Analysis of arsenic in soil and vegetation of a contaminated area in Zarshuran, Iran.

To assess the potential for arsenic (As) hyperaccumulation of native plant species, plant and soil samples were collected from the Zarshuran area (north-western Iran), which has a history of As pollution from mining. Total and water-soluble As in the soil ranged from 11.2 to 6525 and from 0.004 to 13.08 mg kg(-1), respectively. Among 89 plant species, the highest foliar As concentrations were found in Isatis capadocica (up to 3000 mg kg(-1)) and Hesperis persica (up to 1500 mg kg(-1)). Over a broad range of soil As concentrations, these species maintained more than 10-fold increased foliar As concentrations and soil to leaf As transfer coefficients in comparison with all the other species sampled at the same sites. Based on these characteristics, in combination with their ability to accumulate As to concentrations exceeding 1000 mg kg(-1) on a dry weight basis in their foliage, both species should be classified as As hyperaccumulators. I. capadocica and H. persica, both Brassicacaeae, are the first terrestrial angiosperms shown to possess the As hyperaccumulation trait. Both species are fairly robust with relatively high biomass productivity and, therefore, potentially useful in on site phytoremediation, particularly I. capadocica, because of its higher robustness and As accumulation capacity.