Trophic-level accumulation and transfer of legacy and emerging contaminants in marine biota: meta-analysis of mercury, PCBs, microplastics, PFAS, PAHs

Marine ecosystems are increasingly threatened by anthropogenic pollutants, including plastics, persistent organic pollutants, heavy metals, oil, and emerging contaminants. This meta-analysis examined the accumulation patterns of five major contaminants-mercury (Hg), polychlorinated biphenyls (PCBs), microplastics, per- and polyfluoroalkyl substances (PFAS), and polycyclic aromatic hydrocarbons (PAHs)-in relation to trophic level and lifespan across marine species. Data synthesis revealed distinct differences in bioaccumulation and biomagnification between legacy and emerging contaminants. Regression analyses indicated strong correlations between contaminant concentrations and trophic level for microplastics and PAHs across all trophic levels, and for PCBs up to trophic level 4.5. Lifespan significantly predicted the accumulation of PCBs, microplastics, and PAHs. In contrast, PFAS and mercury showed high variability, driven by species-specific metabolic processes, exposure pathways, and localized contaminant distributions. PFAS accumulation was particularly unpredictable due to the diversity of compounds grouped under PFAS and inconsistencies in reported datasets. These findings emphasize the influence of life history traits on contaminant bioaccumulation in marine species and highlight the ecological risks posed by persistent pollutants, which can affect multiple generations and disrupt ecosystem stability over time. To advance understanding, harmonized analytical protocols, comprehensive metadata standards, and open sharing of congener-resolved datasets are needed to enable robust cross-ecosystem comparisons and track long-term shifts in contaminant patterns in marine biota.