A Light Touch: Solar Photocatalysis Detoxifies Oil Sands Process-Affected Waters Prior to Significant Treatment of Naphthenic Acids.

Environmental reclamation of Canada's oil sands tailings ponds is among the single largest water treatment challenges globally. The toxicity of oil sands process-affected water (OSPW) has been associated with its dissolved organics, a complex mixture of naphthenic acid fraction components (NAFCs). Here, we evaluated solar treatment with buoyant photocatalysts (BPCs) as a passive advanced oxidation process (P-AOP) for OSPW remediation. Photocatalysis fully degraded naphthenic acids (NAs) and acid extractable organics (AEO) in 3 different OSPW samples. However, classical NAs and AEO, traditionally considered among the principal toxicants in OSPW, were not correlated with OSPW toxicity herein. Instead, nontarget petroleomic analysis revealed that low-polarity organosulfur compounds, composing <10% of the total AEO, apparently accounted for the majority of waters' toxicity to fish, as described by a model of tissue partitioning. These findings have implications for OSPW release, for which a less extensive but more selective treatment may be required than previously expected.

Comprehensive characterization of organics in oil sands process water in constructed mesocosms utilizing multiple analytical methods.

This study aims to provide a thorough characterization of dissolved organics in oil sands process water (OSPW) in field-based aquatic mesocosms at both molecular and bulk measurement levels using multiple analytical methods. In a 3-year outdoor mesocosm experiment, the analysis of naphthenic acid (NA) species was conducted using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOFMS). The results revealed the removal of both total NAs (38% and 35%) and classical NAs (O2-NAs, 58% and 49%) in undiluted and half-diluted OSPW, respectively. The increased ratios of oxidized NAs (O3-O6 NAs) to classical NAs suggested a transformation trend. The results also indicated that O2-NAs with higher carbon number and lower double bond equivalent (DBE) were more easily degraded in the mesocosm systems. Biomimetic extraction using solid-phase microextraction (BE-SPME) measurement displayed 26% (undiluted OSPW) and 30% (half-diluted OSPW) decrease in total bioavailable organics over 3 years. Naphthenic acids fraction compounds (NAFCs) obtained by liquid-liquid extraction (LLE) were also determined using Fourier transform infrared spectroscopy (FTIR). Reduction in acute toxicity for undiluted (43%) and half-diluted (26%) OSPW was observed over 3 years, which are well correlated with the decreases of NAs and BE-SPME concentrations. Moreover, BE-SPME values were found to be linearly correlated with total NAs concentrations (r = 0.96) and NAFCs (r = 0.96). Additionally, the linear relationships of individual O2-O6 NA species and BE-SPME concentrations unveiled the changes in the relative abundances of O2-O6 NA species in total bioavailable organics over time in the mesocosms. The present study has provided comprehensive insights by integrating various analytical methods, contributing valuable information for assessing the effectiveness of aquatic mesocosm systems in studying the temporal changes of organics in OSPW.

Interlaboratory Comparison of a Biomimetic Extraction Method Applied to Oil Sands Process-Affected Waters.

Biomimetic extraction using solid-phase microextraction is a passive sampling analytical method that can predict the aquatic toxicity of complex petroleum substances. The method provides a nonanimal alternative to traditional bioassays with the potential to reduce both vertebrate and invertebrate aquatic toxicity testing. The technique uses commercially available polydimethylsiloxane-coated fibers that, following nondepletive extraction of water samples, are injected into a gas chromatograph with flame ionization detection. As the predictive nature of the method is operationally defined, it is critical that its application be harmonized with regard to extraction, analysis, and standardization parameters. Results are presented from a round robin program comparing the results from 10 laboratories analyzing four different sample sets of dissolved organics in water. Samples included two incurred oil sands process-affected waters and a cracked gas oil water accommodated fraction. A fourth sample of cracked gas oil blended in an oil sands process-affected water was analyzed to demonstrate the method's ability to differentiate between neutral and ionizable dissolved hydrocarbons. Six of the 10 laboratories applied an automated version of the method using a robotic autosampler where the critical extraction steps are precisely controlled and which permits batch screening of water samples for aquatic toxicity potential. The remaining four laboratories performed the solid-phase microextraction manually. The automated method demonstrated good reproducibility with between-laboratory variability across the six laboratories and four samples yielding a mean relative standard deviation of 14%. The corresponding between-laboratory variability across the four laboratories applying the manual extraction was 53%, demonstrating the importance of precisely controlling the extraction procedure. Environ Toxicol Chem 2022;41:1613-1622. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Characterization of raw and ozonated oil sands process water utilizing atmospheric pressure gas chromatography time-of-flight mass spectrometry combined with solid phase microextractionun.

