Site-specific spatiotemporal occurrence and molecular congener distributions of naphthenic acids in Athabasca oil sands wetlands of Alberta, Canada.

The Athabasca oil sands region (AOSR) of Alberta, Canada is notable for its considerable unconventional petroleum extraction projects, where bitumen is extracted from naturally-occurring oil sands ore. The large scale of these heavy crude oil developments raises concerns because of their potential to distribute and/or otherwise influence the occurrence, behaviour, and fate of environmental contaminants. Naphthenic acids (NAs) are one such contaminant class of concern in the AOSR, so studies have examined the occurrence and molecular profiles of NAs in the region. We catalogued the spatiotemporal occurrence and characteristics of NAs in boreal wetlands in the AOSR over a 7-year period, using derivatized liquid chromatography-tandem mass spectrometry (LC-MS/MS). Comparing median concentrations of NAs across these wetlands revealed a pattern of NAs suggesting NAs in surface waters derived from oil sands deposits. Opportunistic wetlands that formed adjacent to reclaimed overburden and other reclamation activities had the highest concentrations of NAs and consistent patterns suggestive of bitumen-derived inputs. However, similar patterns in the occurrence of NAs were also observed in undeveloped natural wetlands located above the known surface-mineable oil sands deposit that underlies the region. Intra-annual sampling results along with inter-annual comparisons across wetlands demonstrated that differences in the spatial and temporal NA concentrations were dependent on local factors, particularly when naturally occurring oil sands ores were observed in the wetland or drainage catchment.

The application of HPLC ESI MS in the investigation of the flavonoids and flavonoid glycosides of a Caribbean Lamiaceae plant with potential for bioaccumulation.

As part of an exchange technology program between the government of Barbados and Environment Canada, methanolic and aqueous extracts from the flavonoid-rich Lamiaceae family were characterized using negative-ion electrospray mass spectrometry. The species investigated is part of the Caribbean Pharmacopoeia, and is used for a variety of health issues, including colds, flu, diabetes, and hypertension. The extracts were investigated for structural elucidation of phenolics, identification of chemical taxonomic profile, and evidence of bio-accumulator potential. The methanolic and aqueous leaf extracts of Plectranthus amboinicus yielded rosmarinic acid, ladanein, cirsimaritin, and other methoxylated flavonoids. This genus also shows a tendency to form conjugates with monosaccharides, including glucose, galactose, and rhamnose. The aqueous extract yielded four isomeric rhamnosides. The formation of conjugates by Plectranthus amboinicus is thus evidence of high bioaccumulator significance.

Laboratory investigations of stormwater remediation via slag: Effects of metals on phosphorus removal.

The use of electric arc furnace (EAF) slag for the removal of phosphorus (P) from various simulated stormwater blends was investigated in the laboratory. The form of P measured was the inorganic orthophosphate (PO(4)-P). The stormwater solutions used in this preliminary study were synthesized as blends of P and typical concentrations of some of the most common and abundant metals in stormwater (e.g. cadmium, copper, lead and zinc), and contacted with EAF slag to determine P removal efficiency and sorptive competition. Results showed that the presence of cadmium, lead and zinc had minimal effect on the removal process; copper was a significant inhibitor of P uptake by the EAF slag media. P removal was greatest in the metal-free and multi-metal stormwater solutions.

Microwave treatment of naphthenic acids in water.

Naphthenic acids (NAs) are natural constituents of bitumen and crude oil. These compounds are concentrated as part of the oil sands process water (OSPW) during petroleum refining and separation from oil sands. NAs are considered among the major water contaminants in OSPW due to their toxicity and environmental recalcitrance. A laboratory scale microwave system was developed and experiments were conducted to determine the efficiency of NA degradation during microwave treatment. The effects of water source and quality (deionized lab water and river water) and of TiO(2) catalyst in the degradation process were also investigated. Degradation kinetic parameters for both total NAs and individual z-family were calculated. The microwave system degraded OSPW NAs and commercial Fluka NAs in river water in the presence of TiO(2) rapidly, producing half-life values of 3.32 and 3.61 hours, respectively. Toxicity assessments of the NA samples pre-and post-treatment indicated that the microwave system reduced overall toxicity of water containing Fluka NAs from high (5 min. IC(50) v/v = 15.85%) to moderate (5 min. IC(50) v/v = 36.45%) toxicity levels. However, a slight increase in toxicity was noted post-treatment in OSPW NAs.

Evaluation of algal phytodegradation of petroleum naphthenic acids.

The algal phytodegradation of a model naphthenic acid (4-methylcyclohexaneacetic acid) and an oilsands mixture of naphthenic acids (NAs) were evaluated in support of studies to remediate recalcitrant NAs in soils and water. The algae investigated included blue-green algae (Oscillatoria sp.; Aphanizomenon sp.; Anbaena sp.) green algae (Selenastrum sp.; Nannochloris sp.; Ankistrodesmus sp.; Scenedesmus sp.; Haematococcus sp.; Chlorella sp.) and diatoms (Naviculla (1), Naviculla (2) and Nitzschia sp.). Both the cis- and trans-isomers of the model NA were completely uptaken and presumed phytodegraded by the diatom algae Naviculla (2) sp. at a concentration of approximately 5.5 mg/L within a period of 14 days. However, there was no evidence for the phytodegradation of the petroleum oilsands naphthenic acids mixtures, except for possibly experiments utilizing the green algae, Selenastrum sp. The differences in the phytodegradation of the model NA by the diatoms appears to be linked to differences in transport mechanisms by the algae along with differences in the concentration and structure of the respective naphthenic acids.