Environmental Studies · General Awareness

Water Quality and Pollution

1,303 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

What is aquaculture?

  1. microbes in the water

  2. the societal norms of the sea

  3. a charity to save fish

  4. farming of fish
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aquaculture is the controlled cultivation of aquatic organisms, such as fish, crustaceans, and mollusks.

Multiple choice zoology introduction to microbiology microbial pollution control environmental use of microorganism microbes in waste treatment and biogas

Sewage water is purified for reuse by the action of

  1. Protozoans

  2. Micro-organisms

  3. Plants and light

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

Domestic sewage consists biodegradable organic matter and easily decomposes by the micro-organisms. These microorganisms can multiply using these organic substances as substrates and hence, utilize some of the components of sewage. Micro-organisms involved in biodegradation of organic matter in the receiving water body consume a lot of oxygen, and as a result, there is a sharp decline in dissolved oxygen downstream from the point of sewage discharge. This causes mortality of fish and other aquatic creatures. 

Thus, the correct answer is option B. 

Multiple choice zoology introduction to microbiology microbial pollution control environmental use of microorganism microbes in waste treatment and biogas

Which of these is not a key factor that helps in the process of decay?

  1. Wind

  2. Temperature

  3. Water

  4. Micro-organisms
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Decay is what happens when dead animals and plants break down. The key factors involved in decay are: Temperature, Amount of oxygen, Amount of water and the presence of microorganisms. Microorganisms are important in decay. For example, they are used to break down human waste (sewage) and plant waste (compost). Decay recycles important nutrients for plant growth.

Multiple choice zoology introduction to microbiology microbial pollution control environmental use of microorganism microbes in waste treatment and biogas

Sewage water is purified by

  1. Microorganisms

  2. Light

  3. Fishes

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

Sewage is composed of organic matter and domestic waste. The pollutants are removed by the sewage treatment process to mitigate it's adverse impact on the environment when it is released. The sewage pass through primary,  secondary and tertiary treatment. The microorganisms by aerobic and anaerobic metabolism degrade the organic matter in secondary and tertiary treatment respectively making it disinfected.

Hence, the correct answer is 'Microorganisms'.

Multiple choice zoology bio-geo chemical cycles in nature nutrient cycles- flow of substances carbon cycle biogeochemical cycles - gaseous

The wormicide character of _____ destroys worms in water.

  1. Azotobacter

  2. Azolla

  3. Nostoc

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The wormicide character that kills worms in water are Azotobactor.
Azotobactors are one of the Nitrogen-fixing bacteria. Hence they are used as bio-fertilisers for many plants. 
The size of Azotobactor varies from 1-20 μm in length and 1-2 μm. 
Azotobactors can be generally found in alkaline soil and aquatic regions. So, the correct answer is A.
Multiple choice biology classification of plants thallophyta cryptograms kingdom plantae

Algae and other submerged green plants often float in water during daytime and sink at night because

  1. They lose weight at night because fish and other animals eat away at their parts.

  2. They become buoyant due to accumulation of oxygen as a result of photosynthesis.

  3. They become light due to consumption of food.

  4. They come up to enjoy sunlight.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During the process of photosynthesis, phytoplankton produces oxygen as a byproduct. Due to their vast and widespread populations, algae and cyanobacteria are responsible for approximately half of all the oxygen found in the ocean and in our atmosphere. During day time they float, due to the accumulation of oxygen. Whereas the reverse happens during the night, which is explained below.
In addition to providing food and oxygen for nearly all life on Earth, phytoplankton help to regulate inorganic carbon (carbon dioxide) in the atmosphere. During photosynthesis, carbon dioxide and water molecules are used to make sugar for energy. The process of incorporating inorganic carbon into organic carbon (glucose and other biologically useful compounds) is called carbon fixation and is part of the biological carbon pump.
As carbon fixation and oxygen production are part of the same process, the extent of phytoplanktons participation is on the same scale. Phytoplankton consumes a similar amount of carbon dioxide as all land plants combined. While phytoplankton can pull carbon dioxide from the atmosphere or the ocean, it will have a similar effect. Carbon dioxide that is taken from the water is replaced by carbon dioxide from the atmosphere.

Multiple choice geography endogenetic movements endogenic process and creation of mountains major domains of the earth land and oceans study of continents - north america earth's movement and creation of landforms earthquake earthquakes

Pollution of water bodies results in ________________.

