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Summary
Pages 1-8

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From page 1...
... 2 Ecological receptors include any living organisms other than humans, the habitat that supports such organisms, or natural resources that could be adversely affected by environmental contaminations resulting from a release at or migration from a site. 3 In TSCA, the risk assessments are termed risk evaluations because they contain the risk determination, an element that is traditionally outside the risk assessment process.
From page 2...
... THE COMMITTEE'S APPROACH EPA requested that the National Academies of Sciences, Engineering, and Medicine convene a committee to review EPA's 2018 guidance document on Application of Systematic Review in TSCA [Toxic Substances Control Act] Risk Evaluations and associated materials (see Box S-1; the full Statement of Task is included in Chapter 1)
From page 3...
... Figure S-1 provides a schema for how systematic review can be conducted to inform hazard assessment and make risk determinations. Figure S-2 illustrates the OPPT approach to systematic review within TSCA risk evaluations, which differs to an extent from the generic approach in Figure S-1 in that OPPT applies systematic review to all elements of the risk evaluation.
From page 4...
... Within this step, OPPT uses a variety of software tools and approaches to conduct broad searching and to map the available evidence. OPPT uses exhaustive search strategies that include major scientific databases, backward searching for studies in previous chemical risk assessments, additional gray literature sources, studies submitted under TSCA, and studies identified in peer review.
From page 5...
... Due to the decision to apply systematic review beyond the evidence streams of hazard assessment, OPPT developed approaches to apply systematic review to data types such as exposure, fate and transport, and chemical and physical properties. CRITIQUING THE OPPT APPROACH Looking at the core review elements of the Statement of Task, which address whether the TSCA approach to systematic review is "comprehensive, workable, objective, and transparent," the committee finds that the approach presented by OPPT could be broadly improved to better meet these characteristics for the major review steps.
From page 6...
... Lastly, without a clear, documented approach to evidence synthesis and to integration, the risk evaluation process becomes unworkable because staff have to decide on approaches for these critical steps for each new evaluation rather than relying on a protocol or guidance. Objective The committee found the OPPT approach to be lacking objectivity at each step, from not using a defined approach to documenting how the problem formulation and protocol are developed.
From page 7...
... As a general finding, the committee judged that the systematic reviews within the draft risk evaluations considered did not meet the standards of systematic review methodology. Given that systematic review is well established for application to the hazard stream of evidence, the committee reviewed the hazard component of the Draft Risk Evaluation for Trichloroethylene, applying a tool used to assess bias in systematic reviews (AMSTAR-2)
From page 8...
... • With regard to hazard assessment for human and ecological receptors, the committee com ments that OPPT should step back from the approach that it has taken and consider compo nents of the OHAT, IRIS, and Navigation Guide methods that could be incorporated directly and specifically into hazard assessment. • The committee finds that OPPT's use of systematic review for the evidence streams, for which systematic review has not been previously adapted, to be particularly unsuccessful.


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