US Army Corps of Engineers BUILDING STRONG ® Dynamic PCB Partitioning in Ashtabula Harbor, Ohio Sediments Andrew Lenox Environmental Engineer US Army Corps of Engineers, Buffalo District

BUILDING STRONG ® Introduction  Ashtabula Harbor, Ohio ► Federally (USACE) maintained deep-draft harbor ► USEPA Great Lakes Area of Concern (AOC) Restriction on dredging beneficial use impairment (BUI) Contaminants of Concern (COC) listed as mercury, chromium, lead, zinc, chlorinated organic compounds, polychlorinated biphenyls (PCBs), and low level radionuclides

BUILDING STRONG ® Buffalo Cleveland Ashtabula Lake Erie Erie N

BUILDING STRONG ® Lake Erie Ashtabula Harbor

BUILDING STRONG ® Background  PCBs are main COC with respect to dredged material management ► Evaluation based on tiered assessment of bioaccumulation in benthic organisms (Great Lakes Dredged Material Testing and Evaluation Manual ) Use sediment chemistry data to model bioaccumulation Measure uptake into tissue in lab

BUILDING STRONG ® Theoretical Bioaccumulation Potential (TBP) Model ► Equilibrium partitioning theory-based algorithm for bioaccumulation of sediment associated non-polar organic contaminants in benthic organisms ► BSAF – Biota-Sediment Accumulation Factor, a measure of bioavailability that relates TOC normalized contaminant concentration in sediment to lipid-normalized contaminant concentration in organisms

BUILDING STRONG ® Biota-Sediment Accumulation Factor Site-specific BSAF values encompass unique bioavailability influencing parameters including contaminant and sediment sorption properties, resulting in variability

BUILDING STRONG ® BSAF Variability Within Ashtabula Harbor  Bioaccumulation testing show BSAFs within the harbor differ significantly - ranging from 0.25 to 2.43  Lower BSAFs ► Outer Harbor and Lower River Channel  Higher BSAFs ► Upper limits of Federal Channel

BUILDING STRONG ® Outer Harbor BSAFs range from 0.25 to 0.51 Lower River BSAFs range from 0.54 to 0.91 Upper River BSAFs range from 1.20 to 2.43 Lake Erie N

BUILDING STRONG ® Factors Affecting Bioavailability  Physical ► Contaminant resuspension ► Concentration gradient  Chemical ► Contaminant sorption/desorption  Biological ► Organism lipid content, size, growth rate, gender, diet, metabolism

BUILDING STRONG ® Coal Dock and Stockpiles

BUILDING STRONG ® Black Carbon  Coal dock and stockpiles are located at the head of the Ashtabula River ► Condensed, aromatic carbonaceous material show strong and nonlinear sorption, leading to lower bioaccumulation than assumed for natural organic matter ► PCBs partition onto black carbon over time

BUILDING STRONG ® Strong BC Influence  Outer Harbor provides an accumulation area for black carbon affected sediments, leading to increased contact time between PCBs and sediment

BUILDING STRONG ® Moderate BC Influence  Lower River sediments reflect differing degrees of contact time between PCBs and sediment ► Riverine and lacustrine current-based coal soot deposition ► More stable sediments at depth show bioavailability similar to the Outer Harbor

BUILDING STRONG ® Negligible BC Influence  Upper River sediments receive less lacustrine current-based coal soot deposition  BSAFs of 1.2 to 2.43 are more reflective of PCB bioavailability associated with a predominance of natural TOC in sediments

BUILDING STRONG ® BSAF Compared to BC Content Moving Upstream from Outer Harbor

BUILDING STRONG ® Potential Factors Influencing BSAF Variability Throughout the Harbor BSAF Variability Organic Matter Characteristics Equilibrium Time with Sediment Sediment Resuspension/ Mixing

BUILDING STRONG ®  PCB Sediment Quality Criterion (SQC) needed to model future dredging restrictions ► Should emphasize a bioaccumulation endpoint ► Should be spatially variable (due to spatial changes in PCB bioavailability) Incorporating Variability into Dredged Material Management

BUILDING STRONG ® Incorporating Variability into Dredged Material Management  Develop SQG based on TBP model and site-specific BSAFs  Use Lake reference area tissue data  SQG predicts bioaccumulation from harbor sediment similar to that expected in the open-lake

BUILDING STRONG ® Ashtabula Harbor Total PCB Sediment Quality Guidelines (ug/kg)

BUILDING STRONG ® Dredged Material Management Considerations  PCB bioavailability is key driver in the characterization and management of Ashtabula Harbor dredged material ► Variability results in different conclusions throughout the harbor ► Bioavailability rather than bulk sediment concentrations dictates suitability determinations

BUILDING STRONG ® Conclusions  PCB contamination in harbors can be assessed based on bioavailability  Bioavailability can be variable; use of default BSAFs may be overly conservative or inaccurate in estimating bioavailability  TBP model with site specific, empirical BSAFs can be utilized in dredged material testing and evaluation

US Army Corps of Engineers BUILDING STRONG ® Questions?...