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

Effects-Directed Analysis of Dissolved Organic Compounds in Oil Sands Process-Affected Water

“…Moreover, the results of that study were largely inconclusive, in part because the low-resolution infusion-electrospray mass spectrometry method lacks the necessary resolving power to differentiate NAs from isobaric compounds containing nitrogen, sulfur, or multiple oxygen atoms. 40 Acute toxicity of ozonated fractions was recently studied, 38 but it was not possible to explain their results by characterization of the NAs and oxidized NAs, which suggests that other chemical classes of organic chemicals in OSPW could be important for toxicity of OSPW, consistent with the pioneering study of Verbeek et al 17 The goal of the current study was to use the best available analytical technology and an EDA approach to identify the most acutely toxic dissolved organic chemical classes in OSPW. A 96 h fathead minnow (Pimephales promelas) embryo-lethality assay and a 15 min Microtox toxicity bioassay (Vibrio fischeri) were used to assess acute toxicity, and the composition of chemicals in each fraction, generated by liquid−liquid extraction or chromatographic separation, was determined by HPLC−Orbitrap ultrahigh-resolution mass spectrometry.…”

Trace analysis of total naphthenic acids in aqueous environmental matrices by liquid chromatography/mass spectrometry-quadrupole time of flight mass spectrometry direct injection

“…In addition, these components may be below our detection limits, affected by the alkaline dissolution conditions employed in the current method, or potentially an artifact of sample clean-up and processing procedures used by other researchers. A more recent publication studying the effect of ozonation on NAs supported the presence of S heteroatoms but again employed Na 2 SO 4 and H 2 SO 4 in the organic fraction extraction process [35]. Research is worth pursing in application of the current method to the analysis of unprocessed samples that are considered to contain a high heteroatom content.…”

“…An alternative scenario is the transformation of other isomer species present (e.g., reported potential S containing species) to polyoxy species. A recent study by Klamerth et al [35] highlighted the extensive effects of ozonation on NA species. The NA were extracted at alkaline pH and further processed by solvent extraction and acidic pH adjustment using H 2 SO 4 [35].…”

“…A recent study by Klamerth et al [35] highlighted the extensive effects of ozonation on NA species. The NA were extracted at alkaline pH and further processed by solvent extraction and acidic pH adjustment using H 2 SO 4 [35]. While no reference material was listed for this study, it was clear that the oxygenation could significantly affect the ratios of NA species present.…”

Water Analysis: Emerging Contaminants and Current Issues

“…Klamerth et al investigated the effect of ozonation on NAs from oil sands processed water. 224 Following ozonation, fractions of transformation products were extracted at different pH using dichloromethane. Higher pH (>7) fractions contained NAs with a higher number of carbons (14−22), and lower pH fractions (<7) had smaller carbon numbers (7−13).…”