Cambridge IGCSE Environmental Management 0680 — 2020 May/June Paper 2 · Variant 2

1 (a) (i) In Senegal, 2% of the population are involved in coastal fishing. Calculate the number of people in Senegal involved in coastal fishing in 2018. ......................................................... [1] (ii) Senegal has a rapidly increasing population. Describe factors that cause changes in human population. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (iii) Explain why the proportion of the population of Senegal under the age of 25 is likely to continue to increase. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (iv) Only 30% of the crops grown in Senegal are consumed in the country. Suggest what happens to the remaining 70% of crops grown in Senegal. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (v) Suggest reasons why it is a risk to the population of Senegal to rely on only 30% of the country’s crops. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (b) The photograph shows some young mango trees with mango fruits growing on a small farm. The mango trees are planted in rows 10 m apart. Suggest reasons why the farmer has planted the mango trees in this way. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2] (c) The fact sheet shows some information about mango fruits. Mango fruit fact sheet • Mango fruits are an important part of the diet in Senegal • 16 000 tonnes of mango fruits are exported from 2500 small farms • fertilisers and pesticides are not used on small farms • mango fruits are harvested between April and September • the best quality mango fruits are exported from Senegal in July and August • it is only possible to export mango fruits if they are grown 50 km or less from the capital city, Dakar. (i) Calculate the average mass of mango fruits exported from each small farm. .............................................. tonnes [1] (ii) The Casamance region of Senegal grows mango fruits. Suggest reasons why farms in the Casamance region cannot export mango fruits. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (iii) A local farmer said, In September we always have to leave some mango fruits on the trees. The fruits fall off the trees and rot on the ground. Explain how leaving the mango fruits to rot on the ground can help fruit production the following year. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (iv) Suggest one other reason why farmers leave some mango fruits on the trees in September. ........................................................................................................................................... ..................................................................................................................................... [1] (d) A student visited the Casamance region to investigate mango fruit production on small farms. The student talked to two farmers. One farmer said, I grow a variety of mango tree called kent and export the mango fruits. The second farmer said, I only grow local varieties of mango trees to sell the mango fruits in local markets. The student selected one box of mango fruits ready to leave each of the farms. Five fruits were selected and weighed from each box. The table shows the results. kent variety local variety mango fruit mass / g mass / g A 484 390 B 522 397 C 546 420 D 510 410 E 543 433 total mass 2605 .............................. average mass 521 .............................. Complete the table by calculating the total mass and average mass for the local variety of mango fruits. [2] (e) The student decided to use a questionnaire to find out about mango farms in the Casamance region. The student selected 18 mango farms. The results of the questionnaire are shown in the table. question results from 18 mango farms average How many hectares of 1.4 1.5 0.7 2.0 2.2 3.1 1.8 mango trees do you have? 1.0 1.2 1.7 0.5 0.7 1.9 3.2 1.8 2.4 2.5 1.8 1.9 How many tonnes of 2.4 4.3 5.1 3.0 4.4 5.2 3.8 mango fruits do you sell? 2.1 3.1 4.3 2.0 2.7 3.9 5.2 2.8 2.9 2.7 5.6 5.8 How many local varieties of 2 4 3 1 5 4 3.0 mango trees do you grow? 3 2 4 3 5 1 5 2 1 3 2 4 (i) Select information from the table to complete the statements. The smallest area of mango trees on one farm was .......................... ha. The largest mass of mango fruits sold by one farm was .......................... tonnes. The largest number of local varieties of mango trees on one farm was .......................... . [3] (ii) Suggest one other question the student could have asked the mango farmers. ........................................................................................................................................... ..................................................................................................................................... [1] (iii) The student concluded that most of the farms grow two local varieties of mango fruit. To what extent do the results support this conclusion? ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (iv) Suggest one advantage of growing local varieties of mango trees. ........................................................................................................................................... ..................................................................................................................................... [1] (f) The government of Senegal plan to improve many roads that lead to the airport in the Casamance region by 2025. Suggest how improving roads to the airport could benefit farmers and the government. benefit to farmers ...................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... benefit to the government ......................................................................................................... ................................................................................................................................................... ................................................................................................................................................... [3] (g) Food security can be defined as: ‘when people have enough food to meet their dietary needs for an active and healthy life.’ One farmer said, I do not just grow and sell mango fruits. I also grow millet and sorghum crops and keep chickens. (i) Explain why this farmer is likely to have food security every year. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) Explain ways food security could be lost. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (h) The table shows climate data from a weather station in the Casamance region. month Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec average wind speed 12 13 13 10 11 12 13 11 9 8 9 12 / km per h average rainfall 3 3 0 0 10 58 282 500 310 109 18 3 / mm (i) State the months when there is a high risk of soil erosion on farms in this region. Give a reason for your answer. months .............................................................................................................................. reason ............................................................................................................................... ........................................................................................................................................... [2] (ii) Explain how mango trees can protect against soil erosion on farms in the Casamance region. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [5] [Total: 42]

