Some per- and polyfluoroalkyl substances (PFAS) are persistent in the environment and in biological tissues, which can lead to bioaccumulation and biomagnification in terrestrial systems. The main objective of this research was to develop empirical data for the uptake and elimination kinetics of PFAS in terrestrial organisms at different trophic levels to determine food web biomagnification potential for selected, common PFAS. The goals of the project were accomplished by the following technical tasks: 

1. Determining the uptake and elimination of PFAS in soil invertebrates (earthworms) and the associated bioaccumulation factors. 
2. Determining the uptake of PFAS from soil to terrestrial plants and generate bioconcentration and translocation factors. 
3. Determining trophic transfer coefficients (TTC) or biomagnification factors (BMF) of individual PFAS from soil amended with PFAS to soil invertebrates (earthworms) and then to amphibians (American toads). 
4. Determining TTC or BMF for individual PFAS from terrestrial plants grown in PFAS-amended soil to mammals.

This project is assessing the uptake, accumulation and elimination kinetics and potential biomagnification of PFAS in terrestrial systems.

Research was conducted to produce empirical bioaccumulation and bioconcentration data for terrestrial organisms at different trophic levels, and to determine the biomagnification potential of PFAS in herbivorous and carnivorous food chains resulting from exposures to environmentally relevant PFAS concentrations. Studies were designed to track changes in PFAS profiles and concentrations through the biological system from a uniform, abiotic starting point and to test the hypotheses that the PFAS can biomagnify in the terrestrial food web from soil to lower trophic level organisms (primary consumers) to higher trophic level organisms (secondary consumers).

First, the uptake potential of 16 PFAS in primary consumers (i.e., earthworms (Eisenia andrei)) and two terrestrial plants: timothy grass (Phleum pratense) and kale cabbage (Brassica oleracea)) were assessed. Then, the kinetics and biomagnification of mixtures of PFAS from soils to consumers were investigated to assess the potential effect of competitive uptake and selective bioaccumulation of PFAS. The experimental approach was built upon the experience gained in previous SERDP projects (ER-1416, ER-2625, ER-2724) that established uptake and toxicokinetic data for terrestrial plants, soil invertebrates, and wildlife species.

Organisms with divergent diets—even from a common soil background—had varying PFAS burdens. As expected, perfluorooctane sulfonate showed trophic transfer coefficients >2 for toads and rabbits. Surprisingly, the likelihood of trophic magnification of 8:2 fluorotelomer sulfonate (FTS) and perfluorohexanesulfonate (PFHpS) was low in toads, but these PFAS concentrations were high in worms. Similarly, the likelihood of trophic magnification of 8:2 FTS and PFHpS was high in rabbits, but these PFAS concentrations were low in plant diets. 

This research showed that organisms with divergent diets—even from a common soil background—had varying tissue concentrations. The implication of these findings are that predicting body burdens in exposed populations is somewhat species-specific, reinforcing the importance of tailored environmental risk assessments. The successful execution of this research yielded data essential for the development of advanced technologies aimed at enhancing ongoing remediation efforts at impacted sites, thereby providing crucial safeguards for warfighters and installation communities. (Project Completion - 2024)

Lotufo, G.R., R.E. Boyd, P.M. Krupa, Z. Yang, J.E. Guelfo, M. Simini, and R.G. Kuperman. 2025. Uptake and elimination of per-and polyfluoroalkyl substances in earthworms exposed to spiked artificial soil or aqueous medium. Environmental Toxicology and Chemistry, 44(6):1655–1671. doi.org/10.1093/etojnl/vgaf083