Which combination of actions is effective for reducing nutrient pollution entering waterways?

• A. Buffer zones and reducing fertilizer use.
• B. Increase fertilizer usage.
• C. Destroy wetlands.
• D. Increase runoff.

Answer: (A)

Nutrient pollution in waterways is best reduced by cutting the sources of nutrients and by preventing nutrients from leaving fields and entering water quickly. Buffer zones along fields and watercourses act as natural filters: the vegetation and soil slow down runoff, trap sediment, and take up nitrogen and phosphorus before the water reaches streams. Microbial processes and plant uptake help transform and store these nutrients, so less of them reach rivers, lakes, or estuaries. At the same time, using less fertilizer lowers the amount of nutrients that could be washed away or leached into groundwater, cutting the potential pool that could reach waterways.

This combination works because it tackles both ends of the problem: fewer nutrients available to escape, and more opportunity for any nutrients that do run off to be absorbed or slowed down before entering water bodies. Choosing options that increase fertilizer use or remove natural filters like wetlands would worsen pollution by delivering more nutrients to water or by eliminating pathways that remove them before they cause harm.