U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Contaminated Sediments Virtual Workshop Session 2 - Risk Assessment

Sponsored by: US EPA Office of Research and Development (ORD)'s Office of Science Policy

Archived: Wednesday, October 30, 2019
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The US EPA Office of Research and Development / Office of Science Policy (ORD/OSP) in cooperation with the Office of Land and Emergency Management (OLEM) is sponsoring a 4-part virtual workshop series to address current challenges at contaminated sediment sites. The aim of the virtual workshop is to provide interactive discussions between subject matter expert panelists and workshop participants. Consequently, each virtual session will feature brief topic introductions by panelists followed by facilitated panelist/participant discussions which will include opportunities for questions and answers, brainstorming, identification of concerns and research needs, and quick spot surveys. If you have a contaminated sediment site, this is the virtual workshop for you!

Update: Based on the high interest in this series and feedback from Session 1, the event has been extended to allow for more time questions with the presenters. All scheduled presentations with brief Q&A periods will be delivered as planned during the original time from 1 to 2:30pm eastern. Immediately following the scheduled presentations, presenters will remain on the webinar for an additional 30 minutes to address more questions and comments from the participants. If you are unable to stay on for the additional Q&A time, please know the entire event will be recorded and available to playback on demand including the additional Q&A time.

Risk assessment is essential for the development and selection of appropriate cleanup goals at sites. The second session will address the following topics:

  • An overview of toxicity assessments,
  • Ecological considerations with a focus on bioaccumulation, and
  • Benchmark use in screening level human health and ecological risk assessments and updates regarding benchmark gaps and recent advances.

  1. Sharon Thoms (US EPA Region 4)

    Recommendations are provided form a study of performance of screening benchmarks is evaluated for polycyclic aromatic hydrocarbons in sediments for 19 former manufactured gap plants and smelters.

Upcoming Contaminated Sediments Virtual Workshop Series Webinars

Accessibility, Recording, and Content Disclaimer

Rehabilitation Act Notice for Reasonable Accommodation

It is EPA's policy to make reasonable accommodation to persons with disabilities wishing to participate in the agency's programs and activities, pursuant to the Rehabilitation Act of 1973, 29 U.S.C. 791. Any request for accommodation should be made to Jodi McCarty at 773-934-3091 or, preferably one week or more in advance of the webinar, so that EPA will have sufficient time to process the request. EPA would welcome specific recommendations from requestors specifying the nature or type of accommodation needed. Please note that CLU-IN provides both alternate phone call-in options and closed captioning for all webinars, and requests for these specific accommodations are not necessary.

Webinar Recording

By participating in this CLU-IN webinar, you automatically agree to authorize recording of audio and visual content presented during this live event and consent to subsequent use of this recording in the public domain by the U.S. Environmental Protection Agency. This recording may include questions, comments and poll responses provided by you during the live event in addition to your name, voice, image or likeness. This recording will be made available after the conclusion of the live event as part of the CLU-IN webinar archives, and will remain available indefinitely. If you do not wish to consent to the recording, please do not join the live event, and contact Jean Balent at 202-566-0832 or to discuss your concerns.

Content Disclaimer

This webinar is intended solely to provide information to the public. The views and opinions expressed as part of this webinar do not necessarily state or reflect those of the U.S. Environmental Protection Agency. It is not intended, nor can it be relied upon, to create any rights enforceable by any party in litigation with the United States, or to endorse the use of products or services provided by specific vendors. With respect to this webinar, neither the United States Government nor any of their employees, makes any warranty, express or implied, including the warranties of merchantability and fitness for a particular purpose, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.


