Darwin Harbour mangrove sediment metal and arsenic dynamics

The aim of this study was to determine the capacity of mangrove sediment to desorb (release) or adsorb (bind) metals under simulated natural conditions. Specifically the study was designed to: ? Determine the potential for sediment to release metals and arsenic and to provide a risk assessment with reference to ecosystem quality guidelines ? Determine the capacity of sediment to adsorb elevated levels of mobile metals and arsenic in a hypothetical pollution event ? Measure metal distribution coefficients (Kd-values) for solid/liquid exchange of metals and arsenic for use in geochemical and hydrodynamic modelling of metal mobilityThis research was funded by the INPEX-led Ichthys LNG Project.Executive Summary -- List of Figures -- List of Tables -- 1. Introduction and aims -- 2. Darwin Harbour geomorphology and metal pollution status -- 3. Field sampling -- 4. Laboratory analyses -- 5. Results -- 6. Discussion -- 7. Conclusions -- Acknowledgements -- Reference List -- Appendix 1. Summary of grainsize distribution data (full reports for individual samples supplied as an electronic file) -- Appendix 2. Sediment TOC, TN, TS, RIS and potential acidity data -- Appendix 3. Sediment metal and As data (strong acid extraction) -- Appendix 4. Sediment metal and As data (dilute acid extraction) -- Appendix 5. Desorption experiment data -- Appendix 6. Adsorption experiment data -- Appendix 7. Solid/liquid distribution data (Log Kd values)Prepared for: Aquatic Health Unit, Northern Territory Department of Land Resource Management