Two cores (each ~40-cm) were collected using a Russian peat borer. PCB was extracted from Core 1 using standard EPA protocols for soxhlet extraction and analyzed by thin layer chromatography (TLC). An age model was determined from nearby Core 2 by performing 137Cs analysis. Magnetic susceptibility was measured on both cores to correlate them and transfer the age model of Core 2 to Core 1. Sediment grain size of Core 1 was analyzed by laser diffraction.
A 137Cs peak at 11-cm indicates an average sedimentation rate of ~2.8mm/yr. TLC suggests PCB is present, but indications of PCB at the ~1912 horizon imply some downward leaching and thus the timing of introduction remains unclear. PCB is associated with fine sediment perhaps reflecting differential adsorption. If so, clay may play a role in spatial and temporal PCB redistribution. Alternatively, the association of PCB with fines may be an artifact of grain size analysis conducted on raw sediment containing abundant partially-decayed organics.