The EU Standing Committee on Plants, Animals, Food and Feed (SCoPAFF) is currently discussing the adoption of new EFSA guidance (2017) for predicting environmental concentrations of active substances of plant protection products in soil .
Estimation of the Predicted Environmental Concentration in Soil (PECsoil), which will change from a relatively simple calculation to a tiered system of models according to the 2017 EFSA guidance. The changes are broadly analogous to the changes in surface water assessment in the early 2000’s, where simple spray-drift calculations were replaced by the tiered system of FOCUS STEPS surface water models.
After several years of debate, this new guidance is likely to be adopted this year. Many currently-approved products will likely fail their soil risk assessments using lower tier modelling under the new guidance. Passing the new risk assessments will often require higher-tier models, or even new environmental fate and ecotoxicity studies, or restrictions on product use.
A new model, PERSAM, has been developed to support the soil exposure assessment, while the PEARL and PELMO models (previously used for groundwater assessment only) are used to perform numerical modelling at higher tiers.
The new models result in higher soil exposure estimates in almost all cases, even at the highest tier or refinement. Exposure estimates typically increase by a factor of 10 or more at Tier 1, and remain over 50% higher in the refined Tier 3 modelling. The impact of the changes varies greatly between products, depending on the target crops/timings (product GAP) and substance degradation data (especially for metabolites).
Staphyt have been following the development of the EFSA soil exposure guidance and associated models, and are able to guide our clients through these changes. We have performed preliminary risk assessments to help our clients understand the impact of the new models on product approval. We can identify any problems, then determine the solutions, costs and timelines involved. By identifying potential problems early, our clients have time to generate any new data in time to meet regulatory deadlines and keep their products on the market.
If you wish to know more about the changes to soil risk assessment, and how Staphyt can help, please do not hesitate to contact us.
Editor: Michael HALE – Senior Environmental Fate Expert at Staphyt Regulatory Affairs department