Cambridge A Level Environmental Management (AS only) 8291 — 2018 Oct/Nov Paper 2 · Variant 2

1 (a) Fig. 1.1 gives information about the sources of nitrogen compounds and phosphorus compounds (nutrients) entering a lake. source percentage of total percentage of total nitrogen phosphorus compounds compounds sewage 31.5 58.7 urban run-off 5.5 10.0 manured land 9.9 21.5 other crop land 0.7 3.1 rural run-off forest land 0.5 0.3 pasture 0.7 2.9 rural ground water 42.7 2.3 precipitation onto water 8.5 1.2 precipitation urban rural onto water sources sources run-off run-off from from forest urban areas run-off from pasture and manured land excess discharge nutrients from sewage treatment run-off from works algal bloom crop land infiltration lake ground water flow Fig. 1.1 (i) State the source that contributes the highest percentage of nitrogen compounds to the lake, as shown in the table in Fig. 1.1. .......................................................................................................................................[1] (ii) Suggest where the nitrogen and phosphorus compounds (nutrients) in the urban run-off shown in Fig. 1.1 originated. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[3] (iii) Use Fig. 1.1 to calculate the difference between the total percentage of nitrogen compounds and the total percentage of phosphorus compounds entering the lake from rural run-off. Show your working. ........................................................% [2] (iv) Explain why there is a high percentage of nitrogen compounds entering the lake through rural ground water, as shown in Fig. 1.1. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[4] (b) Describe and explain the effects of excess nutrients entering a lake. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[6] (c) Suggest ways in which the pollution of water stores can be reduced. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[4] [Total: 20]

Mark scheme: 1(a)(i) rural groundwater; 1 1(a)(ii) compounds: (decomposing) organic matter / nitrogen oxides / NOx / phosphates/ nitrates / ammonium compounds; sources: (decomposing) organic matter: waste material from streets; waste disposal sites; nitrogen oxides / NOx : air pollutants; from cars / industry; dissolved in precipitation / rainfall; phosphates: e.g. detergents; domestic sources / street cleaning / car washing; nitrates: from garden fertilisers; ammonium compounds: septic tanks / untreated sewage; storm drainage; max 3 1(a)(iii) (Total % of nitrogen compounds 11.8, total % of phosphorous compounds 27.8) / 27.8 – 11.8; 16; 2 Question Answer Marks 1(a)(iv) non-point source of pollution, from a large area; rainfall/precipitation falls on the land ; water is infiltrated into soil; nutrients from e.g. (inorganic) fertiliser / (organic) manure; are dissolved in soil water; some nutrients not absorbed by the forest / cropland / pasture; leaching; percolation / seep to water table / groundwater; groundwater flow to lake; max 4 1(b) eutrophication; reference to algal bloom in Fig.1.1: increased / excessive growth of algae or plants; (algae bloom) blocks out light for underwater plants below; (underwater) plants cannot photosynthesise; resulting in death and decay of algae or plants; increase in population of microorganisms or decomposers or bacteria; oxygen used in respiration; oxygen depletion of water; reduced biodiversity; death of aquatic organisms; max 6 Question Answer Marks 1(c) reduce pollutants in run-off into water store e.g. reduce pollution from sewage / reduce agricultural run-off; improve waste disposal systems; water treatment / tertiary treatment; re-use of grey water / recycling of water; control of agricultural run-off through e.g. timing of fertiliser application or quantity of fertiliser; buffer strips; legislation to reduce industrial sources; fines for polluters: monitoring of nutrient levels in run-off; measuring of water quality variables in water stores; e.g. oxygen concentration, BOD, biotic index; max 4

