Water pollution management
Big idea: Managing water pollution requires a combination of prevention (stopping pollution at source), treatment (cleaning contaminated water), and restoration (repairing damaged ecosystems). Prevention is usually the most effective and lowest-cost approach.
Strategies to reduce nutrient pollution
- Riparian buffer zones
- Precision agriculture — applying fertilizers only where needed
- Cover crops — reducing erosion and absorbing excess nutrients
- Phosphate-free detergents — lowering household phosphorus inputs
- Improved wastewater treatment — removing nitrogen and phosphorus
- Constructed wetlands — using natural processes to filter water
Policy and economic approaches
- Legislation — setting legal pollution limits
- Polluter pays principle — polluters cover the cost of damage
- Subsidies — incentives for sustainable practices
- Fines and penalties — discouraging illegal pollution
- Public education — encouraging responsible behaviour
Strong answers explain HOW each strategy reduces pollution, rather than listing strategies without explanation.
IB-style question — managing nitrate pollution [7]
Nitrate from farm fertiliser is polluting a lake.
Evaluate two different strategies for managing this nitrate pollution, giving advantages and disadvantages of each. [7]
How to answer it, step by step
- Strategy 1 — cut fertiliser at source
• Use less, or switch to slow-release/organic fertiliser, so less nitrate runs off.
• Pro: stops the problem at its origin. Con: may lower crop yields and needs farmers to change habits. - Strategy 2 — buffer zones beside the lake
• Plant strips of vegetation that trap run-off before it reaches the water.
• Pro: cheap and adds habitat. Con: takes up farmland and heavy rain can overwhelm it.
Final answer
Name the pollutant, give two different strategies, and include BOTH a pro and a con for each — one-sided answers cap at 3.