Zn, Pb and Hg Contents of Pistacia lentiscus L. Grown on Heavy Metal-Rich Soils: Implications for Phytostabilization

In this study, we determined the metal (Zn, Pb and Hg) contents in epigean and hypogean organs of Pistacia lentiscus L., a Mediterranean native plant grown on heavy metal-rich soils of Iglesiente (southwestern Sardinia, Italy), in view of its perspective use for revegetation and phytostabilization of mine waste piles. Plant samples were collected from four different areas in the district. Metal contents in the different plant tissues are roughly dependent on their total and mobile (diethylene triamine penta acetic acid (DTPA)-extractable) contents in soil and are shown in the following ranges: 48-628 mg kg(-1) (Zn), 2-354 mg kg(-1) (Pb) and 13-530 mu g kg(-1) (Hg) and usually decrease in the following order: roots>stems>leaves; the apparent exception for Hg, with an order of leaves>stems, is ascribed to foliar absorption of this element. The biological concentration factors are consistently low (<= 0.05) for all metals and support the concept that the strategy of metal tolerance of P. lentiscus is based on exclusion. These results are consistent with most previous literature data, confirming that P. lentiscus is well suited for revegetation actions and could decrease metal mobility through the soil stabilization strategy.