PARENT SESSION
WA6 - Chemistry & Toxicity of Sediments
Chair: Fuji, Taku1, 1 Hart Crowser, Inc., Lake Oswego, OR
8:00 AM to 12:00 PM - Wednesday, 20 November 2002
Room Ballroom B
(535) The Development of Bioaccumulation Factors and Preliminary Remediation Goals for a Sediment Site in San Francisco Bay: Hunters Point Shipyard.
Michael, D*,1, Holder, J2, Swanson, W1, Leather, J3, Pound, M4, 1 Neptune and Company, Inc, Los Alamos, NM, USA2 ENTRIX, Inc, Ventura, CA, USA3 SPAWAR Systems Center San Diego, San Diego, CA, USA4 Southwest Division Naval Facilities Engineering Command, San Diego, CA, USA
ABSTRACT- A weight-of-evidence approach (WOE) was used to integrate four ecologically risk-based endpoints at a subtidal sediment site at Hunter Point Shipyard (HPS) and to identify areas requiring further evaluation in the Feasibility Study (FS). Through the WOE and an evaluation of other ancillary data, bioaccumulation of PCBs was identified as the primary risk driver in one Area. To develop the FS footprint, data that provided the strongest, direct link between sediment contaminants and tissue were evaluated. The data that provided the strongest link were co-located sediment and depurated bent-nose clam (Macoma nasuta) tissue collected at 23 stations at the Area. To calculate a sediment preliminary remediation goal (PRG), a site-specific bioaccumulation factor (BAF) was developed for PCBs at the Area. A curvilinear relationship was observed, with the highest uptake occurring at the lower sediment concentrations. To minimize the underestimation of uptake, a BAF was developed for sediment concentrations below 2000 ppb. This BAF was then used with other exposure and toxicity parameters to develop a range of PRGs protective of benthic-feeding birds such as the surf scoter. To confirm the protectiveness of the PRG for other trophic groups, such as piscivorous birds, the exercise was repeated with field-collected forage fish. The PCB BAF for forage fish was about 4 times that of M. nasuta and a range of PRGs protective of piscivorous birds (double-crested cormorant) was developed. Because the cormorant has a larger home range then the scoter, the scoter PRG was considered adequately protective of piscivorous birds.
Key words: bioaccumulation factors, development of sediment cleanup goals, sediment assessment