Nuclear and isotopic techniques underpinning probabilistic ecological risk analysis in coastal marine systems

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American Geophysical Union
The historical operation of manufacturing, chemical and other industries in the Sydney Harbour catchment over many decades has left a legacy of high chemical contamination in the surrounding catchment, such that a recent report describes Port Jackson as one of the most contaminated harbours in the world (Birch & Taylor, 2005). The legacy in Homebush Bay is amongst the worst in the harbour and presents a considerable management problem. Elucidation of environmental processes is the key to effective ecosystem management, however few tools are available to determine their inter-relationships, rates and directions. This study has four components: (1) determination of linkages between high trophic order species and different habitats resources using stable isotopic analyses of carbon and nitrogen. These studies identify trophic cascades forming the basis for selection of biota for contaminant transfer experiments; (2) short-term (weeks - months) chronology and geochemistry of sediment cores and traps in Homebush Bay to determine rates of sedimentation and resuspension (using environmental/cosmogenic 7Be). Models derived from these studies provide the contaminants levels against which risk is assessed; (3) biokinetic studies using proxy radiotracer isotopes (eg. 75Se & 109Cd for analogous stable metals) of the uptake and trophic transfer of contaminants by specific estuarine biota. Here we identify the rates and extent to which contaminants accumulated and transferred to predators/seafoods; and (4) application of a probabilistic ecological risk assessment model (AQUARISK) set to criteria determined by stakeholder consensus. In this study we analysed the distribution of natural isotopes and redistribution of artificial isotopes injected into ecological compartments to determine the key trophic linkages and contaminant pathways in an estuarine system and contribute to improving the accuracy and specificity of a probabilistic ecological risk assessment strategy. © Author(s) (2006)
Ecosystems, Dynamics, Simulation, Radioisotopes, Trace amounts, New South Wales, Harbors, Habitat, Sediments
Szymczak, R., Twining, J., Hollins, S., Highes, C., Mazumder, D., & Alquezar, R. (2006). Nuclear and isotopic techniques underpinning probabilistic ecological risk analysis in coastal marine systems. Poster presentation to the 2006 Ocean Sciences Meeting, Honolulu, Hawaii, USA, February 20, 2006 - February 24, 2006. Retrieved from