Environmental Studies · General Awareness

Water Quality and Pollution

1,263 Questions

Water Quality and Pollution examines the sources, mechanisms, and impacts of contaminants in aquatic ecosystems. It covers crucial environmental concepts like eutrophication, biochemical oxygen demand, and thermal pollution. This subject frequently appears in general science and environmental studies sections of various examinations.

Eutrophication CausesThermal Pollution EffectsBiochemical Oxygen DemandSynthetic Fertilizer ImpactsWastewater SourcesAquatic Ecosystem Toxicity

Water Quality and Pollution Questions

Multiple choice

The rate of sedimentation is increased by adding ____ to the water.

  1. Salt

  2. Sugar

  3. Alum

  4. Soap
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Explanation: Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration or electromagnetism.

Multiple choice

Which of the following statements is not true?

  1. Aquatic animals can breathe inside the water.

  2. Earthworms cannot breathe inside the soil.

  3. Flour mills can be run by moving air.

  4. Plants cannot live without oxygen for long time.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Earthworms can breathe inside the soil. They come outside only when the water takes the place of air in the soil.

Multiple choice

Water pollution is caused by

  1. Excess drawing of water from water bodies

  2. Addition of untreated sewage in water bodies

  3. Plant growing near water bodies

  4. Aquatic animals living in water
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

fact

Multiple choice

From the time the city administration enforced stringent water contamination guidelines on the local industry; the number of aquatic species seen in the local water bodies has increased dramatically. Similar water contamination guidelines should be imposed in other parts of the country. Each of the following is an assumption made in the argument above EXCEPT

  1. In most parts of the country, water contamination problems are caused almost entirely by the local industry.

  2. Enforcing water contamination guidelines on industry left a significant impact on the quality of water in the local water bodies.

  3. The water contamination problems of the other parts of the country are basically similar to those ones suffered by the city.

  4. An increase in the number of aquatic species seen in the local water bodies is desirable.

  5. The increased number of aquatic species seen in the local water bodies reflects an actual increase in the number of aquatic species in the area.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We know that water contamination guidelines on the local industry in the city have helped increase the number of aquatic species. It means that the local industry then causes a significant amount of water contamination, so the guidelines may have helped to reduce water contamination. Still, the local industry does not need to be 'entirely' responsible for the water contamination in order for the guidelines to help. Perhaps the local industry only caused 30% of the contamination, but the guidelines cut local industry contamination to zero; that would still have a significant impact on the quality of water. Hence option (1) is correct.

Multiple choice

Book gills are associated with

  1. excretion

  2. respiration

  3. nutrition

  4. digestion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Book gills are respiratory organs in limulus or king crab.

Multiple choice

To control marine pollution in Chilka Lake, India, the state government had decided 30 years ago to regularly release a certain chemical Vianzone into Gahirmatha where the turtles abound. The marine pollution was controlled considerably ever since the release of the chemical was begun, but the Olive Ridley turtle inhabiting the lake has started reproducing excessively. So much so that now the population of turtles has crossed the manageable mark and it has resulted in overcrowding. Scientists hypothesize that marine pollution must have been responsible for the lack of enough reproductive capacity among the turtles and the chemical must have been responsible for the increased fertility.

Which of the following, if true, would lend the most support to the scientists' theory?

  1. The Olive Ridley turtles in other marine locations reproduce at the same rates as they did before.

  2. The Olive Ridley turtle has experienced an exponential rise in its population in the past 30 years.

  3. The Olive Ridley turtle is not native to the area and in fact, it was introduced here only 100 years ago.

  4. The presence of a major marine pollutant called D-Methyl Acromane, earlier at 20 parts per million, has declined to 8 parts per million in Gahirmatha after the introduction of Vianzone.

  5. The Olive Ridley turtles in other, polluted marine locations in the state still reproduce at the same rate as they did in Gahirmatha before the release of the chemical Vianzone.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

As turtles are still reproducing at the old rate in other polluted marine locations, it follows that Vianzone has facilitated their increased reproduction.

Multiple choice

Angler: Fish such as suckers, shiners, and chubs are neither fun to catch nor good to eat. They should be eliminated from mountain pound to make way for trout.
Fish and Game Commissioner: The state's policy is to preserve any aquatic ecosystems that are indigenous to a given area. Interfering with fish population in these ponds would violate this policy.

Which of the following, if true, would cast most doubt on the Fish and Game Commissioner's position that the angler's proposal is a violation of state policy?

  1. The suckers, shiners, and chubs in mountain ponds are descendants of fish brought to those ponds by anglers for use as bait in catching the once abundant trout.

  2. The state's policy of preserving natural aquatic ecosystems favors the interest and hobbies of one group of people over those of other groups.

  3. Suckers, shiners and chubs are dull, unattractive fish with none of the graceful beauty of trout.

  4. People who fish in mountain ponds have an appreciation of nature than do people who never visit such areas.

  5. In the past there have been many exceptions to the state policy.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 Only choice (1) points out that trouts constituted the original indigenous ecosystem.

Multiple choice

A biogas plant works to its maximum capacity when

  1. Conditions are aerobic and temperature 40 deg C

  2. Conditions are anaerobic and temperature 40 deg C

  3. Conditions are aerobic and sewage is supplied

  4. Conditions are anaerobic and sewage is supplies
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Biogas production is an anaerobic process that is most efficient at thermophilic temperatures, typically around 40 degrees Celsius.