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

Expansion of BOD

  1. Biochemical Oxygen Diffusion

  2. Biological Oxygen Degeneration

  3. Biochemical Oxygen Demand

  4. Biochemical Oxygen Destruction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

BOD stands for Biochemical Oxygen Demand, which measures the amount of dissolved oxygen required by aerobic microorganisms to decompose organic matter.

Multiple choice

A lake with an inflow of domestic sewage rich in organic waste may result in

  1. drying of the lake very soon due to algal bloom

  2. an increased production of fish due to lot of nutrients

  3. death of fish due to lack of oxygen.

  4. increased population of aquatic food web organisation.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sewage rich in organic waste promotes the growth of microorganisms that consume dissolved oxygen, leading to a decrease in oxygen levels and the subsequent death of fish.

Multiple choice

Presence of _________ is an indicator of water pollution.

  1. E. coli

  2. Chlorella

  3. Beggiatoa

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

E. coli is a coliform bacterium commonly found in the intestines of humans and animals. Its presence in water is a standard indicator of fecal contamination and potential water pollution.

Multiple choice

what is the last stage of cultural eutrofication?

  1. fish kills

  2. increase in anaerobic bacteria

  3. increase in aerobic bacteria

  4. increase in plants such as duckweed
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cultural eutrophication leads to algal blooms, which eventually die and decompose. This decomposition process consumes oxygen, leading to an increase in anaerobic bacteria that thrive in the resulting low-oxygen conditions.

Multiple choice

Thermal pollution causes

  1. dissolved oxygen to decrease

  2. the number of fish to increase

  3. dissolved oxygen to increase

  4. the number of protozoan to increase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Thermal pollution increases water temperature, which decreases the solubility of oxygen in water, thereby reducing the amount of dissolved oxygen available for aquatic life.

Multiple choice

Which of the following helps reduce water pollution?

  1. proper treatment of sewage

  2. wearing gas masks

  3. turning off the water why you brush your teeth

  4. riding your bike
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Proper treatment of sewage removes contaminants from wastewater before it is released into the environment, significantly reducing water pollution.

Multiple choice

What is Eutrophication?

  1. the formation of lakes in volcano craters

  2. the formation of a lake cause by a shift in a river

  3. a tributary

  4. transformation of a lake into a meadow due to dead organisms
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Eutrophication is the process by which a body of water becomes overly enriched with nutrients, leading to excessive plant growth and decay, which eventually depletes oxygen and fills the lake.

Multiple choice

Why would some organisms, like frogs or plants, produce poisons like cyanide?

  1. increases its ability to resist predation

  2. makes it more efficient to breathe

  3. the poisons reach a water source, killing everyone

  4. makes the organisms larger or smaller in size
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chemical defenses like poisons are adaptations that deter predators from eating the organism. This increases the organism's chances of survival and reproduction.

Multiple choice

Which of these processes happen in aquatic ecosystems (like the ocean)?

  1. photosynthesis

  2. cellular respiration

  3. decomposition

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

Aquatic ecosystems involve the same fundamental biological processes as terrestrial ones. Photosynthesis occurs in algae and plants, respiration occurs in all living organisms, and decomposition breaks down organic matter.

Multiple choice evs contaminated water spreads disease mosquitoes and malaria diseases caused by mosquitoes water borne diseases

When domestic sewage mixes with river water

  1. Small animals like rats will die after drinking river - water

  2. The increased microbial. activity releases micronutrients such as iron

  3. The increased microbial activity uses up dissolved oxygen

  4. The river water is still suitable for drinking as impurities are only about 0.1%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

BOD (biochemical oxygen demand) refers to the amount of the oxygen that would be consumed if all the organic matter in one liter of water were oxidized by bacteria. The BOD test measures the rate of update of oxygen by microorganisms in a sample of water and thus, indirectly BOD is the measure of the organic matter present in the water. The greater the BOD of wastewater more is its polluting potential. 

So, the correct answer is 'Small animals like rats will die after drinking river - water'.

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

BOD is ___________ in polluted water and ________in potable water.

  1. more, less

  2. less, more

  3. less in both

  4. medium in both
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A low BOD is an  indicator of good quality of water. Whereas a high BOD indicates polluted water as in that water the dissolved oxygen is consumed by bacteria.
So, the correct option is 'more, less'