Research advances in using constructed wetlands to remove pesticides in agricultural runoff.

Constructed wetlands (CWs) performs excellently in removing pollutants from agricultural runoff, and thus have been widely used as an effective measure to control agricultural runoff pollution. Based on reviews on domestic and overseas literature, we introduced the current situation of water bodies polluted by pesticides. The removal mechanisms of pesticides by CWs were elucidated according to physical, chemical and biological processes, and the main processes were discussed in detail. The removal efficiency of pesticides in CWs vary greatly with pesticide types. Based on their uses, the average removal efficiency of pesticides are in the order of insecticides > fungicides > herbicides. According to their chemical constitution, they follow the order of pyrethroid > organopho-sphorus > triazole > amide > triazine > ureas. Considering comprehensively, subsurface flow CWs perform better than surface flow CWs in removing pesticides. Furthermore, the effects of the physicochemical properties of pesticides, the types and operating parameters of CWs, pesticides concentration in influent, as well as vegetation on the removal of pesticides in CWs were also analyzed. Finally, problems in the current research and the future application of CWs in treating pesticides were discussed.