Screening for PAHs by fluorescence spectroscopy: A comparison of calibrations

Total PAHs were estimated by UV-fluorescence spectroscopy in sediments from the Duluth-Superior Harbor Area of Concern in the Western arm of Lake Superior (USA). The screening method used a simple hexane extraction followed by fluorescence analysis using a standard, un-modified, Turner TD-10 fluorometer equipped with a short wavelength hydrocarbon kit. Three calibration scenarios were evaluated. The accuracy of the method was dependent on the calibration method selected that depended on the knowledge of the site. The method had good overall accuracy for designating “hot spots”(with Total-PAHs > 2,000 μg/Kg dry weight) and for plume delineation, with a relatively low rate of “false positives” (17%) and “false negatives” (18%) at the designated sediment criteria. In addition the method had significant cost advantages over standard GC/MS methodology for sediment assessment.