Multilevel meta-regression analysis of per- and polyfluoroalkyl substances toxicity to aquatic macrophytes

Per- and polyfluoroalkyl substances (PFAS) are widely known for their toxicity and persistence in environmental matrices. Aquatic macrophytes, key components of aquatic ecosystems, are particularly susceptible to these compounds. This study provides the first multilevel meta-regression of PFAS toxicity to aquatic macrophytes, synthesizing 1091 effect sizes across 31 studies and 13 species. PFAS exposure consistently induced significant antioxidant enzyme activation (Hedges 'g = +0.44, p = 0.049) and substantial oxidative damage (Hedges 'g = -0.95, p = 0.020), with decline in total chlorophyll (Hedges 'g = -0.62, p = 0.049). A statistically significant negative linear concentration-response relationship was established across priority PFAS types (beta = -0.155, p = 0.044). Toxicological pathways diverged by functional group: sulfonates driven by strong electronegativity caused systemic oxidative damage, whereas carboxylates executed a broader siege across all primary endpoints, specifically targeting chlorophyll biosynthesis. While emerging short-chain alternatives (e.g., PFBA, GenX) generally displayed lower toxic potency across structural and growth traits than legacy compounds, they still induced non-trivial physiological stress.Rooted submerged macrophytes (represented largely by Vallisneria natans) were identified as the most sensitive plant form relative to emergent and floating taxa. The current results can be applied to point-source contamination sites and remediation environments. Our synthesis suggests that biochemical stress markers could serve as early-warning triggers for a proactive harvesting hypothesis, potentially mitigating biomass collapse and any subsequent PFAS re-release. Testing this hypothesis would require paired field measurements of stress-marker thresholds, biomass collapse dynamics, and PFAS flux to the water column.