Comparison of structure-activity relationships derived from two methods for estimating octanol-water partition...

Area of Science:

• Environmental Toxicology
• Quantitative Structure-Activity Relationships (QSAR)

Background:

• Established linear relationships exist between fish acute toxicity (log LC50) and the octanol-water partition coefficient (log Kow).
• The method used to calculate log Kow can influence these relationships.

Purpose of the Study:

• To compare established linear relationships between log LC50 and log Kow using different log Kow calculation methods.
• To assess the impact of log Kow calculation methods on the prediction accuracy of fish acute toxicity.

Main Methods:

• Examined seven classes of compounds.
• Compared linear equation parameters (slope, intercept, r2, standard error) derived from two different log Kow calculation methods.
• Evaluated prediction accuracies for individual compounds.

Main Results:

• Linear equation parameters (slope, intercept, r2, standard error) were nearly identical for both log Kow calculation methods across all compound classes.
• Prediction accuracies for individual compounds varied between methods but were not significantly different.

Conclusions:

• The method of calculating log Kow has a negligible effect on the established linear relationships with fish acute toxicity.
• The choice of log Kow calculation method does not substantially alter the predictive power for acute toxicity in fish.