Q. Which of the following are the reasons/factors for exposure to benzene pollution?

1. Automobile exhaust
2. Tobacco smoke
3. Wood burning
4. Using varnished wooden furniture
5. Using products made of polyurethane

Select the correct answer using the code given below:

• 1, 2 and 3 only
• 2 and 4 only
• 1, 3 and 4 only
• 1, 2, 3, 4 and 5

Correct Answer: (a) 1, 2 and 3 only

Notes:

• Benzene
  • Benzene is an aromatic compound with a single six-member unsaturated carbon ring.
  • It is a chemical that is a colourless or light yellow liquid at room temperature.
  • It dissolves only slightly in water and will float on top of the water.
  • It is highly flammable.
  • It is formed from both natural processes and human activities.
  • It is found in crude oils and as a by-product of oil-refining processes.
  • It is a known human carcinogen and is linked to an increased risk of developing lymphatic and hematopoietic cancers, acute myelogenous leukaemia, as well as chronic lymphocytic leukaemia. (NCI05)
• Uses
  • It is used in very large quantities to make other chemicals that are used to make plastics, resins, nylon, and synthetic fibres.
  • It is used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides.
  • It is also used in paints, glues, and furniture wax.
• Exposure
  • Benzene is degraded rapidly in the upper atmosphere.
  • Because of its solubility in water, a minor amount may be removed by rain to contaminate surface waters and soil.
• Chronic exposure to benzene can reduce the production of both red and white blood cells from bone marrow in humans, resulting in aplastic anaemia.
• Benzene is a by-product of the combustion of tobacco in cigarettes.
• Benzene is also found in wood smoke and automobile exhaust.