Scientific Opinion about the Guidance of the Chemical Regulation Directorate (UK) on how aged sorption studies for pesticides should be conducted, analysed and used in regulatory assessments

Ockleford, Colin and Hernandez-Jerez, Antonio F. and Hougaard Bennekou, Susanne and Klein, Michael and Adriaanse, Thomas Paulien and Berny, Philippe and Brock, Theodorus and Duquesne, Sabine and Grilli, Sandro and Kuhl, Thomas and Laskowski, Ryszard and Machera, Kyriaki and Pelkonen, Olavi and Pieper, Silvia and Stemmer, Michael and Sundh, Ingvar and Teodorovic, Ivana and Topping, Chris J. and Wolterink, Gerrit and Smith, Robert H. and Gimsing, Anne Louise and Kasteel, Roy and Boivin, Arnaud and van der Linden, Ton and Oriol Magrans, Jose and Egsmose, Mark and Tiktak, Aaldrik (2018) Scientific Opinion about the Guidance of the Chemical Regulation Directorate (UK) on how aged sorption studies for pesticides should be conducted, analysed and used in regulatory assessments. EFSA Journal, 16 (8). ISSN 1831-4732

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Abstract

The EFSA Panel on Plant Protection Products and their Residues reviewed the guidance on how aged sorption studies for pesticides should be conducted, analysed and used in regulatory assessment. The inclusion of aged sorption is a higher tier in the groundwater leaching assessment. The Panel based its review on a test with three substances taken from a data set provided by the European Crop Protection Association. Particular points of attention were the quality of the data provided, the proposed fitting procedure of aged sorption experiments and the proposed method for combining results obtained from aged sorption studies and lower-tier studies on degradation and adsorption. Aged sorption was a relevant process in all cases studied. The test revealed that the guidance could generally be well applied and resulted in robust and plausible results. The Panel considers the guidance suitable for use in the groundwater leaching assessment after the recommendations in this Scientific Opinion have been implemented, with the exception of the use of field data to derive aged sorption parameters. The Panel noted that the draft guidance could only be used by experienced users because there is no software tool that fully supports the work flow in the guidance document. It is therefore recommended that a user-friendly software tool be developed. Aged sorption lowered the predicted concentration in groundwater. However, because aged sorption experiments may be conducted in different soils than lower-tier degradation and adsorption experiments, it cannot be guaranteed that the higher tier predicts lower concentrations than the lower tier, while lower tiers should be more conservative than higher tiers. To mitigate this problem, the Panel recommends using all available higher- and lower-tier data in the leaching assessment. The Panel further recommends that aged sorption parameters for metabolites be derived only from metabolite-dosed studies. The formation fraction can be derived from parent-dosed degradation studies, provided that the parent and metabolite are fitted with the best-fit model, which is the double first-order in parallel model in the case of aged sorption.

Item Type:
Journal Article
Journal or Publication Title:
EFSA Journal
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1110
Subjects:
ID Code:
135657
Deposited By:
Deposited On:
15 Aug 2019 14:20
Refereed?:
Yes
Published?:
Published
Last Modified:
23 Sep 2020 05:28