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

By implementing which of the following factors can the contamination of river water be detected?

a. Presence of coliform bacteria in river water b. Measurement of mineral content in river water c. Measurement of pH of river water

  1. Only a and b

  2. Only a and c

  3. Only b

  4. Only c

  5. Only b and c

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

This is the correct option. The contamination of river water can be found by the presence of coliform bacteria in the river water and by measuring the pH of the river water using universal indicator paper.

 
 

Multiple choice

Why do some ponds appear green when seen from a distance?

  1. Due to excessive growth of plants

  2. Due to excessive contamination by bacteria

  3. Due to excessive contamination by algae

  4. Due to excessive contamination by chemicals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Excessive growth of algae gives a green appearance to ponds. It is caused by excessive quantities of chemicals which act as a source of nutrients.

Multiple choice

Eutrophication leads to death of fish due to

  1. increased O2 content

  2. increased algae content

  3. decreased algae content

  4. decreased O2 content
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Eutrophication is when the environment becomes enriched with nutrients. It causes algal blooms and reduced O2 content in water bodies.

Multiple choice

Which of these statements regarding eutrophication is/are correct?

  1. Primary productivity becomes low.
  2. Eutrophication leads to a state of hypoxia in water bodies.
  3. Availability of oxygen increases.

  1. 1 only

  2. 2 only

  3. 3 only

  4. Both 1 and 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Primary productivity is high in eutrophic water bodies. Due to excessive nutrients, especially nitrogen and phosphorus, these water bodies are able to support an abundance of aquatic plants, thereby leading to a high primary productivity. Because of abundance of aquatic plants and algae, the oxygen availability decreases. When organisms (like aquatic plants and algae) die, they consume the oxygen in the body of water, thereby creating the state of hypoxia.

Multiple choice

Many international cruise ship companies operating in the Baltic Sea dump their sewage straight into the water.

Which of the following refers to the hazardous environmental situation arising from instances as given above?

  1. Hypoxemia

  2. Aquatic hypoxia

  3. Eutrophication

  4. Biodilution

  5. Limnology
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Eutrophication is the increase in addition of nutrients to freshwater or marine systems. It leads to increase in plant and algae growth (biological production) and often to undesirable changes in ecosystem structure and function.

Multiple choice

Which of the following defines 'eutrophication' most appropriately?

  1. Killing of animals due to less availability of edible plants

  2. Excess of carbon-monoxide in water killing plant species

  3. Excess of alkalinity in water killing plants and animals in it

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Eutrophication is the process where water bodies become overly enriched with nutrients (especially nitrogen and phosphorus), leading to excessive algae growth and oxygen depletion. None of the given options A, B, or C correctly describe this process.

Multiple choice

Eutrophic lakes are those

  1. which have rich accumulation of organic matter

  2. which are deep with rocky, steep sides

  3. which have less circulation of nutrients

  4. which are artificially produced
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Eutrophic lakes are characterized by high nutrient content (especially nitrogen and phosphorus), leading to excessive algal and plant growth. This results in rich accumulation of organic matter in the sediments from dead organisms. Option B describes oligotrophic lakes, C describes dystrophic lakes, and D refers to artificial reservoirs rather than natural eutrophic lakes.

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

The correct answer is 'Nitrates and Phosphates'. Eutrophication is the process where water bodies become overly enriched with minerals and nutrients, leading to excessive plant growth. Nitrates and phosphates from agricultural runoff and sewage are the primary nutrients causing this. 'Silt load' causes turbidity, 'sewage' contains nutrients but the question asks what accumulation causes eutrophication (the nutrients themselves), and 'vegetation' is the result not the cause.

Multiple choice

The algae capable of reducing mercury levels in humans is ____________.

  1. Aphanizomenon flos-aquae

  2. Chondrus crispus

  3. Chlorella

  4. Ulva lactuca

  5. Palmaria palmata
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chlorella is very popular in Japan. It is also used as a nutritional supplement with possible effects on metabolic rate. It can reduce mercury levels in humans by chelation of the mercury to the cell wall of the organism.

Multiple choice

Wetlands are useful for human beings because

Directions: Read the passage and answer the question that follows:

Wetlands are indeed the vital link between water and land. It is the collective term for marshes, swamps, and bogs, found along the edges of streams, rivers, lakes and coastlines. Wetlands can be found in nearly every country and climatic zone. Indeed wetlands are found from the Tundra to the Tropics and on every continent. They are so varied. Some are wet all the time. Some wetlands are large and some are very small. Many have been altered by human activities such as farming, building of roads, dams and towns. Wetlands are regarded wastelands sources of mosquitoes, flies, snakes and diseases. People had negative views about them and they eliminated them. Original wetlands have been destroyed; some of them have been converted into farmland, some others filled by industrial wastes.
Wetlands vary widely because of topography, climate, hydrology, water chemistry and vegetation. Wetlands are the coastal mangrove forests, lake marshes and seasonally flooded lands along river courses. Palm swamps, sea grass beds, salt flats, and coral reefs are common wetlands. They are of two types: tidal wetlands and non-tidal (inland) wetlands. Tidal wetlands are found along the Atlantic, Pacific, Alaskan and Gulf Coasts. The salt water and fluctuating water levels create a difficult environment. Some plants have adapted to the environment of saline conditions. Inland wetlands are common in the margins of lakes and rivers. They include wet meadows dominated by herbaceous plants, swamps and shrubs and tall trees. The prolonged presence of water favours the growth of specially adapted plants.
States and tribes play a critical role in the protection and management of wetlands. With the growth of education, people have started understanding ecological processes and their attitude towards wetlands have changed. They have recognised the ecological significance of the wetlands; they are a source of valuable natural wealth. They help regulating water levels within watersheds; reduce flood and storm damages; and provide fish and wildlife habitat. They support hunting, fishing and other recreational activities.

Wetlands are the most productive ecosystems in the world. They have been described as biological supermarkets as they provide great volumes of food and attract many animal species. A variety of insects, amphibians, reptiles, birds, fish and mammals are found in these wetlands. Many species of birds, animals, rely on wetlands for food, water and shelter. The microbes, insects and wildlife are part of global cycles for water, nitrogen, and sulphur. They store carbon within their plant communities and thus help to moderate climate conditions.

  1. they are a source of economic growth

  2. they are productive ecosystems in nature and a source of natural wealth

  3. they are a source of mosquitoes, flies and snakes

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Option (3) can be rejected straightaway, being negative in connotation. Option (1) is a little far-fetched and not borne by the passage. Option (2) can be directly derived from the last two paragraphs.

Multiple choice

When water is boiled, bubbles can be seen coming up from the bottom of the pan. Which of the following is present in the water?

  1. Live microorganisms

  2. Carbon-dioxide

  3. Dissolved air in water

  4. Atmospheric oxygen entering water

  5. Excess of nitrogen gas in water as in atmosphere
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Yes, when water is boiled, air bubbles can be seen coming up from the bottom of the pan. This simple activity shows that air is present in water.