Mark scheme: 1(a)(i) 318 000; 1 1(a)(ii) any three from: birth and death rates; migration; carrying capacity; improved health and education / medical access; access to birth control / family planning; national policies / pronatalist / antinatalist; famine / disease / natural disasters; war / conflict; 3 1(a)(iii) any three from: the population already has a high % of young males and females; of reproductive age; so the birth rate is likely to be high / high number of children per woman; older people die / very few above 62 years / low life expectancy; AVP, e.g. no access to birth control / cultural influences ; 1(a)(iv) any two from: sold as a cash crop; exported; wasted / not good enough to sell / spoilt; fed to animals; used as fertiliser; non-food crops, e.g. biofuels, oil for products; 2 1(a)(v) any two from: food could become too expensive to buy; may not have, much food / food reserve / food security; at risk of crop failure; leading to, famine / starvation / death; 2 Question Answer Marks 1(b) any two from: space for, trees to grow / branches to spread out; easy access to pick fruit; allows farm machinery space to pass through; can grow other crops / graze animals between trees; AVP, e.g. helps to control / reduce plant diseases; 2 1(c)(i) 6.4 (tonnes); 1 1(c)(ii) any two from: over 50 km from Dakar; too far from a port; too far to go around the Gambia; high transport costs make exporting unprofitable; so fruits will spoil / short shelf life of fruit; costs of crossing the Gambia border; AVP, e.g. bad roads damage fruit; 2 1(c)(iii) any two from: fruits release nutrients into soil; taken up by tree next year; reduces chance of mineral deficiency; 2 1(c)(iv) low value due to oversupply / lack of demand / cost too much too pick; 1 1(d) 2050; 410; 2 1(e)(i) 0.5; 5.8; 5; 3 1(e)(ii) any suitable question about mango farming such as: How much does it cost to produce mango fruits? / How much profit do you make? / How much do mango fruits sell for? ; 1 Question Answer Marks 1(e)(iii) results do not agree / false conclusion; evidence to support, e.g. average is 3 / only four farms out of 18 grow two varieties; 2 1(e)(iv) any one from: grow well in local climate / better adapted to local environment; resistant to local pests; less expensive to buy; farmers know how to get the best fruits; 1 1(f) one from each section plus any other one: benefits to farmers: faster transport by road; cheaper transport by road; may be able to export by air; more income; vehicles last longer / are not damaged; fruits not bruised / arrive in better condition; benefit to government: airport used more; more, revenue / airport taxes / eq; so more money to spend on, other projects / named example; more import from / export to, places further away; 3 1(g)(i) any two from: farmer does not rely on (selling) one crop / has a variety of produce; unlikely that all crops would fail in the same year / more than one crop reduces chance of malnutrition / famine; source of protein / meat; sources of grain; source of vitamin C; varied diet covering all major food groups; 2 Question Answer Marks 1(g)(ii) any two from: prolonged drought / floods / natural disaster; infestation of pests / plague of locusts; harvest failure; new disease of, crops / animals; illness / injury to, farmers / workers; conflict; too many farmers replace food crops with cash crops; 2 1(h)(i) Jun / Jul to Sep / Oct; soil washed away; or Nov / Dec to Apr / May; dry soil blown away by wind; 2 1(h)(ii) any five from: protect underlying soil from heavy rain; roots bind soil; roots take up water from soil; increase interception; so more infiltration; surface run off less likely; reduce wind speed / act as wind break; organic matter from trees helps bind soil; 5

2 The geology of Senegal is mostly sedimentary rocks. These include large deposits of phosphate rock. (a) The drawing shows phosphate rock being mined in Senegal. Phosphate rock is a valuable export. rocks water mining machinery (i) Describe the processes involved in the type of mining shown in the drawing. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (ii) Suggest one reason why there is a low risk of water pollution from the mine shown in the drawing. ........................................................................................................................................... ..................................................................................................................................... [1] (b) The phosphate rock can be exported or it can be processed into phosphoric acid and then exported. The table shows the world price of phosphate rock from June 2012 to June 2018. year price / USD per tonne 2012 175 2013 131 2014 129 2015 128 2016 126 2017 100 2018 93 average 126 (i) Plot the world price of phosphate rock from 2012 to 2018 as a line graph. [4] (ii) Suggest why the price of phosphate rock has decreased since 2012. ........................................................................................................................................... ..................................................................................................................................... [1] (c) Phosphoric acid is used to make fertilisers in many countries. (i) The average selling price of phosphate rock produced in Senegal was 93 USD per tonne in 2018. The average selling price of phosphoric acid produced in Senegal was 880 USD per tonne in 2018. Calculate the percentage increase in value from one tonne of phosphate rock to one tonne of phosphoric acid. ...................................................... % [2] (ii) Suggest how increasing production of phosphoric acid in Senegal could benefit the government and the people. benefit to the government ................................................................................................. ........................................................................................................................................... ........................................................................................................................................... benefit to the people .......................................................................................................... ........................................................................................................................................... ........................................................................................................................................... [3] (iii) Name two mineral ions, other than phosphate ions, that are found in fertilisers. 1 ........................................................................................................................................ 2 ........................................................................................................................................ [2] (iv) Large quantities of fertiliser are used in agricultural production. Sometimes, excess fertiliser can enter rivers and cause eutrophication. Describe the impacts of eutrophication on aquatic ecosystems. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [5] [Total: 21]