Ned Black, US EPA Region 9 ( or 415-972-3055)
Ned Black studied microbiology at UC Davis and environmental engineering, biogeochemistry, and aquatic ecology in the Division of Applied Sciences at Harvard University. Throughout his career his focus has been applied biology in an engineering context. He also studied groundwater contamination and was a lecturer in the Civil and Environmental Engineering program at Stanford University and he's worked for the U.S. Environmental Protection Agency in San Francisco since 1994. For most of that time he has been the Regional Ecologist working in the Superfund program. In that role he covers both aquatic and terrestrial ecology in contaminated habitats ranging from tropical reefs to high altitude forests. Considering this broad range of habitats and conceptual site models, his most important skill set involves recognizing when spurious arguments are bandied about.

Sharon Thoms, US EPA Region 4 ( or 404-562-8666)
Dr. Thoms earned her PhD in Environmental Engineering from Cornell University. She completed a post-doctorate with Peter Landrum at the Great Lakes Environmental Research Laboratory on sediment toxicology and bioturbation. She worked in environmental consulting in the D.C. area on the contaminated sediment Report to Congress. In 1995 she began working in consulting in the Atlanta area in risk assessment applied to Federal Facilities and hazardous waste sites. She has been working at EPA in Atlanta since 1998 in a technical support role for ecological risk assessment. She is co-chair of an EPA Ecological Risk Assessment Forum workgroup with Burt Shephard on screening benchmarks for ecological risk assessment. Her interest is in improvements to sediment screening benchmarks and tissue-residue screening benchmarks for application to cleanup sites.

Lawrence Burkhard, US EPA Office of Research and Development ( or 218-529-5164)
Lawrence Burkhard is a Research Chemist employed by the United States Environmental Protection Agency (U.S. EPA), Office of Research and Development, Mid-Continent Ecology Division in Duluth, Minnesota, USA. He has been with the Agency for 30 years. His current research areas are the bioconcentration and bioaccumulation of organic contaminants by benthic invertebrates and fish, food web modeling and trophic magnification of contaminants in aquatic food webs, development of remedial goals based upon concentrations of the contaminants in sediment porewater, and the uptake of super hydrophobic chemicals by benthic invertebrates and fish. He has experience in food web modeling at Superfund sites, in the analysis of environmental samples for organic contaminants, and TIE methodologies for identifying toxicants in sediments and water. He is a member of OLEM's (Superfund) CSTAG and co-chair of SETAC's bioaccumulation science interest group (BSIG).


A photograph of Jean BalentJean Balent, U.S. EPA Technology Innovation and Field Services Division ( or 202-566-0832)
Ms Balent is on the staff of the EPA's Technology Innovation and Field Services Division where she has worked to collect and disseminate hazardous waste remediation and characterization information since 2003. Ms Balent manages the Clean Up Information Network website and actively supports online communication and collaboration resources available to EPA. She formerly worked with the US Army Corps of Engineers Environmental Engineering Division in the Buffalo District. Ms Balent was also a member of the SUNY-Buffalo Groundwater Research Group where she constructed and tested large scale models of groundwater flow. Ms Balent has also conducted research relating to the Great Lakes, environmental remediation, and brownfields re-development. She holds a Bachelor's degree in environmental engineering from SUNY-Buffalo and a Master's degree in Information Technology from AIU.

James Rice, ICF International Inc. (
Mr. Rice is Senior Geologist at ICF with more than 30 years of experience in the environmental consulting industry. Mr. Rice has been involved in a wide range of environmental investigation, assessment and remediation projects for EPA, DOD, DOE and commercial clients using traditional and innovative tools and approaches. He currently provides technical support to EPA OSRTI with optimization and technology innovation and integration where he helps site teams improve characterization and remediation by applying best practices such as systematic planning, 3-dimensional visualization and analysis, high resolution site characterization and CSM development. Mr. Rice also develops and delivers technical training for several EPA courses including Incremental Sampling, Best Practices in Site Characterization through the Remedial Process, and High Resolution Site Characterization.

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If you have a suggested topic or idea for a future CLU-IN internet seminar, please contact:

Jean Balent
Technology Integration and Information Branch

PH: 202-566-0832 | Email:
Michael Adam
Technology Integration and Information Branch

PH: 202-566-0875 | Email: