Geochemical and Statistical Approach for Assessing Heavy Metal Accumulation in the Southern Black Sea Sediments

Abstract

The assessment of heavy metal pollution in the sediment of the Southern Black Sea requires knowledge of pre-anthropogenic metal concentrations. The effects of anthropogenic activities on the accumulation of heavy metals, elements, and other compounds in the sediment were examined. The objective of this study is to investigate the levels of metals, organic carbon, carbonate, and chlorophyll degradation products in order to assess the extent of environmental pollution and to discuss the origin of these contaminants in the sediments of the Southern Black Sea. The heavy metals, metalloid, and elements were assessed by factor analysis. The results of the factor analysis have shown positive and/or negative correlations among Mo, Cu, Pb, Zn, Ni, Co, Mn, Fe, As, Sr, Cd, Sb, Bi, V, Ca, P, Cr, Mg, Ba, Ti, Zr, Sn, S, Y, Hg, organic carbon, carbonate, and chlorophyll degradation products and has indicated that heavy metals in the sediments of the Southern Black Sea have different anthropogenic and natural sources. Also, a sediment pollution assessment was carried out using the enrichment factor and geoaccumulation index. The Igeo accumulation index shows that the surface sediment of the Southern Black Sea is not contaminated with respect to Cu, Pb, Zn, Mn, Fe, As, Sr, Bi, V, Cr, Mg, Zr, Y, Sb, Sn, and Ni, but is moderately contaminated with respect to Hg and Cd, and moderately to strongly polluted with respect to S and Mo. Despite total sedimentary concentrations above their pre-industrial background levels, Igeo shows that the surface sediments are unpolluted with respect to P, Ba, and Ti. The 14C age determinations have shown that surface sediments in stations KD2A and KD5A belong to AD 130-350 and AD 1000 respectively, indicating undersea landslides and turbidity fluxes in the Southern Black Sea are not rare because of the sharp slope in the topography of this region and high bottom transportation in certain places. The requirement of age determination is of