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Field Testing of Activated Carbon Mixing And In Situ Stabilization of PCBs in Sediment ER - 0510 Richard G. Luthy Stanford University In-Progress Review Meeting November 6, 2006. Project Team. Stanford University: R. Luthy, Y-M. Cho J. Tomazewski
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Field Testing of Activated Carbon Mixing And In Situ Stabilization of PCBs in Sediment ER - 0510 Richard G. Luthy Stanford University In-Progress Review Meeting November 6, 2006
Project Team Stanford University: R. Luthy, Y-M. Cho J. Tomazewski Eng. Res. & Dev. Cen., WES: T. Bridges, A. Kennedy Univ. of Maryland, Balt. Co.: U. Ghosh US Navy, NAVFAC San Diego:R. Ahlersmeyer, Tetra Tech; Keith Foreman, BRAC Env. Coor. Aquatic Environments, Inc.: Lance Dohman Compass Environmental, Inc.: Mark Fleri
TECHNICAL OBJECTIVES • Demonstrate and compare the effectiveness of AC application and use of two available, large-scale mixing technologies. • Demonstrate that AC treatment reduces PCB bioaccumulation in field tests. • Demonstrate no significant sediment resuspension and PCB release after large-scale mixing technologies are used.
TECHNICAL APROACH Background Lab Findings for AC Treatment of PCB-contaminated Sediment • PCBs are transferred from sediment to AC • AC - treatment reduces 1. PCB bioaccumulation: clam, worm, amphipod 2. Aqueous PCB concentration 3. PCB uptake in SPMD 4. PCB flux from sediment • If ingested, PCBs on AC are not absorbed • AC is not eroded out of sediment • Important ‘weight of evidence’ 28-day contact time 28-day exposure; 3.4 wt.% AC treatment
Demonstration Site Location Hunters Point Naval Shipyard, San Francisco, CA • PCB hot spot, 1-10 ppm • Inter-tidal zone • Cohesive sediment with low erosion rates • Site managers amenable to AC technology
Demonstration Site Location Hunters Point Naval Shipyard, San Francisco, CA Active Superfund Site undergoing cleanup Work Plan Approval: Federal, state & local groups • ESTCP; Southwest Div. NAVFAC; US EPA Region IX; US Fish & Wildlife Ser.; US Geo. Survey; Calif. Dept. of Toxic Substance Control; Calif. Dept. of Fish & Game; SF Bay Regional Water Quality Control Bd.; City of San Francisco, Dept. of Public Health & Public Utilities Comm.
Equipment for Mixing Carbon & Sediment Injection system (Compass Environmental, Inc., Stone Mountain,GA) Aquamog with rototiller arm (Aquatic Environments, Inc., Concord, CA)
Demonstration Design Plots, Sampling, and Equipment Five sampling locations Four test plots
TECHNICAL PROGRESS 6 Month Post-Treatment Assessments
Pre-Treatment Assessments, 12/2005 Clams SPMDs Cores For each plot: 5 tubes (6 clams + 1 SPMD) 5 sediment cores 5 amphipod samples 5 sediment quadrats (indigenous benthic community) 2 overlying water samples Quadrats Amphipods
Field Water Sampling • Measure PCB in water column before and after carbon deployment • Sample water 6” above sediment at the centre of the plot • Duplicate water samples 20 L each • Trap suspended particles in glass fiber filters • Trap dissolved PCBs in XAD columns • Soxhlet extraction and PCB analysis Teflon tube inlet 0.5 ft above center of plot XAD traps In-line pressure filters
Water Sampling Data (1):Dissolved PCBs above Treatment Plots Before Treatment Clams • PCB homologs with 4-6 chlorines most dominant in dissolved fraction • No significant difference in aqueous PCBs over treatment plots compared to control • No significant increase in dissolved PCBs after treatment One day after treatment
Water Sampling Data (2):Particle-associated PCBs above Treatment Plots Before Treatment Clams • PCB homologs with 6-7 chlorines most dominant in particle-associated fraction • No significant difference in particle-associated PCBs over treatment plots compared to control • Uniform increase in particulate load for both control and treatment plots the day after treatment likely due to wind conditions One day after treatment
Baseline Data : Sediment TOC Reanalyzing some plot F samples
Baseline Data : Sediment PCB Conc. & SPMD uptake • Top six inch sediment cores analyzed for sediment PCBs • Concentrations : 1.0~1.2 ppm • No significant difference over the test plots • SPMD uptake : No significance difference over four test plots
