The Risks from Anthropogenic Pollutants to Great Barrier Reef
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Citation: Waterhouse, J., Brodie, J., Tracey, D., Smith, R., Vandergragt, M., Collier, C., Petus, C., Baird, M., Kroon, F., Mann, R., Sutcliffe, T., Waters, D., Adame, F., 2017. Scientific Consensus Statement 2017: A synthesis of the science of land-based water quality impacts on the Great Barrier Reef, Chapter 3: The risk from anthropogenic pollutants to Great Barrier Reef coastal and marine ecosystems. State of Queensland, 2017. © State of Queensland, 2017 The Queensland Government supports and encourages the dissemination and exchange of its information. The copyright in this publication is licensed under a Creative Commons Attribution 3.0 Australia (CC BY) licence. Under this licence you are free, without having to seek our permission, to use this publication in accordance with the licence terms. You must keep intact the copyright notice and attribute the State of Queensland as the source of this publication. For more information on this licence, visit creativecommons.org/licenses/by/3.0/au/deed.en. This document was prepared by a panel of scientists with expertise in Great Barrier Reef water quality. This document does not represent government policy. Scientific Consensus Statement 2017—Chapter 3 Contents Acronyms, units and definitions ..................................................................................................................... iii Acknowledgements ........................................................................................................................................ vi Executive summary ......................................................................................................................................... 1 Introduction ............................................................................................................................................... 7 Previous findings ........................................................................................................................................ 8 Part A: Hazard and systems at risk ................................................................................................................... 9 Risk assessment framework ....................................................................................................................... 9 Defining and mapping the ecosystems at risk of exposure to anthropogenic river-derived pollutants ..... 13 Defining Marine Zones ........................................................................................................................ 13 Habitats ............................................................................................................................................... 14 Marine ecosystems ......................................................................................................................... 14 Coastal aquatic ecosystems—floodplain wetlands and floodplains ............................................... 15 Basins and catchments ................................................................................................................... 15 Drawing on Chapters 1 and 2: what are the water quality hazards that pose a potential risk to Great Barrier Reef aquatic coastal and marine ecosystems? ................................................................................... 17 Area of hazard from nutrient pressures .............................................................................................. 17 Area of hazard from sediment pressures ............................................................................................ 20 Area of hazard from pesticide pressures ............................................................................................ 23 Changes to hazards and pressures on floodplain wetlands and floodplains due to land-use intensification ................................................................................................................................................... 26 Part B: Likelihood and consequences of pollutant exposure .......................................................................... 28 What is the likelihood and timing of exposure of key pollutants to Great Barrier Reef coastal and marine systems? ........................................................................................................................................................ 28 Supporting evidence ........................................................................................................................... 28 Nutrients ......................................................................................................................................... 29 Suspended sediment ....................................................................................................................... 30 Pesticides ........................................................................................................................................ 30 Assessing the likelihood of exposure to pollutant pressures—marine ecosystems ........................... 33 Nutrients ......................................................................................................................................... 33 Sediments ....................................................................................................................................... 46 Pesticides ........................................................................................................................................ 55 Assessing the likelihood of exposure to pollutant pressures—floodplain wetlands and floodplain ecosystems ....................................................................................................................................................... 55 Floodplain wetlands ........................................................................................................................ 56 Floodplain ecosystems .................................................................................................................... 62 What are the consequences of the water quality exposure? .................................................................... 66 Supporting evidence ........................................................................................................................... 66 Risk from pollutants to the Great Barrier Reef i Scientific Consensus Statement 2017—Chapter 3 Nutrients ......................................................................................................................................... 66 Suspended sediment and turbidity ................................................................................................. 69 Pesticides ........................................................................................................................................ 71 Assessing the consequence of nutrient and sediment exposure to coral reefs and seagrass ............ 72 Nutrients ......................................................................................................................................... 73 Sediments ....................................................................................................................................... 76 Pesticides ........................................................................................................................................ 82 What is the risk of degraded water quality to Great Barrier Reef ecosystems? ........................................ 84 Assessing the risk of pollutant exposure to Great Barrier Reef marine ecosystems .......................... 84 Risk from DIN to coral reefs (Crown-of-Thorns starfish example) .................................................. 84 Risk from fine sediment to seagrass (light) ..................................................................................... 88 Pesticides ........................................................................................................................................ 94 Other pollutants ............................................................................................................................ 104 Synthesis of key findings ........................................................................................................................ 105 Relative priorities between basins and pollutants ............................................................................ 105 Changes from the 2013 assessment.................................................................................................. 112 Improvements to the risk assessment and limitations ........................................................................... 112 Knowledge gaps and areas of further research ...................................................................................... 115 Reference list ......................................................................................................................................... 123 Appendix 1: Method for defining Marine Zones .......................................................................................... 140 Appendix 2: Floodplain wetland and floodplain hazard and likelihood of exposure assessments ................ 147 Appendix 3: Technical details for spatial inputs to the marine likelihood of exposure assessments ............ 161 Appendix 4: Case study of the assessment of pesticide risk in the Great Barrier Reef ................................