment
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• What do you know about water quiz True or False
• 1. Rain, hail, and snow provide Earth with new
  sources of water.
• 2. Humans eat more water than they drink.
• 3. Water can dissolve more substances than any
  other liquid.
• 4. Water is the only naturally occurring
  substance that is found on Earth as a solid, a
  liquid, and a gas.
• 5. Falling raindrops are shaped like tears.
• 6. The purest possible water is what aquatic life
  depends upon for health.
• 7. The greatest home use of water in Canada is
  for drinking.
• 8. Like most other liquids, water contracts (gets
  smaller) when it freezes.
• 9. Approximately 3 of the water on Earth is
  fresh water.
• 10. The largest fresh water lake entirely in
  Canada is Lake Superior, located in Ontario.

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The Quality of Chemicals in the Environment can
be Monitored

• Monitoring keeping track of chemicals or
  populations in the environment to ensure they
  stay at safe and healthy levels.

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• Various chemicals in the environment must be
  monitored so that water and air quality can be
  protected.
• The ozone layer - the function of the ozone layer
  is to shield the Earth from damaging ultraviolet
  radiation from the sun.
• Q How would increased UV rays affect humans?
• Q What do the satellite photos indicate on
  p.212? ( use a ruler )

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Ozone Changes 1979-2008
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• 2.1 Monitoring water Quality
• Water Quality
• Clarity, or how clear the water is, is not a good
  indicator of water quality since acidic lakes are
  often clear and lifeless. Water quality is
  determined by what the water is to be used for.

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• Guidelines exist for 5 categories of water
• Human drinking water
• Recreation
• Livestock drinking water
• Irrigation
• Protection of aquatic life
• Scientists monitor water quality with both biotic
  and chemical indicators.

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• A. Biological indicators organisms that live in
  water help determine its quality.
• 1. Microbiological samples are taken from
  water sources people use to determine the number
  and type of microscopic organisms, such as
  bacteria, that are there in order to avoid
  illness.
• 2. Aquatic - invertebrates (animals without
  backbones) such as insects, crustaceans, worms
  and mollusks can be used as indicators of water
  quality since different invertebrates prefer
  different living conditions, such as dissolved
  oxygen, pH and temperature.

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• In Aquatic Environments, the diversity of all
  organisms decreases as acidity increases and
  dissolved oxygen decreases.

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• B. Chemical Factors that Affect Organisms
• 1. Measuring Chemicals the concentration of
  chemicals is measured in parts per million (ppm)
  or milligrams per litre (mg/L).
• 1 ppm means there is 1 unit of that chemical in
  1 million units of solution.
• Eg. How many ppm is 0.02 mL juice in 100 mL
  solution?
• 0.02mL x (ppm) 200 ppm
• 100mL 1 000 000

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• 2. Dissolved Oxygen the amount of oxygen
  dissolved in a body of water depends upon
• water temperature - more oxygen in cold water
• Turbulence - more oxygen in turbulent water
• amount of photosynthesis
• number of organisms living in it - they consume
  oxygen.
• 5 ppm of oxygen will support most organisms.
• See Figure 2.4, p.217.

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• 3. Phosphorus and Nitrogen Content these
  nutrients are added to water by sewage and runoff
  from fertilized fields.
• Higher concentrations leads to increased growth
  of algae and green plants and eventually a
  buildup of dead matter.
• This encourages a decomposer bloom, then
  bacteria increases to decompose the algae, then,
  dissolved oxygen decreases.
• As a result, many fish and insects die. See
  Figure 2.7, p. 219.

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• 4. Acidity as the pH of a water system drops
  the diversity of plants and animals that can live
  in the water decreases. Below 4.5, most fish
  disappear. Acid deposition is a problem in areas
  where soil and water lack bases to neutralize it.
  (eg, Canadian Shield)
• Spring acid shock occurs when acid builds up in
  the snow and then is released into the waterways
  as the snow melts, causing a dramatic drop in pH
  that seriously affects water organisms.

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• 5. Pesticides some have long term toxic effects
  because they dont degrade and become trapped in
  the tissues of animals. Many today are
  engineered to decompose after 1 season so they
  are no longer toxic.
• One problem resistance.
• As pests become resistant to pesticides, more
  must be developed and more chemicals are added to
  the soil. As this happens, one or more
  pesticides may combine to form even more toxic
  substances.

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• 6. Measuring Toxicity different chemicals
  affect organisms in different ways, so it can be
  difficult to compare the toxicity of a substance
  to other substances.
• A measurement called LD50 indicates the amount
  of the substance that will cause 50 of the
  population to die
• (LD lethal dose).
• The greater the toxicity of a substance
• the lower the LD50 is.
• LD50 testing is done on rats and mice and is
  given either orally or applied to the skin. See
  table, p. 221.