Baseline Data : Aqueous Equilibrium Concentration • 14 day contact on a roller • No significance difference over four test plots
Laboratory Method: Bioaccumulation Studies : Deployed Clams
Laboratory Method: Bioaccumulation Studies: Indigenous Amphipods
Baseline Data : Macoma & Amphipods Bioaccumulation Clams • Similar uptake across test plots prior to treatment
Laboratory Method : Benthic Community Survey Clams
Baseline Data : Benthic Community Survey Clams Mean total abundance for six major phyla Segmented Worms Annelid: Capitellidae Unsegmented Worms Nemertea Cnidaria: Sea Anemone Mollusca: Clam Arthropod: Amphipod Nematode
6 Month Post-Treatment Assessments, 07/2005 Clams Core sampling Quardrat sampling Sampling location remarking Amphipod sampling Clam cage & clam deployment
6 Month Post-Treatment Assessments, 08/2005 Clams Clam retrieval Clam cage retrieval SPMD retrieval
6 mo. Post Assessment Data : SPMD uptake • Plot D showed significant reduction of SPMD uptake (66%) compare to Plot C (mix only). • Plot F also showed significance reduction (63%) of uptake compare to Plot C (mix only). • Mix only plot C showed increased SPMD uptake due to enhanced contact between sediment and SPMDs and possibly enhanced sediment concentration.
6 mo. Post Assessment Data : Particle Size Analyses • AC was found on No. 60 and No. 120 sieves for plot D and F. • Layered structures disappeared for mixed plots (Plots C, D, and F). Median particle size 0.2-1 mm • Plot E (unmixed control) retained layered structure.
Measures of Success • Field measures: • Homogeneous AC mixing • Reduced PCB uptake by Macoma nasuta • Reduced PCB uptake by resident Corophium spp. • No detriment to indigenous community structure due to AC application • Reduced PCB uptake by SPMDs • Minimal sediment resuspension & PCB release • Lab measures: • Reduced Caq • Reduced sediment PCB desorption rate Macoma nasuta retrieved from clam cages
ACTION ITEMS Action Item: Provide a white paper (due 8 May 2006) that provides a discussion of the best possible uses for the plot that was unable to be tested with the Injection System (Plot G), while staying within the already budgeted resources. Response: The white paper was submitted via email to Andrea Leeson on 5/4/06. In this white paper, we have proposed analyzing the THg and CH3Hg+ bioaccumulation in the clam sample splits obtained from Plots C, D, and E, in addition to the planned analyses of PCB bioaccumulation. In this way, we will be able to assess the efficacy of using AC as a multifunctional amendment for reducing the chemical and biological availability of both Hg species and PCBs.
TECHNOLOGY TRANSFER ER-0510 Web Page Feasibility Study AC Treatment Technology is under evaluation as an alternative option in the Hunters Point Shipyard Parcel F Feasibility Study. http://www.stanford.edu/group/luthygroup/ESTCP.htm
PROJECT PLAN Demonstration Plan • ESTCP Office approved. • Local regulatory agencies reviewed and commented. (U.S. EPA Region IX, DTSC, San Francisco Water QC Board, U.S. Fish and Wildlife, USGS, San Francisco PUC and Dept. of Pub. Health and others)
PUBLICATIONS • Application of Activated Carbon Amendment for In-situ Stabilization of PCBs in Sediment: Field-Scale StudiesYeo-Myoung Cho, Dennis W. Smithenry, Upal Ghosh, Alan J. Kennedy, Rod N. Millward, Todd S. Bridges, Richard G. Luthy • CALFED Bay-Delta Program Science Conference, Abstract for Oral Presentation, Oct 25 2006 • Field Testing of Activated Carbon Mixing and In Situ Stabilization of PCBs • in SedimentYeo-Myoung Cho, Dennis W. Smithenry, Upal Ghosh, Alan J. Kennedy, Rod N. Millward, Todd S. Bridges, Richard G. Luthy • Partners in Environmental Technology Technical Symposium & Workshop, Abstract for Poster Presentation,Nov 28-30 2006 • Field methods for amending marine sediment with activated carbon and assessing treatment effectivenessYeo-Myoung Cho, Dennis W. Smithenry, Upal Ghosh, Alan J. Kennedy, Rod N. Millward, Todd S. Bridges, Richard G. LuthyMarine Environmental Research, Journal Paper (Submitted Aug 2006)