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Geochemical Characterization of Greek Ophiolitic Environments Using Statistical Analysis

2015; Springer Science+Business Media; Volume: 2; Issue: S1 Linguagem: Inglês

10.1007/s40710-015-0097-z

2198-7491

Nefeli Bompoti, Maria Chrysochoou, D. Dermatas,

Heavy Metals in Plants

The presence of elevated Cr and Ni levels in the geoenvironment may be attributed to both anthropogenic sources and natural weathering processes of ultramafic rocks. Understanding the origin of these metals is important in environmental management. This study employed statistical methods, such as factor analysis and Pearson correlations, and specialized diagrams, in order to determine the origin of elevated metal levels as a function of the geologic background in five areas in Greece. Factor analysis indicated that each area had distinct geochemical characteristics with three geological background types involved: ultramafic, carbonate and silica rich rocks. Vergina has the strongest ultramafic background, while Thermi consists mostly of rocks with high silica content. Avlonas has a mixed ultramafic background with silica enrichment and Thiva has admixtures of ultramafic with carbonate rocks components. Inofita consists of primarily carbonates, with silica rocks contribution in the surficial samples and ultramafic components in the deeper samples. Accordingly, the highest Cr (up to 12,000 mg/kg) and Ni (up to 3140 mg/kg) concentrations in soil were observed in Vergina and the lowest in Thermi. In groundwater, Cr(VI) levels in Inofita exceeded 500 μg/L and are considered anthropogenic, as they are accompanied by high Cl− levels and not justified by soil Cr levels. Cr(VI) in groundwater was below 200 μg/L in all other areas. In Vergina, with only agricultural activity and pure ultramafic background, half of the groundwater samples were at or above the 50 μg/L threshold for Cr in drinking water. Also there is evidence of Ni concentrations exceeding 20 μg/L in the groundwater of Inofita and Thermi, both of which are attributed to the high ionic strength of groundwater.