Branching off the southwestern edge of Lake Michigan, the Indiana Harbor and Ship Canal (IHSC) in East Chicago, IN is designated as an Area of Concern by the International Joint Commission and is a major source of PCBs to Lake Michigan. Hydroxylated polychlorinated biphenyls (OH-PCBs) are toxic and bioaccumulative breakdown products of PCBs and were measured in surficial sediment from IHSC and five original Monsanto Aroclors. These compounds were measured using gas chromatography with tandem mass spectrometry (GC-MS/MS) and certified standards that allowed us to identify 65 individual or co-eluting congeners. Concentrations in the sediment ranged from 0.20 to 26 ng/g dry weight (Figure 1). Profiles of most samples were similar and were dominated by mono- to penta-chlorinated OH-PCBs. Interestingly, most of the samples strongly resembled the OH-PCB profiles of Aroclors 1221, 1242, 1248 and 1254, yet 25% of OH-PCBs measured in the sediment were not detected in Aroclors. A strong positive correlation was found between SOH-PCB and SPCB (p < 0.0001) and also between many individual OH-PCB:PCB pairs (p < 0.05). Analysis of OH-PCB:PCB pairs suggest PCB degradation is unlikely as a major source of OH-PCBs in IHSC sediment. We are the first to report levels of OH-PCBs in sediment and Aroclors, and our discovery is significant because it is likely that OH-PCB contamination exists in sediment anywhere that PCB contamination from Aroclors is present.

Discovery of hydroxylated polychlorinated biphenyls (OH-PCBs) in sediment from a Lake Michigan waterway and original commercial Aroclors

248th National Meeting (2014)

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