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

Municipal sewage pollutants account for

Directions: The passage in this part is followed by question based upon its contents. Read the passage carefully and choose the best answer for the question.

Environmental protection and management is deservedly attracting a lot of attention these days. This is a desirable development in the face of the alarming rate of natural resource degradation which greatly hampers their optimal utilization. When waste waters emanating from municipal sewage, industrial effluent, agriculture and land runoffs, find their way either to ground water reservoirs or other surface water sources, the quality of water deteriorates, rendering it unfit for use. The natural balance is disturbed when concentrated discharges of waste water is not controlled. This is because the cleansing forces of nature cannot do their job in proportion to the production of filthy matter.

According to the National Environment Engineering and Research Institute (NEERI), a staggering 70 percent of water available in the country is polluted. According to the Planning Commission: “From the Dal lake in the North to the Chaliyar rivers in the South : from Damodar and Hooghly in the East to the Thane creek in the West, the picture of water pollutio n is uniformly gloomy. Even our large perennial rivers, like the Ganga, are today heavily polluted”.

According to one study, all the 14 major rivers of India are highly polluted. Beside the Ganga, these rivers include the Yamuna, Narmada, Godavari, Krishna and Cauvery. These rivers carry 85 percent of the surface runoff and their drainage basins cover 73 percent of the country. The pollution of the much revered Ganga is due in particular to municipal sewage that accounts for 3/4th of its pollution load. Despite India having legislation on water pollution [The Water (Prevention and Control of Pollution) Act, 1974] and various water pollution control boards, rivers today have become synonymous with drains and sewers.

Untreated community wastes discharged into watercourses from human settlements account for four times as much waste water as industrial effluent. Out of India's 3,119 towns and cities, only 217 have partial (209) or full (8) sewerage treatment facilities and cover less than a third of the urban population. Statistics from a report of the Central Board for Prevention and Control of Water Pollution reveal that 1,700 of 2,700 water-using industries in India are polluting the water around their factories. Only 160 industries have waste water treatment plants. One estimate suggests that the volume of waste water of industrial origin will be comparable to that of domestic sewage in India by 2000 AD. Discharges from agricultural fields which carry fertilizing ingredients of nitrogen, phosphorous and pesticides are expected to be three times as much as domestic sewage. By that date, thermal pollution generated by discharges from thermal power plants will be the largest in volume.

Toxic effluents deplete the levels of oxygen in the rivers, endanger all aquatic life and render water absolutely unfit for human consumption, apart from affecting industrial production. Sometimes these effects have been disastrous. A recent study reveals that the water of the Ganga, Yamuna, Kali and Indus rivers have considerable concentrations of heavy metals due to inflow of industrial wastes, which pose a serious health hazard to the millions living on their banks. Similarly, the Cauvery and Kapila rivers in Karnataka have been found to contain metal pollution which threatens the health of people in riverine towns. The Periyar, the largest river of Kerala, receives extremely toxic effluent that result in high incidence of skin problems and fish kills. The Godavari of Andhra Pradesh and the Damodar and Hooghly in West Bengal receive untreated industrial toxic wastes. A high level of pollution has been found in the Yamuna, while the Chambal of Rajasthan is considered the most polluted river in Rajasthan. Even in industrially backward Orissa, the Rushikuta river is extremely polluted. The fate of the Krishna in Andhra Pradesh, the Tungabhadra in Karnataka, the Chatiyar in Kerala, the Gomti in U.P., the Narmada in M.P and the Sone and the Subarnarekha rivers in Bihar is no different.

According to the W.H.O., eighty percent of diseases prevalent in India are water-borne; many of them assume epidemic proportions. The prevalence of these diseases heighten under conditions of drought. It is also estimated that India loses as many as 73 million man-days every year due to water prone diseases, costing Rs. 600 crore by way of treatment expenditure and production losses. Management of water resources with respect to their quality also assumes greater importance especially when the country can no more afford to waste water.

