Earth Science: Economy and Ecology – Accidents
Many chemicals have dark sides. Both smog and polluted waters are among the numerous side effects of chemical production, especially in countries that do not have stringent environmental regulations.
Even the staunchest believers in the benefits of applied chemistry are willing to admit that when it comes to chemical plants, safety is not guaranteed. It is widely accepted that as global conditions continue to change, humankind’s reliance on these techniques will only increase, making Earth’s situation even more precarious.
Chemical plants sometimes catch fire or explode, and still more accidents have occurred while transporting chemicals. The most serious incident to date occurred in 1984, when 40 tons of methyl isocyanate leaked from a tank of gas in the Indian city of Bhopal.
The resulting chemical cloud killed at least 2,000 people, injured more than 100,000, and exposed over 500,000 to harmful gases.
Side effects
Chemical production brings with it negative and long-term consequences. In Asia and South America, regulations (such as those concerning the desulfurization of gaseous waste) are less stringent than those in Europe and North America. But when weather conditions keep gaseous waste-caused by industrial production and emitted from vehicles—from escaping into the higher atmosphere, smog forms. “Summer smog” is formed by emissions from solvents that release volatile compounds.
Solar radiation causes these compounds to react with the nitric oxide in vehicle exhaust, forming ozone and other pollutants that affect breathing, irritate mucous mem- branes, and lead to circulatory disorders.
Long-term consequences
If environmental pollution is not detected in time, the effects may not be known until years after the damage has already been done, making countermeasures remedial instead of preventative.
Such environmental problems include the CFC (chlorofluorocarbon)-produced hole in the ozone layer, damage done to forests by acid rain, and global pollution of the environment by DDT (dichloro-diphenyl-trichloroethane).
Poisonous dioxins
Dioxins are produced by such things as garbage incineration, paper manufacturing, forest fires, and diesel engines. They quickly spread in the environment where they can be found in small quantities in foods and humans.
As extremely toxic substances, dioxins can increase the likelihood of cancer. In 1976, a cloud released from a chemical factory near the Italian town of Seveso killed many animals and caused chloracne in about 200 people. Dioxins comprise about 210 compounds of a similar chemical structure with varying toxicity.
DDT (DICHLORO-DIPHENYL-TRICHLOROETHANE)
This insecticide proved to be an effective tool against mosquitoes and malaria, which was significantly reduced in the middle of the 20th century. It was realized only later that DDT, sprayed in vast quantities by farmers, wound up heavily concentrated in the food chain.
This caused an array of health issues, such as cancers and asthma, as well as child development problems. It also affected wildlife by thinning the eggshells of birds. DDT was gradually prohibited in all industrial countries