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THE DISTRIBUTION OF 137CESIUM AND OTHER TRACE CONSTITUENTS IN GREEN BAY, LAKE MICHIGAN
Citation:
Edgington, D. N., J. B. Manchester, J. A. Robbins, AND R. Rossmann. THE DISTRIBUTION OF 137CESIUM AND OTHER TRACE CONSTITUENTS IN GREEN BAY, LAKE MICHIGAN. Presented at International Association for Great Lakes Research - 2001 Annual Conference, Green Bay, WI, June 10-14, 2001.
Description:
137Cs, Cadmium, and PCBs were measured in a series of sediment cores collected in Green Bay between 1987 and 1989. Analysis of the spatial distribution of the chemicals can be shown to be dependent on the nature of the input - totally from the atmosphere, totally riverine, and a mixture of the two. For each chemical the ultimate distribution pattern must reflect the historical distribution of the actual sedimenting particles and be related to the variation in in sedimentation rate. A comparison of the inventories of these three chemicals shows that 137Cs, which was deposited uniformly over the lake surface, most closely mirrors the depositional pattern of the actual sediments. On the other hand, the distribution of PCBs, which have been predominantly released to Green Bay by release into and transport down the Fox River, is concentrated towards the eastern shore of the bay, following the flow of water and particles from the Fox River northwards. In time, the particle transport processed occurring in the bay will eventually result in a movement of the PCB load westwards and northwards to the major sediment deposition zone south of Chambers Island just north of Sturgeon Bay. Based on our experience in Lake Michigan, these sediment resuspension-redeposition processes occur with a half-time of decades.