Determination of Sediment Polycyclic Aromatic Hydrocarbon (PAH) Bioavailability using Direct Pore Water Analysis by Solid-Phase Microextraction (SPME)

摘要

Polycyclic aromatic hydrocarbons (PAHs) are often detected in many sediments adjacent to sites where industrial processes have operated. By their nature, PAHs are very hydrophobic, and tend to be tightly bound to the organic materials within sediments, making them unavailable for exposure to aquatic organisms. As a result of this binding phenomenon, there is often no correlation between the measured total PAH concentrations in sediments and those concentrations that adversely affect benthic organisms. Rather, these adverse effects are correlated to the dissolved-phase PAHs that are detected in sediment pore water. In spite of these observations, most PAH-contaminated sediment sites are evaluated and managed based on the total PAH concentrations determined on whole sediment samples. To be protective of the environment and at the same time provide a more realistic process for evaluating the risks of PAHs to benthic organisms, a framework was developed by the U.S. EPA (EPA) entitled Evaluating Ecological Risk to Invertebrate Receptors from PAHs in Sediments at Hazardous Waste Sites (EPA-600-R-06-162F)(U.S. EPA, 2009).