The recent Clean-the-Ganga Project with an action plan estimated to cost the exchequer Rs. 250 crore (which has been accorded top priority) is a trend setter in achieving this goal. The action plan evoked such great interest that offers of assistance have been received from France, UK, US and the Netherlands as also the World Bank. This is indeed laudable. Poland too has now joined this list. The very fact that these countries have volunteered themselves to contribute their mite is a healthy reflection of global concern over growing environmental degradation and the readiness of the international community to participate in what is a truly formidable task. It may be recalled that the task of cleansing the Ganga along the Rishikesh - Hardwar stretch under the first phase of the Ganga Action Plan has been completed and the results are reported to be encouraging.

The crisis of drinking water is deepening because water resources are drying up and the lowering of ground water through overpumping; this is compounded by the pollution of water sources. All these factors increase the magnitude of the problem. An assessment of the progress achieved by the end of March 1985, on completion of the first phase of the International Drinking Water Supply and Sanitation Decade (1981-’91) reveals that drinking water has been available to 73 percent of the urban population and 56 percent of the rural population only. This means that nearly half the country's rural population has to get drinking water facilities. This needs to be urgently geared up especially when considered against the Government’s professed objective of providing safe drinking water and sanitation to all by the end of the International Drinking Water Supply and Sanitation Decade i.e. March 1991. The foremost action in this would be to clean up our water resources.

As per surveys conducted by the NEERI, per capita drinking water losses in different cities in the country range between 11,000 to 31,000 litres annually. This indicates a waste level of 20 to 35 percent of the total flow of water in the distribution system primarily due to leaks in main and household service pipes. Preventive maintenance programme would substantially reduces losses, wastages and would certainly go a long way in solving the problem.

According to the Union Ministry of Works and Housing, out of 2.31 lakh problem villages have been provided with at least one source of drinking water as of March, 1986. The balance (38,748) villages are expected to be covered during the seventh plan. A time bound national policy on drinking water is being formulated by Government wherein the task is proposed to be completed by the end of the seventh plan. An outlay of Rs. 6,522.47 crore has been allotted for the water supply and sanitation sector in the seventh plan period against an outlay of Rs. 3,922.02 crore in the sixth plan. Of this, outlay for rural water supply sector is Rs. 3,454.47 crore. It is expected that this outlay would help to cover about 86.4 percent of the urban and 82.2 percent of the rural population with safe drinking water facilities by March 1991. Hygienic sanitation facilities would be provided to 44.7 percent and 1.8 percent of the urban and rural population respectively within the same period.

  1. the lowest percentage of water pollution

  2. 75 percent of the Ganga's water pollution load

  3. twice the volume of the waste water of industrial origin

  4. three times as much as the discharge from agricultural fields

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

It is mentioned in 3rd paragraph,”The pollution of the much-revered Ganga is in particular due to municipal sewage that accounts for 3/4th of its pollution load.”

Multiple choice

The degradation of natural resources will necessarily lead to

Directions: The passage in this part is followed by question based upon its contents. Read the passage carefully and choose the best answer for the question.

Environmental protection and management is deservedly attracting a lot of attention these days. This is a desirable development in the face of the alarming rate of natural resource degradation which greatly hampers their optimal utilization. When waste waters emanating from municipal sewage, industrial effluent, agriculture and land runoffs, find their way either to ground water reservoirs or other surface water sources, the quality of water deteriorates, rendering it unfit for use. The natural balance is disturbed when concentrated discharges of waste water is not controlled. This is because the cleansing forces of nature cannot do their job in proportion to the production of filthy matter.

According to the National Environment Engineering and Research Institute (NEERI), a staggering 70 percent of water available in the country is polluted. According to the Planning Commission: “From the Dal lake in the North to the Chaliyar rivers in the South : from Damodar and Hooghly in the East to the Thane creek in the West, the picture of water pollutio n is uniformly gloomy. Even our large perennial rivers, like the Ganga, are today heavily polluted”.

