HA1 Contaminated Harbour and River Sediment
256 Portland Ballroom
8:00 AM - 12:00 PM, Thursday
() Activated carbon amendment reduces bioavailability of polychlorinated biphenyls from sediment to the clam Macoma balthica.
McLeod, P1, van den Heuvel-Greve, M2, Werner, D1, Luoma, S3, Luthy, R1, 1 Stanford University, Stanford, CA, USA2 National Institute for Coastal and Marine Management, Middelburg, Netherlands3 United States Geological Survey, Menlo Park, CA, USA
ABSTRACT- Polychlorinated biphenyls (PCBs) have long been prioritized among the top chemicals of concern in the environment because they are ubiquitous, recalcitrant, and bioaccumulative. Despite years of research, experts still disagree on the best remediation strategies for PCB-contaminated sediments. Dredging, traditionally the most popular technique, is expensive, disruptive to habitats, and inevitably leaves PCB residuals at the site. In this work we evaluated granular activated carbon (GAC) amendment, a novel in-situ remediation strategy, for its ability to sequester PCBs and control their bioavailability to Macoma balthica, a benthic clam. We conducted laboratory-run 28-day bioaccumulation studies with Macoma and GAC-treated and untreated sediment from Hunters Point Naval Shipyard (Superfund site in San Francisco Bay, CA). The results showed that GAC applied at a dose of two times the organic carbon content of the sediment and mixed for one month reduced PCB uptake by clams by 68 ± 8% in one experiment, and 78 ± 6% in another. Follow-up studies demonstrated the effects of varying GAC dose and size on treatment efficacy. As suggested by mass transfer modeling, increasing GAC dose and decreasing GAC size resulted in lower bioaccumulation of PCBs by the clams. These studies are complemented by physicochemical laboratory tests and bioaccumulation tests using other benthic organisms, and represent preliminary work towards field-scale GAC application at Hunters Point.
Key words: bioavailability, polychlorinated biphenyl, sediment remediation, activated carbon