W11 AM Environmental Chemical Forensics
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in 343-344

(BOE-1118-031311) Determining the Sources of Polycyclic Aromatic Hydrocarbons in the Hylebos Waterway.

Boehm, Paul¹, Stout, Scott², Wyatt, Glen³, ¹ Exponent, Inc, Maynard, MA, USA² NewFields, LLC, Norwell, MA, USA³ Weyerhaeuser Company, Federal Way, WA, USA

ABSTRACT- One of the drivers for cleanup of sediment contamination in the Hylebos Waterway, Commencement Bay, WA is the presence of polycyclic aromatic hydrocarbons (PAHs) at levels triggering environmental concern. In any multiuse, urban, waterway contaminant sources have numerous origins - both point sources from specific industrial properties, and non-point sources from urban runoff and atmospheric fallout. Potential source types are both petrogenic (petroleum sources) and pyrogenic (high temperature combustion-derived). Our investigation focused on one segment of the Waterway, the "Turning Basin" to determine the nature and specific source(s) of the PAHs in sediments. The major focus of the investigation were sediments from a contaminated ditch adjacent to several properties, which in turn represented a major potential pathway of PAHs to the Waterway. Other areas of foci were the shoreline of the Waterway; a log sort yard bordering on the Waterway; and an adjacent aluminum smelter facility. Additional potential source samples were obtained from stormsewer (runoff) manholes and from ambient particulate air samples. Using detailed measurements of parent and alkylated PAHs and other supportive chemical measurements, combined with principal components analyses (PCA), a PAH source allocation model was developed. This model was supported by a mass balance approach, wherein the PAH content of various source materials was developed to support the allocation model. Results indicated that the vast majority of the PAHs were of a pyrogenic origin and were sourced from the aluminum smelter (e.g., potliner effluents and fugative particulate emissions ) and that the petrogenic or pyrogenic PAH inputs to the Waterway from the log sort yard machinery, wood debris, and its associated piling dock were negligible.

Key words: polycyclic aromatic hydrocarbons, Chemical Fingerprinting, Hylebos Waterway, Sediments