Early in 2020, a client approached us with a problem with aquatic risk assessment that is common to many companies and for many products. “How can we determine the optimum mitigation options, application rates, crop growth stages and application timings for all the separate countries in Europe?” There is a trade-off between all of these factors, and it can be hard to find the best solution, especially because countries have slightly different ways of choosing the options. Each country has its own requirements on which FOCUS scenarios are relevant and which mitigations are acceptable. This means, for example, that one country may allow a wider drift buffer than another and thus a higher rate of application. One country may require any single runoff scenario to pass, whereas another may allow a label restriction based on soils covered by the D2 drainage scenario. Of course, this problem can be solved using the standard tools of SWASH and SWAN: the real question concerns finding the optimum solutions quickly, without endless iteration and revision.
The Enviresearch approach
We needed an approach that could automatically calculate the Predicted Environmental Concentration (PEC) for the active substance for all usage options and mitigations. We chose to use the Acre software for this task as the software can run the surface water simulations quickly, and has a flexible reporting function for post-processing of the results. We wanted to exploit the flexible reporting to deliver results adapted to the client’s reporting template.
The first stage was to run the complete set of simulations. This included all the model scenarios and all the available mitigation options, such as drift reduction or runoff reduction. Using Acre, this could be achieved by defining all the simulations in a single data table and letting the software work through this list of several hundred simulations.
The next stage was to filter the results through a database of the country-specific requirements for more than 20 countries in the EU. The whole process from processing the model output, filtering by country requirements, selection of critical scenario, and the maximum sustainable application rate for each usage and mitigation option, was automated in the Acre reporting tool.
We were able to provide a summary table that shows the critical scenario for each country, the main route of entry of the pesticides into the water, the relevant mitigation options and the maximum application rate. This was customised to the client standard format, thus allowing the client to communicate within the company about the planning of the trials and product labels in each country. Enviresearch was pleased to produce exactly what the client needed to help evaluate the economic viability of this product line. The client is planning to use this approach for other products that they are developing.