The importance of the age when evaluating mercury pollution in fishes: the case of &lt;em&gt;Diplodus sargus&lt;/em&gt; (Pisces, Sparidae) in the NW Mediterranean

Margarida Casadevall,Conxi Rodríguez-Prieto,Jordi Torres

doi:10.3934/environsci.2017.1.17

Abstract

The aim of this study was to analyse the concentration of mercury (Hg) in the muscle of a common littoral, omnivorous fish such as the white seabream, <em>Diplodus sargus</em>, and to evaluate its relationship with the age and size of the specimens. Large, older predatory fishes have typically been the main target species for risk assessment of Hg intake in humans. The white seabream is neither a big fish nor a predator, but all sizes of NW Mediterranean specimens of this species showed high levels of Hg, with clear increases in older specimens. In addition, although the Se:Hg molar ratio was high and could reduce the impact of high concentrations of Hg in smaller fishes, it could not in the older specimens of <em>D. sargus</em> analysed because it decreased with age. This is not a major concern for human health because the white seabream is not a widely consumed species. However, in special situations involving toddlers, children and women of childbearing age, problems might arise if the white seabream or similar species are consumed in place of those that current recommendations advise against eating. In these cases it is very important to consider the species of fish consumed in each country and carefully assess the risk of Hg intake.

Highlights

Human exposure to heavy metals depends on dietary habits and geographic location, and consuming edible marine species contributes most to mercury (Hg) intake [1]
In special situations involving toddlers, children and women of childbearing age, problems might arise if the white seabream or similar species are consumed in place of those that current recommendations advise against eating
Of the D. sargus individuals analysed, 26 out of 39 (67%) presented values of Hg clearly above the limit established by European legislation (500 ng g−1), while 15 specimens (38%) presented Hg values above 1000 ng g−1, the limit established by European Commission regulations for fish species prone to bioaccumulation of this metal

Summary

Introduction

Human exposure to heavy metals depends on dietary habits and geographic location, and consuming edible marine species contributes most to mercury (Hg) intake [1]. Tuna, swordfish, cod, and whiting are mostly responsible for methylmercury dietary exposure in adults, while these same species, with the addition of hake, are the most important contributors to exposure in children [2]. This is due to the high Hg concentrations in these species, and to their popularity as the most commonly consumed species. Hg has been associated with damaging cardiovascular and neurological effects [4], which impair neurodevelopment and can range from foetal death to delayed development and cognitive changes [5] Maximum levels of this metal in fishery products are laid down by European Commission regulations. The role of selenium (Se) should be considered, as some studies suggest that a Se:Hg molar ratio >1 could protect against potentially adverse Hg effects [8,9,10]

Methods

Results

Discussion

Conclusion