Screening for heavy metal accumulators amongst autochtonous plants in a polluted site in Italy.

The site around ACNA factory (Northern Italy) is characterized by multi-metal contamination, therefore it can be considered as a source of autochthonous plants able to tolerate or accumulate heavy metals (HMs). The hill A5, a waste dump of the chemical factory, was chosen as the study area, in order to assess the metal accumulation ability of the vegetation growing under HM stress. The plant species, biodiversity and health were related to the concentration of HMs in four areas of the hill A5, and to the metal accumulation in shoots and roots. Uptake of HMs occurred at different extent in the various plant species and differed according to the considered organ and metal. Polygonum aviculare hyperaccumulated Hg in the shoot suggesting its possible exploitation in phytoextraction. A number of species, that can be useful in phytoremediation plans, accumulated simultaneously more than two heavy metals both in the shoot and in the root.