Saturday, May 19, 2007

Land Pollution: Cntd

Land pollution is the degradation of the Earth's land surface through misuse of the soil by poor agricultural practices, mineral exploitation, industrial waste dumping, and indiscriminate disposal of urban wastes. It includes visible waste and litter as well as pollution of the soil itself.

Abandoned or neglected waste disposal sites are a particularly difficult and expensive problem for society. Sometimes, hazardous waste is disposed of illegally and in an even more dangerous manner because the owner cannot find a cheap way to get rid of it. If chemical waste materials are deposited in an unsafe area, they could be hazardous as the chemicals might harm the people living near them. Because of their toxicity, flammability, explosive potential, radiation or other dangerous properties, there is a possibility that living organisms nearby, especially humans, will suffer health problems, especially cancer.
The following measures can be used to control land pollution:
  • anti-litter campaigns can educate people against littering;
  • organic waste can be dumped in places far from residential areas;
  • inorganic materials such as metals, glass and plastic, but also paper, can be reclaimed and recycled.

Land Pollution: The Various Kinds

  1. Rubbish or non-decomposable waste: either combusible (such as paper, wood and cloth) or non-combusible (such as metal. glass and ceramic).
  2. Large wastes: demolition and construction debris, trees and dead animals.
  3. Sewage treatment solids: material retained on sewage treatment screens, settled solids and biomass sludge.
  4. Industrial wastes: such materials such as chemicals, paint and sand.
  5. Mining wastes: slag heaps and coal refuse piles.
  6. Agricultural wastes: farm animal manure and farm residues.

Global Warming(continued)

Firstly, Global Warming will result in floods, but that is only the beginning. Changes in temperature all over the globe will result in tornadoes, hurricanes and other natural disasters to occur because of the sudden change in direction of the wind currents. A movie has already been made depicting this, The Day After Tomorrow, and its contents are not exaggerated. Ice Age 2 will begin, and major cities like New York will be flooded. The world's economy will be hit. Those not fortunate enough will be drowned or frozen to death. The entire planet will be covered with a blanket of ice and no one knows when the new ice age will stop.

Global Warming: A Worrying Factor

Global Warming is an enhanced stage of the greenhouse effect, which is actually a natural process to keep the Earth warm. Greenhouse gases consist of carbon dioxide, CFCs, nitrous oxide and methane. These gases trap heat in the Earth's atmosphere to keep the planet at a suitable temperature for life.
However, human activities, especially industrial ones, have released more greenhouse gases into the atmosphere. For example, factories release massive amounts of CFCs and greenhouse gases into the air. Agricultural activities like wet rice farming and the rearing of cattle(cows), release exorbitant amounts of methane into the atmosphere. These extra amounts of greenhouse gases trap much more heat than what is needed for the Earth's temperature.
Do you know that if the Earth's temperature was to rise by 1 degree Celsius, massive floods would occur all over the world, as the increase in temperature will cause the polar caps in the arctic regions to start melting. Not only would the countries hit by floods be affected, arctic animals such as polar bears will be affected as their habitat would be lost.

Tuesday, May 8, 2007

Air Pollution: The Impact On The World

The Connection Between Ozone Depletion and UVB Radiation

Reductions in ozone levels will lead to higher levels of UVB reaching the Earth's surface. The sun's output of UVB does not change; rather, less ozone means less protection, and hence more UVB reaches the Earth. Studies have shown that in the Antarctic, the amount of UVB measured at the surface can double during the annual ozone hole. Another study confirmed the relationship between reduced ozone and increased UVB levels in Canada during the past several years.

Effects on Human Health

Laboratory and epidemiological studies demonstrate that UVB causes nonmelanoma skin cancer and plays a major role in malignant melanoma development. In addition, UVB has been linked to cataracts. All sunlight contains some UVB, even with normal ozone levels. It is always important to limit exposure to the sun. However, ozone depletion will increase the amount of UVB and the risk of health effects.

Effects on Plants

Physiological and developmental processes of plants are affected by UVB radiation, even by the amount of UVB in present-day sunlight. Despite mechanisms to reduce or repair these effects and a limited ability to adapt to increased levels of UVB, plant growth can be directly affected by UVB radiation.

Indirect changes caused by UVB (such as changes in plant form, how nutrients are distributed within the plant, timing of developmental phases and secondary metabolism) may be equally, or sometimes more, important than damaging effects of UVB. These changes can have important implications for plant competitive balance, herbivory, plant diseases, and biogeochemical cycles.