According to one study, all the 14 major rivers of India are highly polluted. Beside the Ganga, these rivers include the Yamuna, Narmada, Godavari, Krishna and Cauvery. These rivers carry 85 percent of the surface runoff and their drainage basins cover 73 percent of the country. The pollution of the much revered Ganga is due in particular to municipal sewage that accounts for 3/4th of its pollution load. Despite India having legislation on water pollution [The Water (Prevention and Control of Pollution) Act, 1974] and various water pollution control boards, rivers today have become synonymous with drains and sewers.

Untreated community wastes discharged into watercourses from human settlements account for four times as much waste water as industrial effluent. Out of India's 3,119 towns and cities, only 217 have partial (209) or full (8) sewerage treatment facilities and cover less than a third of the urban population. Statistics from a report of the Central Board for Prevention and Control of Water Pollution reveal that 1,700 of 2,700 water-using industries in India are polluting the water around their factories. Only 160 industries have waste water treatment plants. One estimate suggests that the volume of waste water of industrial origin will be comparable to that of domestic sewage in India by 2000 AD. Discharges from agricultural fields which carry fertilizing ingredients of nitrogen, phosphorous and pesticides are expected to be three times as much as domestic sewage. By that date, thermal pollution generated by discharges from thermal power plants will be the largest in volume.

Toxic effluents deplete the levels of oxygen in the rivers, endanger all aquatic life and render water absolutely unfit for human consumption, apart from affecting industrial production. Sometimes these effects have been disastrous. A recent study reveals that the water of the Ganga, Yamuna, Kali and Indus rivers have considerable concentrations of heavy metals due to inflow of industrial wastes, which pose a serious health hazard to the millions living on their banks. Similarly, the Cauvery and Kapila rivers in Karnataka have been found to contain metal pollution which threatens the health of people in riverine towns. The Periyar, the largest river of Kerala, receives extremely toxic effluent that result in high incidence of skin problems and fish kills. The Godavari of Andhra Pradesh and the Damodar and Hooghly in West Bengal receive untreated industrial toxic wastes. A high level of pollution has been found in the Yamuna, while the Chambal of Rajasthan is considered the most polluted river in Rajasthan. Even in industrially backward Orissa, the Rushikuta river is extremely polluted. The fate of the Krishna in Andhra Pradesh, the Tungabhadra in Karnataka, the Chatiyar in Kerala, the Gomti in U.P., the Narmada in M.P and the Sone and the Subarnarekha rivers in Bihar is no different.

According to the W.H.O., eighty percent of diseases prevalent in India are water-borne; many of them assume epidemic proportions. The prevalence of these diseases heighten under conditions of drought. It is also estimated that India loses as many as 73 million man-days every year due to water prone diseases, costing Rs. 600 crore by way of treatment expenditure and production losses. Management of water resources with respect to their quality also assumes greater importance especially when the country can no more afford to waste water.

The recent Clean-the-Ganga Project with an action plan estimated to cost the exchequer Rs. 250 crore (which has been accorded top priority) is a trend setter in achieving this goal. The action plan evoked such great interest that offers of assistance have been received from France, UK, US and the Netherlands as also the World Bank. This is indeed laudable. Poland too has now joined this list. The very fact that these countries have volunteered themselves to contribute their mite is a healthy reflection of global concern over growing environmental degradation and the readiness of the international community to participate in what is a truly formidable task. It may be recalled that the task of cleansing the Ganga along the Rishikesh - Hardwar stretch under the first phase of the Ganga Action Plan has been completed and the results are reported to be encouraging.

The crisis of drinking water is deepening because water resources are drying up and the lowering of ground water through overpumping; this is compounded by the pollution of water sources. All these factors increase the magnitude of the problem. An assessment of the progress achieved by the end of March 1985, on completion of the first phase of the International Drinking Water Supply and Sanitation Decade (1981-’91) reveals that drinking water has been available to 73 percent of the urban population and 56 percent of the rural population only. This means that nearly half the country's rural population has to get drinking water facilities. This needs to be urgently geared up especially when considered against the Government’s professed objective of providing safe drinking water and sanitation to all by the end of the International Drinking Water Supply and Sanitation Decade i.e. March 1991. The foremost action in this would be to clean up our water resources.

