Salinity and Heavy Metal Tolerance, and Phytoextraction Potential of Plants from a Sandy Coastal Beach.

The aim of the present study was to evaluate tolerance to salinity and different heavy metals as well as the phytoextraction potential of plants from a brackish coastal sandy beach habitat. Four separate experiments were performed with plants in controlled conditions: (1) the effect of NaCl gradient on growth and ion accumulation, (2) the effect of different Na and K salts on growth and ion accumulation, (3) heavy metal tolerance and metal accumulation potential, (4) the effect of different forms of Pb salts (nitrate and acetate) on plant growth and Pb accumulation. A negative effect of NaCl on plant biomass was evident at 0.5 g L Na and growth was inhibited by 44% at 10 g L Na, and this was associated with changes in biomass allocation. The maximum Na accumulation (90.8 g kg) was found in the stems of plants treated with 10 g kg Na. The type of anion determined the salinity tolerance of plants, as Na and K salts with an identical anion component had a comparable effect on plant growth: nitrates strongly stimulated plant growth, and chloride treatment resulted in slight but significant growth reduction, but plants treated with nitrites and carbonates died within 4 and 5 weeks after the full treatment, respectively. The shoot growth of plants was relatively insensitive to treatment with Mn, Cd and Zn in the form of sulphate salts, but Pb nitrate increased it. Hyperaccumulation threshold concentration values in the leaves of were reached for Cd, Pb and Zn. can be characterized as a shoot accumulator of heavy metals and a hyperaccumulator of Na. A relatively short life cycle together with a high biomass accumulation rate makes useful for dynamic constructed wetland systems aiming for the purification of concentrated wastewaters.