Eutrophication, distrophication or hypertrophication, is when a body of water becomes overly enriched with minerals and nutrients which induce excessive growth of algae. This process may result in oxygen depletion of the water body. Answer : (b)

The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without this atmosphere. Radiatively active gases in a planet's atmosphere radiate energy in all directions. Answer : (c)

Phosphorus pollution is caused by excessive use of fertilizers and manure, particularly when compounded by soil erosion. Phosphorus is also discharged by municipal sewage treatment plants and some industries. Answer : (d)

Answer : (b)

Presently, CSIR-NEERI is functioning with Headquarters at Nagpur and five Zonal Laboratories located at Mumbai, Kolkata, Delhi, Chennai and Hyderabad. Answer : (b)

Carbon dioxide contributes 60% to global warming Methane contributes 20% to global warming CFC contibutes 14% to global warming N2O contibutes 6% to global warming. Answer : (c)

Gases such as carbon dioxide, carbon monoxide, methane and sulfur dioxide are normal constituents of the clean air. However, they often reach much higher concentrations to make the air polluted and harmful to the environment and human life. Answer : (c)

a mutagen is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer, mutagens are therefore also likely to be carcinogens. In the above options, hydrocarbons are carcinogenic hence mutagenic pollutant. Answer : (c)

The CSIR-National Environmental Engineering Research Institute (CSIR-NEERI) is a research institute created and funded by Government of India. It was established in Nagpur in 1958 with focus on water supply, sewage disposal, communicable diseases and to some extent on industrial pollution and occupational diseases found common in post-independent India. NEERI is a pioneer laboratory in the field of environmental science and engineering and part of Council of Scientific and Industrial Research (CSIR). Answer : (a)

The concentration of DDT increases at successive trophic levels; say if it starts at 0.003 ppb (ppb = parts per billion) in water, it can ultimately reach 25 ppm (ppm = parts per million) in fish-eating birds, through biomagnification Answer : (c)

Atmospheric aerosols can alter the direct and diffuse components of global solar radiation, which further influences terrestrial gross primary productivity (GPP) via photosynthesis. Answer : (d)

Eutrophic lake will be rich in nutrient and organic matter. Dissolved oxygen in water will be consumed by microbes for decomposing this organic matter and hence higher will be biochemical oxyhen demand. Answer : (c)

Carbon monoxide(CO) has 200 times affinity to haemoglobin than oxygen. Thus CO combines with haemoglobin to form stable complex called carboxyhaemoglobin which reduced oxygen carrying capacity og haemoglobin. Answer : (b)

Eutrophication is the natural aging of a lake by nutrient enrichment of its water. Accelerated eutrophication due to contaminant like phosphates.The prime contaminants are nitrates and phosphates, which act as plant nutrients. They overstimulate the growth of algae, causing unsightly scum and unpleasant odours, and robbing the water of dissolved oxygen vital to other aquatic life. At the same time, other pollutants flowing into a lake may poison whole populations of fish, whose decomposing remains further deplete the water’s dissolved oxygen content. In such fashion, a lake can literally choke to death. Answer : (a)

Chloroflurocarbons (CFCs) also known as freons are ozone depleting substances. Answer : (c)

he Bhopal disaster, also referred to as the Bhopal gas tragedy, was a gas leak incident on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh, India. It is considered among the world's worst industrial disasters. Over 500,000 people were exposed to methyl isocyanate (MIC) gas. The highly toxic substance made its way into and around the small towns located near the plant Answer : (b)

Industries and large number of automobiles are present in big cities. Industries and automobiles uses large amount of fossil fuel and contributes to most of pollution. Answer : (a)

scrubber can remove gases like sulphur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime. Catalytic converters, having expensive metals namely platinum-palladium and rhodium as the catalysts, are fitted into automobiles for reducing emission of poisonous gases electrostatic precipitator remove over 99 per cent particulate matter present in the exhaust from a thermal power plant. Answer : (d)

tai-itai disease was the name given to the mass cadmium poisoning of Toyama Prefecture, Japan, starting around 1912. The term "itai-itai disease" was coined by locals for the severe pains felt in the spine and joints. Answer : (b)

DDT is a persistent organic pollutant that is readily adsorbed to soils and sediments, which can act both as sinks and as long-term sources of exposure affecting organisms. DDT run-off with rain water in water bodies and lead to biomagnification. The concentration of DDT is increased at successive trophic levels; say if it starts at 0.003 ppb (ppb = parts per billion) in water, it can ultimately reach 25 ppm (ppm = parts per million) in fish-eating birds, through biomagnification Answer : (d)

Catalytic converters, having expensive metals namely platinum-palladium and rhodium as the catalysts, are fitted into automobiles for reducing emission of poisonous gases. Motor vehicles equipped with catalytic converter should use unleaded petrol because lead in the petrol inactivates the catalyst. This result in more pollution if leaded petrol is used. Lead emitted from the vehicular exhausts is a harmful pollutant because it persists in the environment as dust for an indefinite time period. Anaemia, weakness, kidney failure, neurological disorders are the symptoms of lead poisoning in humans. Children are more prone to lead poisoning than adults. Answer : (b)

Biomagnification refers to increase in concentration of the toxicant at successive trophic levels Answer : (b)

Secondary treatment or Biological treatment : The primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and air is pumped into it. This allows vigorous growth of useful aerobic microbes into flocs (masses of bacteria associated with fungal filaments to form mesh like structures). While growing, these microbes consume the major part of the organic matter in the effluent. This significantly reduces the BOD (biochemical oxygen demand) of the effluent. Once the BOD of sewage or waste water is reduced significantly, the effluent is then passed into a settling tank where the bacterial ‘flocs’ are allowed to sediment. This sediment is called activated sludge. A small part of the activated sludge is pumped back into the aeration tank to serve as the inoculum. Answer : (b)

Due to depletion of ozone, UV-B radiation reaches the earth's surface. UV-B damages DNA and mutation may occur. It causes aging of skin, damage to skin cells and various types of skin cancers. In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness, cataract, etc. Such exposure may permanently damage the cornea. Answer : (d)

Hay fever is caused by an allergic response to outdoor or indoor allergens, such as pollen, dust mites, or tiny flecks of skin and saliva shed by cats, dogs, and other animals with fur or feathers (pet dander). Answer : (c)

UVB light causes thymine base pairs next to each other in genetic sequences to bond together into pyrimidine dimers, a disruption in the strand, which reproductive enzymes cannot copy. It causes sunburn and it triggers the production of melanin. Other names for the "direct DNA damage" are: thymine dimers. Answer : (a)

Pesticide cannot be metabolized or excreted, it accumulates into fat of the body. Answer : (b)

electrostatic precipitator removes over 99 per cent particulate matter present in the exhaust from a thermal power plant. It has electrode wires that are maintained at several thousand volts, which produce a corona that releases electrons. These electrons attach to dust particles giving them a net negative charge. The collecting plates are grounded and attract the charged dust particles. The velocity of air between the plates must be low enough to allow the dust to fall. Answer : (d)

The main human-generated sources of methane in India are cattle production, wastewater, landfills, rice agriculture, biomass burning, and fossil fuels Answer : (a)

Lead poisoning is a type of metal poisoning caused by lead in the body. The brain is the most sensitive. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, inability to have children, and tingling in the hands and feet. It causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems. Some of the effects are permanent. In severe cases anemia, seizures, coma, or death may occur. Answer : (d)