Mercury in fish tissues from the Galapagos marine reserve: Toxic risk and health implications

Abstract

Fishing is one of the most important economic and cultural activities in Galapagos and Hg presence in aquatic ecosystems is a serious problem for human health, so its concentrations should be studied. We sampled five demersal species (Caulolatilus princeps, Caulolatilus affinis, Mycteroperca olfax, Hyporthodus mystacinus and Pontinus clemensi) and four pelagic species (Coryphaena hippurus, Acanthocybium solandri, Thunnus albacares and Seriolella violacea) to evaluate Hg concentration in muscle, liver and gonads. Hg was analyzed by Cold Vapor Atomic Absorption Spectrophotometry with Flow Injection System (CV-AAS-FIAS). Demersal species had higher Estimated Weekly Intakes (EWI) of Hg than pelagic species. According to the Codex Alimentarius (1995), EFSA (2018), FDA (2021) regulations, and according to the regulations in Europe, A. solandri, P. clemensi, and H. mystacinus were found above the maximum allowed concentration (MAC) (0.65, 0.65 and 1.26 mg/kg wet weight, respectively) so they could not be ingested nor commercialized. The Margin of Safety (MoS) of these species was above 1, so they could pose a risk to human health. We hypothesize that the Hg concentrations found in the studied species could come from the volcanism of the archipelago, since no major sources of anthropogenic Hg contamination can be found in the islands.