Binding of Polycyclic Aromatic Hydrocarbons by Size Classes of Particulate in Hamilton Harbor Water

In aquatic systems there is considerable transport of organic contaminants on suspended particles that act as carriers and influence the redistribution, bioavailability, and ultimate fate of contaminants. Using methodology not previously applied to the analysis of lake water, we demonstrate that polycyclic aromatic hydrocarbons (PAH) in Hamilton Harbor are predominantly sorbed to suspended flocs. Techniques employed were as follows: (i) differential cascade sedimentation and centrifugation to separate suspended particles; (ii) scanning transmission electron microscopy and energy-dispersive spectroscopy to identify flocs and individual particles in the size range of 10 - 3 −10 3 μm; (iii) gas chromatography−mass spectrometry to identify PAH in extracts prepared from size classes. Heterogeneous flocs larger than 20 μm accounted for roughly 98% of phenanthrene binding, 89% of fluoranthene binding, and 85% of pyrene binding.