Unravelling the magnitude and drivers of PFAS trophic magnification: a meta-analysis

Per- and polyfluoroalkyl substances (PFAS) threaten ecosystems worldwide due to their persistence, bioaccumulation, and toxicity. Through a global-scale meta-analysis of 119 aquatic and terrestrial food webs from 64 studies, we analyse 1009 trophic magnification factors (TMFs) for 72 PFAS and identify key variability drivers. On average, PFAS concentrations double with each trophic level increase (mean TMF = 2.00, 95% CI:1.64-2.45), though magnification varies considerably by compound. Notably, the industrial alternative F-53B exhibits the highest magnification (TMF = 3.07, 95% CI:2.41-3.92), a critical finding given its expanding use and minimal regulatory scrutiny. Methodological disparities across studies emerge as the dominant source of TMF variability. Our models explain 85% of the variation in TMFs, underscoring predictive capacity. This synthesis establishes PFAS as persistent trophic multipliers and provides a framework to prioritise high-risk compounds and harmonise biomagnification assessments. Our results call for consideration of stricter PFAS regulation to curb cascading ecological and health impacts. PFAS are “forever chemicals” that build up in living things and can move through food webs. This study shows their levels roughly double with each step up the food chain, highlighting widespread chemical magnification in nature.