Distribution of trace elements in the tissues of smooth hound Mustelus mustelus (Linnaeus, 1758) from the southern-eastern waters of Mediterranean Sea (Italy)

Trace element concentrations (Hg, Cd, Pb, Cr, Ni, Cu, Zn) were determined in the muscle, gonads, skin, and brain of smooth hound Mustelus mustelus in order to define the metal distribution patterns. The data indicated that metal accumulation depended on the tissues probably as a consequence of metabolic needs, physiochemical properties, and detoxification processes specific for each element. Metal concentrations were higher in gonads (Hg 0.10–0.70 μg g − 1; Cd 0.02–0.10 μg g − 1; Pb 0.08–0.39 μg g − 1; Cr 0.06–0.36 μg g − 1; Ni 1.37–3.00 μg g − 1; Zn 9.15–16.30 μg g − 1; Cu 1.95–21.62 μg g − 1) and skin (Hg 0.16–0.66 μg g − 1; Cd 0.01–0.04 μg g − 1; Pb 0.10–0.62 μg g − 1; Cr 0.15–0.68 μg g − 1; Ni 1.60–7.20 μg g − 1; Zn 9.00–16.00 μg g − 1; Cu 0.78–6.80 μg g − 1) than brain (Hg 0.04–0.34 μg g − 1; Cd 0.01–0.05 μg g − 1; Pb 0.03–0.59 μg g − 1; Cr 0.08–0.48 μg g − 1; Ni 5.59–9.69 μg g − 1; Zn 5.90–7.35 μg g − 1; Cu 0.90–4.02 μg g − 1), while muscle always exhibited the lowest levels (Hg 1.03–2.58 μg g − 1; Cd 0.01–0.06 μg g − 1; Pb 0.02–0.16 μg g − 1; Cr 0.05–0.28 μg g − 1; Ni 1.13–2.48 μg g − 1; Zn 2.64–5.06 μg g − 1; Cu 0.33–2.23 μg g − 1). Ni and Hg took exception having the highest concentrations in brain and muscle, respectively. An assessment of the risk for human due to the consumption of these marine organisms was also undertaken. Regarding Cd and Pb intakes, consumption did not guide to any concerns, while it should be extremely moderate when considering Hg intake. The comparative analyses revealed that Mediterranean sharks were exposed to higher Hg levels than biota inhabiting open ocean.