Science Inventory

Review of per- and polyfluoroalkyl substances (PFAS) bioaccumulation in earthworms

Citation:

Burkhard, L. AND L. Votava. Review of per- and polyfluoroalkyl substances (PFAS) bioaccumulation in earthworms. Environmental Advances. Elsevier B.V., Amsterdam, Netherlands, 11:100335, (2023). https://doi.org/10.1016/j.envadv.2022.100335

Impact/Purpose:

Purpose The report assembles from the scientific literature biota-soil accumulation factors for earthworms. The report summarizes the available data, provides average and median values for carboxylic and sulfonic acids, and provides an analysis of gaps and limitations in the currently available data. Audience The product is intended for two audiences. First, Superfund performs risk assessments on terrestrial sites and for terrestrial sites with PFAS contamination, biota-soil accumulation factors for earthworms are required. Second, by assembling the data, EPA’s researchers and other researchers can plan and implement research efforts to fill the gaps and limitations in the current data. Impact One of the goals of this literature review is to provide PFAS bioaccumulation data for earthworms assembled in a form for others to work with without having to grind through the scientific literature. The assembled data will provide a springboard for others to advance our understanding of PFAS universe of chemicals.

Description:

Per- and polyfluoroalkyl substances (PFAS) are widely used across the globe in commercial products such textiles, firefighting foams, and surface coatings. Some PFAS, such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are known to be bioaccumulative. Numerous terrestrial ecosystems including sites near PFAS manufacturing facilities, facilities using PFAS in their manufacturing processes, firefighting training areas, landfills, and agricultural fields treated with some pesticide formulations, have been contaminated with PFAS. Earthworms reside at the base of the terrestrial food chain and to perform risk assessments at terrestrial sites contaminated with PFAS, information on the bioaccumulation of PFAS is needed. To understand the bioaccumulation of PFAS by earthworms, a literature search was performed, and biota-soil accumulation factors (BSAFs), measured in laboratory tests and at field sites contaminated with PFAS, were assembled and evaluated in this review. Based on this review, we conclude that there is enough data available for carboxylic and sulfonic acid PFAS classes to derive useful BSAFs for terrestrial risk assessments. Laboratory tests with PFOS and PFOA will be close to or at steady-state conditions with standardized testing protocols, and for the longer chain carboxylic and sulfonic acids, it is unlikely they will reach steady-state with the completion of the uptake exposure. For PFAS classes beyond the carboxylic and sulfonic acids, data are limited and performing terrestrial risk assessments with these PFAS will be difficult. Lastly, additional measurements are needed for non-acid PFAS classes as well as from field settings for all PFAS classes. Across all studies, PFOS and PFOA had average (standard deviation, count) BSAFs (kg-OC/kg-ww) of 0.167 (0.311, 60) and 0.0413 (0.175, 47), respectively.