Spider Webs as Noninvasive Indicators of Biomagnification and Tissue Partitioning of Halogenated Organic Contaminants in Mangrove Ecosystems

Mangrove ecosystems are increasingly threatened by halogenated organic contaminants (HOCs), posing a significant threat to resident arthropods, including spiders and insects. Spider webs, due to their distinctive chemical composition and adsorption properties, have emerged as promising tools for monitoring environmental pollutant. This study quantified 58 HOCs in insects, spider tissues, and webs of <i>Nephila pilipes</i> across mangroves with varying pollution levels, using quantitative fatty acid signature analysis (QFASA) to estimate spider diets. Significantly elevated concentrations of dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), alternative halogenated flame retardants (AHFRs), hexabromocyclododecanes (HBCDs), and tetrabromobisphenol A (TBBPA) were observed in all matrixes from heavily polluted areas, driven by habitat contamination and dietary intake. Concentrations of HCHs, PCBs, PBDEs, and AHFRs in spider webs were highly correlated with those in spider tissues (cephalothorax and abdomen; <i>p</i> < 0.05), whereas DDTs and HBCDs exhibited weak correlations (only in the abdomen; <i>p</i> < 0.05), and TBBPA showed no significant correlation, potentially attributed to compound-specific properties and web characteristics. Integration of HOC concentrations in spider webs with chemical properties (log <i>K</i>_OW, log <i>K</i>_OA, and molecular weight) yielded significant correlations with biomagnification factors (<i>R</i>² = 0.415-0.539, <i>p</i> < 0.01) and with tissue HOC levels (<i>R</i>² = 0.511-0.795, <i>p</i> < 0.001), supporting predictive models for biomagnification and tissue partitioning. These findings underscore the potential of spider webs as noninvasive, sustainable bioindicators that integrate pollutant data to enhance ecological risk assessments and pollution monitoring in sensitive ecosystems, providing a viable alternative to destructive sampling.