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Which one of the following is not a bioindicator of water pollution?

  • Sludge-worms

  • Blood-worms

  • Stone files

  • Stone files


C.

Stone files

Stoneflies (e.g., Perla sp.) belong to order Plecoptera of class insecta which has the terrestrial mandibulates.

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Limit of BOD prescribed by Central Pollution Control Board for the discharge of industrial and municipal waste water into natural surface water, is:

  • < 3.0 ppm

  • < 10 ppm

  • < 100 ppm

  • < 100 ppm


B.

< 10 ppm

The central pollution control board prescribed the BOD limit for the discharge of industrial and municipal waste water as < 10 ppm.

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Photochemical smog pollution does not contain

  • ozone

  • nitrogen dioxide

  • carbon dioxide

  • carbon dioxide


C.

carbon dioxide

Photochemical smog is highly oxidising polluted atmosphere comprising largely of ozone (O3), oxides of nitrogen (NOx), hydrogen peroxide (H2O2), organic peroxides, peroxy acetyl nitrate (PAN) and peroxy benzyl nitrate (PBzN).
Some sulphates and nitrates can also be formed in photochemical smog due to oxidation of sulphur containing components (SO2,  H2S) and NOx (N2O5, NO2) but it does not contain carbon di-oxide (CO2). Photochemical smog materials and causes damage to plants, human health hazards and corrosion problems.

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Which one of the following statements is not valid for aerosols?

  • They are harmful to human health

  • They alter rainfall and monsoon patterns

  • They cause increased agricultural productivity

  • They cause increased agricultural productivity


C.

They cause increased agricultural productivity

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Montreal Protocol which calls for appropriate action to protect the ozone layer from human activities was passed in the year

  • 1986

  • 1987

  • 1988

  • 1988


B.

1987

In 1987, twenty seven industrialized countries signed the Montreal Protocol for reduction in production and release of ozone layer depleting CFCs(Chloro fluoro carbons) into the atmosphere. It was followed by increasingly stringent amendments in London in 1990 and in Copenhagen in 1992.

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