Edexcel IGCSE Biology 4.16 Sewage pollution consequences
Practise explaining how sewage entering rivers changes nutrients, decomposer activity, oxygen levels, disease risk and animal biodiversity.
- Syllabus
- First assessment 2019
- Course
- Biology 4BI1
Exam points
- explain the sewage sequence from waste nutrients to decomposers, oxygen fall and animal death
- interpret river graphs to link pollution levels with reduced biodiversity downstream
4.16 Sewage pollution consequences question 1
[Maximum number: 6]
Pollution can occur in the atmosphere and in rivers.
Water pollution can occur if sewage enters a river.
Explain the biological consequences of sewage pollution on a river ecosystem.
An explanation that makes reference to six of the following points:
- pathogenic bacteria / cause disease
- urea / urine / nitrogenous waste / nitrate / phosphate
- decomposition / decomposed / decomposers (ONCE)
- eutrophication / plant growth / algae growth
- (plants) block light / prevents photosynthesis
- respiration (ONCE)
- (less) oxygen ( 1 )
- death of organisms (ONCE) / reduce biodiversity / eq
All question bank results loaded