Sedimentary records of non-Aroclor and Aroclor PCB mixtures in the Great Lakes

► Non-Aroclor PCB congeners (e.g., PCBs11, 206, 207, 208, 209) were detected in the sediments. ► Non-Aroclor PCB congeners have a different source from ΣPCBs. ► ΣPCB concentration trends reflect manufacture and use of commercial Aroclor mixtures. ► Local use of Aroclors is preserved in the sediments. ► The production of pigments and dyes matches the accumulation of inadvertent PCB congeners.