Mark scheme: 2(a)(i) any three from: vegetation cleared; soil removed; overburden removed; explosives used; mining machinery used to dig out rocks / ore / phosphate rock; solid ore transported to processing plants (on trucks); 2(a)(ii) any one from: only a small body of water; and level ground / no slope towards stream/river; 1 2(b)(i) both axes fully labelled; linear scale such that plots occupy at least half the grid; line graph plotted correctly;; 4 2(b)(ii) over production / reduced demand; 1 2(c)(i) 880 – 93 / 787; (787 ÷ 93 × 100 =) 846(%); 2 2(c)(ii) one from each section plus any other one: benefit to government: increase value of exports; stronger economy; earns foreign exchange; benefit to people: more jobs available, in processing / transporting; earnings increase; improved standard of living, qualified / named example, e.g. more medical facilities; 3 2(c)(iii) nitrate (ion) / NO3–; potassium (ion) / K+; 2 Question Answer Marks 2(c)(iv) any five from: (toxic / harmful) algal blooms; subsequent bacterial blooms / decomposers; respiration increases; oxygen depletion; fish / aquatic animals die; loss of / change in, biodiversity; clogging / drying up of, ponds / lagoons; makes water smell / decreases water transparency; 5

3 Some gold deposits have been found in the east of Senegal. (a) Gold is formed in igneous rocks. When igneous rocks are eroded, small pieces of gold are washed away and redeposited in sedimentary rocks. Describe the formation of igneous rock. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [3] (b) Many local people work in family groups to extract gold from small mines between October and June each year. One method of finding small pieces of gold is shown in the drawing. water sediment containing gold pan (i) Describe how gold can be extracted by this method. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) Another method of extracting gold is to use mercury. Mercury is a toxic metal. Liquid mercury is mixed with sediment. The mercury combines with the gold and the mixture is easily removed. The mixture of mercury and gold is then heated to make all the mercury turn to gas. Mercury costs 14 USD per 100 grams. Gold can be sold for 30 USD per 1 gram. Suggest reasons why people use mercury to extract gold even when they know mercury is toxic. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (c) An advisor visited this mining area. The advisor explained to the miners the damage mercury does to human health and to the local river. (i) Describe the environmental impacts caused by toxic substances, such as mercury, entering a river. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (ii) The advisor gave the miners a rock-crushing machine and a table-shaker machine. These machines can extract more gold than using mercury. The advisor trained the miners how to use and maintain these machines. Suggest reasons why the miners had not used these machines before. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (iii) Suggest reasons why the advisor should keep visiting these miners in the future. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (iv) The mining families have been extracting gold in this region for many years. Many miners do not have a mining licence. However, the government has no plans to make this mining illegal. Suggest reasons why the government does not plan to make this mining illegal. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] [Total: 17]

Mark scheme: 3(a) any three from: hot / liquid magma; from the mantle; moves into the Earth’s crust; cools and solidifies; within or on surface of Earth; metallic crystals form; quick cooling forms small crystals / slow cooling forms large crystals; 3(b)(i) any two from: washing / swirling; to separate sediment and gold / wash lighter sediment away; looking for heavy gold left / gold pieces left in pan; 2 3(b)(ii) any three from: easy to extract gold / efficient method; know how to do it; mercury, very cheap compared to value of gold / readily available; want / need, to earn money (quickly); do not worry about long term toxicity; already invested in this method; 3 Question Answer Marks 3(c)(i) any three from: absorbed by, plants / producers / first consumers; small fish eat plants and small amounts of (toxic) mercury; large fish eat small fish, accumulate large amounts of (toxic) mercury; passes up the food chain / bioaccumulates; high concentration of mercury in large fish causes death; mercury poisons drinking water supply; 3 3(c)(ii) any two from: not a traditional method / did not know about them; could not afford to buy the machines; did not know how to use / maintain them / had no training; machines were not available; 2 3(c)(iii) any two from: to find out if the miners are still using / maintaining the machines; to check that the claim they can recover more gold is correct; to update training / train more miners; to help with repairs / maintenance; 2 3(c)(iv) any two from: many families would have to keep mining anyway; it is a traditional / well-established activity; difficult to enforce a ban / it might be very unpopular; helps to keep people on the land; reduces pull factor to urban areas; families will not require help from the government; 2