Models for the No-Observed-Effect Concentration (NOEC) and Maximal Half-Effective Concentration (EC50)

Area of Science:

• Environmental toxicology
• Computational chemistry
• Ecotoxicology

Background:

• Current in silico ecotoxicology models lack endpoint diversity.
• There is a need for broader predictive capabilities in environmental risk assessment.

Purpose of the Study:

• To develop novel in silico models for predicting ecotoxicological endpoints.
• To establish models for the No Observed Effect Concentration (NOEC) in *Chironomus riparius* and the EC50 for *Lemna gibba*.

Main Methods:

• Utilized data from the EFSA OpenFoodTox database.
• Developed Quantitative Structure-Activity Relationship (QSAR) models based on CORAL software's 2D descriptors.
• Employed the Monte Carlo method to determine algorithm correlation weights.

Main Results:

• Achieved determination coefficients of 0.74 for NOAEC (harlequin fly) and 0.85 for EC50 (swollen duckweed) in external validation.
• Successfully modeled specific ecotoxicological endpoints for two distinct species.

Conclusions:

• The developed models represent a novel approach to increasing endpoint diversity in ecotoxicology.
• These models demonstrate good predictive performance for NOEC and EC50 values, supporting their use in risk assessment.