Concentrations and source identification of PAHs, alkyl-PAHs and other organic contaminants in sediments from a contaminated harbor in the Laurentian Great Lakes

Abstract

As a result of historical industrial activity, the sediments in the inner harbor of Owen Sound Bay in the northeastern part of Lake Huron in Ontario, Canada are contaminated with organic compounds. The present study showed that the concentrations of Ʃ PAH16-EPA in all sediments in the inner harbor were above the sediment quality guidelines for the province of Ontario, Canada, with mean Ʃ PAH16-EPA concentrations at the most contaminated site of 46,000μg/kg dry weight. The concentrations of polychlorinated biphenyls, brominated diphenyl ethers, and organochlorine compounds were all below sediment quality guidelines. The patterns of PAH and alkyl-PAH compounds in sediment cores indicated that contamination is from mixed sources, with a strong indication of pyrogenic contamination from industries that used to operate in the area, including a coal gasification plant. Other areas of the bay are impacted by petrogenic contamination, potentially from spills of fuel. The even distribution of PAH and alkyl-PAH compounds throughout core profiles at depths up to 25cm indicates that this is a dynamic system and contaminated sediments are not being covered by deposition of less contaminated sediments. This study illustrates the value of determining the patterns of both PAH and alkyl-PAH compounds in sediments for regulatory purposes and also for forensic source tracking.