Effect Factor

OpenChemFacts provides an effect factor (EF) for all chemicals.

Definition

Effect Factor (EF) represents the increase in the potentially affected fraction of species (PAF) per unit increase in chemical concentration, based on a concentration–response relationship.

It's expressed in PAF·m³·kg⁻¹.

The concentration-response slope factor is derived from taking the slope on the SSD at the HC20. It represents an incremental change in the potentially affected fraction of species due to an incremental exposure to the bioavailable concentration of a chemical at the HC20 level.

Details

Effect factors (EF) are available from (i) API and (ii) static files on DataGouv platform.

Effect factors are dervied from HC20 values (the hazardous concentration that kills 20% of species in an exposed ecosystem).

These results have been calculated in Python from jupyternotebooks.

The method used is based on latest scientific guidance : "Ecotoxicity characterization of chemicals: Global recommendations and implementation in USEtox" from 2023 accessible here .

Main methodological steps implements for each database available on the platform.