Solution: a)

The Chilika Lake in Odisha has emerged as the “single largest habitat of Irrawaddy dolphins in the world” with the spotting of 155 such animals. Chilika is Asia’s largest brackish-water lagoon with an estuarine character, and one of India’s first Ramsar Convention sites.

Solution: b)

• Bioremediation is the use of living microorganisms to degrade the environmental contaminants into less toxic forms.
• Bioremediation can be effective only where environmental conditions permit microbial growth and activity.
• Statement 3:  This will be a standard practice in the industry in coming years. For e.g.  Alcanivorax, a bacteria with oil-eating abilities, can be used to create species that are much more capable of cleaning oil spills.
• Bio-remediation is a slow process, so. Heavy metals such as cadmium and lead are NOT readily absorbed or captured by microorganisms.

Solution: d)

• Photosynthetically Active Radiation (PAR)is the amount of light available for photosynthesis, which is light in the 400 to 700 nanometer wavelength range. PAR changes seasonally and varies depending on the latitude and time of day.
• Levels are greatest during the summer at mid-day.
• Air pollution also affects PAR by filtering out the amount of sunlight that can reach plants.
• Photosynthetically Active Radiation is needed for photosynthesis and plant growth. Higher PAR promotes plant growth.

Solution: a)

• In-situ conservation, the conservation of species in their natural habitats. It includes National parks, wildlife sanctuaries, biosphere reserves and sacred groves (Khasi and Jaintia hills in Meghalaya).
• Ex-situ conservation is the preservation of components of biological diversity outside their natural habitats. It includes Gene banks, Captive breeding of animals and artificial propagation of plants, zoos, aquaria, and botanic gardens.

Solution: d)

Scientists have found widespread uranium contamination in groundwater from aquifers across 16 states in India, much above the WHO provisional standard for the country. The findings published in the journal Environmental Science & Technology Letters are the first to demonstrate the predominant prevalence of uranium in India’s groundwater.

The WHO has set a provisional safe drinking water standard of 30 micrograms of uranium per litre for India, a level that is consistent with US Environmental Protection Agency standards. Despite this, uranium is not yet included in the list of contaminants monitored under the Bureau of Indian Standards’ Drinking Water Specifications.

While the primary source of uranium is geogenic (naturally occurring), anthropogenic (human caused) factors such as groundwater table decline and nitrate pollution may further enhance uranium mobilisation. Using geochemical and uranium isotope data, it suggests factors that may drive high uranium concentrations in groundwater, including uranium content in aquifer rocks, oxidation state, and groundwater chemistry that promotes the formation of soluble uranyl carbonate complexes.

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