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2 (a) Fig. 2.1 shows the distribution of the tundra biome and Fig. 2.2 shows the number of polar bears living in this biome. Arctic Circle, 66.5 °N Tropic of Cancer, 23.5 °N Equator Tropic of Capricorn, 23.5 °S Key tundra biome Fig. 2.1 RUSSIA Area 2 Area 3 ? Area 1 Area 4 Arctic Ocean Area 5 Area 18 Area 12 ? Pacific ALASKA Area 17 Ocean Area 8 Area 14 Key Area 16 Area 7 GREENLANDnumber of polar bears <200 Area 13 Area 9 Atlantic 200–500 CANADA Ocean 500–1000 Area 10 1000–1500 Area trend 15 1500–2000 declining Area 11 2000–2500 Area 6 stable increasing 2500–3000 0 500 1000 insufficient data ? unknown km Fig. 2.2 (i) With reference to Fig. 2.1, describe the distribution of the tundra biome. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[2] (ii) Outline factors that influence the distribution of the tundra biome. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[4] (iii) With reference to Fig. 2.2, describe the evidence which suggests that the polar bear is at risk of extinction. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[4] (b) Fig. 2.3 shows part of a food web in the Arctic. polar bear Arctic birds Arctic fox Arctic char fish ringed seal bearded seal Arctic cod fish amphipods shrimps capelin fish mussels zooplankton phytoplankton Fig. 2.3 Describe the effects of a decrease in the number of polar bears on the food web shown in Fig. 2.3. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[4] (c) Explain the importance of international protocols in the management of the tundra biome. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[6] [Total: 20]

Mark scheme: 2(a)(i) high latitude; northern hemisphere; within Arctic Circle; surrounding the Arctic Ocean; max 2 2(a)(ii) climate; low average temperatures (–20 to 15); low average rainfall (less than 70 mm); soil; permafrost / permanently frozen soil layer; bare rocky areas / limited soil; vegetation; limiting factors for growth / productivity; vegetation is restricted to grasses, mosses, lichens, dwarf shrubs / low growing plants; treeless plains; latitude; effect on day length / insolation; ocean currents; max 4 2(a)(iii) populations are very low in some areas; less than 200 in Area 12 and Area 8 (Lancaster Sound / Kane Basin); populations are declining in 6 / 50% / examples of areas); a population range of less than 2000 in areas where the populations are declining; even in areas where the population is stable the range is only 1000–3000; there are only a few, areas where the population is currently increasing; population change and population numbers are unknown for large areas; max 4 Question Answer Marks 2(b) increase in population of polar bear prey; e.g. bearded seal; increased availability of food for other predators; e.g. ringed seal; increase in population of other predators; reduced competition; e.g. Arctic fox ; max 4 2(c) agreements / treaties are required in order to manage the environment; different nations must share a collective responsibility for the biosphere including the tundra biome; other countries can have an effect on the tundra not just those in the immediate region; problems originate in the industrialised nations far away from where the effects are felt; e.g. air pollution – greenhouse gases; resulting in global warming / rising temperatures; resulting in earlier spring melting / shrinking of sea ice; habitat loss for polar bear; e.g. marine pollution – due to shipping; oil pollution; ocean currents spread maritime pollution; impact on food web; max 6

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3 Fig. 3.1 shows information about fresh water availability for selected regions and the contributions made by these regions to the total supply of desalinated water globally. fresh water availability for selected regions region average fresh water availability / m3 per person per year Middle East 500 Sub-Saharan Africa 1000 Asia 2970 Europe 4741 South America 7200 North America 13 401 percentage contribution made by the selected regions to the total supply of desalinated water globally 0.6% South America 2.1% others 6.2% Sub- Saharan Africa 10.1% Europe 10.6% Asia 53.4% Middle East 17% North America Fig. 3.1 (a) With reference to Fig. 3.1, suggest reasons for the regional variation in the supply of water by desalinisation. [10] (b) Briefly outline one process of desalinisation. Discuss the advantages and the disadvantages of desalinisation as a method of supplying fresh water. [30] [Total: 40]

