Supplementary data for "Co-deployment of passive samplers and mussels reveals major source of ongoing PCB inputs to the Anacostia River in Washington DC"

Remedial investigations of sites contaminated with legacy pollutants like polychlorinated biphenyls (PCBs) have traditionally focused on mapping sediment contamination to develop a site conceptual model and select remedy options. This sediment-focused approach often leads to an incomplete understanding of the impacts of ongoing inputs to the water column and over-estimation of potential effectiveness of sediment remediation. Here we demonstrate the utility of co-deployment of passive equilibrium samplers and freshwater mussels as dual lines of evidence to identify ongoing sources of PCBs from eight main tributaries of the Anacostia River in Washington, DC that has been historically polluted from industrial and other human activities. The freely dissolved PCB concentrations measured using passive samplers tracked well with the accumulation in mussels and allowed predictions of biouptake within a factor of 2 for total PCBs and a factor of 4 for most congeners. One tributary was identified as the primary source of PCBs to the water column and became a focus of additional ongoing investigations. Co-deployment of passive samplers and mussels provide strong lines of evidence to identify ongoing sources critical to control to achieve river water quality standards and reduce bioaccumulation in the aquatic food web.