Default Values And Read-Across Proposal For Dermal Absorption Based On Human Skin In Vitro Studies Dataset With Pesticides

Abstract

AbstractThe skin is the main route of exposure to plant protection products for operators, workers, residents, and bystanders. Assessing dermal absorption is key for evaluating pesticide exposure risks. However, conductingin vitrodermal absorption studies using human skin is resource-intensive. Therefore, establishing realistic regulatory default values is essential for non-dietary risk assessment and ensuring safety. This project analysed 468in vitrodermal absorption studies with human skin compiled by ProHuma. Combined with a prior database by Aggarwal et al. (2015), the dataset comprised 759 GLP-compliant studies covering 25 formulation types and 248 active substances at various concentrations. The assessment confirmed earlier findings that dermal absorption shows no correlation with molecular weight or log Pow and does not increase linearly with dilution. Based on the comprehensive ProHuma/ECPA dataset, dermal absorption default values are proposed: 2% for solid concentrates, 5% for liquid concentrates, 30% for solid dilutions, and 34% for liquid dilutions. These values, derived conservatively using the 95th percentile, better represent formulations and agricultural use cases, reducing the need for unnecessary studies. The project also suggests read-across between different formulation types. By proposing more realistic default values and read-across approaches, it streamlines decision-making and supports safety in agriculture.