Air Pollution – Problem Solving



IGCSE Unit 12 Name: ____________

Human Influence on the environment

1. The Following information was collected by studying eight different species of snail present in six Scottish lochs.

(+ = snails present) (ppm = parts per million).

| |Species of snail |Concentration of calcium (ppm) |

| | |in loch water |

|Loch |A |

| field mouse |32 |

|shrew |16 |

|vole |12 |

|small bird |4 |

a) Present the information in the table as a graph.

b) Construct a food chain which includes a barn owl.

c) Some farmers shoot barn owls on sight, claiming that they are a threat to their poultry. Does the information given in the table support this view? Explain your answer.

d) Other farmers welcome the presence of barn owls on their land. Suggest why.

3 The diagram below shows a form of atmospheric pollution.

Match the numbered boxes in the diagram with the following lettered descriptions to show the correct sequence of events.

A acid rain falls on land and water environments

B fossil fuels burned by industry, power stations and motor vehicles

C acid gases form rain clouds

D trees suffer dieback and fish die

E acid gases released into the atmosphere

4.

Pesticides

DDT is a poisonous chemical that used to be sprayed on crops to kill insect pests. The molecules of DDT are non-biodegradable (i.e. are not broken down by decay microbes into harmless substances). They therefore gathered in the soil and were washed by rain into lakes near farmland.

The following diagram shows the concentration of DDT in parts per million (ppm) found in the cells of the members of a lake community.

a) Construct a food chain which includes the four types of organism shown in the diagram.

b) Draw up a table to show the concentration of DDT found in the cells of each type of organism and arrange the information in increasing order.

c) (i) What relationship exists between the food chain and the concentration of DDT in the cells of its members?

(ii) Explain the relationship that you gave as your answer to question c) (i) using the terms non-biodegradable, accumulation and pyramid of numbers in your answer.

(iii) Which animal do you think was found to suffer most and often die as a result of DDT poisoning? Explain your answer.

d) Suggest why use of DDT has now been banned in Britain.

e) The accompanying bar graph shows the concentrations of pesticide residue found in the muscle tissues of three different water birds.

(i) Account for the difference in concentration found between grebe and moorhen.

(ii) Suggest why gannets are less severely affected than grebes.

5 Fig. 5.1 shows vehicles driving past a power station in Namibia and women carrying firewood they have cut.

(a) Describe how an increase of carbon dioxide in the atmosphere can affect the environment.

(b) Without further reference to carbon dioxide, explain how each of the following may have undesirable effects on the environment:

(i) the power station;

(ii) cutting down trees and burning the wood;

(iii) running motor vehicles such as the van or car.

[pic]

[pic]

Read the case study before answering these questions:

a. Describe how samples of the organisms at A, B and C would be taken.

b. Draw three bar charts to show the number of each species at each sample site.

c. Describe where you think the sewage pipe joins the river. Explain your choice.

d. Describe what is meant by an indicator species.

e. What evidence is there that the river can recover from the effects of sewage discharge?

f. Which type of organism shown on the graph could be used as an indicator of pollution?

g. Which organism not shown on the graph might be used as an indicator of unpolluted water?

h. Fishermen reported dead fish floating in the water at a point on the river. Which of the points A to E might this be?

7. Polluted River Survey

Changes in the degree of pollution can cause changes in a community of aquatic organisms in a river.

The activities of bacteria in water convert organic waste into harmless substances and in doing so use up all the available oxygen. As you go further downstream, oxygen will enter water from the air and eventually the community of aquatic organisms will return to normal.

Study the information below.

[pic]

At five places along the river samples of water were taken and tested for turbidity (how cloudy the water is), oxygen concentration and numbers of bacteria. In addition, aquatic invertebrates were collected at each site. The results of this survey are shown below.

