Contribution of commercial fish species to human mercury exposure: An evaluation near the Mid-Atlantic Ridge

Abstract

Fish consumption is frequently associated with the prevention of some human diseases, being simultaneously a major pathway of mercury (Hg) exposure. Therefore, the aim of the study was to evaluate the contribution of 28 commercial fish species to the human Hg exposure in the Azores archipelago (Portuguese region with highest fish consumption per capita). These species potentially contributed on average to 7.47 mg of Hg per capita, although low Hg levels had been detected in fish. Mora moro and Zeus faber exceeded the maximum permitted for fish consumption (> 0.5 μg g−1 ww) even though they were not the species contributing the most to human Hg exposure. On the other hand, Katsuwonus pelamis was the main contributor due to increased fish landings. Furthermore, an increase in Hg content with trophic level has been suggested, as carnivore fish exhibited higher Hg levels than omnivores. In addition, demersal fish generally presented higher Hg concentration (although non-significant) than pelagic ones, possibly related with increased Hg values of their prey at this depth. Notwithstanding, THQ (Target Hazard Quotient) being < 1 for all species indicates that the daily human exposure to Hg via fish consumption is not likely to cause any negative health risks.