Variability Between Datasets and Statistical Approaches-Rethinking Estimation of Default Dermal Absorption Values for...

Area of Science:

• Environmental toxicology
• Risk assessment science
• Dermal absorption studies

Background:

• Dermal absorption values are critical for plant protection product risk assessment.
• Current default values are based on the European Food Safety Authority 2017 Guidance (EFSA GD2017).
• An updated dataset of 356 human in vitro studies is now available.

Purpose of the Study:

• To derive updated dermal absorption default values using recent human in vitro data.
• To compare these new values with existing EFSA GD2017 default values.
• To assess the impact of an alternative 'concentrate' definition on default values.

Main Methods:

• Applied empirical and modeling approaches from EFSA GD2017 to a new dataset.
• Evaluated 356 recent human in vitro studies.
• Compared default values for concentrates and dilutions across formulation types.

Main Results:

• New default values are considerably lower than current values, particularly for diluted solids.
• The alternative definition of 'concentrate' (>50 g/L) had minimal impact.
• The updated dataset provides a more current basis for risk assessment.

Conclusions:

• Revision of current dermal absorption default values is warranted.
• Newer studies evaluated under current guidance lead to lower risk assessment values.
• This impacts the safety evaluation of plant protection products.