Polychlorinated biphenyl release from resuspended Hudson River sediment

Three shear turbulence resuspension mesocosms (STORM tanks) were used to examine the release of polychlorinated biphenyls (PCBs) from resuspended Hudson River sediment. Twenty-two percent of the resuspended PCBs desorbed after 2 h, and 35% +/- 8% of PCBs were in the dissolved phase after apparent steady state was reached in 2 days. After the first resuspension event, the solids were allowed to settle and the quiescent time was varied to determine whether the labile pool of PCBs is recharged during sediment consolidation. The steady-state log Koc values for the third subsequent resuspension were higher than for the first event due to lower dissolved PCB concentrations; the particulate PCB concentrations were constant between events. With 1 day of consolidation between resuspension events, the dissolved concentration of all congeners decreased an average of 8% +/- 5% between subsequent resuspension events. With 4 days between events, only the dissolved pentachlorinated PCBs decreased significantly (p = 0.002), suggesting that the easily desorbable PCBs recharge when there is sufficient time between resuspension events.