Extraction, Analysis and the Role of Co-contaminants on Sulfolane Biodegradation
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2019-04-18
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Sulfolane’s extensive use in various oil and gas industries has led to its increased environmental contamination throughout Alberta. The impact of co-contaminants and complex matrices in sulfolane polluted areas can produce challenges in analytical and remediation efforts and generate vastly different results from those obtained in a laboratory setting. Particularly, the low regulatory guidelines of 0.18 mg/kg in soils and 0.09 mg/L in groundwater has created challenges for commercial testing laboratories as these levels are often too close to their instrument detection limits. Potential interferences and false positives have become a cause for concern especially in complex matrices with high organic content. Similarly, groundwater bioremediation efforts can be positively or negatively impacted depending on the type of co-contaminant present alongside sulpholane. A spiking study was conducted to investigate sulfolane analytical challenges faced by various testing labs when analysing sulfolane in peat and clay soils, as well as groundwater samples. It was observed that soil spiked with high sulfolane concentrations (>0.5mg/kg) resulted in more reliable data compared to low concentrations (<0.5mg/kg), with mineral soils providing more reproducible data than the highly-organic peat soil. Similarly, groundwater analysis also provided less variable results in higher concentrations (0.5 mg/L) than lower levels (0.1 mg/L). Soil water extraction efficiency of sulfolane improved with an increase in soil to water ratio, however, clay soils will require additional aliquots to achieve maximum recovery. GC-MS analysis demonstrated that organic soils can produce false positives. Therefore, at low concentrations, interferences, loss of sulfolane due to biodegradation and sample heterogeneity will significantly impact results. Impact of co-pollutants (As (III), fulvic acid, and diisopropanolamine) on sulfolane biodegradation in groundwater was also investigated in this research. Three concentrations of As (III) (low, medium and high) were observed to have negligible impact on sulfolane degradation. Similarly, at environmentally relevant concentrations, fulvic acid did not significantly effect sulfolane removal. Diisopropanolamine, however, was observed to positively and negatively impact sulfolane removal depending on the biological, chemical and physical characteristics of the water matrix used.
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Hassanvand-Gandaei, N. (2019). Extraction, analysis and the role of co-contaminants on sulfolane biodegradation (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.