Pesticide Removal

Pesticides are chemicals designed to fight insect, weed and pathogen pests. While necessary, they pose potential concerns should they be released into the environment in large doses.

Wetlands deal with these chemicals through one of 5 major means:

1. Volatilization - chemicals are vaporized
2. Oxidation - chemical modification
3. Sedimentation - chemicals settle out and are trapped in the bottom of the wetland
4. Sorption - chemicals become attached to clay or organic matter
5. Biological degradation - microbes transform the chemicals and break them down

All chemicals that have been examined in wetlands have been degraded to some degree. Currently, wetlands are widely used to treat effluent from paper and petroleum plants. Pesticides are typically organic (made up largely of hydrogen and carbon) compounds. Due to the diversity of pesticides, data is not available for all of them. Generally, however, for the compounds tested, wetlands have removed significant amounts of the contaminants. There are some issues with removal of chlorinated pesticides like DDT. Atrazine and others have been significantly degraded by wetlands.

In the future, scientific knowledge will allow for wetlands to more effectively process chemicals in runoff. Currently, results are promising.