The role of organic acids in assisted phytoremediation processes of salt marsh sediments

Some plants have high ability to absorb heavy metals in high concentrations. In this study, Spartina maritima was tested in conjunction with low molecular weight organic acids (LMWOA), in order to evaluate the possible use of this plant in phytoremediation processes in salt marshes. Three different LMWOA (citric acid, malic acid and acetic acid) were applied to contaminated intact cores of S. maritima colonized sediment and several heavy metals (Cd, Zn, Pb, Cu, Cr and Ni) were analyzed in sediment and plant parts. Acetic acid application proved to be the most efficient, enhancing greatly the uptake of all metals analyzed. Citric acid also showed good results, while malic acid proved to be very inefficient in most of the cases. The highest enhancement was observed for Cr with a 10-fold increase of the uptake upon application of acetic acid, while improving the Pb uptake proved to be the most difficult, probably due to its low solubility.