Total mercury concentrations in muscles of little tunny species (Euthynnus alletteratus) sold in the city of Cabo Frio, State of Rio de Janeiro, Brazil

Abstract Mercury (Hg) is a trace metal that is considered a major contaminant of fresh and marine waters due to natural sources and anthropogenic sources such as gold mining and industrial processes. From a toxicological point of view, Hg is one of the most widely studied elements, especially in the area of food, due to its high toxicity, high absorption levels, and low excretion rates, which lead to an increase in its concentrations in the food chain. It enters the human body through the consumption of fish, posing a risk to human health. Owing to these facts, this study aimed to determine total mercury (THg) concentrations in the tuna species, little tunny (Euthynnus alletteratus), to compare the concentrations between males and females, and to analyze whether these concentrations fall within the maximum limit established by Brazilian and international legislations for predatory (carnivorous) fish, which is 1.0 mg.kg-1. In our study, the Hg concentration found in males ranged from 0.034 mg.kg-1 to 1.930 mg.kg-1, while in females it ranged from 0.036 mg.kg-1 to 1.980 mg.kg-1. The maximum values discovered were nearly twice as high as the recommendations of Brazilian and international legislations for carnivorous fish. Therefore, it is concluded that regular consumption of this species may endanger human health.