Freshwater Invertebrate sampling

|Freshwater Invertebrate |Sample Site |

| |1 |2 |3 |4 |5 |

|Stonefly nymph |15 |0 |0 |0 |12 |

|Mayfly nymph |14 |0 |0 |0 |13 |

|Caddisfly larva |3 |0 |0 |1 |1 |

|Blood worm |0 |0 |30 |15 |0 |

|Sludge worm |0 |59 |33 |0 |0 |

|Water louse |1 |0 |0 |20 |2 |

|Shrimp |2 |0 |0 |1 |1 |

|Rat tailed maggot |0 |24 |4 |0 |0 |

Questions:

a. In which part of the river is the turbidity greatest?

b. What causes the water to be cloudy?

c. Why is there a large number of bacteria at sample site 2?

d. Why is there a low concentration of oxygen at sample site 2?

e. Why does the water get less cloudy as you go downstream of sample site 2?

f. Why do the numbers of bacteria decrease as you go downstream of sample site 2?

g. Give two reasons why the oxygen level increases as you go downstream of sample site 2?

h. Construct a bar chart to show the number of different kinds of species at each sample site.

i. What effect does the amount of sewage have on the number of different kinds of species at each sample site?

j. Construct a bar chart to show the total number of organisms at each sample site.

k. What effect does the amount of sewage have on the total number of organisms at each sample site?

8. Air Pollution – Problem Solving

Air is a mixture of four gases; nitrogen, oxygen, carbon dioxide and water vapour. When fuels burn, oxygen from the air is used up and smoke, ash, carbon dioxide, sulphur dioxide, nitrogen oxides and hydrocarbons are produced, which can pollute the air.

|Pollutant |Source |

|(tonnes) | |

| |Power stations |Motor vehicles |Burning waste |Industry |

|Soot particles |8 000 000 |1 000 000 |900 000 |6 900 000 |

|Sulphur dioxide |22 200 000 |800 000 |1 000 000 |6 700 000 |

|Nitrogen dioxide |9 200 000 |7 400 000 |600 000 |300 000 |

|Carbon monoxide |1 600 000 |57 800 000 |7 000 000 |8 100 000 |

|Hydrocarbons |600 000 |15 100 000 |1 500 000 |4 200 000 |

The table above shows how much of each of these pollutants were produced in one year in America.

a. Name three gases present in the air.

b. Which gas in the air is used up when fuels are burned?

c. How much carbon monoxide was produced by motor vehicles in one year?

d. Which source of air pollution is the greatest in one year?

e. Suggest one method of reducing the level of this pollutant.

9. Indicators of Air Pollution - Problem Solving

The burning of fossil fuels such as coal and oil releases the gas sulphur dioxide into the air. Lichens are one group of plants which are sensitive to the presence of sulphur dioxide in the atmosphere.

There are three types of lichen:

|Crusty |Leafy |Shrubby |

|[pic] |[pic] |[pic] |

There are many different lichens in each group. The presence or absence of each type of lichen indicates the level of air pollution.

The table below shows the numbers of different species of each type in each square kilometre around the city centre. Complete the table.

|Distance from city centre in |No. of lichen species in each square kilometre |

|kilometres | |

| |Shrubby lichen |Leafy lichen |Crusty lichen |Total number of species |

|1 |0 |0 |1 | |

|2 |0 |0 |1 | |

|3 |0 |0 |2 | |

|4 |0 |1 |6 | |

|5 |0 |1 |8 | |

|6 |0 |2 |12 | |

|7 |0 |4 |13 | |

|8 |1 |8 |13 | |

|9 |3 |9 |13 | |

|10 |7 |10 |13 | |

|11 |8 |10 |13 | |

|12 |8 |10 |13 | |

The level of sulphur dioxide in the air around the city was also measured.

|Distance from city centre (km) |Amount of sulphur dioxide |

|0 |170 |

|2 |125 |

|4 |70 |

|6 |50 |

|8 |50 |

|10 |35 |

|12 |0 |

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6. Case Study – freshwater pollution

A small town pumps sewage into a river which runs through a woodland. The level of pollution that this causes is investigated by taking samples of bacteria from the water and also by measuring the amount of dissolved oxygen. The information is shown on the graph below:

[pic]

Questions:

a. How many species of leafy lichen are there 8km, from the city centre?

b. What is the total number of lichen species 8km, from the city centre?

c. What happens to the total number of lichen species as you move further away from the city centre?

Questions continue:

d. (i) Plot the level of sulphur dioxide against distance from the city centre.

(ii) Plot a graph of total number of lichen species against the distance from the city centre

e. Using the information obtained from the graph give a reason for the change in the total number of different species of lichen as you move further away from the city centre.

f. Which type of lichen is most affected by sulphur dioxide?

g. If you found crusty, leafy and shrubby lichens what conclusion could you make about the amount of sulphur dioxide pollution in the air?

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