Three decades of investigations on heavy metals in coastal sediments, North Arctic Alaska: A synthesis

Abstract

Concentrations of V, Cr, Cu, Ni, Zn, As, Cd, Pb, Ba, Fe, Mn, total and methyl Hg were measured in muddy sediments from urbanized Elson Lagoon adjacent to Barrow Village, industrialized Colville Delta-Prudhoe Bay, and relatively pristine Beaufort Lagoon adjacent to the Arctic National Wildlife Refuge, Beaufort Sea, north Arctic Alaska. Comparison of the mean concentrations of the metals at approximately 10-year intervals (1977, 1986, 1997), within the Colville Delta-Prudhoe Bay shows significantly increased concentrations of V in 1986 and 1997 from 1977 and an increase in Ba from 1986 to 1997. No significant changes were noted in the concentrations of other elements. The sources of V and Ba contaminants are unknown. The levels of all metals are below or similar to those in unpolluted marine sediments. The geochemical partitioning of selected metals was deduced from metal analyses in the lithogenous and non-lithogenous sediment fractions. Of the total contents -50% of Mn, 25-35% Co, 15-20% Zn, Cu and Ni, 10% of V and Fe and <3% of Cr are bound in the non-lithogenous phase, presumably in organic matter, clays and Fe-Mn oxide/hydroxides. In contrast, almost all of Cr, Cd and Ba are lattice-held, and <1% of Hg is methylated.