  1. loss of aquatic ecosystem

  2. impure quality of water

  3. scarcity of fresh water

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Water pollution is the contamination of water by various pollutants. The effect of water pollution depends upon the kind of chemicals and other pollutants being dumped into the water. The following are the effects of water pollution:
1) The main effect of water pollution is that there is a loss of the aquatic ecosystem. The fishes that depend upon water get killed by the harmful chemicals or plastics in the water. 
2) Another effect is that the water becomes impure by water pollution. The pollutants are so much harmful that the healthy bacteria living in the water get killed by the chemicals and water becomes unfit for any purposes. 
3) With water pollution there occurs a significant scarcity of freshwater. The water becomes unfit for drinking purposes. With the increasing water pollution and increase in falls in the groundwater, there arises a serious issue of freshwater.
Multiple choice evs - i for a pollution free nature ways to prevent air pollution ways to reduce air pollution reducing air pollution

Thermal pollution causes a decrease in dissolved oxygen.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Thermal pollution is when an industry or other human-made organization takes in water from a natural source and either cools it down or heats it up. They then eject the water back into the natural resource, which changes the oxygen level and can have a disastrous effect on the local ecosystem. 

Multiple choice biology respiration in living organisms breathing underwater respiration in other organisms respiration in organism

The excessive increase in the number of aquatic plants creates a disturbance for the aquatic animals because

  1. It decreases dissolved oxygen content.

  2. It increases dissolved oxygen content.

  3. It increases dissolved carbon dioxide content.

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • In aquatic environments, free-floating microscopic plants known as algae, and larger submersed plants (macrophytes), release oxygen directly into the water where it is used by animals and other organisms, including the plants themselves. 
  • Fish and other aquatic organisms don’t use oxygen from water molecules ($H _2O$). This is because the single oxygen molecule ($O$) is bound to the two hydrogen molecules ($H _2$) and is not useable in this form.
  •  Instead, aquatic organisms depend on dissolved oxygen gas ($O _2$), a colourless, tasteless and odourless substance that enters the water from plants and the atmosphere. Hence, The excessive increase in the number of aquatic plants creates a disturbance for the aquatic animals because It decreases dissolved oxygen content.
So, the correct answer is 'It decreases dissolved oxygen content.'.
Multiple choice biology respiration in living organisms breathing underwater respiration in other organisms respiration in organism

Why do fishes die when taken out of water?

  1. Fishes respire with the help of gills.

  2. Gills are richly supplied with blood capillaries and can readily absorb oxygen dissolved in water.

  3. Both A and B.

  4. Fishes can not tolerate the atmospheric air pressure.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fishes respire with the help of gills. Gills are richly supplied with blood capillaries and can readily absorb oxygen dissolved in water. But gills can not absorb gaseous oxygen. Since fishes cannot absorb gaseous oxygen they die soon after they are taken out of the water.

Multiple choice evs water in our life where do we get water from? why conserve water uses of water

Estuaries are considered as nutrient trap due to the mixing of

  1. River and sea water

  2. Pond and lake

  3. A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Estuaries are the delicate water bodies where the fresh water from the river and salty water from the sea water meet and mix-up. They are responsible for transporting and mixing the nutrients. The difference in sedimentation of the water of rivers and sea-water, the wind action and the tidal activity allow the trapping and transport of the nutrients. Reefs, deltas and barrier islands protect the estuaries from the ocean forces.

Hence, the correct answer is 'River and sea water'.

Multiple choice zoology microbes in human welfare biogas environmental use of microorganism microbes in waste treatment and biogas

What would happen if oxygen availability to activated sludge flocs is reduced ?

  1. It will slow down the rate of degradation of organic matter.

  2. The center of flocs will become anoxic, which would cause death of bacteria and eventually breakage of flocs.

  3. Flea would Increase in size as anaerobic bacteria would grow around flocs.

  4. Protozoa would grow in large numbers.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Oxygen is very important for the microorganism to break down and degrade the organic matter which is present in the sewage or the activated sludge. If the oxygen availability of the activated sludge floc is reduced then the degradation rate will slow down.

So, the correct option is 'it will slow down the rate of degradation of organic matter'

Multiple choice zoology microbes in human welfare biogas environmental use of microorganism microbes in waste treatment and biogas

Polluted water can be purified by using

  1. Micro-organisms

  2. Algae

  3. Pesticides

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

Water pollution due to organic sources like pollution due to sewage can be prevented by treating sewage before passing into the water course, in sewage or effluent treatment plants (ETP). Domestic sewage primarily contains biodegradable organic matter, which readily decomposes by bacteria and other micro-organisms, which can multiply by using these organic substances as substrates and hence reduce some of the components of sewage. Thus, the correct answer is option A.

Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

Anaerobic sludge digesters and inoculums are part and parcel of _____________.

  1. Primary sluge

  2. Activated sludge

  3. BOD

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

Anaerobic digestion is a collection of a process by which microorganism break down biodegradable material in the absence of oxygen and some of these processes are used in the waste Industries to manage the waste. Primary sludge is a result of the capture of suspended solids and organics materials. In the primary process of waste management, the material is treated in a variety of ways. During the biological treatment of the waste a part of activated sludge is used as inoculum and they are passed into the last tank which is known as anaerobic sludge digester. The microorganism present in the sludge gets killed.


So, the correct option is 'Primary sludge'.