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Systematic evidence mapping of potential exposure pathways for per- and poly-fluoroalkyl (PFAS) chemicals based on measured occurrence in multiple media
Citation:
Holder, C., N. DeLuca, J. Luh, P. Soleymani, J. Minucci, Dan Vallero, AND E. Hubal. Systematic evidence mapping of potential exposure pathways for per- and poly-fluoroalkyl (PFAS) chemicals based on measured occurrence in multiple media. Society of Risk Analysis Conference, Virtual, Virtual, December 05 - 09, 2021. https://doi.org/10.23645/epacomptox.17041607
Impact/Purpose:
Limited data are available to assess potential chemical risks to humans from manufacture, use, and disposal of consumer products and articles – esp. related to PFAS. Tools are needed to access and leverage available data on chemical manufacture, use, and occurrence for important chemical exposure scenarios and pathways across the product lifecycle. Scientific workflows are designed to execute a series of computational or data manipulation steps. The simplest automated scientific workflows are scripts that call in data, models, and other inputs and produce outputs that may include analytical results and visualizations. The value of using this approach is that domain-specific data types and tools can be made available to the exposure scientist and easily accessible to the exposure assessor for specific decision contexts. This product provides regulatory scientists, students and researchers with the ability to effectively access and exploit the many in silico data streams to support different regulatory purposes and supports current Agency efforts to reduce mammal study requests by 30% by 2025, and completely eliminate all mammal study requests and funding by 2035.
Description:
Rationale: The ubiquitous presence of PFAS chemicals in humans as demonstrated by the National Health and Nutrition Examination Survey (NHANES) suggests that exposure sources beyond contaminated water may play an important role. PFAS chemicals may be present in and released from a vast number of building materials, consumer products, and food packaging materials in residential environments. Data on the nature and level of PFAS in residential environments and diet is required to identify, understand, and mitigate important pathways for human exposure. The objective of this work is to investigate evidence for important pathways of exposure to PFAS chemicals by reviewing literature reporting measured occurrence of PFAS chemicals in exposure media. Approach: We targeted eight well-studied PFAS chemicals (PFOA, PFOS, PFBA, PFBS, PFDA, PFHxA, PFHxS, and PFNA) and their real-world occurrences primarily in human matrices and media commonly related to human exposure (outdoor and indoor air, indoor dust, drinking water, food, food packaging, articles and products, and soil). We identified 3,622 peer-reviewed papers matching these criteria and published 2003–2020. We employed a systematic-mapping process with ICF’s litstreamTM software to conduct title-abstract (TiAb) and full-text screening, and to extract relevant primary data into a comprehensive evidence database. Parameters of interest included: sampling dates and locations (emphasizing locations in the US, Canada, and Europe), numbers of collection sites and participants, analytical methods, limits of detection and detection frequencies, and occurrence statistics. Results and Discussion: We extracted detailed data on PFAS occurrence in high-priority household and environmental media from 210 studies (our focus here), and limited data on human matrices from 422 additional papers. Studies of PFAS occurrence became numerous after about 2005 and were most abundant for PFOA and PFOS. Many studies analyzed additional chemicals, particularly PFNA and PFHxS and particularly in food, drinking water, indoor dust, and soil. Co-measurements for PFAS occurrence in human matrices plus other media, while relatively infrequent, were typically related to food and drinking water. Most studies found detectable levels of PFAS, and half or more of the limited studies of indoor air and products detected PFAS in 50% or more of their samples. Management/Policy Implications: This study produced a database with over 14,000 rows of meta-data and quantitative information from peer-reviewed studies on the occurrence of PFAS in scenarios potentially relevant to human exposure. These data should enable or improve interpretation of PFAS biomonitoring data and inform understanding of important sources and pathways related to personal exposure to PFAS, including through modeling. Users may find this database useful to identify where a focused systematic review of data subsets might further illuminate specific research questions, or to conduct a meta-analysis to synthesize results across multiple studies. We encourage users of these data to conduct their own critical appraisal of the data that suits their specific research needs. Disclaimer: The views expressed in this presentation are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.
URLs/Downloads:
DOI: Systematic evidence mapping of potential exposure pathways for per- and poly-fluoroalkyl (PFAS) chemicals based on measured occurrence in multiple media
8PFAS OCCURRENCE POSTER_SRA 2021_FINAL.PDF (PDF, NA pp, 816.583 KB, about PDF)