Bioaccumulation and Trophic Magnification of Endocrine-Disrupting Chemicals in an Estuarine Food Web

Endocrine-disrupting chemicals (EDCs) are widespread contaminants in coastal ecosystems, yet their bioaccumulation and trophic transfer in estuarine food webs remain poorly understood. Here, we investigated the occurrence, bioaccumulation, and trophic magnification of 31 EDCs─including personal care products, bisphenols, and estrogens─in seawater, sediments, and representative biota from the Pearl River Estuary, South China. Trophic levels were determined using stable nitrogen isotope analysis, and bioaccumulation factors (BAFs) and trophic magnification factors (TMFs) were calculated. EDCs were detected across all matrices and trophic levels, with total concentrations in biota ranging from 7.3 to 79 ng g–1 wet weight; personal care products dominated the profiles. Bioaccumulation varied widely among compounds and species (log BAFs: 0.23–5.3) and was not positively correlated with hydrophobicity, suggesting enhanced bioavailability of moderately polar EDCs. Several EDCs, including parabens, triclosan, and selected bisphenols, showed clear trophic magnification (TMF > 1), whereas others exhibited trophic dilution, reflecting compound-specific food-web transfer. These results provide field evidence that endocrine-disrupting chemicals, including moderately polar compounds often considered to pose low bioaccumulation risk, can bioaccumulate and biomagnify in estuarine food webs and that dietary exposure is an underestimated pathway for higher-trophic-level organisms, challenging water-based risk assessment of EDCs in estuarine ecosystems.