Moermond et al. (6) account for two pools of organic carbon in sediment; amorphous organic carbon (AOC) and black carbon (BC). The fraction of AOC equals the difference between the fraction of TOC and the fraction of BC (fAOC = fOC − fBC). The amorphous organic carbon−water partitioning coefficient KAOC (cm3/g) and the lipid−water partitioning coefficient KLIP (cm3/g) were both approximated by KOW, and a relationship between CS and Caq shown in eq 5 was obtained. The black carbon−water Freundlich coefficient (KFr,BC (g/g BC)(g/cm3)−n) accounts for PCB sorption to BC described by the Freundlich isotherm and was obtained using a KOW based estimate according to eq 6. The relationship in eq 6 was obtained for a Freundlich exponent n of 0.7. To maintain consistency with the other equations, the units of KFr,BC were adapted from those used by Moermond et al. (6).