Water Pollution and Its Control Questions and Answers

Answer: C

The emergency was declared in the northern coastal area.

The spill came from Petroperu's Talara refinery in the Piura region on Peru's northern Pacific coast, where crude oil spilled into the Pacific, leading the government to declare an environmental emergency for that stretch of coast.

Peru's coast runs north to south along the Pacific, so 'western' and 'eastern' do not describe a part of it, and the spill was not in the south.

Answer: C

The correct set is 2016 - National Ganga River Basin Authority (NGRBA) - Union Minister of Jal Shakti.

The National Council for Rejuvenation, Protection and Management of River Ganga (National Ganga Council) was set up by an order of October 2016, replacing the National Ganga River Basin Authority of 2009. The order also created an Empowered Task Force on the river, chaired by the Union Minister of Water Resources, now the Minister of Jal Shakti.

The other options give wrong years or names: the NGRBA was an authority, not an Act, set up in 2009; and the bodies named in the 2013 and 2018 options did not precede the Council.

Answer: A

Only statement A is correct, so the answer is A is correct.

The Central Ganga Authority was set up in February 1985 to oversee the Ganga Action Plan, launched in 1986 to restore the river's water quality by intercepting and treating sewage.

Statement B is wrong: the Authority was chaired by the Prime Minister, not the President. The President has no executive role in chairing such bodies. The Authority was later reconstituted as the National River Conservation Authority, and today the National Ganga Council is also headed by the Prime Minister. So 'B is correct' and 'both correct' are wrong, and 'both incorrect' ignores the true statement A.

Answer: A

High BOD indicates the presence of organic matter and polluted water.

Biological Oxygen Demand is the amount of dissolved oxygen used by micro-organisms to decompose the organic matter in water. The more biodegradable organic waste, such as sewage, the more oxygen they consume, so a high BOD means heavy organic pollution.

Clean water and rainwater have low BOD. Insoluble substances that are not biodegradable do not raise BOD.

Answer: A

The water-borne disease is cholera.

Cholera is caused by the bacterium Vibrio cholerae and spreads chiefly through drinking water or food contaminated with faeces, causing acute watery diarrhoea.

Fluorosis is caused by excess fluoride in water, a chemical cause rather than a water-borne pathogen. Influenza and tuberculosis are air-borne, spread by droplets from coughing and sneezing.

Answer: B

Minamata disease was caused by salt of mercury.

From the 1950s, a chemical factory at Minamata in Japan discharged mercury compounds into the bay, where they were converted into methylmercury. This accumulated in fish and shellfish and, through the food chain, poisoned the people who ate them, damaging the nervous system.

Cadmium caused Itai-itai disease in Japan, and arsenic, copper and iron salts are not linked to Minamata.

Answer: B

Blue baby syndrome is caused by excess nitrates.

Nitrate in drinking water, often from fertilisers and sewage, is converted to nitrite in an infant's gut. Nitrite oxidises haemoglobin to methaemoglobin, which cannot carry oxygen, so the baby's skin turns bluish. Infants below six months are most at risk.

Arsenic in groundwater causes arsenicosis and skin lesions, fluoride causes fluorosis, and copper causes gastrointestinal and liver problems, not methaemoglobinaemia.

Answer: D

Blue baby syndrome is caused by excess of nitrates in drinking water.

In infants, nitrate is converted to nitrite, which oxidises the iron of haemoglobin to form methaemoglobin. Methaemoglobin cannot carry oxygen, so the baby's skin turns bluish (methaemoglobinaemia). The usual source is groundwater polluted by fertilisers and sewage.

Excess arsenic causes skin lesions and cancers, iron deficiency causes anaemia, and atmospheric methane is a greenhouse gas with no link to the syndrome.

Answer: B

Itai-itai disease is caused by cadmium.

The disease appeared in the Jinzu river basin of Toyama, Japan, where mining waste contaminated rice fields with cadmium. Chronic cadmium poisoning damaged the kidneys and softened the bones, causing severe pain, the 'itai-itai' (ouch-ouch) of the name.

Mercury caused Minamata disease, arsenic causes arsenicosis, and nitrate causes blue baby syndrome.

Answer: C

Minamata disease first occurred in Japan.

It was identified in 1956 in the town of Minamata on Kyushu, where the Chisso chemical factory discharged methylmercury into Minamata Bay. The mercury accumulated in fish and shellfish, and people who ate them suffered severe nerve damage: numbness, loss of coordination, impaired speech and vision, and in many cases death. The disaster gave its name to the Minamata Convention on Mercury (2013).

Mexico, Morocco and India have had their own pollution problems, but Minamata disease is specifically the methylmercury poisoning first recorded in Japan.