Assessment and Prediction of Biostabilization of Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments

Abstract

This work applied new investigative techniques to assess the locations, distributions, and associations of polycyclic aromatic hydrocarbons PAHs in dredged harbor sediment. Dredged materials from the Milwaukee Confined Disposal Facility were collected and homogenized to provide sufficient sample for four month bioslurry treatment testing and for P AH analyses on various size and density fractions before and after biotreatment. Sediment P AH analyses included both whole-sample measurements and, most importantly, the determination of P AH distribution by sediment particle size and type. Microprobe two-step laser desorptionlaser ionization mass spectrometry was used to identify and characterize P AHs on the subparticle scale and scanning electron microscopy with wavelength dispersive X-ray spectroscopy was used for elemental microanalysis. Physicochemical analyses included room temperature Tenax bead aqueous desorption experiments and thermal program desorption-MS studies to assess P AH binding energies on sediment particle types. Thermal programmed desorption-MS experimental protocols and data reduction techniques were developed to evaluate apparent P AH binding activation energies on sediment particles. Microbial ecology testing used phospholipid fatty acid PLF A and DNA procedures and radiolabeled microcosm studies. Earthworm bioassays studied the acute toxicity effects and PAH bioaccumulation from untreated and biotreated PAR-impacted dredged materials. Overall, the results were used to synthesize and correlate data to assess the availability and treatability of PAHs in dredged sediments.