Floating treatment wetlands improved removal of copper, fine suspended particles, and dissolved reactive P as compared to a control. Mats with artificial roots did not provide the same benefits as mats with living roots, indicating that living roots provide a key water treatment role beyond surface area.
Tanner, Chris C., and Tom R. Headley. (2011). Components of floating emergent macrophyte treatment wetlands influencing removal of stormwater pollutants. Ecological Engineering, 37(3), 474-486.