Distribution and bioavailability of Cr in central Euboea, Greece

Abstract

Plants and soils from central Euboea, were analyzed for Cr (total), Cr(VI), Ni, Mn, Fe and Zn. The range of metal concentrations in soils is typical to those developed on Fe-Ni laterites and ultramafic rocks. Their bioavailability was expressed in terms of concentrations extractable with EDTA and 1 M HNO3, with EDTA having a limited effect on metal recovery. Cr(VI) concentrations in soils evaluated by alkaline digestion solution were lower than phytotoxic levels.Chromium and Ni - and occasionally Zn - in the majority of plants were near or above toxicity levels. Cr(VI) concentrations in plants were extremely low compared to total chromium concentrations.Cr(total) in ground waters ranged from <1 μg.L-1 to 130 μg.L-1, with almost all chromium present as Cr(VI). With the exception of Cr(total) and in some cases Zn, all elements were below regulatory limits for drinking water. On the basis of Ca, Mg, Cr(total) and Si ground waters were classified into three groups: Group(I) with Cr concentrations less than 1 μg.L-1 from a karstic aquifer; Group(II) with average concentrations of 24 μg.L -1 of Cr and relatively high Si associated with ophiolites; and Group(III) with Cr concentrations of up to 130 μg.L-1, likely due to anthropogenic activity. Group(III) is comparable to ground waters from Assopos basin, characterized by high Cr(VI) concentrations, probably due to industrial actrivities. © Versita Warsaw.