Incorporating Bioavailability Considerations ITRC Contaminated Sediments Team Team Leaders: John Cargill, Delaware DNREC - [email protected] into the Evaluation of The Contaminated Sediments Team is a group of toxicologists, geologists, chemists, biologists and other environmental professionals from 11 State Agencies, DoD, DoE, EPA, Kim McEvoy , New Jersey DEP- [email protected] Contaminated Sediment Sites 23 Private Industries, Universities and Stakeholders.Stakeholders

In 2011, the ITRC Contaminated Sediments Team. developed a Web-based Technical Regulatory Guidance on the concepts, process, and use of bioavailability in a risk-based decision framework at contaminated sediment Why is Bioavailability Important? sites. This Guidance describes the fundamental concepts of bioavailability in contaminated sediment ¾If contaminants are not physically accessible, or chemically or biologically available, they should not be included in the management by: calculation of risk; ¾outlining how bioavailability considerations can be incorporated into the conceptual site model (CSM) ; ¾Can define the extent of cleanup required to be protective and can be an important factor in balancing the risks caused by 70 – 95 um ¾identifying and describing available tools (biological, chemical, and predictive) and models that are used to remedial action with the risks addressed by remedial action; and, thick measure and characterize the fate and transport and potential bioavailability of contaminants; ¾Can provide optimization of remedial approach and cost. SPME

¾modifying remedial goals based on estimates of bioavailability during the exposure assessment and risk 50 um thick Fish and Aquatic Invertebrates Tools to Assess the Fish and Aquatic 0.5 m evaluation; and, Pathway (Chapter 5) Invertebrates Pathway

X Chemical • Apply accumulation factors to measures of bulk sediment chemistry to ¾becoming resource to communicate these bioavailability-based conclusions, especially to the public. estimate tissue residue concentrations, and compare to fish or amphibian tissue-based TRVs PED • Measure water quality above sediment bed and compare to AWQC or (PED and SPMD allow appropriate state standards molecules <600 Daltons molecular weight) 2.5 cm X Biological SPME SPMD (containing triolien) • Carry out laboratory sediment toxicity tests using site-appropriate organisms and conditions • Conduct population surveys and compare to similar reference conditions What is Bioavailability? • Measure in situ bioavailability from field-collected organisms X Predictive • Compute contaminant bioavailability using: ƒ Accumulation Factors “…individual physical, chemical, and biological interactions that determine the exposure of – Bioconcentration Factor – Bioaccumulations factor – Biota-Sediment Accumulation Factors plants and animals to chemicals associated with soils and sediment.” – Biomagnification Factor ƒ Food Web Models (National Research Council, 2003) ƒ Biotic Ligand Models Introduction Invertebrates Specifically, bioavailability addresses the fact that only a fraction of the contaminant

concentration present in the environment may be taken up or result in an effect on an Fish and Aquatic Specific Exposure Pathways organism. Case Studies Trident Probe Ultraseep System The Guidance A total of 35 case studies were received primarily from state and federal regulators. These case studies incorporated bioavailability considerations into the risk assessment process to obtain a clearer understanding of contaminant toxicity, Provides a description of available tools used for the such that remedy selection decisions can be optimized. An example of how bioavailability was used to understand exposure evaluation of bioavailability in the context of evaluating to contaminants is presented in the Mocks Pond case study: exposure pathways of benthic invertebrates, fish and Case Study: Case Study: aquatic invertebrates, wildlife, plants and human health. Mocks Pond Area Muncie, Indiana Mocks Pond Area Muncie, Indiana

X Site History: X • Abandoned limestone quarry received treatment sludge from galvanized (zinc- Remedial Action: Metal contaminated sediments coated) wire product manufacturer were remediated with installation of a sand cap. • Lime added to neutralize the waste solutions before discharge, forming The effectiveness of the cap was evaluated insoluble metal hydroxides. through the collection of: Benthic Exposure Pathway & Bioavailability Tools • COPC’s were heavy metals (i.e., lead, zinc) – present at high conc. (greater than sediment screening criteria). • in situ porewater samples collected via large diameter • Pond bottom consisted of unconsolidated sediment devoid of organic material & peepers (targets only the bioavailable fraction of the metal bottom-dwelling insects contamination) Tools to Assess the Benthic Pathway Tools to Assess the Benthic Pathway Tools to Assess the Benthic Pathway • Testing suggested that deposited material were stabilized and not biologically • surface water samples – metals analysis Benthic Pathway (Chapter 4) available Biological Chemical Predictive X Potential Receptors: • Pelagic fish, snapping turtles, belted kingfishers, great blue herons, raccoon and Results of post-remedial monitoring: X Sediment X Bioassays X Equilibrium potentially river otter metals were tightly sequestered and not • Bulk Sediment • Bulk sediment, interstitial pore water, spiked sediment, X Porewater (Direct) • Limited human exposure with fence. TOC/SOC Partitioning biologically available - porewater and surface elutriate, in situ bioassays • • Centrifugation • Acid Volatile Sulfide (AVS) water results were below applicable • Mortality, growth, reproduction & behavior • Suction Devices X Narcosis Model CSM: Hypothesis that sludge-sediment would not support aquatic life • Piezometers X Macroinvertebrate surveys and that metal hydroxides are not biologically available standards. • Syringes X AVS/SEM Peepers consisted of dialysis tubing • Benthic Indexes (i.e., Benthic Response index, Index of Benthic integrity, etc) Equilibrium partitioning through dissociation in porewater or surface water filled with reagent grade water • Trident probe X Biotic Ligand Model • River invertebrate prediction and classification system X Porewater (Indirect) • Ultraseep placed into a protective sheath, and • Integration of benthic community categories • Peeper then inserted to a depth of 10 cm • Direct Porewater (EPA SW-846 X Toxicity Identification into the sediment • Rapid Bioassessment Protocol • Dialysis Bags 8272/ ASTM D73-63-07) • Diffusion Equilibration In Thin Films Evaluation • Invertebrate indexes (i.e., Macroinvertebrate Aggregate or Bioassessment index) • Semipermeable Membrane Devices • Benthic infaunal abundance (SPME, POM, Polyethylene) X Bioaccumulation studies • Gore module • Diffusive flux • Tissue Residue Analysis This Guidance was completed in March 2011. A free Internet-based training will be offered during 2011 – 2013 on the proper use • Resuspension flux • Macroinvertebrate surveys • Air Bridge Biotic Ligand Model of this Guidance visit Contaminated Sediment Project Home page at www.itrcweb.org.