Heavy metals in the Galápagos Archipelago: a One Health scoping review

Background Heavy metal contamination is a global concern due to its persistence, bioaccumulation, and toxicity to ecosystems and human health. The Galápagos Archipelago, with its high endemism and limited industrial activity, provides a unique setting where natural and anthropogenic sources may interact. This review aimed to synthesize evidence on the presence, distribution, sources, and effects of heavy metals in environmental matrices and wildlife in the Galápagos. Methods A systematic search was conducted in PubMed, Scopus, and Web of Science. Studies evaluating heavy metals and metalloids in environmental matrices and terrestrial or marine organisms within the archipelago were included, without restrictions on language or publication year. Results Evidence was mainly concentrated in environmental compartments (soils, sediments, water, and fumarolic systems) and wildlife, particularly fish, seabirds, pinnipeds, and invertebrates. The most frequently assessed metals were mercury, cadmium, lead and copper. Cadmium exceeded EFSA maximum levels in all evaluated commercial fish species, posing the highest risk in Caulolatilus affinis . Mercury exceeded EFSA/FDA/Codex limits in Acanthocybium solandri, Pontinus clemensi , and Hyporthodus mystacinus . Furthermore, mercury in Grapsus grapsus from San Cristóbal exceeded the EPA threshold, and was detected in feathers of 8 seabird species, showing higher levels during La Niña upwelling. Lead in Zalophus wollebaeki bone was lower than in Mauritania and Uruguay, which act as relatively unpolluted references. Both natural and localized anthropogenic sources were identified, including agriculture, phosphate fertilizers, and maritime activities. Conclusions Important gaps persist, particularly in human biomonitoring and integrated surveillance. Future research should adopt a One Health approach to better link environmental contamination with ecological and public health outcomes.