Effects on Marine Ecosystems

Phytoplankton form the foundation of aquatic food webs. Phytoplankton productivity is limited to the euphotic zone, the upper layer of the water column in which there is sufficient sunlight to support net productivity. The position of the organisms in the euphotic zone is influenced by the action of wind and waves. In addition, many phytoplankton are capable of active movements that enhance their productivity and, therefore, their survival. Exposure to solar UVB radiation has been shown to affect both orientation mechanisms and motility in phytoplankton, resulting in reduced survival rates for these organisms. Scientists have demonstrated a direct reduction in phytoplankton production due to ozone depletion-related increases in UVB. One study has indicated a 6-12% reduction in the marginal ice zone.

Solar UVB radiation has been found to cause damage to early developmental stages of fish, shrimp, crab, amphibians and other animals. The most severe effects are decreased reproductive capacity and impaired larval development. Even at current levels, solar UVB radiation is a limiting factor, and small increases in UVB exposure could result in significant reduction in the size of the population of animals that eat these smaller creatures.

Effects on Biogeochemical Cycles

Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles, thus altering both sources and sinks of greenhouse and chemically-important trace gases e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS) and possibly other gases, including ozone. These potential changes would contribute to biosphere-atmosphere feedbacks that attenuate or reinforce the atmospheric buildup of these gases.

Effects on Materials

Synthetic polymers, naturally occurring biopolymers, as well as some other materials of commercial interest are adversely affected by solar UV radiation. Today's materials are somewhat protected from UVB by special additives. Therefore, any increase in solar UVB levels will therefore accelerate their breakdown, limiting the length of time for which they are useful outdoors.

Water Pollution: A Major Threat

Over two thirds of Earth's surface is covered by water; less than a third is taken up by land. As Earth's population continues to grow, people are putting ever-increasing pressure on the planet's water resources. In a sense, our oceans, rivers, and other inland waters are being "squeezed" by human activities—not so they take up less room, but so their quality is reduced. Poorer water quality means water pollution.

We know that pollution is a human problem because it is a relatively recent development in the planet's history: before the 19th century Industrial Revolution, people lived more in harmony with their immediate environment. As the world is developing at a accelerated rate, so does the pollution rate. More and more polluting of water bodies are occuring. When Earth's population was much smaller, no one believed pollution would ever present a serious problem. It was once believed that the oceans were far too big to pollute. Today, with over 8 billion people on the planet, it has become apparent that there are limits. Pollution is one of the signs that humans have exceeded those limits.

Sad to say, pollution is caused by humans literally. Other than the occasional volcanic eruptions that makes water unclean and forest fires that dirty water, pollution is what we have "achieved" single-handedly. I still vividly remember when my teacher told me about the exxon valdez oil spill. What a terrible incident it was! More than 50 million litres of oil spilled into the sea which spread over a distance of 900km. But, one more of the more major problems are the ways we dispose our waste.

Thursday, May 3, 2007

Pollution: A Global Issue

If anyone has noticed, in the recent newspapers, The Strait Times, has mentioned about forest fires and smog created in Indonesia by forest fires. Fortunately for us, the winds aren't blowing in our direction or we will be facing a haze crisis like last year.
In this post, we will be talking about forest fires and how they cause a pollution in the environment.

Most forest fires are generally caused by the dry climate, high temperature and low rainfall. This causes all the plants and trees in the forest to become very dry. Once the plants are dry, they are able to ignite at a single spark. Once the temperature rises, the heat is too much for the plants in the forests and they catch fire. Unfortunately, the plants are tightly packed together, letting the fire spread rapidly and within hours, a few kilometers square of forest are aflame. This is why forest fires are so hard to contain, and fire-fighting efforts to quench them may take up to days.
Once the trees and bushes are burnt, large amounts of carbon dioxide are released into the air. Carbon dioxide is a greenhouse gas, which traps heat. Plants help to maintain the level of carbon dioxide during photosynthesis. However, once the forests are razed down, the carbon dioxide level rises drastically. Massive amounts of heat are trapped and this enhances the greenhouse effect, leading to global warming. Breathing in too much carbon dioxide is unhealthy too. Once the Earth's temperature rises, the polar caps will melt and low-lying areas will experience floods. Dry climates will become drier and will cause droughts. Pests who breed in hotter climates will thrive. This will cause a spread of diseases like malaria and dengue fever.