Assessment of the phytoremediation potential of Canola (Brassica Napus) and Vetiver (Vetiveria Zizanioides L.) for toxic elements

Phytoremediation permits to contain or remove contaminants in soils by using pollutantaccumulating plants that can immobilize or extract and translocate them to the harvestable parts. We report about a study carried out for assessing the phytoremediation potential of canola (Brassica Napus L.) and vetiver (Vetiveria Zizanioides L.) in soils contaminated by toxic elements, in the framework of a pot-experiment. The plants were grown in soils sampled in a contaminated area, using two different agricultural conditions: with and without phosphatic fertilization. With the aim to consider all the input and output of toxic elements, not only soils and vegetable tissues, but also the irrigation waters (or rainwater), the added fertilizers and the percolation waters were analyzed. Main physical-chemical properties of soils were determined; the total contents of toxic elements before and after the plant growing were compared. As concerns canola and vetiver plants, the toxic element contents were determined in the different tissues apart. Moreover, considering that the total elemental content in soils is insufficient – in respect to the bioavailable fractions – to explain their translocation from soils to plants, soils were submitted to selective extraction procedures for obtaining information about the mobile (or mobilizable) fractions of toxic elements. In this way, it was possible to determine the Translocation Factor (TF) of each toxic element in the two plant species in the two different agricultural conditions and to evaluate the Bioconcentration Factors (BF), in respect not only to the elemental total contents in soils, but also to the bioavailable fractions.