As per surveys conducted by the NEERI, per capita drinking water losses in different cities in the country range between 11,000 to 31,000 litres annually. This indicates a waste level of 20 to 35 percent of the total flow of water in the distribution system primarily due to leaks in main and household service pipes. Preventive maintenance programme would substantially reduces losses, wastages and would certainly go a long way in solving the problem.

According to the Union Ministry of Works and Housing, out of 2.31 lakh problem villages have been provided with at least one source of drinking water as of March, 1986. The balance (38,748) villages are expected to be covered during the seventh plan. A time bound national policy on drinking water is being formulated by Government wherein the task is proposed to be completed by the end of the seventh plan. An outlay of Rs. 6,522.47 crore has been allotted for the water supply and sanitation sector in the seventh plan period against an outlay of Rs. 3,922.02 crore in the sixth plan. Of this, outlay for rural water supply sector is Rs. 3,454.47 crore. It is expected that this outlay would help to cover about 86.4 percent of the urban and 82.2 percent of the rural population with safe drinking water facilities by March 1991. Hygienic sanitation facilities would be provided to 44.7 percent and 1.8 percent of the urban and rural population respectively within the same period.

  1. poor economic utilization of resources

  2. contamination of water from municipal sewage

  3. water unfit for human consumption

  4. none of these

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

Refer to the line 2 of paragraph 1, ”This is a desirable development in the face of the alarming rate of natural resources degradation, which greatly hampers their optimal utilisation” which explains that option 1 is the correct answer.

Multiple choice
  1. they can be turned to important diet in future

  2. they purify atmosphere

  3. both 1 and 2

  4. none of these

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

Algae are important because they are a potential food source (rich in nutrients) and they perform photosynthesis, which helps in purifying the atmosphere by consuming CO2 and releasing oxygen.

Multiple choice
  1. Salt

  2. Sugar

  3. Alum

  4. Soap

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

Explanation: Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration or electromagnetism.

Multiple choice
  1. Aquatic animals can breathe inside the water.

  2. Earthworms cannot breathe inside the soil.

  3. Flour mills can be run by moving air.

  4. Plants cannot live without oxygen for long time.

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

Earthworms can breathe inside the soil. They come outside only when the water takes the place of air in the soil.

Multiple choice
  1. Excess drawing of water from water bodies

  2. Addition of untreated sewage in water bodies

  3. Plant growing near water bodies

  4. Aquatic animals living in water

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

fact

Multiple choice
  1. In most parts of the country, water contamination problems are caused almost entirely by the local industry.

  2. Enforcing water contamination guidelines on industry left a significant impact on the quality of water in the local water bodies.

  3. The water contamination problems of the other parts of the country are basically similar to those ones suffered by the city.

  4. An increase in the number of aquatic species seen in the local water bodies is desirable.

  5. The increased number of aquatic species seen in the local water bodies reflects an actual increase in the number of aquatic species in the area.

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

We know that water contamination guidelines on the local industry in the city have helped increase the number of aquatic species. It means that the local industry then causes a significant amount of water contamination, so the guidelines may have helped to reduce water contamination. Still, the local industry does not need to be 'entirely' responsible for the water contamination in order for the guidelines to help. Perhaps the local industry only caused 30% of the contamination, but the guidelines cut local industry contamination to zero; that would still have a significant impact on the quality of water. Hence option (1) is correct.

Multiple choice
  1. The Olive Ridley turtles in other marine locations reproduce at the same rates as they did before.

  2. The Olive Ridley turtle has experienced an exponential rise in its population in the past 30 years.

  3. The Olive Ridley turtle is not native to the area and in fact, it was introduced here only 100 years ago.

  4. The presence of a major marine pollutant called D-Methyl Acromane, earlier at 20 parts per million, has declined to 8 parts per million in Gahirmatha after the introduction of Vianzone.

  5. The Olive Ridley turtles in other, polluted marine locations in the state still reproduce at the same rate as they did in Gahirmatha before the release of the chemical Vianzone.

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

As turtles are still reproducing at the old rate in other polluted marine locations, it follows that Vianzone has facilitated their increased reproduction.