REMEDIATION AT A MARINE SUPERFUND SITE - SURFICIAL SEDIMENT PCB CONGENER CONCENTRATION, COMPOSITION, AND REDISTRIBUTION

New Bedford Harbor (NBH) is an estuary severely contaminated with poly chlorinated biphenyls (PCBs) and is undergoing a multistage Superfund remediation. A longterm monitoring program was developed to assess the effectiveness of this remediation. Seventy-two stations were monitore d in the harbor and in adjacent Buzzards Bay. Sediments were collected at each station before and after the initial remedial phase (the ''ho t spot'' removal), and the concentrations of 18 PCB congeners were qua ntified. A qualitative graphical technique was combined with explorato ry statistical techniques to examine the spatial and temporal variabil ity in concentrations of PCBs and proportions of the congeners. The co mbination of the two techniques with PCB congener ratios revealed subt le changes after remediation that were not evident by a more tradition al statistical analysis of total PCB concentrations. Although major re distributions of contaminated sediments were confined to the immediate vicinity of remedial activities, there is evidence that low molecular weight PCBs were transported farther.