PCB Volatilization from Sediments

The loss of polychlorinated biphenyls (PCBs) from sediment by volatilization is currently under scrutiny by polluters, regulators, and researchers. In this research, a one-dimensional mathematical model for the volatilization of PCBs from sediment was developed. The model considers a system with three phases: A watersaturated PCB contaminated sediment, the overlying water, and air above the water. A simple microcosm consisting of sediment, water and air that allows for (pseudo)-one-dimensional transport of PCB from the sediment to the gas phase was utilized to perform PCB transport studies using two PCB congeners: 4,4ʹdichlorobiphenyl (DCB) and 2, 2ʹ,4,4ʹ,5,5ʹ-hexachlorobiphenyl (HCB). The experimental data on DCB were used to calibrate and validate the mathematical model. The calibrated model was then used to simulate the effect of sediment layer thickness, depth of the overlying water, and the level of contamination on the rate of DCB volatilization.