Bioretention is a best management practice which uses vegetation to improve the pollutant removal rates in the rain water management.To select the best plant species to remove multiple pollutants in a bioretention system,we tested thirty species of plants in a laboratory in Beijing,China.We found that the ability of the plants to reduce concentrations of heavy metals including cadmium(Cd),lead(Pb),zinc(Zn),and ammonium(NH4?–N)is more than90%.The removal efficiencies for NH4?–N,nitrate(NO3-–N),total phosphorus,and copper(Cu)varied markedly among plant species.The single overall best plant was not easy to be determined.To select the best plant species,we used a dynamic neural network to establish an assessment index system,assessment criteria,and an assessment model that is used here for the first time for multiple pollutants’removal.Applying the theory and model,we discovered that Plantago asiatica L.and Digitaria sanguinalis(L.)Scop.are the overall best plants for removing the seven typicalpollutants.This paper will provide a simple and useful guide for the comprehensive assessment of multiple pollutant removal by plants in complex ecological systems.
Xiaohua YangYing MeiJun HeRong JiangYuqi LiJianqiang Li
