“…Preparation, extraction, and cleanup procedures for measuring PCB sediment concentrations were performed as described previously (Martinez and Hornbuckle 2011). Briefly, ~ 0.5 g of wet sediment was mixed with combusted diatomaceous earth, spiked with 50 ng of surrogate standard [PCB14 (3,5-dichlorobiphenyl), PCB65-d5 (2,3,5,6-tetrachlorobiphenyl-d5, deuterated) and PCB166 (2,3,4,4′,5,6-hexachlorobiphenyl)] and extracted by pressurized fluid extraction (ASE, Dionex ASE-300).…”