Mobility of PAHs, PCBs and TPHs from Fresh and Aged Dredged Sediments

The management of dredged sediments on land is an environmental concern worldwide since they may be overloaded with a wide range of pollutants. In this study, percolation tests were carried out to provide insight about the emission of selected polycyclic aromatic hydrocarbons (PAHs), Polychlorinated Biphenyls (PCBs), total petroleum hydrocarbons (TPHs) in five fresh and matured (1.5 years) dredged contaminated sediments. Although the studied sediments were heavily contaminated, less than 1% of the contaminants were emitted in column tests with an L S-1 ratio of 10 L kg(-1). Emissions of hydrophobic organic compounds were facilitated (by a factor of 30 to 1000 times) by colloids. The dissolved organic matter was identified as vector for the transfer of contaminants in leachates: PAH concentrations were correlated with humic acids and hydrophobic neutral organic carbon (HON) concentrations, and PCB concentrations with HON concentrations. Maturation of the sediments (moderate drying/rewetting cycles under oxidizing conditions for 1.5 years) dramatically reduced the emissions (TPH >= 60%, less hydrophobic PAHs >= 50%, PAHs with log Kow > 5.1 and PCBs = 100%, < LOQ).