The role of black carbon in influencing availability of PAHs in sediments

In addition to natural organic matter, sediment organic carbon also comprises black carbon particles such as coke, charcoal, and soot, which are known to have extremely high sorption capacities. Industrial processes such as manufactured gas plant operations that released PAHs into soils and sediments also produced and released black carbon such as coke and soot, which alters the binding behavior of the organic carbon matrix in the geosorbents. Elevated PAH partitioning observed in sediment samples can be explained based on the black carbon content and known high PAH sorption capacity of black carbon. The sorption of PAHs to black carbon in sediments may also affect in situ bioavailability of PAHs. The application of black carbon availability models to describe PAH partitioning in sediments requires: (1) the correct understanding of the type of organic carbon responsible for PAH binding in sediments, and (2) accurate description of the partitioning characteristics of the different organic carbon phases in the sediment.