Oral Presentation- Symposium 12th International Mammalogical Congress

Health implications for dolphins with heavy metal contamination in South Australia: A case study of two species in Spencer Gulf (#57)

Catherine M Kemper 1 , Ikuko Tomo 1 , Amy Watson 2 , Gilian Ross 2 , Robert Reid 2 , Trish Lavery 3 , Alessia Ciraolo 1 , Valentina Sciutteri 1
  1. South Australian Museum, Adelaide, South Australia, Australia
  2. The University of Adelaide, Adelaide, South Australia, Australia
  3. Department of the Environment and Energy, Commonwealth of Australia, Canberra, Australian Capital Territory, Australia

Industrial and agricultural pollutants have resulted in high concentrations of heavy metals in the sediments and biota of Spencer Gulf. The present study examined 307 opportunistically-collected Indo-Pacific bottlenose and short-beaked common dolphins with the aim of identifying relationships between heavy metal concentration in kidney and bone (by ICPMS and ICPAES), indicators of pathology in bone and kidney, age, sex, collection locality and circumstance of death. The highest kidney concentrations of cadmium (134 mg kg-1 wet weight), zinc (93 mg kg-1) and lead (11 mg kg-1) were found in bottlenose dolphins. Several individuals had elevated concentrations of more than one metal. Lead was weakly correlated with age for bottlenose dolphins. Preliminary evidence was found for transfer of zinc from mother to neonate during foetal life and while suckling. Cadmium accumulation may begin soon after birth. Nephritis was the most often recorded kidney pathology, usually as a chronic condition. Bowman’s capsule, in the kidney, was larger in dolphins from Spencer Gulf than elsewhere. Older dolphins had more skeleton pathology than younger ones. Degenerative lesions, which are normally associated with age, were more frequent in young bottlenose than common dolphins at similar ages. Extreme congenital skeleton pathology was observed in a bottlenose dolphin from upper Spencer Gulf and it had the highest cadmium and zinc concentrations. Multivariate analysis of results may reveal relationships between the studied variables. Bottlenose dolphins in northern Spencer Gulf are exposed to many threats, including heavy metals and their toxic effects.