What is the primary role of wetlands in pollution control?

• A. It reduces sedimentation
• B. It emits greenhouse gases
• C. Wetlands can filter pollutants, trap sediment, absorb nutrients, and protect water quality
• D. It increases nutrient runoff

Answer: (C)

Wetlands act as natural water-treatment systems. They slow down water, allowing sediments to settle and particulates to be trapped, while plants and microbial life in the wetland take up and transform pollutants. Nutrients like nitrogen and phosphorus are absorbed by vegetation and soils, and microbes break down or convert contaminants, all of which helps protect and improve downstream water quality. That combination of physical filtration, sediment trapping, and nutrient removal is why wetlands are so effective for pollution control.

Emitting greenhouse gases isn’t the primary pollution-control function of wetlands, even though they can produce methane under some conditions. They don’t increase nutrient runoff; instead, they generally reduce nutrient loads through uptake and transformation. And while sediment trapping is part of their action, the broader, more impactful role is their ability to filter pollutants and protect water quality.