Sediments contamination and remobilization of adsorbed contaminants increases their potential transfer along the trophic levels and exposure risks to the benthic dwelling communities. However, metal availability and toxicity is inherently related to metal speciation. Shallow littoral, deep and very deep limnetic areas within the Winam Gulf and the open lakes zones were sampled and analysed for major and trace elements. Spatially, the lake sediments reveal variable characteristics when moving from the littoral to the deeper zones. The elemental concentrations, sedimentary organic matter, carbonate and water contents were compared across the lake and water zones. The organic matter and carbonate contents revealed significant variation across the lake zones, but with no significant relationships (p < 0.05) with the elements. Sediment water contents in littoral and very deep sediments showed significant (p < 0.05) differences. The iron (Fe) lead (Pb), nickel (Ni) and copper (Cu) contents varied significantly between the sediment fractions (un-fractioned and finer fraction). Magnesium, silver, nickel and iron concentrations exhibited significant differences. between the water and lake zones. The sediment were enriched with Ag and Cu, but the geo-accumulation index shows uncontaminated sediments, except for silver. This implies lithological sources for the major elements and anthropogenic sources for silver, copper and lead. The bioavailability of the minor potentially toxic elements is controlled by their association with the surface sediments. Evaluations for lead, copper and nickel levels are a concern due to their exceedance of the threshold effect levels, and probable adverse effects to bottom dwelling organisms.
