Distribution of heavy metals in recent sediments in the Archipelago Sea of southwestern Finland

The distributions of organic carbon, sulphur, phosphate, and heavy metals (Ni, Co, Cu, Zn, Pb, Cd, Mn, Fe) were analyzed in marine surface sediments in the Archipelago Sea of southwestern Finland. Variations in heavy metal contents are caused mainly by physical not chemical processes. Lateral transport processes of particulate matter, including organic matter, strongly influence the distribution pattern of heavy metals in the study area. In addition, variable environmental conditions between stations contribute to differences in heavy metal contents. In the harbor, close to the mouth of the Aurajoki, there is a relatively high potential for the binding of heavy metals by oxides/hydroxides. In contrast, sulphide precipitations of heavy metals in the sediments may become relatively more important with increasing water depth, i.e. towards the outer Archipelago Sea. For chromium, aluminium, titanium and vanadium detrital binding was considered to be dominant.