Uptake of Per- and Polyfluoroalkyl Substances (PFAS) in plants: A systematic review and meta-analysis research protocol

Lorenzo Ricolfi , Kara Fry, Antti Mikkonen

Per- and polyfluoroalkyl substances (PFAS) transfer from contaminated environments into plants, contributing to food chain accumulation and an exposure pathway central to human health risk assessment. Regulatory risk assessments commonly use plant bioconcentration factors (BCFs) to estimate dietary exposure and support the derivation of health-based guideline values, yet they have not been derived from a formal quantitative synthesis of the evidence. Following PRISMA-P guidance, this protocol describes a systematic review and multilevel meta-analysis that will map the evidence base on PFAS plant BCFs, derive pooled BCFs for the plant species and categories, and quantify the principal biological, environmental, and methodological drivers of variability in PFAS uptake across plant species. Peer-reviewed studies will be identified through systematic searches of Scopus and PubMed, supplemented by BASE and ProQuest for grey literature; eligible studies must be primary empirical investigations of PFAS uptake in plants grown for human consumption or livestock feed, reporting plant-to-matrix concentration ratios or data sufficient to calculate them. Risk of bias will be assessed using a tool adapted from SYRCLE's framework. The primary effect size, the natural logarithm of the bioconcentration factor [ln(BCF)], will be synthesised using multilevel random-effects meta-analysis and meta-regression, with sensitivity and publication-bias analyses assessing robustness.