Accumulation of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the snowpack of Minnesota and Lake Superior

The winter snowpack is a significant reservoir of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), and may be utilized as a surrogate receptor for assessing net atmospheric deposition. Seasonal snow cores were collected in late winter before snowmelt in northern and central Minnesota and at Eagle harbor, Michigan on Lake Superior between 1982 and 1992. Snowpack concentrations of Sigma-PCBs ranged from 1 to 14 ng/L with no significant decrease in concentrations from 1986 through 1992. Sigma(21)-PAH concentrations in 1989 and 1992 ranged from 35 to 3280 ng/L with significantly higher concentrations nearer urban areas. Similarities between chemical accumulations in the snowpack and collection of integrated snowfall at Eagle Harbor support the hypothesis that dry deposition to accumulated snow is negligible at these remote locations. Tributary discharges from spring snowmelt to Lake Superior in 1992 contributed 7 to 11 kg of Sigma-PCBs and 220 to 350 kg of Sigma(21)-PAHs.