WP16 Sediment Quality Assessment
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(HAL-1115-830471) A sediment quality triad study for evaluating the impacts of an oil refinery effluent on aquatic biota in the Delaware River.

Hall, L¹, Dauer, D², Alden, III, R³, Uhler, A⁴, Burton, D¹, Anderson, R¹, ¹ University of Maryland, Queenstown, Maryland, USA² Old Dominion University, Norfolk, Virginia, USA³ University of Nevada - Las Vegas, Las Vegas, Nevada, USA⁴ NewFields Environmental Forensics, Rockland, Massachusetts

ABSTRACT- Triad studies consisting of chemical characterizations in sediment, sediment toxicity testing, and benthic community assessments were used to determine the impacts of Motiva Enterprises oil refinery effluent (primarily polynuclear aromatic hydrocarbons - PAHs) on aquatic biota in the Delaware River. Triad studies were conducted at 15 near-field, mid-field and far-field sites near the Refinery during the spring and summer of 2001 and 2002. Fingerprinting analysis showed that Motiva related PAHs may be present at four near-field sites. A summary of all Triad data by site for 2001 shows a strong case for contaminant induced degradation at one near-field site in the discharge canal of the Refinery and two far-field sites as all three lines of evidence suggest impairment. Stressful conditions for benthic communites at the near field site include elevated temperature and various pesticides. Toxicity at the near-field site may also be related to the presence of pesticides exceeding sediment quality guidelines. Due to exceedances of Effects Range Low (ERL) values for two individual PAHs, the Motiva effluent can not be eliminated as a potential stressor at the near-field site during the summer of 2001. A summary of Triad data for the 15 Delaware River sites sampled in 2002 shows only one mid-field site where all lines of evidence suggest impairment. Toxicity and benthic community impairment at this mid-field site may be related to PCBs and low molecular weight PAHs. Three individual PAH ERL values were exceeded at the three near-field sites in 2002. The source of these PAHs is a combination of both background signature and the Motiva effluent.

Key words: Sediment Quality Triad, Polynuclear aromatic hydrocarbons, Polychlorinated biphenyls, Delaware River