Mark scheme: 3(a) Most desalination, over 50% (53.4%), occurs in the arid areas of the Middle East. These areas have water scarcity, a limited availability of freshwater from surface water and depleted groundwater stores. On average, only 500 cubic metres of freshwater is available per person per year. All other regions collectively account for only 46.6%, of desalination. These regions have on average more freshwater available per person per year, from 1000 to 13 401 cubic metres. Regions with abundant water resources and low population density require minimal desalination for example South America with only 0.6% of desalinisation, as freshwater availability of 7200 cubic metres per person per year, is the second highest of all regions. Regions with a high population density and a high water demand for domestic supply and agriculture, have on average less freshwater available per person and more desalination for example Asia with 2970 cubic metres per person per year and 10.6% desalination. Less economically developed countries have a minimal supply of water from desalination, for example Sub-Saharan Africa with only 6.2% of desalination even though this region has the second lowest freshwater availability, after the Middle East. Although North America has the highest water freshwater availability of 13 401 cubic metres per person per year, it has the second highest amount of desalinisation 17%, due to a high demand for water for intensive agriculture, using irrigation. please use level descriptors 1 10 Question Answer Marks 3(b) The question requirements are: • to outline one process of desalinisation • to discuss the advantages of desalinisation • to discuss the disadvantages of desalinisation. Indicative content: Methods of desalination include for example electro dialysis, reverse osmosis, freezing and distillation. Advantages include the provision of potable water and reduced salt content of water. Desalinisation allows the use of brackish borehole water and the treatment of industrial and sewage effluents or polluted river water for reuse. Disadvantages include power consumption, the ecological impact of brine disposal, effectiveness of the process on a large scale and cost implications. please use level descriptors 2 30

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(a) With reference to Fig. 4.1, compare and contrast the trends in changes to forest reserves globally. Suggest reasons for the trends. [10] (b) Assess the effectiveness of methods used in the conservation of a named ecosystem. [30] [Total: 40]

Mark scheme: 4(a) Overall there is a greater decrease in forest reserves. Europe has the largest forest area in 2010 and also the largest increase, with a gain of 20 000 thousand hectares between 1990 and 2010. Although in 1990, Asia has the second lowest area of forest of all the regions with only 580 000 thousand hectares; Asia has increased forest cover between 2000 and 2010 by 10 000 thousand hectares. Decreases in forest area have occurred in S. America and Africa. These regions had the second and third highest area of forest cover of 940 000 thousand hectares and 750 000 thousand hectares in 1990. The largest decrease occurred in S. America with a loss of 80 000 thousand hectares in 20 years. Africa lost 60 000 thousand hectares with the largest decrease occurring between 1990 and 2000. There was increasing forest cover in North America cover between 1990 and 2000 but since then forest cover has remained constant at 670 000 thousand hectares. Exploitation of forests, the unsustainable harvesting of forest wood resources or use of forests for fuel wood contributes to the decrease in forest area. Rapid population growth with forests cleared to provide land for agricultural use, commercial cattle farming, plantations and urbanisation as well as building of infrastructure, dams, mining and climate change can also account for losses. Reasons for increases may include the conservation of the forest resources, forest restoration and afforestation. The more sustainable use of forest resources, alternative uses of forests for example in ecotourism, the establishment of protected areas and international agreements have also contributed to increases in forest cover. please use level descriptors 1 10 Question Answer Marks 4(b) The question requirements are: • to consider the conservation of a named ecosystem • to detail the strategies • to assess the effectiveness of the strategies. Indicative content: Content will be dependent upon the chosen example, e.g. a coral reef ecosystem or a forest ecosystem. Assessment should consider the extent to which the strategies have been effective in conserving the ecosystem or whether strategies have been ineffectual due to other factors which can impact upon the ecosystem. please use level descriptors 2 30

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5 Fig. 5.1 shows the water demands of different groups of countries for the year 2000 and the predicted water demands for 2050 by sector. 6000 5000 water 4000 Key sectors demand / km3 electricity 3000 manufacturing 2000 domestic agriculture 1000 0 2000 2050 2000 2050 2000 2050 MEDCs emerging LEDCs economies (BRICS)* groups of countries * BRICS = Brazil, Russia, India, China and South Africa Fig. 5.1 (a) Compare the water demands of the groups of countries for the year 2000 with those predicted for each group for 2050. Suggest reasons for any increases or decreases in demand. [10] (b) With reference to examples, assess the impact of population growth and the growing demand for water on the quality and quantity of natural water supplies. [30] [Total: 40]

