|
Environmental RTDI Programme 2000-2006, Phase 1
SMALL SCALE STUDY
Organochlorine Concentrations in Resident Bottlenose Dolphins (Tursiops truncatus) in the Shannon Estuary, Ireland
(Ref.2000-SS-1-M1)
Project Start Date: September 2000
Project Duration: 1 week sampling, 12 months analyses
Project Leader: Dr Simon Berrow, Shannon Dolphin and Wildlife Foundation, Merchants Quay, Kilrush, Co. Clare
Research Partners: Brendan McHugh, Denise Glynn, Evin McGovern, Marine Institute, Abbotstown, Castleknock, Dublin 15, Ireland
Kim Parsons, Department of Zoology, University of Aberdeen, Tillydrone Avenue, Aberdeen, UK
Robin Baird, Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Sascha Hooker, British Antarctic Survey, High Cross, Madingley Road, Cambridge, UK
Project Cost: €3,175
Project Description:
Persistent pollutants are ubiquitous in the marine environment. Cetaceans are marine top predators and as such are particularly susceptible to persistent pollutants that may bio-accumulate through the food chain. Resident bottlenose dolphins in the Shannon estuary were sampled using biopsy darts. The gender of the bottlenose dolphins sampled was determined using a molecular genetic approach from a skin sample. Blubber samples were analysed for seven organochlorines (HCB, a-HCH, b-HCH, pp-DDE, lindane, trans-chlordane, and trans-nonachlor) and 11 individual chlorobiphenyls and the sum of the seven congeners (CB 28, 52, 101, 118, 138, 153, 180) recommended by ICES for monitoring purposes.
The highest concentrations of individual OC were for p,p' DDE (42.0 and 32.5 mg kg-1 lipid) followed by the PCB congeners CB153 (28.1 and 22.4 mg kg-1 lipid weight) and CB138 (18.3 and 14.0 mg kg-1 lipid weight). Concentrations of trans-nonachlor and CB180 were elevated in #4 and #7. A maximum concentration of 59.6 mg kg-1 lipid was recorded in #6 and 48.4 mg kg-1 lipid in #4, both male dolphins. The highest concentration recorded in a female was 13.3mg kg-1 lipid in #8. The pattern of contamination is similar for all dolphins with CB153 contributing to around 40% of the total PCB burden and CB138 25-30%. CB180 would be the next most abundant congener contributing 10-15% of the total sum of ICES 7 PCB burden.
The results from this study suggest that the mean levels of OCP and PCB contaminants are higher in bottlenose dolphins from the Shannon estuary compared to results reported for harbour porpoise and common dolphin incidentally caught in fishing nets in Irish waters, but are similar to those from a mass stranding of white-sided dolphins from Killala Bay, on the west coast of Ireland. PCB concentrations of between 50-200 mg kg-1 wet weight in blubber may put the health of cetaceans at risk. Levels in this study were much less than these (maximum 18.3 mg kg-1 wet weight) and are not thought to pose a risk to health.
For further information, contact the project co-ordinator:
Dr Simon Berrow,
Project Manager
Shannon Dolphin and Wildlife Foundation
Merchants Quay
Kilrush
County Clare
Tel: 065 9052326
Mobile: 086 8545450
Email: Dr. Simon Berrow
|
