Analytical and toxicological evaluation of bioavailable naphthenic acids from oil sands process-affected water and groundwater using biomimetic extraction solid phase microextraction

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Naphthenic acids (NAs) are a highly complex mixture of organic compounds naturally present in bitumen. Recent evidence suggests that NAs are among the most acutely toxic chemical classes present in oil sands process water (OSPW). Traditional analytical methods to characterize NA contamination are not suitable predictors of potential ecotoxicity because these methods fail to characterize the bioavailability of individual NA compounds. This project aims to develop a biomimetic extraction - solid phase microextraction (BE-SPME) method as a surrogate to estimate the toxicity of bioavailable NAs from OSPW and groundwater. The BE-SPME technique will be used as a tool to compare toxicity test results on the basis of system exposure (i.e., lipid uptake) rather than on external water concentrations. Gas chromatography flame ionization detection (GC-FID) and atmospheric pressure gas chromatography time-of-flight mass spectrometry (APGC-TOFMS) will be used to characterize the chemical profile of the bioavailable fraction. Microtox assay will be used to investigate the acute toxicity of the bioavailable fraction. Treated samples using physico, chemical and biological treatment processes (i.e., adsorption, ozonation and biological treatment) will be used to validate the method. By using this technique, the characterization of the bioavailable organic acids in both untreated and treated process water will be conducted, helping to increase our understanding of the potential impacts of treated process water on the environment. Overall, this work will support other studies focusing on effluent testing, field monitoring, site assessment and remediation by providing an improved screening tool for analytical and toxicological evaluation and will also be beneficial for the supporting organization - Imperial Oil - to provide a hazard assessment tool that may be used for risk assessment purposes.