Heavy metal accumulation and toxicity in smoothhound (Mustelus mustelus) shark from Langebaan Lagoon, South Africa

Together with several health benefits, fish meat could introduce toxins to consumers in the form of heavy metal contaminants. High levels of mercury (Hg), especially, are frequently detected in certain predatory fish species. Mustelus mustelus fillets were analysed for 16 metals and three individual Hg species (inorganic Hg, ehtylmercury, methylmercury) with inductively coupled plasma mass spectrometry (ICP-MS) and HPLC-ICP-MS respectively. Eleven of the 30 sharks had total Hg levels above the maximum allowable limit with toxic methylmercury found as the dominant mercury species with a strong correlation (r = 0.97; p < 0.001) to total mercury concentrations. Limited correlations between metals and shark size parameters were observed; therefore metal accumulation in M. mustelus is mostly independent of size/age. Average values for arsenic (28.31 ± 18.79 mg/kg) exceed regulatory maximum limits and Hg (0.96 ± 0.69 mg/kg) is close to the maximum limit with all other metals well below maximum limits.