Concentrations of metallic elements in kidney, liver, and lung tissue of Indo-Pacific bottlenose dolphin Tursiops aduncus from coastal waters of Zanzibar, Tanzania

Concentrations of metallic elements in kidney, liver and lung tissues of Indo-Pacific bottlenose dolphins Tursiops aduncus from coastal waters of Zanzibar were determined using inductively coupled plasma - optical emission spectroscopy. Cadmium, chromium, copper, and zinc were quantifiable in all tissues at concentration ranges of 0.10-150, 0.08-3.2, 1.1-88 and 14-210 μg/g dry mass, respectively. Copper and zinc was significantly higher in liver, and females had significantly higher Cd in liver, and chromium in lung. Generally, T. aduncus dolphins from coastal waters around Zanzibar carry low concentrations of metals compared with dolphins from other areas. Cadmium increased significantly with age in kidney and lung. Copper decreased significantly with age in liver, probably due to foetal metallothionein. This study supplied baseline data against which future trends in marine mammals in the Indian Ocean, the world's third largest, can be assessed.