How do swamps filter pollution?

Answer 1

Swamps help to remove water pollutants. As water filters through wetland vegetation and soils, nutrients, sediments, and pollutants are removed. Wetlands improve water quality in several ways. For example, low oxygen levels in swamp water and soils promote the removal of nitrate-nitrogen through denitrification. Nitrate is formed from the combination of one nitrogen atom with three oxygen atoms. Free oxygen atoms like the ones we breathe are rare in swamp water. But swamp bottom bacteria can "breathe" with the oxygen atoms in nitrate. In this bacterial breathing process, nitrate is broken apart (denitrified) and the nitrate's nitrogen atoms are released to the air as a gas. Nitrate from human and animal wastes can leach into groundwater supplies and contaminate wells. Human babies are susceptible to nitrate poisoning, known as blue baby disease. High levels of nitrate in drinking water can prevent oxygen from being carried through the blood and in severe cases babies turn blue from a lack of oxygen. Additionally, low oxygen levels and organic soils can promote other biochemical reactions that can detoxify other pollutants.

Wetland plants also uptake nutrients for their growth. But plant material falling into swamp water is slow to decompose. This results in a build up of organic soils where nutrients are trapped. Wetland plants also slow water movement allowing pollutant particles to settle out. Scientists, engineers and biologists have long recognized the water quality improvement properties of wetlands and have created wetlands to help purify wastewater and storm water runoff.