Mark scheme: 5(a) Overall increases in water demand are predicted for both BRICS and LEDCs while in MEDCs an overall decrease in demand is predicted. Increases in water demand are predicted in the electricity sector in both BRICS and LEDCs. The demand for water in both domestic and manufacturing industry sectors is expected to increase in all groups of countries but with greater increases in BRICS and LEDCs. There is a predicted overall decrease in water demand in the agricultural sector in both MEDCs and BRICS. Economic development and industrialisation in BRICS and LEDCs will result in increased demand in electricity and manufacturing sectors. These competing demands for water will leave little scope for water for irrigation. Thus the agricultural sector will have less water and while irrigation use in agriculture is still the largest use of water, a decreasing demand for water for agriculture is predicted due to water scarcity and decreasing supplies. The reduced demand for water in MEDCs may develop from the sustainable use of water, water conservation, the recycling of water, metering of water or legislation. Increasing population in BRIC’s and LEDCs increases the demand for a domestic supply so that overall domestic demand is expected to increase. please use level descriptors 1 10 Question Answer Marks 5(b) The question requirements are: • to use examples of different countries to consider population growth and the growing demand for water • to assess the impact on quality of natural water supplies • to assess the impact on quantity of natural water supplies. Indicative content: Population is expected to reach 10 billion by 2050 and overall water demand will increase by a third, mostly in the economically developing countries. There is growing demand for water with economic development which will continue to increase demand in domestic and industrial sectors. More water is required for energy. This will Impact on the quality of water. Increased domestic use will generate more waste water and more industry, manufacturing and power generation will produce more pollutants resulting in increased water pollution. Increased agricultural output will be required to feed an increasing global population, resulting in the increased use of fertilisers and more eutrophication. Increased water demand will impact upon the quantity of water. The increased of extraction from rivers, and groundwater stores will deplete water resources. For example the overuse of wells for irrigation water will deplete groundwater stores. please use level descriptors 2 30 Section B descriptor levels: Descriptor Award Mark Consistently meets the level criteria Mark at top of level Meets the criteria, but with some inconsistency Middle, mark to just below top mark Meets most of level criteria, but not all convincingly Just below middle, mark to just above bottom mark On the borderline of this level and the one below Mark at bottom of level Section B descriptor levels: Section B (part a) Level descriptors 1 8–10 marks The response: • contains few errors • shows a very good understanding of the question • shows a good use of data or the information provided, where appropriate • provides a balanced answer 5–7 marks The response: • may contain some errors • shows an adequate understanding of the question • shows some use of data or the information provided, where appropriate • may lack balance 1–4 marks The response: • may contains errors • shows limited understanding of the question • shows little or no use of data or the information, where appropriate • lacks balance Section B descriptor levels: Section B (part b): Level descriptors 2 Responses: Level one, 25–30 marks • fulfil all the requirements of the question • contain a very good understanding of the content required • contain a very good balance of content • contain substantial critical and supportive evaluations • make accurate use of relevant vocabulary Level two, 19–24 marks • fulfil most of the requirements of the question • contain a good understanding of the content required • contain a good balance of content • contain some critical and supportive evaluations • make good use of relevant vocabulary Level three, 13–18 marks • fulfil some requirements of the question • contain some understanding of the content required • may contain some limited balance of content • may contain brief evaluations • make some use of relevant vocabulary Level four, 6–12 marks • fulfil limited requirements of the question • contain limited understanding of the content required • may contain poorly balanced of content • may not contain evaluations • make limited use of relevant vocabulary Section B descriptor levels: Level five, 1–5 marks • fulfil a few of the requirements of the question • contain a very limited understanding of the content required • are likely to be unbalanced and undeveloped • evaluative statements are likely to be missing • make no use of relevant vocabulary

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