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Soil Bioavailability at Superfund Sites: Technical Assistance

The goal of the Technical Review Workgroup for Metals and Asbestos (TRW) is to support and promote consistent application of the best science in the field of risk assessment for metals and asbestos at contaminated sites nationwide. The TRW is composed of three committees: the Lead Committee, the Asbestos Committee and the Bioavailability Committee.

On this page:

Bioavailability Committee Mission

The TRW’s Bioavailability Committee develops new guidance concerning human health risk assessment at hazardous waste sites. The Bioavailability Committee will also provide site consultation in support of regional requests and identify research needs to address data gaps relevant to contaminant bioavailability in soil site assessment activities.

The TRW’s Bioavailability Committee acts as the primary point of contact, information archive and repository of outreach materials for the methods recommended in the guidance document. They will meet on an as-needed basis to review site-specific applications, provide assistance to the Regions and issue additional guidance, as necessary. Moreover, the committee will review new methods for assessing bioavailability of inorganic soil contaminants (new method validation).

In addition, the TRW’s Bioavailability Committee will compile and evaluate information on applications of bioavailability assessments in EPA site risk assessments, with the objective of promoting consistent application of the framework described in this guidance across EPA Regions. To facilitate collection of this information, the Regions are asked to report all site risk assessment applications of the in vitro inorganic bioaccessibility methodology or in vivo juvenile swine model to the Bioavailability Committee. The Regions are also asked to contact the committee for information on any other bioavailability assessment methodologies under consideration for use in site risk assessment.

U.S. EPA Technical Review Workgroup for Metals and Asbestos Charter and Operating Principles (PDF) (9pp, 960K)
This charter and operating principles memo describes the purpose, organization, and procedures for all three TRW committees, including the Bioavailability Committee. 

Expertise of the Bioavailability Committee

The principal members of the Bioavailability Committee are technical staff from:

  • EPA Regions
  • Office of Land and Emergency Management (OLEM) Headquarters
  • Office of Research and Development (ORD)

Bioavailability Committee members generally have an active interest and recognized scientific expertise in human health risk assessment.

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Annual Reports for the TRW Bioavailability Committee

TRW Bioavailability Committee Annual Reports describe the actions taken by the committee. The reports summarize the committee's accomplishments and activities for the calendar year and provide a list of committee members who served on the committee during that period.

If you have questions regarding the reports, please contact Matt Lambert (, 703-603-7174.

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Accessing the Bioavailability Committee

Regional and state risk assessors and project managers may submit written or electronic requests for Bioavailability Committee review to the Bioavailability Committee co-chairs:

  • Matt Lambert ( (Office of Superfund Remediation and Technology Innovation, EPA Headquarters)
  • Karen Bradham ( (Office of Research and Development, Research Triangle Park, North Carolina)
  • Sophia Serda ( (Region 9, San Francisco, California)

If there are confidentiality concerns, documents should be submitted to the Bioavailability Committee through regional legal counsel.

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Response from the Bioavailability Committee

For a response to a site-specific request:

  • The time required for the Bioavailability Committee to complete a site-specific review will depend on the nature of the request and the extent of the review requested (i.e., a brief consultation or a thorough, in-depth review). Because the Bioavailability Committee meets monthly via teleconference, a substantial request for assistance should be submitted at least two months prior to a desired response.
  • Technical Review Workgroup Technical Support: Please contact Technical Review Workgroup Technical Support with questions concerning the assessment, removal or remediation of bioavailability soil contamination at hazardous waste sites.

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TRW Hotline

Questions may be submitted to the TRW hotline in either of the following ways:

  • For bioavailability questions, e-mail
  • Call the toll-free TRW hotline at 1-866-282-8622. If a hotline staff member is not available, please leave a voicemail message.

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