DEVELOPMENT OF A TOXICITY-BASED FRACTIONATION APPROACH FOR THE IDENTIFICATION OF PHOTOTOXIC PAHS IN POREWATER.  P. A. Kosian, E.A. Makynon (Email address of presenting author), U.S. EPA, Mid-Continental Ecology Division, Duluth, MN 55555; and P.D. Monson, University of Rhode Island, Narragansett, RI 02882.

Environmental matrices (e.g. effluent, sediment) often contain complex mixtures of chemical compounds.  Typically, only a few of these ...................