On May 31, 2018, EPA released the draft systematic review approach for chemical risk evaluations required under the Lautenberg Chemical Safety for the 21st Century Act (LCSA) amendments to the Toxic Substances Control Act (TSCA). The systematic review framework will have a 45-day comment period upon publication of the final Federal Register notice. EPA indicates, however, that it will continue to consider comments on the framework after this period, and that aspects of the approach will be revised over time.
Systematic review is the process of identifying, selecting, assessing, and integrating the results of multiple studies in a transparent and objective manner to reach overall conclusions. EPA’s systematic review approach document serves as internal guidance for risk evaluations required under TSCA. The guidance outlined for some aspects of a systematic review methodology – including data searches, data screening, and data extraction – is quite comprehensive. However, EPA provides only general expectations for other phases of the risk evaluation, particularly regarding the critical process of evidence integration in which one synthesizes all of the available evidence. Additional guidance on this topic is expected in the draft risk evaluations for the first ten chemicals (due in December of 2019).
A critical theme throughout the document is the importance of “fit for purpose” evaluations tailored to specific substances, and as such, an iterative evaluation process. EPA recommends the use of “pilot testing” at various phases of the evaluation. For example, EPA will test the validity of search strategy methods (e.g., chosen search keywords) through reference cross-checks, then update the strategy if needed.
Another focus of the document is considering study quality and relevance in the risk evaluation process. The draft guidance contains an extremely detailed study-quality evaluation methodology for each individual “stream” of evidence (including physical/chemical, environmental fate, ecological, toxicological, epidemiological, and in vitro data). Notably, the evaluation involves quantitative scoring of each aspect of study quality to arrive at an overall rating of quality for each study or data source. Studies or data sources determined to be “unacceptable” will not be considered further in the risk evaluation.
Aspects of the draft approach, such as the focus on thorough processes for data identification and evaluation of study quality, mirror those in other agency approaches, whereas some specifics (e.g., quantitative quality scores) differ quite noticeably from others. However, given that there are critical areas yet to be wholly developed, such as evidence integration, the full implications of this systematic review approach on the results of TSCA risk evaluation process remain to be seen. Please contact us if you have any questions about how the systematic review approach may affect EPA’s risk evaluation process for your chemicals.
| Lorenz R. Rhomberg, Ph.D., ATS
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