Tag: human influences on the environment

Questions Related to human influences on the environment

If BOD of river is high, it means that the river 

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

  1. Is not polluted

  2. Is very polluted

  3. Does not have green plants

  4. Get least amount of light

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Correct Option: B
Explanation:

Biochemical oxygen demand is a measure of how much dissolved oxygen is being consumed as microbes break down organic matter. A high demand, therefore, can indicate that levels of dissolved oxygen are falling, with potentially dangerous implications for the river's biodiversity. High biochemical oxygen demand can be caused by: high levels of organic pollution, caused usually by poorly treated waste water; high nitrate levels, which trigger high plant growth. Both result in higher amounts of organic matter in the river. When this matter decays, the microbiological activity uses up the oxygen.

'Biological Oxygen Demand' (BOD) is a measure of

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

  1. Industrial wastes poured into water bodies

  2. Extent to which water is polluted with organic compounds

  3. Amount of carbon monoxide inseparably combined with haemoglobin

  4. Amount of oxygen needed by green plants during night

Show answer
Correct Option: B
Explanation:

Biochemical oxygen demand is a measure of how much dissolved oxygen is being consumed as microbes break down organic matter. A high demand, therefore, can indicate that levels of dissolved oxygen are falling, with potentially dangerous implications for the river's biodiversity. High biochemical oxygen demand can be caused by high levels of organic pollution, caused usually by poorly treated wastewater; high nitrate levels, which trigger high plant growth. 

Measuring 'Biochemical Oxygen Demand' (BOD) is a method used for  

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

  1. Estimating the amount of organic matter in sewage water.

  2. Measuring the activity of Saccharomyces cervisae in producing curd on a commercial scale.

  3. Working out the efficiency of RBCs, about their capacity to carry oxygen.

  4. Working out the efficiency of oil driven automobile engines.

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Correct Option: A
Explanation:

Biochemical oxygen demand (BOD) is the amount of oxygen, expressed in mg/L or parts per million (ppm), that bacteria take from water, when they oxidize organic matter. 

Bacteria in water live and multiply when organic matter is available for food and oxygen is available for oxidation. About one-third of the food bacteria consumed becomes the solid organic cell material of the organisms. The other two-thirds is oxidized to carbon dioxide and water by the biochemical action of the bacteria on the oxygen dissolved in the water. 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. 

BOD is

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

  1. The-amount of $O _2$ utilised by organisms in water

  2. The amount of $O _2 $ utilised by micro organisms for decomposition

  3. The total amount of $O _2 $ present in water

  4. All of the above

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Correct Option: B
Explanation:

Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. 

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. 

The major source of BOD in the river Ganga is 

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

  1. Leaf litter

  2. Fishes

  3. Human waste

  4. Aquatic plants

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Correct Option: C
Explanation:

The Ganges river basin is one of the most fertile and densely populated regions in the world that covers an area of 1,80,000 $km^2$. The river flows through 29 cities with population over 100,000; 23 cities with population between 50,000 and 100,000, and about 48 towns. 

A large proportion of the waste in the Ganges is from this population through domestic usage like bathing, laundry and public defecation. An analysis of the Ganges water in 2006 showed significant associations between waterborne or enteric disease due to the use of the river for bathing, laundry, washing, eating, cleaning utensils, and brushing teeth.

'Biological Oxygen Demand' (BOD) is a measure of 

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

  1. Industrial wastes poured into water bodies.

  2. Extent to which water is polluted with organic compounds.

  3. Amount of carbon monooxide inseparably combined with haemoglobin.

  4. Amount of oxygen needed by green plants during night.

Show answer
Correct Option: B
Explanation:

Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The BOD measures the amount of oxygen consumed by biochemical oxidation of waste contaminants. The total amount of oxygen consumed when the biochemical reaction is allowed to proceed to completion is called as the ultimate BOD. The BOD is universally adopted as a measure of relative pollution effect.

BOD is related with 

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

  1. Organic matter

  2. Microbes

  3. Both A and B

  4. None of the above

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Correct Option: C
Explanation:

Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. 

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. 

Increase in BOD of water reservoir is due to

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

  1. Algae

  2. Soil

  3. Moss

  4. Waste product

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Correct Option: D
Explanation:

Biochemical oxygen demand is a measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria) in the oxidation of organic matter. Natural sources of organic matter include plant decay and leaf fall. However, plant growth and decay may be unnaturally accelerated when nutrients and sunlight are overly abundant due to human influence. Urban runoff carries pet wastes from streets and sidewalks, nutrients from lawn fertilizers; leaves, grass clippings, and paper from residential areas, which increase oxygen demand. Oxygen consumed in the decomposition process reduces other aquatic organisms of the oxygen they need to live. If dissolved oxygen concentrations drop below 5 parts per million (ppm), fish will be unable to live for very long. This can occur in the form of organic pollution for sources such as domestic sewage, septic tank leakage, and fertilizer runoff, or could be in the form of inorganics from domestic or industrial sources. 

Therefore, the correct answer is option D.

What is B.O.D.?

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

  1. The amount of $O _2$ utilised by organisms in water.

  2. The amount of $O _2 $ utilized by microorganisms for decomposition.

  3. The total amount of $O _2$ present in water.

  4. All of the above.

Show answer
Correct Option: B
Explanation:

Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. 

A water body has high BOD, indicating that water is

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

  1. Being contaminated with sewage

  2. Being aerated

  3. Receiving minerals

  4. Atrophic

Show answer
Correct Option: A
Explanation:

Biological oxygen demand (BOD) is one of the most common measures of pollutant organic material in water. BOD indicates the amount of putrescible organic matter present in water. Therefore, a low BOD is an indicator of good quality water, while a high BOD indicates polluted water. The BOD test serves an important function in stream pollution-control activities.