Copper hydrophytoremediation by wetland macrophytes in semi-hydroponic and hydroponic mesocosms.

High levels of trace metals such as copper (Cu) can affect water quality and induce toxic effects on living organisms in aquatic ecosystems. This research assesses the potential capacity for Cu phytofiltration by three emergent macrophytes from Cu-contaminated sediments and water containing five concentrations of Cu (0, 50, 100, 150, and 200 µM). We conducted a greenhouse study using semi-hydroponic and hydroponic experimental conditions to simulate a natural wetland system. We selected three plant types that were collected in Quebec (Canada): native Typha latifolia, and native and, exotic Phragmites australis. Under semi-hydroponic, the responses indicated an almost 3-fold higher mean root Cu-accumulation from Cu-0 to Cu-Sediment (80.3-226.1 mg kg-1) and an 8.6-fold increase (122.2-1045.5 mg kg-1) for Cu-0 to Cu-200 µM under hydroponic conditions, resulting in Cu translocation < 1 and BCF >1 under both conditions. We found an inverse correlation between increasing doses of Cu with mean aboveground and belowground biomass together with height, and root length of selected plants under hydroponic conditions. Our results indicate that these wetland macrophytes could be useful in heavy-metal removal from Cu-contaminated sediments and Cu-enriched water.

Studies in wetland phytoremediation have focus on either contaminated soil or water. This research highlights the comparison of three emergent macrophytes in removing copper from both soil (a simulated riparian wetland) and water (floating treatment wetland). This study compares the phytoextraction and rhizofiltration capacity of Typha latifolia, with native versus exotic Phragmites australis with a translocation factor for Cu < 1 and bioconcentration factor > 1 in the Cu-Sediment and Cu-enriched water.