Evaluation of heavy metals seasonal accumulation in Phalaris arundinacea in a constructed treatment wetland

Constructed wetland for treatment of municipal wastewater was studied with focus on seasonal dynamics of heavy metals in the aboveground biomass of Phalaris arundinacea. Aboveground biomass was harvested and evaluated in one or two-month intervals during the period May 2011-March 2012 and concentrations of Cd, Cr, Cu, Ni, Pb, Zn were determined. Using the heavy metal concentration and biomass values, accumulation as standing stock was calculated for each heavy metal. The results indicated that maximum standing stock values occurred at different time for each heavy metals. The results therefore revealed that it is not easy to set the optimum time for aboveground biomass harvest in order to remove maximum of all heavy metals at one time. However, it seems that the harvest during the early growing season may be the most effective.