An Integrated Approach to the Toxicity Evaluation of Irish Marine Sediment - Chemical Assessment

This project was a collaborative project between the Marine Institute (MI) in Galway and Radiation and Environmental Science Centre (RESC) in the Technological University Dublin (DIT). In Ireland, at present, sediment quality assessments are generally reliant on chemical analysis alone with limited bioassay techniques available to further characterise the sediment. Some causative agents of toxicity to biological organisms are below analytical detection limits. Integration of bioassay data with chemical analysis is essential in order to complete a full ecotoxicological assessment of the quality of the marine environment. This project describes the chemical analysis of marine sediment for persistent pollutants from selected locations around the coast of Ireland. A novel analytical technique is developed for extraction and quantification of organotins (OTCs) from sediment and for subsequent exposure onto fish cell lines. Fish cell cultures are additionally exposed to a range of reference OTC chemicals. The method for organotin extraction is additionally utilised in a Toxicity Identification Evaluation study whereby a crude solvent extract is assayed on two biological organisms namely the Microtox (employing the marine bacterium Vibrio fischeri) and the marine copepod Tisbe battagliai and chemically analysed. A further fractionation of the extract is then performed and further testing conducted on the organisms, therefore potentially pinpointing the source of toxicity. An in-situ study using caged Nucell lapillus and Crassostrea gigas to monitor TBT induced bioeffects in Irish harbours was also developed which was correlated with stable isotope ratios, condition indices and measurement of OTCs in the various biota tissues and sediment samples. This short term exposure methods showed a rapid development of imposex in gastropod species and shell abnormalities in oysters at a TBT polluted location.