This work describes a novel application of atmospheric pressure gas chromatography time-of-flight mass spectrometry (APGC-TOF-MS) combined with solid-phase microextraction (SPME) for the simultaneous analysis of hydrocarbons and naphthenic acids (NAs) species in raw and ozone-treated oil sands process water (OSPW). SPME method using polydimethylsiloxane (PDMS)-coated fibers was validated using gas chromatography with flame ionization detector (GC-FID) to ensure the SPME extractions were operated appropriately. The ionization pathways of the hydrocarbon species in OSPW in the APGC source were verified by analyzing a mixture of eight polyaromatic hydrocarbons which were ionized primarily via charge transfer to produce [M+] while NAs in OSPW were found to be ionized through protonation to generate [MH+] in the wet APGC source. SPME/APGC-TOF-MS analysis demonstrated a different composition profile in OSPW #1, with 74.5% of hydrocarbon species, 23.4% of O2-NAs, and 2.1% of the oxidized NA species at extraction pH 2.0 compared with that obtained by UPLC-TOF-MS analysis (36.9% of O2-NAs, 26.8% of O3-NAs, 24.9% of O4-NAs, 9.1% of O5-NAs, 2.3% of O6-NAs). Moreover, the peak areas of the total NAs and the total peak areas of NAs + hydrocarbons measured by SPME/APGC-TOF-MS correlated excellently with the total NA concentration determined by UPLC-TOF-MS (R2 = 0.90) and the concentrations of the total acid-extractable organics determined by SPME/GC-FID (R2 = 0.98), respectively. APGC-TOF-MS integrated with the SPME techniques could extend the range of target compounds and be a promising alternative to evaluate and characterize NAs and hydrocarbon in different water types.

Advancing methods for health priority setting practice through the contribution of systems theory: Lessons from a case study in Ethiopia.

Setting priorities for health services is a complex and value laden process. Over the past twenty years, there has been considerable scholarly attention paid to strengthening fairness and legitimacy using the prominent ethical framework, Accountability for Reasonableness (A4R). A variety of case studies applying A4R have advanced our conceptual understanding of procedural fairness, and have highlighted the significance of context through its application. There is a paucity of research, however, that rigorously examines how and to what extent context influences health priority setting processes and the establishment of procedural fairness. We argue here that to study context rigorously requires taking a holistic view of the system by examining the dynamics and interrelationships within it. Using the Transformative Systems Change Framework (TSCF), this investigation sought to examine the influence of system factors on priority setting practice and procedural fairness. A qualitative case study of Ethiopian district health planning was undertaken in 2010 and 2011. Methods included 58 qualitative interviews with decision makers, participant observation, and document analysis. Data analysis followed in three phases: i) an inductive analysis of district health priority setting to highlight experiences across each of the three districts selected, ii) deductive analysis applying A4R and the TSCF independently; and iii) a synthesis of concepts of priority setting practice and procedural fairness within a broader, theoretical understanding of the system. Through the application of the TSCF, a nuanced understanding of priority setting practice is revealed that situates this process within a system of interdependent components that include: norms, operations, regulations, and resources. This paper offers a practical guide attuned to system features influencing the design, implementation, and sustainability of greater fairness in health priority setting practice.

Conceptualizations of fairness and legitimacy in the context of Ethiopian health priority setting: Reflections on the applicability of accountability for reasonableness.

A critical element in building stronger health systems involves strengthening good governance to build capacity for transparent and fair health planning and priority setting. Over the past 20 years, the ethical framework Accountability for Reasonableness (A4R) has been a prominent conceptual guide in strengthening fair and legitimate processes of health decision-making. While many of the principles embedded within the framework are congruent with Western conceptualizations of what constitutes procedural fairness, there is a paucity in the literature that captures the degree of resonance between these principles and the views of decision makers from non-Western settings; particularly in Africa, where many countries have only recently, within the last 20-30 years, become more democratic. This paper contributes to the ethics literature by examining how Ethiopian decision makers conceptualize fair and legitimate health decision-making, and reflects on the degree of conceptual resonance between these views and the principles embedded in A4R. A qualitative case study approach from three districts in Ethiopia was undertaken. Fifty-eight decision makers from district, regional, zonal, and national levels were interviewed to describe their conceptualization of fairness and legitimacy in the district health planning process. Findings revealed that Ethiopians have a broad conception of fairness and legitimacy that while congruent with procedural justice, also aligned with principles of distributive and organizational justice. Researchers and practitioners seeking to strengthen procedural fairness in health priority setting must therefore recognize the significance of other philosophical dimensions influencing how fairness and legitimacy of health decision-making are constructed within the Ethiopian setting.