CHALLENGE
Tier-1 aquatic exposure assessments of surface water revealed a potentially unacceptable risk to aquatic plants. Losses of surface water from sub-surface drainage and surface run-off were identified as the primary reasons for the unacceptable risk assessed in particular scenarios. A suitable solution did not exist among the limited number of mitigation options for drainage loss. The challenge was to identify higher-tier refinements for the exposure assessment that could show additional safe-uses.
SOLUTION
Battelle refined model input parameters for the compound of interest, based on field dissipation data combined with an understanding of the model assumptions, processes, and their impact on the exposure assessment. By considering long-term sorption processes (kinetic sorption), important mechanisms for significantly reducing the availability of material for loss to drainage systems (as well as run-off), Battelle determined two higher-tier refinements.
BENEFITS
- A significant reduction in the calculated predicted environmental concentrations
- Considerable improvement in the aquatic risk assessment for both the EU Annex 1 inclusion and also during subsequent Member State country registrations