Predicting the toxicity of physically and chemically dispersed oil: a modelling case study with American lobster larvae (Homarus americanus).

This article focuses on validating a two-step modeling approach combining the Target Lipid Model (TLM) and PetroTox software to predict the toxicity of crude oil water-accommodated fractions (WAF) and chemically dispersed WAF (CEWAF) to American lobster (Homarus americanus) larvae. Using chemical composition data from White Rose crude oil and species-specific critical target lipid body burden (CTLBB) values derived from single polycyclic aromatic compound toxicity, the study accurately predicted toxic units (TUs) and observed mortality in controlled laboratory exposures. Results showed that CEWAF was more toxic than WAF on a nominal basis due to increased bioavailability of petroleum hydrocarbons, while toxicity expressed as TUs normalized these differences, demonstrating the model’s utility for oil spill risk assessment. The approach supports improved interpretation of complex oil toxicity data and can aid spill response planning by linking single-compound toxicity to whole-oil exposures.