Development of a Method for Estimating the Toxicity of Pesticide Mixtures and a Pesticide Risk Baseline for the Reef 2050 Water Quality Improvement Plan
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Development of a Method for Estimating the Toxicity of Pesticide Mixtures and a Pesticide Risk Baseline for the Reef 2050 Water Quality Improvement Plan Reef 2050 Water Quality Improvement Plan i Prepared by: Water Quality and Investigations Unit, Environmental Monitoring and Science Group, Department of Environment and Science © State of Queensland, 2021. The Department of Environment and Science acknowledges Aboriginal peoples and Torres Strait Islander peoples as the Traditional Owners and custodians of the land. We recognise their connection to land, sea and community, and pay our respects to Elders past, present and emerging. The department is committed to respecting, protecting and promoting human rights, and our obligations under the Human Rights Act 2019. The Queensland Government supports and encourages the dissemination and exchange of its information. This work is licensed under a Creative Commons Attribution 4.0 International License. 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 the publication. For more information on this licence, visit https://creativecommons.org/licenses/by/4.0/ Disclaimer This document has been prepared with care, based on the best available information at the time of publication. The department holds no responsibility for any errors or omissions within this document. If you need to access this document in a language other than English, please call the Translating and Interpreting Service (TIS National) on 131 450 and ask them to telephone Library Services on +61 7 3170 5470. This publication can be made available in an alternative format (e.g. large print or audiotape) on request for people with vision impairment; phone +61 7 3170 5470 or email <[email protected]>. Citation Warne MStJ, Neelamraju C, Strauss J, Smith RA, Turner RDR, Mann RM. 2020. Development of a method for estimating the toxicity of pesticide mixtures and a Pesticide Risk Baseline for the Reef 2050 Water Quality Improvement Plan. Brisbane: Department of Environment and Science, Queensland Government. December, 2020 Development of a method for estimating the toxicity of pesticide mixtures and a Pesticide Risk Baseline for the Reef 2050 Water Quality Improvement Plan Michael St J Warne1,2,3, Catherine Neelamraju2, Jennifer Strauss2, Rachael A Smith4, Ryan D R Turner2, Reinier M Mann2 1. School of Earth and Environmental Sciences, University of Queensland, St Lucia, Queensland. 2. Water Quality and Investigations, Environmental Monitoring and Assessment Sciences, Department of Environment and Science, Brisbane, Queensland. 3. Centre of Agroecology, Water and Resilience, Coventry University, United Kingdom. 4. Office of the Great Barrier Reef, Department of Environment and Science, Brisbane, Queensland. December 2020 i Contents Executive Summary ............................................................................................................................................... xvi Recommendations ............................................................................................................................................. xix Introduction ................................................................................................................................................................ 1 Aims and Objectives .................................................................................................................................................. 4 Methods ...................................................................................................................................................................... 5 Overview ................................................................................................................................................................. 5 Problem Formulation ............................................................................................................................................ 6 The Pesticides to be Included ........................................................................................................................... 6 The Waterways to be Considered (i.e. the Spatial Scale) ............................................................................. 7 The Timescale to be Considered (i.e. the Temporal Scale) ........................................................................... 7 The Organisms to be Considered (i.e. the Biological Scope) ....................................................................... 8 Exposure Assessment ............................................................................................................................................ 8 Measuring Pesticide Aqueous Concentration Values .................................................................................. 8 Quality Assurance and Quality Control of the Pesticide Concentration Data ....................................... 10 Effects Assessment............................................................................................................................................... 10 Collation of Toxicity Data ............................................................................................................................... 10 Quality Assurance and Screening of Toxicity Data .................................................................................... 10 Calculating Species Sensitivity Distributions and Protective Concentrations ........................................ 11 Risk Characterisation .......................................................................................................................................... 11 Estimating the Toxicity of Pesticide Mixtures ............................................................................................. 11 Calculation of the Toxicity of Mixtures of the 22 Selected Pesticides ...................................................... 12 Choosing a Relevant Time Period to Estimate Pesticide Mixture Toxicity ............................................. 14 Choosing an Appropriate Percentage of Species Affected to Estimate Pesticide Mixture Toxicity .... 14 Calculation of the Average Percentage of Species Affected During the Wet Season ............................ 15 Development of Pesticide Mixture Toxicity – Land Use Relationships ................................................... 17 Selection of the Best Pesticide Mixture Toxicity – Land Use Relationships ............................................ 21 Validation of the Pesticide Mixture Toxicity – Land Use Relationships .................................................. 22 Predicting the Pesticide Mixture Toxicity for 35 Basins, Six NRM Regions and the Great Barrier Reef Catchment Area ............................................................................................................................................... 22 Ground-Truthing Predictions of the Pesticide Mixture Toxicity— Land Use Relationships ............... 23 Qualitative Confidence Ranking of the Pesticide Risk Baseline ............................................................... 24 Risk Management ................................................................................................................................................ 25 Classification of the Risk Posed by Pesticide Mixtures .............................................................................. 25 ii Calculation of the Relative Contribution of Individual Pesticides and Pesticide Groups to Total Pesticide Mixture Toxicity .............................................................................................................................. 27 Reporting Data ..................................................................................................................................................... 27 Results and Discussion ........................................................................................................................................... 28 Appropriateness of the Selected Pesticides ...................................................................................................... 28 Species Sensitivity Distributions ....................................................................................................................... 28 Land use, Hydrological and Spatial Explanatory Variables for the Monitored Sites ................................ 32 Correlation Coefficient Values ........................................................................................................................... 33 Pesticide Mixture Toxicity Results .................................................................................................................... 34 Bioavailability ....................................................................................................................................................... 36 Interpretation of the Results from the Pesticide Risk Metric ......................................................................... 36 Pesticide Mixture Toxicity — Land Use Relationships .................................................................................. 37 The Relationship for PSII Herbicides ............................................................................................................ 37 The Relationship for Other Herbicides