Nikolaus Klamerth

Advanced Analytical Mass Spectrometric Techniques and Bioassays to Characterize Untreated and Ozonated Oil Sands Process-Affected Water

Oil sands process-affected water (OSPW) is a toxic and poorly biodegradable mixture of sand, silt, heavy metals, and organics. In this study, qualitative and quantitative comparisons of naphthenic acids (NAs) were done using ultraperformance liquid chromatography time-of-flight mass spectrometry (UPLC TOF-MS), Fourier transform ion cyclotron resonance (FT-ICR) MS, and ion mobility spectrometry (IMS). The unique combination of these analyses allowed for the determination and correlation of NAs, oxidized NAs, and heteroatom (sulfur or nitrogen) NAs. Despite its lower resolution, UPLC-TOF MS was shown to offer a comparable level of reliability and precision as the high resolution FT-ICR MS. Additionally, the impacts of ozonation (35 mg/L utilized ozone dose) and subsequent NAs degradation on OSPW toxicity were assessed via a collection of organisms and toxicity end points using Vibrio fischeri (nonspecific), specific fish macrophage antimicrobial responses, and fish olfactory responses. Fish macrophages exposed to ozonated OSPW for 1 week showed higher production of reactive oxygen and nitrogen intermediates; however, after 12 weeks the responses were reduced significantly. Fish olfactory tests suggested that OSPW interfered with their perception of odorants. Current results indicate that the quantification of NAs species, using novel analytical methods, can be combined with various toxicity methods to assess the efficiency of OSPW treatment processes.

Effect of ozonation on the naphthenic acids' speciation and toxicity of pH-dependent organic extracts of oil sands process-affected water

The presence of naphthenic acids (NAs) and other organic constituents in oil sands process-affected water (OSPW) stored in tailings ponds, poses a serious environmental threat due to their potential toxicity to aquatic organisms and wild life. In this work, four fractions of OSPW, extracted by dichloromethane at different pHs, were ozonated to determine the ozone impact on NAs degradation. Extracts distributions showed that high carbon number NAs (14-22) were associated with higher pH fractions (pH>7) and smaller carbon number NAs (7-13) with lower pH fractions (pH≤7). Extracts showed similar hydrogen deficiency (Z-number) patterns centered on Z=6. Analysis of the speciation of NAs and oxidized NAs in the four fractions showed that ozonation degraded most NAs (55% to 98%). Despite the high degradation levels, there was still significant toxicity of the fractions toward goldfish macrophages and measurable toxicity toward Vibrio fischeri. The toxicity of such a complex matrix as OSPW may be attributed to other organic compounds and degradation by-products not currently detected. Thus, there is a need to elucidate which compounds are responsible for the remaining OSPW toxicity and to determine if combined processes, such as ozonation followed by biological treatment, are able to completely detoxify OSPW. This work is taking the first steps into this direction, narrowing down the range of compounds which might be responsible for the toxicity.

Comparison of methods for determination of total oil sands-derived naphthenic acids in water samples

There are several established methods for the determination of naphthenic acids (NAs) in waters associated with oil sands mining operations. Due to their highly complex nature, measured concentration and composition of NAs vary depending on the method used. This study compared different common sample preparation techniques, analytical instrument methods, and analytical standards to measure NAs in groundwater and process water samples collected from an active oil sands operation. In general, the high- and ultrahigh-resolution methods, namely high performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) and Orbitrap mass spectrometry (Orbitrap-MS), were within an order of magnitude of the Fourier transform infrared spectroscopy (FTIR) methods. The gas chromatography mass spectrometry (GC-MS) methods consistently had the highest NA concentrations and greatest standard error. Total NAs concentration was not statistically different between sample preparation of solid phase extraction and liquid-liquid extraction. Calibration standards influenced quantitation results. This work provided a comprehensive understanding of the inherent differences in the various techniques available to measure NAs and hence the potential differences in measured amounts of NAs in samples. Results from this study will contribute to the analytical method standardization for NA analysis in oil sands related water samples.

Positive and negative electrospray ionization analyses of the organic fractions in raw and oxidized oil sands process-affected water.

This work investigated the oxidative transformation of the organic species in oil sands process-affected water (OSPW) using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) in both negative and positive electrospray ionization (ESI) modes. This is the first time to apply FTICR-MS to investigate species transformation in OSPW treatments by ferrate (VI), UV/H2O2, and molecular ozone, and also this is the first preliminary study to use positive ESI to investigate organic species in addition to naphthenic acids (NAs) in these treatment processes. The oxidation processes with potassium ferrate (VI), UV/H2O2, and ozone transformed the distribution profiles of Ox, OxSy, and OxNy organic fractions (i.e., species containing oxygen, sulfur, and nitrogen, with x, y specifying the oxygen number and sulfur/nitrogen number, respectively), with OxSy distribution profiles showing the most sensitive responses to the oxidation extent and can be used as a signature fraction to evaluate the oxidation effectiveness. Negative mode UPLC-TOF-MS confirmed the transformation pattern of Ox species observed with FTICR-MS, but positive mode UPLC-TOF-MS results showed severe discrepancies with FTICR-MS results and should be subjected for future further investigation, regarding the relatively low mass resolution of UPLC-TOF-MS. The investigation of the transformation patterns of different organic species using two ionization modes was a preliminary study to enhance the understanding of the efficiency, selectivity, and mechanism of different oxidation processes in OSPW remediation for both NAs and non-NA species.

Monitoring of classical, oxidized, and heteroatomic naphthenic acids species in oil sands process water and groundwater from the active oil sands operation area

The classical, oxidized, and heteroatomic naphthenic acids (NAs) species were monitored in the oil sands process water (OSPW) and groundwater from the active oil sands operation area, using solid phase extraction sample preparation and high resolution mass spectrometry analysis. Groundwater samples include Pleistocene channel aquifer groundwater (PLCA) and oil sands basal aquifer groundwater (OSBA) from different depth of underground. The concentrations of Ox-NAs decreased from OSPW to PLCA, and then increased from PLCA to OSBA, which is deeper than PLCA. The NAs in PLCA mainly comprised of Ox-NAs and N-NAs and the percentage of S-NAs was negligible. Results revealed relative abundances of individual NA species in total NAs varies among different water layers and the potential environmental impacts are expected to be variable. Principal component analysis results of O2-NAs or O4-NAs could be used for differentiation of water types. O2-NAs with n = 12-16 and |Z| = 4-6, and O4-NAs with n = 14-20 and |Z| = 6-8, were identified as marker compounds that could serve as surrogates of the larger complex NA mixture for source differentiation. This work utilized a combination of sample preparation, instrumental analysis, and statistical analysis methods to obtain knowledge of the occurrence, composition, and transfer of NAs in the groundwater of the Alberta oil sands operation area.