Pollution and Degradation
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Transcript of 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.
• Fertilizers and pesticides threaten Biodiversity and kill microorganisms that help maintain soil balance.
• Use of heavy machines: compacting of soil, less oxygen available for
microorganismsRain water does not sink it but runs off the surface
carrying away soil and nutrients water erosion
Reduce soil fertility
Soil depletion is the loss of soil fertility
Contamination is the abnormal presence of a harmful substance in the environment
Hydrocarbons from oil spills and and leaky gas station tanks
Heavy metals from leaky land fills and industrial pollution
Acidic waste from mining
Contamination from the atmosphereSulfur dioxide (SO2) and Nitrogen oxides (NOx) from combustion of fossil fuels and other industry
carried by wind
Gases dissolve in rain Acid rain
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)
Impact of acid rain depends on soilA soil’s BUFFERING CAPACITY is its ability to resist changes in pH when acidic or alkaline products are added.
Sandy soil has a low buffering capacity
Silt and clay soils have a higher buffering capacity
Soils with low buffering capacity more vulnerable to effects of acid rain
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)
• Point sources– Pollution can be traced to well defined site.
• Non point sources– Difficult to locate exact origin of pollution
Pollution and Contamination of water
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
• Heat:Solubility of Oxygen
decreases with in-creasing temperature
Bad for animals and microorganisms.
Pollution and Contamination of water
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
EUTROPHICATION
Process by which natural waters lose their oxygen because of an excessive accumulation of of organic matter and nutrients
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.
sediment
sediment
Time: Decades
Fertilizers form agriculture (particularly Phosphorus) and warming of water promote rapid growth of algae:
High production of organic material
Bacteria decomposing organic matter consume a lot of oxygen warm water less oxygen than cold water
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?
pond
creek
Contamination of oceans with OIL
Through:• Pumping of oil from under the oceanSome leaks• Oil tankers clean out on open sea• accidents
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
• Notes on contamination of hydrosphere
Clip herbicides and frogs
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
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
Ozone layer• Ozone = O3; Chemical filter, absorbs UV…
… when created: … when destroyed:
Where: In StratosphereO2
O3
CFCs destroy the Ozone layerCFCs = Chlorofluorocarbons
Used in:• insulation foam• refrigeration and air conditioning systems• in aerosols
Look for:
How do CFCs act:1
1. Release chlorine atoms
2. chlorine atoms destroy ozone
23. ClO catches oxygen atom and reproduces chlorine atom. 3
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).
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
• Note taking page 124• Homework: – P. 110 all– P. 126 # 4– P. 104 # 3, 4
http://www.youtube.com/watch?v=kdDSRRCKMiI