Antarctic Marine Sediments: Distribution of Elements and Textural Characters

Abstract

The analysis of trace metals and their distribution in marine sediments is a very importantstep toward understanding geochemical and environmental processes and their possible changes due to anthropogenic activities. The present work reports results concerning the distribution of some major (Al), (Fe), and trace (Be, Cd, Cr, Mn, Ni, Pb, Sn, Zn) elements in Antarctic marine sediments. Chemical data were evaluated before and after extraction with 0.5 N HCl, taking into account the textural character of the sediments. The mean values of total metals in the <2-mm granulometric fraction were (mg/kg) (Al) 56,100 ± 3900; (Be) 2.04 ± 0.25; (Cd) 0.26 ± 0.16; (Cr) 20.3 ± 8.3; (Fe) 16,400 ± 4800; (Mn) 359 ± 108; (Ni) 6.31 ± 3.5; (Pb) 20.7 ± 2.8; (Sn) 2.12 ± 0.71; and (Zn) 42.3 ± 10.4. With the exception of Be, all the elements showed higher concentrations in the fraction <63 μm. The efficiency of extraction with 0.5 N HCl was generally low, as expected for unpolluted sediments. The relative percentage extraction of various elements was similar in the two fractions, with the exception of lead which presented a sensibly increased value in the fraction <63 μm. The results indicate that our samples are typical of areas not affected by anthropogenic inputs of elements and that potential polluting compounds are not bound within the structure of clay minerals.