Some halogen containing compounds are useful in daily life. Some compounds of this class are responsible for exposure of flora and fauna to more and more of UV light which causes destruction to a great extent. Name the class of these halocompounds. In your opinion, what should be done to minimise harmful effects of these compounds.
These carbon compounds contain multiple halogen groups and have wide application in industry and have wide application in industry. They are commonly known as polyhalogen compounds. The various compounds and their effects on life as follows:
1. Dichloromethane or methylene chloride: This is used as a solvent as paint remover, as a propellant in aerosols, as a process solvent in the manufacture of drugs and also as a metal cleaning and finishing solvent. Dichloromethane has been known to harm the central nervous system. Exposure to low levels of this compound can lead to slightly impaired hearing and vision, while higher levels in air cause dizziness, nausea, tingling and numbness in the fingers and toes. In humans, direct skin contact with methylene chloride causes intense burning and mild redness of the skin. Direct contact with the eyes can burn the cornea.
2. Trichloromethane or chloroform: This is mainly used as a solvent for fats, alkaloids, iodides and others and mainly used in production of a Freon R-22. It used to have applications in medicine as an anaesthetic but lesser toxic versions like ether are used. Chronic exposure to chloroform is fatal as it gets converted to phosgene, causing liver and kidney damage and skin sores.
3. Tetrachloromethane or carbon tetrachloride was widely used in the manufacture of cleaning liquids, chlorofluorocarbons and propellants for aerosols. CCl4 usage has caused depletion of ozone layer, which protects the earth from UV rays, which has led to higher cases of skin cancer and other disorders.
4. p,p’-dichlorodiphenyltrichloroethane or DDT: DDT was widely used as insecticide. They are chlorinated organic insecticides whose usage increased greatly after World War II because they were highly effective against mosquitoes causing malaria and lice carrying typhus. The serious effects of this started with insects gaining resistance to DDT, and a high toxicity towards fish. The chemical stability of DDT and its fat solubility compounded the problem. In the chemical aspect, DDT is not metabolised very rapidly or solubilized effectively by animals. It is deposited and stored in the fatty tissues. If ingestion continues at a steady rate, DDT builds up within the animal over time, damaging the environment.