New EU Guidance for Aged Sorption Studies
DG Sante have released new EU guidance on how aged sorption studies for pesticides should be conducted, analysed and used in regulatory assessments.
Further revisions to this guidance are expected but the Standing Committee have agreed the current version will be brought in for use in regulatory dossiers from April 2021.
Aged sorption is a phenomenon whereby the sorption of a substance to soil increases over time. The FOCUS groundwater guidance of 2009 included some discussion of aged sorption and its use, but due primarily to a lack of standardisation its regulatory acceptance so far has been low.
The new guidance seeks to address this issue and describes in detail how to design the necessary studies, derive the relevant parameters and use them in modelling.
For those substances which do exhibit significant aged sorption behaviour, the inclusion of this process in groundwater modelling may provide a substantial reduction in predicted environmental concentrations compared to the first-tier approach. Consequently, for situations where active substances or metabolites currently exceed the relevant groundwater threshold concentration, this higher-tier approach may allow successful registration without the need to resort to measures such as reducing the application rate.
If you do have questions on the guidance do not hesitate to get in touch with one of our experts, and the DG Sante guidance is available here.
