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  1. 1. 1 Pollution PHScience
  2. 2. 2 Challenge • To define pollution; • To determine threats to our air/water/land resources; • To develop solutions to some of these problems using SCIENCE!
  3. 3. 3 Contamination • Contamination is the abnormal presence of a harmful substance in an environment; • E.g. Selenium metal is necessary in low dosages, but in high dosages it is toxic; • The Toxicity Threshold is the level of concentration above which an contaminant causes one or more harmful effects in an organism. • The Lethal Dose is the amount of contaminant needed to kill an organism. • The LD50 is the amount needed to kill 50% of a population.
  4. 4. 4 Background • To understand how the biosphere gets polluted, we must study each of the “spheres” of the biosphere (where all life exists) and how they interact: – the atmosphere (air layers) – the lithosphere (soil and rocks); – the hydrosphere (watery & icy regions); – and the ecosphere (plants and animals).
  5. 5. 5 Lithosphere • The lithosphere is the hard shell of the Earth, consisting of the crust and the topmost part of the upper mantle.
  6. 6. 6 Minerals • Minerals are solid inorganic substances with clearly defined composition and properties; • Rocks or Ore are made of different proportions of minerals. • There are many different types of granite rock depending on the relative concentrations of the minerals - feldspar (red), quartz (white) and mica (black) • A mineral deposit is said to exist when the amount and concentration of a mineral in the ore is high enough to be mined.
  7. 7. 7 Rocks • Rocks are classified according to their: – Density – mass/volume; – Hardness – Mohs Scale; – Colour – colour of rock on the inside; – Streak – of colour on a porcelain tile; – Transparency – how you can see thru’ it; – Acid test results – does HCl make it bubble; – Origin – sedimentary, igneous, metamorphic;
  8. 8. 8 Soil • Soil is the mixture of – Organic matter – decomposing plants and animals; – Minerals; – Broken-down rock material; • The 5 soil horizons or layers are: – Organic matter/humus; – Topsoil; – Subsoil; – Fragmented parent rock; – Unaltered parent rock (bedrock);
  9. 9. 9 Life in the soil • For soil to support life it must have: – A sufficient amount of dissolved minerals; – Enough moisture; – A good soil pH that is neither too acidic (pH 1-6), nor too basic (pH 8-14); o Soil acts as a buffer/cushion so that its acidity does not change too much;
  10. 10. 10 Fossil Fuels and the Atmosphere • Fossil fuels result from the transformation of organic residue like plants, animals; • These energy resources consist of: – Oil; – Natural gas; – Coal; • Burning these fossil fuels releases Carbon Dioxide (CO2) into the atmosphere. • These add to the natural Greenhouse Gases which act as a blanket to trap the Earth’s heat; • Global Warming is caused by too high a concentration of Greenhouse Gases which increases the world’s average temperature;
  11. 11. 11 Pollution from Plastics • Fossil fuels are used to make plastics; • Plastics can take 100s of years to decompose; • Burning fossil fuels releases their chemical energy in the form of thermal energy or heat for use in car engines; • One of the products of burning fossil fuels is Carbon Dioxide (CO2 ); • This also increases the greenhouse gas effect and warms the Earth up; • Other products are Nitrogen Oxides (NOx) and Sulphur Dioxide (SO2) which form Acid Rain;
  12. 12. Ozone Layer • Ozone (O- 3)is one of the gases that make up the air. • The ozone layer in the stratosphere primarily absorbs the sun’s ultra-violet rays. • Aerosols gases like Chlorinated FluoroCarbons (CFCs) reduce the ozone layers allowing more CFCs in. 12
  13. 13. 13
  14. 14. Activity • Soil Analysis Demo • Page 214, Q. 1-9 14
  15. 15. 15 Alternate Energy Sources • Atmosphere – Wind Energy – from energy of the wind; • Hydrosphere – Tidal Energy – from motion of oceans due to the moon’s and sun’s gravitational pull; – Hydro-Electric Energy – from falling water; – Current Energy – from the ocean’s currents; • Lithosphere – Geothermal Energy – from energy of the Earth; – Nuclear Energy – the energy stored in the bonds inside the atom; • Solar Energy – from energy of the Sun;
  16. 16. Tides • A tide is the rise and fall of water in the seas and the oceans caused by the gravitational force (pull) of the Moon, and to a lesser extent, the Sun. • There are two high tides and two low tides daily.
