Assessment of Heavy Metal Accumulation in Two Aquatic Macrophytes: a Field Study

In order to assess the potential of two autochthonous plant species of Argentina as bioindicator and/or fitoremediator of metals, the accumulation of zinc, copper, cadmium and mercury in Schoenoplectus californicus and Ricciocarpus natans was studied. Total and labile contents of surface (SS) and near root sediments (NRS) were analyzed. Labile contents in NRS were lower than in SS, which was associated to the presence of S. californicus. Copper and zinc were positively correlated with total organic matter (TOM) whereas cadmium was not, suggesting low affinity of Cd to TOM. S. californicus presented the same pattern of distribution of those found in sediments (Zn > Cu > Cd). Bioaccumulation factors were close to (cadmium) or higher (zinc) than 1, while it was not conclusive for copper, revealing the S. californicus behaviour as an accumulator for zinc and indicator for cadmium. R. natans presented the highest metal levels among all studied matrix, with the presence of mercury. These findings showed the capacity of both S. californicus and R. natans to accumulate and remove heavy metals from sediments and water, which might be useful for phytoremediation programs. Keywords: aquatic macrophytes, S. californicus, R. natans, heavy metals, phytoremediation, bioindicator.