IB ESS SL 4.4.8 Eutrophication Management Levels Questions
Compare local, national and international responses to eutrophication.
- Syllabus
- First assessment 2026
- Course
- ESS SL
- Level
- SL
Exam points
- identify prevention and limiting strategies for eutrophication, including fertilizer control, organic farming, legislation, wastewater treatment, buffer zones and restoration
- explain how each strategy reduces nutrient inputs, runoff, algal growth or oxygen depletion
- evaluate eutrophication management by comparing prevention with clean-up, costs, feasibility, time scale and unintended effects
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IB ESS SL 4.4.8 Eutrophication Management Levels Questions question 1
[Maximum number: 7]
Evaluate two strategies for preventing eutrophication.
Strategy: [1max]
a. Avoid use of inorganic fertilisers by education / switch to organic fertilisers via taxes/laws;
Pros: [2max]
b. Eliminates origin of problem;
c. Organic fertilisers may be gained cheaply from natural waste;
d. Organic fertilisers provide slow release of nitrates/phosphates;
e. Education should have long-term impacts, especially if addressed to young generations;
f. Reduces GHG emissions/energy use during manufacturing of synthetic fertilizers;
Cons: [2max]
g. May reduce productivity;
h. Involves a change of farming practice that may not be popular;
i. Leads to inflation/passing higher prices to consumers;
j. Educational programs/laws/taxes need to be enforced effectively;
k. Taxes/laws may be unpopular/considered coercive;
Strategy: [1max]
I. Plant buffer zones to prevent agricultural run off;
Pros: [2max]
m. Prevents nitrates/phosphates from entering nearby water bodies;
n. Increases biodiversity of farmlands;
o. Low cost solution;
p. Reduces soil erosion;
Cons: [2max]
q. Requires considerable labour in short term;
r. Takes up space that could be used for more crops;
s. Heavy rainfall may overwhelm the buffer zone;
t. Does not eliminate origin of pollution;
Strategy: [1max]
u. Phosphate stripping/nitrate removal at sewage/domestic wastewater treatment facilities;
Pros: [2max]
v. Prevents phosphates/nitrates from reaching water bodies / completely removes from water;
w. Biological removal decreases sludge production;
x. Physical removal recovers phosphorus for re-use;
y. Some methods of phosphate stripping are considered cost-effective / fit for LEDCs, too;
Cons: [2max]
z. Chemical precipitation/removal results in more toxic sludge;
aa. Usually require high initial investment / high operational costs / large-scale facilities;
bb. Require continuous monitoring / high expertise;
Note to examiners: Credit any valid advantage or disadvantage of up to two valid strategies. If more than two strategies are evaluated, credit the two that gain the more marks and ignore the other strategies.
Do not credit similar evaluative KSs for both strategies (e.g MPm \& MPv will get mark once, but allow both MPb \& MPt).
Do not credit restoration strategies.
To get the strategy mark, there should be a little more than just naming;
especially for strategies like "construction of a dam" or "scrubbers reducing NOx" there should be outline of how these strategies would prevent eutrophication. Still allow ECF.
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