Using Biomimetic Extraction-Solid Phase Microextraction (BE-SPME) for evaluating the chronic toxicity of oil sands process-affected water in early life stage rainbow trout (Oncorhynchus Mykiss)

Early life-stage rainbow trout (Oncorhynchus mykiss) were exposed for ~30 days in 2021 and 2022 to whole OSPW series dilutions and treated OSPW to evaluate the toxicity of OSPW. Biomimetic extraction-solid phase microextraction (BE-SPME) quantified OSPW's complex bioavailable organic fraction to develop a rapid animal-free, cost-effective hazard assessment tool. Significant differences in endpoints including mortality; a 3-day hatching delay; craniofacial, skeletal, and edemas deformities; incomplete yolk sac absorption; and length and weight reductions were mainly observed in dilutions 10.0% to 100% OSPW. OSPW treatment significantly reduced toxic effects. Non-specific narcosis, cardiovascular problems, and endocrine disruption could have affected embryonic development and larval stages. The LC50 is 20.8 µmol/mL PDMS in 2021 and 10.1 µmol/mL PDMS in 2022. The EC50 for total deformities is 20.2 µmol/mL PDMS in 2021 and 10.3 µmol/mL PDMS in 2022. Compositional changes in the organic fraction of treated OSPW could have overestimated toxicity predictions using BE-SPME.