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