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• LD50 DOSE WHICH KILLS 50 OF TEST ANIMALS

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• ORAL LD50 VALUES
• nicotine 0.3 mg/Kg (mice)
• 2,3,7,8-TCDD 0.002 mg/Kg (guinea pig)
• 0.3 mg/Kg (mouse)
• 5 mg/Kg (hamster)
• 1,3,6,8-TCDD gt1500 mg/Kg (guinea pig)
• gt3000 mg/Kg (mouse)
• octa-CCD gt4000 mg/Kg (mouse)
• 2,3,7,8-TCDF 0.1 mg/Kg (guinea pig)
• gt6 mg/Kg (mouse)

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• PCBs 1295 mg/Kg (rat)
• Aspirin 1100 mg/Kg (mouse)
• sodium cyanide 6.4 mg/Kg (rat)
• caffeine 127 mg/Kg (mouse)
• methylisocyanate 305 mg/Kg (rat)
• ethanol 1200 mg/Kg (rat)
• sodium chloride 3750 mg/Kg (rat)

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• 7. Heavy Metals metals such as copper, lead,
  zinc, mercury, cadmium and nickel have densities
  greater than 5 g/cm3 and are therefore called
  heavy. They occur naturally in the environment
  but not usually in large amounts.
• Human activities can increase the amount of
  these metals acid water can dissolve lead
  pipes, cadmium can be found in fertilizer as an
  impurity and garbage can contain many of these
  metals.
• These metals are toxic to many organisms, but are
  very harmful for children. Their use in products
  is now limited and waste disposal is closely
  monitored to keep these metals from entering the
  environment.

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• Section 2.2 Air Quality
• Air is made up of 78 nitrogen, 21 oxygen, less
  than 1 argon and other trace gases (0.03).
• Its quality is determined by
• 1) measuring the pollutants
• (more accurate)
• 2) estimating the amount of emissions from
  pollution sources.

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• 1. Sulfur Dioxide (SO2(g)) this pollutant comes
  from industrial processes, like the oil and gas
  industry in Alberta, and from the burning of
  fossil fuels (coal, oil and gas).
• It contributes to smog and acid rain and can
  affect your respiratory system.
• Scrubbers are used to remove up to 99 of sulfur
  from industrial emission by using limestone
  (calcium carbonate) to convert it to a useful
  product called gypsum, and carbon dioxide.

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• 2. Nitrogen Oxides (NOX(g)) the X indicates
  either NO or NO2. These pollutants are formed
  mainly by fossil fuel emissions and by combustion
  at generating plants and industrial processes.
• NO is formed first and then it combines with
  oxygen in the air to form NO2, which is a brown
  gas that gives smog its color. These pollutants
  also affect the respiratory system and eyes and
  contribute to acid rain.

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• 3. Carbon Monoxide (CO(g)) the silent killer,
  colorless and odorless, it is a deadly gas that
  is produced by the burning of fossil fuels and
  can be produced when anything containing carbon
  is burned (wood like when heating homes or in
  forest fires, natural gas, cigarettes and
  industrial processes).
• Catalytic converters make CO2 out of CO since it
  is very toxic when inhaled it leads to
  headaches, sleepiness, brain damage and death.
• Catalytic converters use Platinum and Palladium
  to remove pollutants from vehicle exhaust.

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• 4. Ground-Level Ozone (O3(g)) a colorless,
  odorless gas in the upper atmosphere that
  protects the earth from harmful UV radiation. At
  the earths surface, ozone is formed by reactions
  between oxygen, nitrogen and volatile organic
  chemicals (VOCs emitted from solvents and
  gasoline).
• Ozone at the earths surface is a pollutant
  because it affects the respiratory systems of
  people with asthma, lung disease and colds. It
  also negatively affects crops such as wheat,
  soybeans and onions and causes plastics to
  deteriorate.

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• Section 2.3
• Monitoring the Atmosphere

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• 1. Carbon Dioxide - A Greenhouse Gas
• We live in a natural greenhouse, where gases in
  the atmosphere trap heat from the suns
  radiation. These greenhouse gases include water,
  methane, nitrogen oxides and carbon dioxide.
• CO2 is released naturally into the air by people
  breathing, driving vehicles and combusting
  materials.
• With the large amount of people doing all of
  these things, what effect will the increased
  amount of carbon dioxide have on the planet?

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• Many scientists support the theory that human
  activities enhance the greenhouse effect which
  increases the global temperature (global
  warming).
• This trend can lead to climate change, increase
  the amount of violent storms and flooding, and
  increase the spread of disease. Behind water,
  carbon dioxide contributes most to the greenhouse
  effect.
• See Figure 2.17, p. 231 for the upward trend of
  CO2 concentration in our atmosphere from 1960
  until today.

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• Global warming is increasing due to natural
  processes such as volcanic eruptions and forest
  fires, but also because of human activities.
• Some countries have begun to reduce CO2 emissions
  by turning to alternate energy sources such as
  wind and are also investing in forest projects to
  increase the amount of CO2 absorbed.

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• 2. The Ozone Layer
• The ozone layer is 15 to 50 km above the earth
  and protects us from UV rays. Scientists have
  found that this layer has become thinner over the
  years, some places so thin that they are called
  holes.
• As a result, more UV rays are getting to the
  earths surface and many effects are being seen,
  from skin cancer, to cataracts, to death of
  plankton.
• CFCs, or cholorfluorocarbons, are thought to
  cause thinning of the ozone layer. They were
  used in refrigerators, aerosol cans, and fire
  extinguishers.

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• UV causes CFCs to break down into substances
  (like chlorine) that breakdown ozone into O2(g).
  
• One chlorine molecule can break down 100 000
  ozone molecules. In colder regions (south pole),
  ice particles in the atmosphere speed up this
  reaction. Many countries have signed
  international agreements to reduce the use of
  CFCs.

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• global warming link