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 HNO 3 , 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.

Spatial Evolution of the Chromium Contamination in Soils from the Assopos to Thiva Basin and C. Evia (Greece) and Potential Source(s): Anthropogenic versus Natural Processes

“…This order is consistent with that in previous studies [17,23,24]. Also, preliminary results on long time (one week) water extraction (leaching test) using natural Cr-free water and samples of soil and peridotites of varying degree of alteration revealed the following order of leaching: soils > highly serpentinized peridotites > less serpentinized peridotites, and an increasing trend between Cr concentrations in leachates and Cr, Mn, Fe, Co, Ni contents in soil samples.…”

“…On the basis of metal portion extractable using EDTA, expressed as a percentage of their total concentrations, the relative availability of the studied metals followed the order: Zn > Mn > Ni > Cr > Fe [17][18][19][20][21][22]. This order is consistent with that in previous studies [17,23,24].…”

“…Average metal values in soils range from 50 to 190 ppm Cr in the Oropos area, from 130 to 520 ppm at the Avlona area (Assopos basin), 230 to 310 ppm Cr (occasionally 800 ppm) in the Thiva basin, with an increasing trend from the southern part towards north (Mouriki), which is in a close proximity with Ni-laterite deposits (like Akrefnio) and ophiolites (Table 1; Figure 2), and a wide range of Cr in Evia (Figure 2) [17][18][19][20][21][22]. Similarly increasing trends from the Assopos basin towards north of Thiva basin, and furthermore to Evia soils are apparent for the Fe, Co and Mn versus Ni plots (Figure 2).…”

A Geochemical Investigation of Soils, Apples and Leaves in Agia Area, Central Greece

“…One would expect that, since these trees grow on soil enriched in Fe its elevated concentrations would be directly associated with their geogenic origin. Possibly, because Fe is found in resistant minerals is not readily available (Megremi, 2010;Petrotou et al, 2010).…”

Aspects of Hexavalent Chromium Pollution of Thebes Plain Aquifer, Boeotia, Greece

“…Also in the USA., in four major lakes of the Mississippi, pollutant toxic metals including chromium have been detected [5]; additionally, pollutant substances have been found in bottom sediments of Lake Symsar, Poland [6]. In several areas of Greece, Cr (VI) has been detected, such as Central Euboea and Avlonas [7,8].…”