Status of the Contamination in Sediments and Biota from the Western Beaufort Sea (Alaska)

Surficial sediments in the western Beaufort Sea contained generally high concentrations of arsenic (up to 58 ppm as corrected for grain size), very low amounts of organochlorine compounds and concentrations of total polycyclic aromatic hydrocarbons (PAHs) ranging from 160 to 1100 ng/dry weight. Invertebrates contained higher concentrations of total PAHs than fish, with naphthalene being the largest contributor. Diagnostic ratios of various PAH compounds in our samples do not suggest crude oil as the main source of PAHs. Other sources of PAHs to the region include rivers outflow, coastline erosion, oil seeps, diagenesis, and long-range atmospheric transport. Organochlorine contaminants were consistently found in our samples at concentrations generally lower than those found in other parts of the United States. 137Cesium (Cs) was found in measurable amounts in all sediments and biota samples. Isotopic ratios showed that radionuclides originated most likely from global fallout. Compared to other coastal areas off Alaska, the Arctic, and the conterminous United States, Beaufort Sea contamination appears generally low.