Anthropogenically derived heavy metals in recent sediments of the Gulf of Finland, Baltic Sea

The anthropogenic loads of selected heavy metals in Recent soft sediments in the Gulf of Finland were studied through gravity corer sampling. Metals derived from silicates was excluded by applying a partial leach. Substraction of background values gave averages for the anthropogenically derived part of the heavy metal concentrations. The horizontal distribution of the metals in the surface sediments shows relatively high concentrations, especially in the eastern Gulf of Finland. The vertical distribution patterns vary from one part of the study area to another. Levels of all metals are relatively high in the upper part of the sediment profiles, usually with a decreasing trend in the topmost part of the profile. Averaged over the years 1993 to 1995 the annual accumulations of anthropogenically derived metals were, chromium 199 t, copper 158 t, cadmium 7.9 t, zinc 728 t, lead 165 t, cobalt 43.7 t and mercury 1.5 t.