Fig. 4: Effects of chemical and ecological categorical moderators on PFAS trophic magnification factors.

Trophic magnification factor (TMF) of per- and polyfluoroalkyl substances (PFAS), stratified by PFAS chemical class (A), food webs of exclusively water breathing organisms versus mixed breathing types (B), and food webs with either air breathing or water breathing top predators (C). The meta-analytic mean estimate for each stratification is represented by a red-filled circle with a black outline. Thicker bars denote the 95% confidence interval, while thinner bars represent the 95% prediction interval. Light grey circles show individual effect sizes, scaled by precision (inverse of the standard error, as indicated in the legend). The number of studies is indicated in parentheses, with ‘k’ representing the number of effect sizes. The red dotted line marks a trophic magnification factor (TMF) of 1, with values above 1 indicating biomagnification and those below 1 indicating biodilution. TMF values are capped at 14 for improved visual clarity (refer to Fig. S11–S13 for full versions). R² values represent the proportion of variance explained only by the fixed effects in the model (marginal R²). Source data are provided as a Source Data file.