BINDING OF POLYCYCLIC AROMATIC-HYDROCARBONS BY SIZE CLASSES OF PARTICULATE IN HAMILTON HARBOR WATER

In aquatic systems there is considerable transport of organic contamin ants on suspended particles that act as carriers and influence the red istribution, 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 Ha rbor are predominantly sorbed to suspended flocs. Techniques employed were as follows: (i) differential cascade sedimentation and centrifuga tion to separate suspended particles; (ii) scanning transmission elect ron microscopy and energy-dispersive spectroscopy to identify flocs an d individual particles in the size range of 10(-3)-10(3) mu m; (iii) g as chromatography-mass spectrometry to identify PAH in extracts prepar ed from size classes. Heterogeneous flocs larger than 20 mu m accounte d for roughly 98% of phenanthrene binding, 89% of fluoranthene binding , and 85% of pyrene binding.