A re‐evaluation of PETROTOX for predicting acute and chronic toxicity of petroleum substances

PETROTOX was developed to perform aquatic hazard assessment of petroleum substances (PS) based on substance composition. The model relies on the Hydrocarbon Block Method which is widely used for conducting PS risk assessments providing further justification for evaluating model performance. Previous work described this model and provided a preliminary calibration and validation using acute toxicity data for limited PS. The objective of this study is to re-evaluate PETROTOX using expanded data covering both acute and chronic toxicity endpoints on invertebrates, algae, and fish for a wider range of PS. Results indicated that recalibration of two model parameters was required, namely the algal critical target lipid body burden and the logKOW limit, used to account for reduced bioavailability of hydrophobic constituents. Acute predictions from the updated model were compared to observed toxicity data and found to generally be within a factor of three for algae and invertebrates but overestimated fish toxicity. Chronic predictions were generally within a factor of five of empirical data. Further, PETROTOX predicted acute and chronic hazard classifications that were consistent or conservative in 93 and 84% of comparisons, respectively. PETROTOX is considered fit for purpose for characterizing PS hazard in substance classification and risk assessments. This article is protected by copyright. All rights reserved