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Taking Environmental Fate Modelling to the Next Level



Acre is an innovative approach to environmental modelling and is the result of extensive research and investment. The modelling tool was originally developed to make surface water modelling more efficient and allows the running of FOCUS surface water models from start to finish by a single click of a button. Plus multiple crops and substances can be included in the same project - there is no limit to the number of simulations that can be included in a single project! 

Acre provides crop protection companies with faster, easier and more cost-effective access to multiple data sets on environmental risk assessment than has been previously possible. A key feature of the system is the simplicity of its data tables, which allow product developers to take in complex information at a glance.  The key benefits are that modelling time is vastly improved, there is a single interface screen and there is consistency across multiple runs.

Which uses may be feasible from environmental risk perspective?

1.      Initial scoping assessment

This is a fully automated process producing PECsw and PECgw for all FOCUS crops, including those not previously considered (one usage scenario per crop – risk envelope). It’s most useful at the early stage of product development, to explore the possible uses of an active substance.  Early stage assessment of the risks to GW and SW across all FOCUS crops.

It produces a standard report for surface water and groundwater showing for each crop which FOCUS scenarios fail. It also includes standard Step 4 for surface water to test if scenarios may pass after mitigation.

This is a preliminary assessment across the board that allows to pre-assess whether the assessments will easily pass or if there could be issues. It can flag early which of the proposed uses are feasible, so no efforts are wasted on uses that may become too costly to develop. The assessment includes:

Surface water assessment (FOCUS Steps 3 and 4):

  • Running the FOCUS surface water models (MACRO, PRZM, TOXSWA) for all FOCUS crops, for single and multiple applications
  • We standard add on the Step 4 simulations with drift and runoff mitigation
  • Assessment: comparison of the predicted concentrations (PECsw) against the regulatory acceptable concentration (RAC)
  • Acre report for surface water, listing the PECsw values for all crops and scenarios, and outcome of the assessment (pass/fail or pass after mitigation)

Groundwater assessment:

  • Running the groundwater model FOCUS PELMO for all FOCUS crops. (If passing in PELMO, then it is likely to also pass in FOCUS PEARL, so we only run PELMO for preliminary assessments)
  • Comparison with the regulatory limit for groundwater (pass/fail)
  • Acre report for groundwater, listing the concentrations in groundwater (PECgw) and whether passing or failing the regulatory limit.

Further detail:

  • The critical application details (rate, frequency and timing) that give the highest environmental risk is selected. The outcome will tell us if these application details will need refining to pass the assessment.  
  • All input parameters will be listed in the Acre report.
  • We will advise on the implications of the results and what steps may be needed re further refinements.  

If you would If you would like to consider difference usages for different countries, please consider Gap Analysis.

2.      GAP analysis

This is a cost-effective preliminary assessment for products with large number of uses. It’s relevant for a pre-defined GAP (e.g. existing/preliminary GAP, several uses), for example during active renewal. And involves an early stage assessment of the risks to GW and SW across the whole GAP, producing Step 3 and 4 PECsw for all uses listed in the GAP.

It covers all usage scenarios in the GAP in one Acre run. Included is Step4 modelling for one mitigation scenario, for example a 20m runoff buffer. This would allow you to immediately see the impact on the assessment when the maximum reduction is applied. Additional mitigation scenarios can be added if required with an option to include groundwater assessments.

If you would like to explore alternative rates or dates, please consider Solution Finding.

3.      Mitigation Analysis

Mitigation analysis provides Step 4 PECsw across all mitigation options and is helpful once it has been established that mitigations are required for specific product uses. One Acre run produces the full mitigation table (combinations of drift reduction nozzles and buffer strips) and therefore provides a quick overview of which combinations provide sufficient mitigation. Also, different mitigations options are accepted by different MS, therefore it helps to have a complete overview.

There is one Acre run to produce table with all mitigation outcomes which can be performed for one specific use or a set of predefined uses.

If you would like to consider alternative rates and dates, please consider Solution Finding.

4.      Solution Finding

When the existing GAP fails, and mitigations do not provide sufficient reduction of the PEC values, then other solutions can be explored, such as reduced application rates, splitting the dose over a number of applications, or shifting the application timing and intervals. Acre can be used for efficiently testing a large range of options in a cost-efficient way.

It allows you to scan across a large number of variations in application rates and timings. The project can be aimed at specific metabolites, the scenarios that failed and the required mitigation.

It can be performed in steps to allow trial-and-error.

For example, we want may want to explore the options for a substance that is failing the assessment when applied at 2 x 250 g/ha post-emergence in spring. To find a solution we may want to explore for example applying the substance at 1 x 250 g/ha, 2 x 150 g/ha, 3 x 100 g/ha with intervals of 7 days or 14 days. We may also want to explore delaying the application to 2 weeks post-emergence or from BBCH20, and we want to check if we can pass with a 15m or 20m runoff buffer. Combining these options would give at least 30 usage scenarios. We would use Acre to run all these in one go, and produce one table showing the options that pass or fail.

For further information please contact our experts directly at This email address is being protected from spambots. You need JavaScript enabled to view it..


Acre webinar available to watch online

Watch the webinar here  to learn more about Acre and to receive a special promotional offer. In the addition, we have produced a video summarising Acre ’s capabilities: 


Mixture Toxicity Calculations and Integrated Risk Reporting-Improving Formulation Assessments with Acre.

Acre, Enviresearch’s innovative surface water risk assessment framework, has been designed to deliver maximum value for formulation risk assessments. Acre executes the standard FOCUS models (PRZM, MACRO, TOXSWA) to deliver the same environmental fate values you would achieve via the standard means but in a more efficient manner which is less prone to error. However the real value lies in the way it has been optimized to consider complete formulation assessments. The entire potential use pattern for a product, including mitigation options, is defined in a single step which is then applied to all relevant actives. In practice this facilitates formulations with complex usage patterns and/or multiple actives to be assessed both more efficiently and with greater precision.

An area where we have found Acre particularly useful is in the assessment of formulations with multiple active substances. Acre eliminates the need to manually split projects based on active substances so all calculations are completed in a single harmonized step. Aquatic effects endpoints can be included in this assessment such that exceedances are automatically identified. This can be done for the full mixture/combination toxicity assessment as well as the individual substances providing a single summary table which covering the complete risk profile of a formulation. An example summary output table showing environmental fate and toxicity calculations for a two-way mixture formulation is provided below.

Being able to quickly look at the data in this format has a number of potential advantages, but the becomes especially powerful when coupled to Acres ability to cross reference member state specific requirements for both scenarios and refinements. As Acre can run any number of Step 4 mitigation options in parallel with the Step 3 assessments it is possible to precisely match the minimum mitigation required to pass an assessment on a member state level without having to run numerous Step 4 runs in series. This saves time and removes the guess work from formulation optimizations.   

Enviresearch staff working on Acre


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Further Information