engleski

Mercury concentrations in the liver of bottlenose dolphins (Tursiops truncatus) stranded on the Croatian Adriatic Coast

Mercury (Hg) pollution in the Mediterranean Sea is particularly relevant, as this is a semi-enclosed body of water with high natural and anthropogenic inputs of this metal. Natural sources include weathering of the large cinnabar ore deposits found along the seabed bottom. Anthropogenic emissions include intensive current and past mining, fossil fuel combustion, cement production and specific industries such as chlor-alkali plants. The aim of this study was to determine Hg concentrations in stranded bottlenose dolphins collected along the Croatian Adriatic coast, in order to increase the sparse database of contaminant data available for this species and to compare the concentrations found to those in other species from the study area. Between 2010 and 2013, 42 stranded bottlenose dolphins (Tursiops truncatus) were sampled along the Croatian Adriatic coast. Mercury concentrations in liver tissues were determined by a flow injection mercury system. Concentrations in liver ranged from 0.449 to 933 mg kg-1. A high correlation was observed between total Hg concentration and age. Also, adult dolphins contained statistically significant higher Hg concentrations compared to juvenile dolphins, suggesting a major impact of age on the accumulation of Hg. Using benchmarks relevant to marine mammals, this study indicated that the maximum Hg threshold of 400 mg kg-1, defined to indicate hepatic damage, was exceeded in six individuals.

mercury; contamination; bottlenose dolphin; liver; Adriatic coast

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