2021-2024 Pesticide Risk Metric data with flow and water level

We applied the expanded PRM of Neelamraju et al (2025 - see below) to estimate the combined toxicity of mixtures of 42 pesticides detected in water samples collected by the Great Barrier Reef Catchment Loads Monitoring Program. Mixture toxicity was calculated for every water sample in the time series for all sites and years included in the study, then clipped to the wet season window (first flush + 182 days) for further analysis. Hydrological variables were prepared for the dual purposes of, a) quantification of bias in the existing simple imputation approach, and b) for testing and development of more appropriate infilling methods, with the relative suitability of each variable assessed for this purpose based on model performance and practical applicability. Mixture toxicity estimates for the five PRM groups (other herbicides, fungicides, insecticides, PSII herbicides, and total PAF) were aligned to the flow and time-based explanatory variables using time-matching thresholds: ±30 minutes for discharge data and ±5 minutes for water level data. This process created a matrix of observed and missing PRM data aligned to the explanatory variables, for each of the five PRM groups, for every day of the wet season at each site and sampling year. Neelamraju, Cath A., Mann, Reinier M., Bainbridge, Zoe T., Mitchell, Hannah C., and Turner, Ryan D. R. (2025). Improvement in mixture risk assessment: a multi-national application of the Pesticide Risk Metric. Environmental Advances 22 100676 100676. https://doi.org/10.1016/j.envadv.2025.100676