  17. 17. 17 Hydrosphere • The Hydrosphere is the Earth’s outer layer of water: – Liquid water – water – Solid water – ice – Gaseous water – water vapour
  18. 18. 18 Cryosphere • The Cryosphere consists of all the frozen water of the Earth’s surface; • E.g. The Polar Ice Caps are floating masses of ice at the North and South Poles; • Melting of the Polar Ice Caps would release water into the ocean, dilute the denser sea water, and affect the Thermohaline Circulation; • The Thermohaline Circulation is the movement of salty ocean water around the world due to its density and temperature. • The air masses that are over the oceans pick up the heat. • This helps create prevailing wind patterns.
  19. 19. 19 Glaciers • Glaciers are large land-based masses of ice. • Global warming causes the glaciers to melt and slide towards the oceans. • This may cause the water levels of the oceans to rise.
  20. 20. 20 Causes of Ocean Pollution • The Pacific Gyre is a place in the Pacific Ocean where most of the water-borne plastics come together.
  21. 21. 21 Activity • Rock collection; • Workbook, page 97 & 99, 101 & 102; • Textbook page 215, Q. 20-23
  22. 22. 22 Watershed • A watershed is an area of land in which all inland waters drain into the same larger body of water; • E.g. In Quebec, we have three: – St. Lawrence River watershed; – Ungava Bay watershed; – Hudson Bay watershed;
  23. 23. 23 Watershed Factors • Factors that affect how water flows within a watershed are: – Topography – shape, slope, terrain of area; – Geology – type, depth, structure of the bedrock; – Climate – rain or snowfall, winds and temperature; – Vegetation – density and diversity; – Land use – agricultural, industrial or urban;
  24. 24. 24 Problems • Soil depletion – the loss of soil fertility; • Soil erosion – soil being washed away; • Soil contamination - the abnormal presence of harmful substances; • Water depletion – loss of water because of over-use reduces its availability for others; • Water contamination – contaminated water will move downstream and affect other areas.
  25. 25. 25 Causes of Freshwater Pollution • Industries release heated water – Thermal pollution • Farming activities release – Pesticides – Herbicides – Phosphates – Nitrates • Bio-accumulation is the tendency among certain contaminants to accumulate over time in the tissues of living organisms. • Toxins bio-accumulate more in higher trophic level organisms.
  26. 26. 26 Eutrophication • Eutrophication is the process by which natural waters lose their oxygen because of an excessive accumulation of organic matter and nutrients; • E.g. fertilizer • This harms organisms at different trophic levels in local food chains or food webs.
  27. 27. Disturbance • A disturbance is an event that damages an ecosystem. • It can lead to the elimination of organisms and alter the availability of resources. • Disturbances are described by their: • Type: natural, human-caused • Frequency: seasonal, freak • Seriousness: hailstorm, tornado 27
  28. 28. Food Relationships Sun Troph Vores Trophic Level Grass Autotroph - Producer Cow Heterotroph Herbivore Primary Consumer Wolf Heterotroph Carnivore Secondary Consumer Bear Heterotroph Omnivore Tertiary Consumer Vulture/Worm/Fungus Heterotroph Detritivore Decomposer 28
  29. 29. Primary Productivity • It is the amount of new bio-mass generated by producers. • Primary productivity is a measure of what mass (kg) of plant growth can occur in one year. • E.g. crop or tree growth • It depends on the availability of light, heat, water and nutrients. 29
  30. 30. Energy Flow in Trophic Systems • Only 10% of the energy is transferred between levels; • Most is lost to motion, heat, waste. 30
  31. 31. Activity • Textbook page 216, Q. 33-36, A,B,D; • Misconceptions on Global Climate Change 31
  32. 32. 32 Student Science Solution Brainstorming Problems Solutions Land - Land - Air - Air – Water - Water -