Soil Pollution Questions and Answers

Answer: A

The sources are (i) and (ii), so the answer is Only (i) and (ii).

Selenium contamination comes from industrial sources such as coal combustion and fly ash, mining and metal processing, and from agricultural practices such as the use of phosphate fertilisers and irrigation that mobilises selenium from seleniferous soils, as seen in parts of Punjab.

Groundwater, in the key's reading, is the medium that carries selenium into crops and drinking water rather than a source of it; the selenium in it comes from the rocks, soils and human activities above. That rules out the options naming groundwater, alone or with other items.

Answer: B

The element is Cadmium (Cd).

Itai-itai disease (Japanese for 'ouch ouch') broke out in the Jinzu river basin of Toyama, Japan, where mining waste carrying cadmium contaminated paddy fields. Cadmium occurs in nature with zinc ores, behaves chemically like zinc and is taken up by rice plants along with it. In people it damages the kidneys and softens the bones, causing severe bone pain and fractures, which gave the disease its name.

Mercury poisoning is Minamata disease, not itai-itai. Tin is of low toxicity in its inorganic forms, and chromium (especially hexavalent chromium) is known for skin ulcers and cancer risk, not for this bone disease.

Answer: A

Oilzapper is an eco-friendly technology for the remediation of oily sludge and oil spills.

It was developed by The Energy and Resources Institute (TERI) together with Indian Oil Corporation. It is a consortium of oil-eating bacteria, grown and supplied on a carrier, that break the hydrocarbons in oily sludge and spilled crude down into harmless carbon dioxide and water. It has been used at refineries and at oil spill sites to clean contaminated soil.

It is a bioremediation agent, so it is neither an exploration technology nor a crop variety, and it has nothing to do with putting out fires at oil wells.