Treatment of pesticides in constructed wetlands: from the natural attenuation to the management of bioremediation and phytoremediation

Abstract

Most of pesticides contained in runoff waters go through constructed wetlands (CW). A decrease in pesticide concentrations is usually shown at the outlet of CW, without being optimized nevertheless. Basing on abiotic and biotic (microorganisms, macrophytes) parameters, this review aims at explaining the CW functioning for pesticide treatment. Suggestions are made to enhance performances of these processes. In particular, a minimum residence time of pesticides compatible with their biological degradation/extraction rate (bioremediation, phytoremediation) must be respected. Residence time can be set irrespective of the runoff level by improving pesticide adsorption on materials placed in CW.