Review of U.S. EPA's ORD Staff Handbook for Developing IRIS Assessments 2020 Version (2022) / Chapter Skim
Currently Skimming:
2 Overview of Organization and Content of the Handbook
2 Overview of Organization and Content of the Handbook
Pages 19-32
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From page 19... ...
has made in its IRIS process for developing draft assessments. For instance, the process includes sophisticated, state-ofthe-art methods related to using systematic evidence maps for scoping and systematic review methods for hazard identification.
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From page 20... ...
published for each IRIS assessment provides details on specific methods and approaches that are employed for specific IRIS assessments. Nevertheless, if each step in the IRIS assessment process were clearly outlined in the handbook, it would make the IRIS assessment process more transparent while simultaneously benefitting the handbook users who conduct IRIS assessments.
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From page 21... ...
In addition, the handbook does not clearly illustrate when and where in the process the outcomes for the PECO questions for the systematic reviews for hazard identification are defined or refined. The systematic review protocol is shown as a single step in the IRIS assessment process, but multiple systematic review protocols could be part of a single IRIS assessment.
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From page 22... ...
Examples include the use of the term "protocol" to describe the general plan for an IRIS assessment rather than a detailed plan for conducting a specific systematic review; the use of the terms "preliminary literature survey," "systematic evidence map," and "literature inventory" to refer to an evidence database, when all three terms have different established meanings; and the use of "scoping review" to refer to a complex process that includes engaging stakeholders in the identification of programmatic needs, rather than a survey of a body of evidence conducted to inform a research planning process. Use of Systematic Review Methods As recommended in previous National Academies reports, systematic review methods are being incorporated into the IRIS assessment process.
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From page 23... ...
, and then carrying that information consistently throughout the rest of the document. TABLE 2-1 Common Uses of Mechanistic and Toxicokinetic Evidence in IRIS Assessments Mechanistic Evidence Toxicokinetic (ADME)
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From page 24... ...
For example, it is not always clear when mechanistic data would be treated as a separate data stream for hazard identification, when it would be used to increase or decrease confidence in animal or human studies based on biological plausibility, and when it would potentially serve both roles. Despite this shortcoming, it is laudable and significant that the IRIS program is striving to incorporate mechanistic data in a manner that is consistent with efforts to move toward decreased reliance on animalbased studies and increased use of New Approach Methods (NAMs)
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From page 25... ...
Thus, the description of the process for deriving toxicity values could be streamlined substantially to focus on the most common practices, while noting by reference where less common approaches based on mechanistic, TK, or novel quantitative methods may be obtained and applied. The committee concluded that the transparency and usability of the handbook could be improved by streamlining all of its text to focus on the major steps in the IRIS process, eliminating repetition among the chapters, incorporating examples from IRIS assessments and software tools such as HAWC, and ensuring that terminology is used consistently across chapters.
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From page 26... ...
2 to evaluate the occurrence and impact of funding bias and author conflicts of interest on systematic reviews of trials. Funding and publication biases can also be investigated at the evidence synthesis and integration stages.
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From page 27... ...
Incorporating systematic reviews from other sources into IRIS assessments could enhance process efficiency. Quality Assurance Previous National Academies reports have noted weaknesses in the quality assurance of the IRIS process.
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From page 28... ...
FINDINGS AND RECOMMENDATIONS General Finding: The handbook reflects the significant improvements EPA has made in its IRIS assessment process. For instance, the process includes sophisticated, state-of-theart methods related to using systematic evidence maps for scoping and systematic review methods for hazard identification.
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From page 29... ...
The IRIS program is applying systematic review methods appropriately to parts of the process (e.g., evidence evaluation and synthesis for hazard identification)
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From page 30... ...
There are multiple places in the handbook that describe how the evidence base for susceptible populations should be incorporated into IRIS assessments. However, the handbook treats this area of hazard identification as a special case evaluation that may not be required unless animal, human, or mechanistic evidence points to a particular susceptibility or life stage.
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From page 31... ...
For example, it is unclear how the results of the systematic reviews that are conducted for hazard identification are used to select studies for the dose-response assessment. As described, hazard identification and toxicity value determination appear to be disconnected processes.
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From page 32... ...
Recommendation 2.14: The handbook should include discussions that recognize new types of research and describe how EPA is preparing for possible inclusion of additional study types into IRIS assessments. To enhance the efficiency of the IRIS assessment process, EPA should consider how it will identify, evaluate, and incorporate systematic reviews from other sources, as they become more available.
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