30 exam-style questions. Write your answer, check it against the mark scheme and tick the points you earned. Your marks stay on this device. Your writing is not saved.
Ratings are saved in this browser on this device, under a KS4 key kept separate from International A Level recall. Written answers are temporary and cleared when you leave the page. Use Reset to clear the ratings on this device.
Plan it with CORMMSS: Design an investigation (Logic Lab).
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Explain how untreated sewage entering a river can kill fish.
(5)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 5 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Why does sewage reduce oxygen in a river?
(1)Total for this question: 1 mark
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Explain why sewage in water can be a health risk to humans.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Illustrative survey data.
| Site | Distance / km | Oxygen / mg per dm³ | Bacteria / relative | Mayfly larvae per sample |
|---|---|---|---|---|
| A | 0.5 above | 9.0 | 5 | 25 |
| B | 0 | 2.5 | 90 | 0 |
| C | 2 | 4.0 | 60 | 1 |
| D | 6 | 7.5 | 20 | 12 |
| E | 10 | 8.8 | 8 | 22 |
Describe the changes in oxygen concentration along the river.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
| Site | Distance / km | Oxygen / mg per dm³ | Bacteria / relative | Mayfly larvae per sample |
|---|---|---|---|---|
| A | 0.5 above | 9.0 | 5 | 25 |
| B | 0 | 2.5 | 90 | 0 |
| C | 2 | 4.0 | 60 | 1 |
| D | 6 | 7.5 | 20 | 12 |
| E | 10 | 8.8 | 8 | 22 |
Explain the changes in the number of bacteria.
(3)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 3 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
| Site | Distance / km | Oxygen / mg per dm³ | Bacteria / relative | Mayfly larvae per sample |
|---|---|---|---|---|
| A | 0.5 above | 9.0 | 5 | 25 |
| B | 0 | 2.5 | 90 | 0 |
| C | 2 | 4.0 | 60 | 1 |
| D | 6 | 7.5 | 20 | 12 |
| E | 10 | 8.8 | 8 | 22 |
Explain why mayfly larvae are absent at site B.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
| Site | Distance / km | Oxygen / mg per dm³ | Bacteria / relative | Mayfly larvae per sample |
|---|---|---|---|---|
| A | 0.5 above | 9.0 | 5 | 25 |
| B | 0 | 2.5 | 90 | 0 |
| C | 2 | 4.0 | 60 | 1 |
| D | 6 | 7.5 | 20 | 12 |
| E | 10 | 8.8 | 8 | 22 |
Suggest why oxygen recovers downstream.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
| Site | Distance / km | Oxygen / mg per dm³ | Bacteria / relative | Mayfly larvae per sample |
|---|---|---|---|---|
| A | 0.5 above | 9.0 | 5 | 25 |
| B | 0 | 2.5 | 90 | 0 |
| C | 2 | 4.0 | 60 | 1 |
| D | 6 | 7.5 | 20 | 12 |
| E | 10 | 8.8 | 8 | 22 |
Calculate the percentage decrease in oxygen from site A to site B.
(2)Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Illustrative data from the survey.
| Distance / km | Oxygen / mg per dm³ |
|---|---|
| 0 | 2.5 |
| 2 | 4.0 |
| 6 | 7.5 |
| 10 | 8.8 |
Plot oxygen concentration against distance for sites B to E. Join your points with straight lines using a ruler.
(5)Graph skills: SLAPUK and choosing a scale
Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 5 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Explain why some invertebrates are used as indicator species for water pollution.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Identify one indicator species of clean water and one of polluted water.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Explain why sludge worms are found in high numbers near sewage outlets.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Describe how to measure the effect of a sewage outlet on invertebrates in a stream.
(3)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 3 marks
Plan it with CORMMSS: Design an investigation (Logic Lab).
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Link: practise planning on /subjects/igcse-biology/logic-lab/design-an-investigation.
Design an investigation to find out whether a sewage outlet affects the number of invertebrate species in a stream.
(6)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 6 marks
5.16 Water pollution by sewage
Exam question
Mark points shown after marking
Explain why samples should be taken at the same depth and flow rate.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
