Bioconcentration Assessment in Fish Based on In Vitro Intrinsic Clearance: Predictivity of an Empirical Model...

Area of Science:

• Environmental Chemistry
• Toxicology
• In Vitro Assays

Background:

• Bioconcentration factor (BCF) estimation is crucial for environmental risk assessment.
• In vitro intrinsic clearance (CLIN VITRO,INT) from rainbow trout liver S9 fractions (RT-S9) is a potential tool for BCF prediction.
• Existing in vitro-in vivo extrapolation (IVIVE) models have uncertainties in parameterization.

Purpose of the Study:

• To evaluate an alternative regression model for predicting BCF using CLIN VITRO,INT.
• To assess the accuracy and robustness of this new model compared to IVIVE.
• To establish the predictive power of the RT-S9 assay for regulatory purposes.

Main Methods:

• A regression model (log BCF = a × log Kow + b × log CLIN VITRO,INT) was developed.
• Coefficients were fitted using a training set of 40 chemicals.
• Model performance was validated on independent datasets of neutral organic chemicals.

Main Results:

• The regression model demonstrated high robustness and accuracy in BCF prediction.
• Predictions were comparable or superior to IVIVE models, with lower misprediction factors.
• Species-matched models did not improve prediction accuracy.

Conclusions:

• The developed regression model effectively utilizes RT-S9 data for BCF prediction.
• This approach shows significant promise for regulatory acceptance and replacing animal experiments.
• The RT-S9 assay, integrated into this model, is a valuable tool for environmental risk assessment.