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

A city’s sewage was disposed into a water body. It was noticed that the aquatic animals in the body started dying. What effect of sewage led to the death of aquatic life?

  1. Utilisation of oxygen from water body

  2. Utilisation of CO2 from water

  3. Increasing temperature of water body

  4. Increasing metal content in water body
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sewage is an oxygen-consuming material. It decreases the oxygen content of the water body and thus, the amount of oxygen available for aquatic organisms decreases.

Multiple choice

Why is ammonotelism mostly found in aquatic animals?

  1. Because they have liver to detoxify ammonia

  2. Because ammonia is highly soluble in water and a large volume of water is needed to dissolve ammonia

  3. Because ammonia is non-toxic to aquatic animals

  4. Because they are the only producer of ammonia as a result of catabolism of proteins

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ammonia is highly soluble in water and a very large volume of water is needed by the animal to dissolve ammonia. 1 gm of ammonia needs about 300 - 500 ml of water. But this is not a problem for animals living in an aqueous habitat which are generally found to be ammonotelic.

Multiple choice

Biological magnification occurs in environment as a result of water pollution. Which of the following factors may be involved in biological magnification?

  1. Chlorinated hydrocarbons

  2. Oil spills

  3. Sewage water

  4. Chlorofluorocarbons
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chlorinated hydrocarbons are present in pesticides and are involved in biological magnification. These chemicals may be selectively accumulated by organisms to much larger concentrations than that can cause toxicity.

Multiple choice

Which of the following is the effect of siltation in water pollution?

  1. Reduction in primary production

  2. Excessive growth of phytoplanktons

  3. Heavy mortality among fishes

  4. Rapid multiplication of dinoflagellates
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Siltation is the phenomenon by which the gills of fishes are deposited with silt. This causes heavy mortality among fishes.

Multiple choice

Eutrophication of lacks is consequence effect of the accumulation of

  1. Silt load

  2. Sewage

  3. Nitrates and Phosphates

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

Eutrophication occurs when a body of water receives an excess of nutrients, specifically nitrates and phosphates, often from agricultural runoff or detergents. This nutrient overload leads to algal blooms, which deplete oxygen levels and harm aquatic life.

Multiple choice

Despite protests from industry, pollution control board officials have ordered the levels of microorganisms in various water bodies to be measured and that the results be published.

  1. the levels of microorganisms in various water bodies to be measured and that the results be published

  2. that various water bodies should be measured for their levels of microorganisms, with the results being

  3. the measure of levels of microorganisms in various water bodies and the results to be

  4. various water bodies measured for levels of microorganisms, with their results

  5. that the levels of microorganisms in various water bodies be measured and the results
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The subjunctive mood must be used with order or recommendation verbs like order, mandate, recommend, ask and demand. To properly use the subjunctive, the sentence structure is: [subject] [verb] that [next subject] [infinitive form of next verb, without "to"]. The missing 'that' makes options (1), (3) & (4) unsuitable. Option (2) has 'should' a term that becomes redundant with an order or recommendation verb. Hence (5).

Multiple choice

________ gives green color to water.

  1. Melanin

  2. Phytoplankton

  3. Fungi

  4. Amoeba

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phytoplankton are microscopic marine algae that contain chlorophyll, which gives water a green appearance, especially in nutrient-rich areas.

Multiple choice

Acid rain can cause

  1. water to become polluted

  2. fish to die

  3. damage to buildings

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Acid rain is a broad environmental issue that lowers the pH of water bodies, harming aquatic life, and chemically weathers stone and metal structures.

Multiple choice

Which of the following statements is incorrect regarding algal blooms?

  1. The freshwater and ocean blooms have been found to be anthropogenic.

  2. Looms may be observed in freshwater aquariums.

  3. Freshwater algal blooms are the result of deficiency of nutrients.

  4. Bright green blooms are a result of cyanobacteria.

  5. Red tide is a term often used to describe HABs in marine coastal areas.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Freshwater algal blooms are the result of an excess of nutrients, particularly some phosphates. 

Multiple choice

Which of the following gets reduced as a result of 'Eutrophication'?

  1. Dissolved hydrogen

  2. Dissolved nitrates

  3. Dissolved calcium

  4. Dissolved potassium

  5. Dissolved oxygen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the correct option. Eutrophication is the process by which dissolved oxygen in water gets reduced due to excessive growth of algae as a result of extra loading of nutrients in the water body. This is a wrong option as the correct option is dissolved oxygen.

Multiple choice

Which of the following statements is/are false?

a. Micro-organisms decompose the inorganic matter present in the sewage. b. Discharge of untreated sewage into water bodies is a main source of water pollution and many diseases. c. During the process of decomposition, the micro-organisms use up the sewage water's oxygen and release poisonous substances like ammonia.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The statement. micro-organisms decompose the inorganic matter present in the sewage, is  false. Micro-organisms decompose the organic matter present in the sewage.