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ICSE Class 9 Answered

Explain the threats posed by the following to marine and aquatic life:     Sewage   Industrial wastes   Surface run off water   Transportation accidents   Hazardous wastes      
Asked by Topperlearning User | 08 Jan, 2015, 07:58: AM
answered-by-expert Expert Answer
  1. Sewage: Sewage is waste water which is drained out of industries, kitchens and toilets. If sewage is not treated, it may result in the uncontrolled growth of algae over large parts of the oceans. It results in the depletion of oxygen from water endangering and killing various forms of marine life.

     

  2. Industrial wastes: Industrial wastes usually consist of chemicals that are discharged into drains and rivers. Some chemicals are highly poisonous like polychlorinated biphenyls. These have been now banned in many countries. The discharge of heavy metals like Cadmium, Lead and Mercury into rivers, lakes and oceans affect the marine life.

     

  3. Surface run off water: Surface run off water mainly from agricultural fields consists of dangerous pesticides, insecticides and fertilisers. Many pesticides do not degrade and remain in water for a long period of time. Thus they enter into the food chain through aquatic plants and animals.

     

  4. Transportation accidents: Spilling of oil from oil tanks in the ocean and accidents occurring due to off shore drilling affect marine life.

     

  5. Hazardous wastes: Radioactive and nuclear wastes are extremely hazardous to aquatic and marine life.
Answered by | 08 Jan, 2015, 09:58: AM
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