Polycyclic Aromatic Hydrocarbons Through the One Health Lens: Integrating Human, Animal, and Environmental Health Perspectives.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous combustion-derived contaminants that represent a significant cross-cutting threat to human, animal, and environmental health. Viewed through an explicit One Health lens, this review shows how the shared combustion sources, evolutionarily conserved toxicological mechanisms, and food-web linkages connecting environmental contamination to wildlife and human exposure justify an integrated, cross-domain approach to PAH risk assessment and management. PAHs are generated predominantly through incomplete combustion of organic materials and are globally distributed through atmospheric transport, aquatic runoff, and food-web transfer, persisting in soils and sediments for decades. The present review synthesizes current knowledge on PAHs through an explicit One Health lens, examining shared sources, environmental fate, and convergent health effects across species and health domains, while also highlighting the need to move beyond the classical US EPA priority PAHs to include high-molecular-weight PAHs (>302 Da), alkylated homologues, and transformation products such as oxy- and nitro-PAHs. Common pathways such as dietary intake of grilled and smoked foods, inhalation of contaminated air, and occupational exposure create parallel toxicological burdens in both human and wildlife populations, particularly through genotoxic mechanisms mediated by aryl hydrocarbon receptor (AhR) activation and CYP1A1/CYP1B1-catalyzed bioactivation to reactive diol epoxides. The resulting DNA adduct formation links environmental PAH exposure to carcinogenicity, reproductive toxicity, immunosuppression, and developmental impairment across vertebrate species with remarkable mechanistic consistency. Wildlife, especially fish, marine mammals, and seabirds, serve as critical sentinels for environmental PAH contamination, while simultaneously facing direct health impacts on immune function, reproduction, and population viability. Vulnerable human populations, including children, subsistence communities, occupational workers, and residents near combustion-intensive industries, bear disproportionate burdens reflecting underlying environmental justice concerns. Integrated intervention strategies encompassing source control, dietary exposure reduction, site remediation, and coordinated biomonitoring are urgently needed. By incorporating emerging PAH classes with distinct persistence, trophic behavior, and toxicological potency, the One Health paradigm provides a more comprehensive conceptual framework for modern environmental surveillance, food safety, and integrated risk assessment, recognizing that the health of terrestrial and aquatic ecosystems is inseparable from that of the animals and humans within them.