- POLLUTION:
Pollution occurs when harmful materials occur in unwanted places or in harmful amounts.
"Harmful" often means hazardous to health and safety, but it can also mean unpleasant or bothersome.
Pollution is often a problem of quantities, so people who monitor pollution need to measure quantities or concentrations.
If one person defecates in the woods, their feces will be broken down naturally and harmlessly in a matter of days, but the
accumulated toilet wastes of a whole town or city creates a big health problem.
Below are some examples of types of pollution problems and proposed solutions to them.
Sewage and wastewater treatment:
Small amounts of toilet wastes are Biodegradable, meaning that natural processes (including the action of bacteria, fungi, and other decomposers)
will break down the harmful substances
into harmless ones within a reasonable time.
The same is generally true of dinner wastes and the wastes from most types of food processing.
Larger quantities of sewage and animal wastes can accumulate faster than they ban be biodegraded naturally.
One solution is to enhance the natural biodegradation with supplementary cultures of the
bacteria that carry out the biodegradation,
or to adjust the conditions (acidity, temperature, or oxygen levels) to promote the most effective biological degradation.
This often happens in well-run
waste treatment plants, but plants that are not so efficient may let undegraded wastes
overflow into natural waterways and overwhelm many natural ecosystems.
Some sewage and wastewater is simply spread on fields and allowed to decompose; some is even used as fertilizer if it is disinfected first.
This method has its limits, however, and new fields must
continually be found if the existing ones fill up.
Agricultural pollution:
Runoff from agricultural fertilizers often causes Algal blooms that rapidly deplete ponds and rivers of oxygen, killing off many fishes whose
dead bodies then compound the problem until the
water turns to a "dead zone" when all the oxygen is used up.
Insecticides and other pesticides are often poisonous to nontarget species, including beneficial insects (such as pollinators), pets, and
even the people using these chemicals. Runoff from long-lasting
pesticides can also poison local waterways and oceans.
Acid Rain:
In the Northeastern United States and in Northern Europe, acid rain is mostly caused by sulfur oxides, which produce sulfuric acid.
Sulfur occurs in many mineral ores (especially those of copper, nickel, and heavy metals such as lead). When these metals are extracted
from their ores, sulfur dioxide (SO2) is released to the atmosphere.
Sulfur also occurs as an impurity in coal,
and sulfur dioxide is released whenever the coal is burned, especially in coal-fired power
plants using soft (bituminous) coal.
Sulfur dioxide combines with oxygen in the air to produce sulfur trioxide (SO3). The sulfur trioxide
immediately dissolves in rainwater to make
sulfuric acid (H2SO4). When this form of acid rain falls
in areas where most of the rocks are granite-like in composition, the rocks fail to
neutralize the acid rain and the ponds and lakes become acidified.
Acidified water (low in pH) kills most fishes, which then decay, and the decay
process kills even more species by making the water anoxic (low in oxygen).
The damage is usually done hundreds of miles downwind from the source
of the pollution, making environmental legislation difficult. For example,
most of the acid rain pollution in upstate New York and New England
originates from coal-fired power plants in Illinois and Indiana over which the legislatures
in New York and New England have no control.
Similarly, most of the acid rain pollution in Sweden and neighboring countries originates from coal-burning
industries in Poland and further south.
In the Western United States, most of the acid rain pollution is caused by nitric oxides, which produce nitric acid (HNO3).
Both nitric oxide (NO) and nitrogen dioxide (NO2) occur in automobile exhausts and in the emissions of electric utilities and many industries as well.
These oxides
react with oxygen in the air to produce N2O5, which then dissolves in rainwater to form nitric acid.
Industrial pollution:
Many manufacturing industries create toxic byproducts, and these are often hard to deal with because they are usually not biodegradable.
A few countries, like Sweden, have tried to pass laws mandating that
companies convert these toxic wastes into harmless materials
before releasing them, but enforcement of such laws is problematical even in places where such laws exist.
Pollution also occurs from industrial accidents, including oil spills and leakage from storage tanks.
In a few cases, Bioremediation
(which includes enhancement with bacteria that can biodegrade the spill) can help reduce the problem, but often this is not enough.
Mercury (from thermometers, thermostats, and many electronics) is a special problem that needs to be profesionally handled, and the costs are usually large.
Electronics (and also many household appliances) may contain many toxic substances, some of which can be recovered and sold at a profit,
while others need to be treated as toxic waste.
Some electronics manufacturers have recycling programs for worn-out or broken electronics.
Sweden has laws mandating that manufacturing such products must be willing to take them back and dispose of them properly.
Industrial pollutants may be solid, liquid, or gas. Solids and liquids can sometimes be buried, which often conceals the problem but
does not solve it, and the eventual clean-up is so expensive that it
has caused many companies to go bankrupt.
Liquids are commonly dumped into local waterways, poisoning many species and often resulting in expensive lawsuits and, eventually, in
expensive clean-up.
Many people can be poisoned by living near a toxic dump, most often by increasing rates of cancer; the case of
Erin Brokovitch was made into an award-winning movie.
Gases (and soot) from smokestacks can poison the air surrounding an industrial facility.
Carbon dioxide pollution:
Carbon dioxide (CO2) is a special case because it emitted by nearly every business and home, most cars and trucks, and even by people and animals.
(Thus, nobody can be blamed individually for causing the problem because nearly all of it is everyone else's fault.)
Since the vast majority of carbon dioxide pollution comes from the burning of fossil fuels, alternative means of energy production must be encouraged.
- NIMBY ("Not In My Back Yard"):
Some people respond to pollution by simply asking to move it to a more distant location-- "Please put this garbage dump far away, not next to my house"
This does not really solve the problem, it just relocates it, and other people will complain that they don't want the pollution near their neighborhood.
Sometimes, people with political power can succeed in getting pollution sites moved away from their neighborhoods to the places
where other people, often poor, have little power to oppose the move.
This is sometimes called "environmental racism".
The main problem with NIMBY thinking is that we are running out of places to put harmful or undesirable wastes.
Another problem is that water and sometimes wind will carry the pollution from the waste site to places where it will do new harm,
such as washing into
streams and killing fish, or washing into the oceans and killing many species.
- Reduce, Reuse, Recycle:
Nearly every type of pollution can be dealt with more easily if the quantities are much smaller. Pollution becomes increasingly hard to remediate
when quantities get larger.
Proposed solutions to pollution (and also to energy shortages) often include the Three R's: Reduce, Re-use, Recycle.
Reduce means to use less of materials that will generate pollution.
Re-use means to use things over and over again (or to give them to someone else who will) and to re-purpose things for as long as possible.
Recycle means to find new uses for old, worn-out materials that might otherwise pollute. Some examples:
- Corrugated cardboard (for boxes and other packing material) can be made from recycled materials.
- Many paper products can be made from recycled materials.
- Certain forms of plastics can be recycled into weather-resistant construction materials, used instead of lumber for park benches, picnic tables, or outdoor porches.
- Soda bottles can be ground down, sterilized, and recycled into new plastics of various kinds.
- Aluminum (from soda cans and many household items) can be made into new aluminum products at about one-tenth the cost of making aluminum from the original aluminum ore.
The same is true of copper and several other metals.
- Most iron and steel can be recovered and used to make new iron and steel.
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