Domestic and wild animals as sentinels for environmental monitoring of emerging contaminants: a One Health framework for biomonitoring and human exposure assessment.

Emerging contaminants are increasingly detected across environmental, domestic, agricultural and food-chain matrices, where low-dose chronic exposure, mixtures, and delayed toxicological outcomes challenge conventional human-centred surveillance. This critical narrative review and monitoring-framework article uses structured keyword selection and literature mapping informed by SANRA quality criteria to integrate evidence on companion animals, livestock and wildlife as sentinels of per- and polyfluoroalkyl substances (PFAS), endocrine disruptors, micro- and nanoplastics, pesticides, pharmaceuticals, and food-chain contaminants. Companion animals can support reconstruction of shared indoor and lifestyle exposures; livestock can identify contamination at the interface between feed, water, soil, and animal-derived foods; and wildlife can integrate ecosystem, trophic, and landscape-level exposure. The proposed framework outlines monitoring modules, normalization considerations, biospecimen-banking options, and tiered operational triggers connecting sentinel detection to environmental verification and targeted human biomonitoring. Two application models-a hypothetical localized PFAS plume involving waterfowl and dairy cattle and an evidence-informed Arctic sled dog model for chronic long-range transported mixtures-illustrate how animal signals can support exposure reconstruction, hotspot identification, and public-health prioritization. Animal sentinel evidence should be interpreted as early warning and triangulating evidence, not as stand-alone proof of human health risk.