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Pollution and Degradation

Pollution and Degradation. …of the Lithosphere, Hydrosphere and Atmosphere. Our farming practices have changed:. Impact of Intensive agriculture on soils:. Gigantic fields vulnerable to wind erosion in dry periods.

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Pollution and Degradation

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  1. Pollution and Degradation …of the Lithosphere, Hydrosphere and Atmosphere

  2. Our farming practices have changed:

  3. Impact of Intensive agriculture on soils: • Gigantic fields vulnerable to wind erosion in dry periods. • Fertilizers and pesticides threaten Biodiversity and kill microorganisms that help maintain soil balance. • Use of heavy machines: • compacting of soil, less oxygen available for microorganisms • Rain water does not sink it but runs off the surface carrying away soil and nutrients water erosion Reduce soil fertility

  4. Soil depletion is the loss of soil fertility

  5. Contamination is the abnormal presence of a harmful substance in the environment Hydrocarbons from oil spills and and leaky gas station tanks Acidic waste from mining Heavy metals from leaky land fills and industrial pollution

  6. Contamination from the atmosphere Sulfur dioxide (SO2) and Nitrogen oxides (NOx) from combustion of fossil fuels and other industry carried by wind Gases dissolve in rain Acid rain

  7. Effect of acid rain on lithosphere • Leaching of soil minerals are dissolved and carried away with the water (washed out). • Mobilization of aluminum minerals aluminum toxic for living organisms (particularly for plants) • Acidification of soil upsetting of vegetation (some species prefer acidic soil and others can’t tolerate it  change in vegetation will occur)

  8. Impact of acid rain depends on soil A soil’s BUFFERING CAPACITY is its ability to resist changes in pH when acidic or alkaline products are added. Soils with low buffering capacity more vulnerable to effects of acid rain Sandy soil has a low buffering capacity Silt and clay soils have a higher buffering capacity

  9. Summary: Degradation / Pollution of the lithosphere • Soil depletion because of intensive farming: • large fields  more wind erosion • Use of pesticides and fertilizer  reduce biodiversity • Heavy machines  soil compacting, less oxygen, water erosion • Contamination by • hydrocarbons (gas stations, cars) • Heavy metals (leaky land fills) • Acid waste (from mining) • Contaminants from atmosphere (acid rain)

  10. Pollution and Contamination of water • Point sources • Pollution can be traced to well defined site. • Non point sources • Difficultto locate exact origin of pollution

  11. Sources of Pollution and Contamination of water Rain / Acid rain: acidifies water  some species more sensitive Dissolves aluminum from aluminum minerals and transports it into rivers and lakes. Aluminum toxic Farming: Run off water carries fertilizer and pesticides into water Domestic and industrial sewage: • Organic and chemical pollutants • heat

  12. Pollution and Contamination of water • Heat: • Solubility of Oxygendecreases with in-creasing temperature • Bad for animals and microorganisms.

  13. Sources of Pollution and Contamination of water Rain / Acid rain: acidifies water  some species more sensitive Dissolves aluminum from aluminum minerals and transports it into rivers and lakes. Aluminum toxic Farming: Run off water carries fertilizer and pesticides into water Domestic and industrial sewage: • Organic and chemical pollutants • heat

  14. Eutrophication Process by which natural waters lose their oxygen because of an excessive accumulation of of organic matter and nutrients

  15. sediment sediment Time: Centuries Over time sediment accumulates in lake  Water becomes shallower.  More plant growth, more production of organic material.  Bacteria decompose plant material, consuming large amounts of oxygen.

  16. sediment sediment Time: Decades Fertilizers form agriculture (particularly Phosphorus) and warming of water promote rapid growth of algae: High production of organic material Bacteriadecomposing organic matter consume a lot of oxygen warm water less oxygen than cold water

  17. Effect of pollutants depends on: • Their concentration • Their nature (toxicity) • How long they will remain in the environment how quickly is water exchanged/ renewed Which one will be affected more easily? creek pond

  18. Contamination of oceans with oil • Through: • Pumping of oil from under the ocean • Some leaks • Oil tankers clean out on open sea • accidents

  19. Pollution and contamination of water • Point source vs. non point source • Contamination through: • Acid rain • Pesticides, fertilizer and manure from farming • Sewage, either domestic or industrial • Heat • Hydrocarbons, oil (in particular oceans) • Heat and fertilizer cause Eutrophication of lakes

  20. Notes on contamination of hydrosphere Clip herbicides and frogs

  21. Contamination of the atmosphere • Green house gases • “acid rain” gases (Clean rain pH 5.5 -5,7, acid rain pH 3-5.) • Heavy metals (mercury (Hg), arsenic (As), lead (Pb))  from combustion of oil, coal, waste incineration • Chlorofluorocarbons (CFCs) – destroy Ozone • Smog – CO2, H2O, N2O, CH4 – SO2 and NO, NO

  22. Waste incineration, oil / coal combustion • Release Heavy metals into the atmosphere: (mercury (Hg), arsenic (As), lead (Pb)) toxic Lead replaces other metals in enzymes but not functionally, in humans in particular enzymes involved in hemeproduction -> anemia

  23. Ozone layer • Ozone = O3; Chemical filter, absorbs UV… … when created: … when destroyed: Where: In Stratosphere O2 O3

  24. CFCs destroy the Ozone layer CFCs = Chlorofluorocarbons Look for: • Used in: • insulation foam • refrigeration and air • conditioning systems • in aerosols

  25. How do CFCs act: 1 1. Release chlorine atoms 2. chlorine atoms destroy ozone 2 3. ClO catches oxygen atom and reproduces chlorine atom. 3

  26. In 1987 … • Montréal Protocol to gradually phase out use of CFCs until 2010. • Prediction: Ozone layer will recover by the middle of this century (2050).

  27. Smog Thick mixture of fog (water vapor), smoke (particles) and atmospheric pollutants atmospheric pollutants: ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2) can cause asthma. forms when high pressure system prevents gases from rising ozone very reactive molecule harmful to our health when it enters our lungs

  28. Note taking page 124 • Homework: • P. 110 all • P. 126 # 4 • P. 104 # 3, 4 http://www.youtube.com/watch?v=kdDSRRCKMiI

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