Mercury and cadmium in striped dolphins (Stenella coeruleoalba) stranded along the Southern Tyrrhenian and Western Ionian coasts

Pollution from heavy metals is becoming a serious and widespread problem due to their persistent and bioaccumulative nature, moreover in the Mediterranean Sea, threatening food safety and the health of humans and marine animals. Cadmium and mercury in particular, are considered two of the most toxic metals to living organisms. Their presence is associated with the contribution of human activity, implying an increased level in the different environmental compartments and the inevitable bioaccumulation in the food chain.In this study, levels of cadmium and mercury were determined in liver, kidney, and muscle tissue of dolphinid specimens of Stenella coeruleoalba stranded in different locations along the coastal areas of the Tyrrhenian and Ionian Sea in Southern Italy, during the period 2015–2018 by Atomic Absorption Spectrophotometry. Data were compared with those reported for other locations along the Mediterranean sea. The correlations between biometric data (body length, weight and gender) and cadmium and mercury concentrations in samples of cetaceans were statistically analysed in order to investigate the risk these contaminants may pose to the delphinids health.Examination of the pattern of contaminants revealed a significantly high distribution for mercury in all the matrices analyzed (liver, kidney and muscle tissue). On the contrary, elevated concentrations of cadmium were found only in liver (range: 0.005 - 8.95 mg/kg w.w.) and kidney (range: 0.005 - 34.1 mg/kg w.w.) due to accumulator role of these organs in long-term exposures.