Page 42 - Curriculum Visions Dynamic Book

Carbon-based chemicals and the environment
Carbon is found in nine-tenths of all the known compounds. In gases, it has also been used in making more synthetic materials than any other element. People are more concerned about
the effects of synthetic materials because it is not always known how they react with people, animals and plants.
People are less concerned about the use of inorganic carbon-based compounds, such as limestone, than they are about organic carbon products, such as oil and coal. For example, the extraction of limestone from a quarry produces a limited environmental impact that can be understood and evaluated easily. The extraction of organic carbon-based chemicals produces much more complex problems. For example, some are made from forest products, and this can have grave implications for forest renewal. Many products are burned, adding to the Greenhouse Effect (see page 12). Oil is extracted from the ground and transported
 Burning fossil fuels produces carbon dioxide in the air, adding to the Greenhouse Effect.
Pesticides and herbicides
Some carbon-based dyes and pesticides have been found to be very hazardous to health. The pesticide DDT, for example, was found to be very effective and was used all over the world. Years later, however, it was found to be very harmful to fish and birds and its use is now banned in most parts of the world.
Oil
The main area of concern involves oil spills, because the thick layers of oil take time to be oxidised to carbon dioxide gas, or to be digested by organisms in water. Before natural processes can react with the oil, many animals are likely to die from ingesting the oil.
 Clearing up after the Exxon Valdez spill in Prince William Sound, Alaska.
as a liquid, with the accompanying danger of possible oil spills.
Organic products cause concern because
of the way they may interact with people
and other living things. Many are designed
as weedkillers, pesticides and so on, so it is possible that others produced for different purposes could have harmful side effects
on living things. All this causes continuing concern, which is why regulation of the organic chemicals industry is so vital.
42
42