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Naphthenic acids (NAs) are natural constituents in many petroleum sources, including bitumen in the oil sands of Northern Alberta, Canada. Bitumen extraction processes produce tailings waters that cannot be discharged to the environment because NAs are acutely toxic to aquatic species. However, aerobic biodegradation reduces the toxic character of NAs. In(More)
A laboratory bench procedure was developed to efficiently extract naphthenic acids from bulk volumes of Athabasca oil sands tailings pond water (TPW) for use in mammalian oral toxicity testing. This solvent-based procedure involved low solvent losses and a good extraction yield with low levels of impurities. Importantly, labour-intensive centrifugation of(More)
Microcosm experiments with natural indigenous phytoplankton communities were conducted to assess the effects of waters from oil sands extraction processes, emphasizing the naphthenate and salt constituents. Process waters of varying ages (zero to eight years) remediation histories, and chemical composition were obtained from outdoor mesocosms and inoculated(More)
The water produced during the extraction of bitumen from oil sands is toxic to aquatic organisms due largely to a group of naturally occurring organic acids, naphthenic acids (NAs), that are solubilized from the bitumen during processing. NAs are a complex mixture of alkyl-substituted acyclic and cycloaliphatic carboxylic acids, with the general chemical(More)
The oil sands industry in Northern Alberta produces large volumes of oil sands process water (OSPW) containing high concentrations of persistent naphthenic acids (NAs; C(n)H(2n+Z)O(2)). Due to the growing volumes of OSPW that need to be reclaimed, it is important to understand the fate of NAs in aquatic systems. A recent laboratory study revealed several(More)
In the past decade, the large tailings pond (Mildred Lake Settling Basin) on the Syncrude Canada Ltd. lease near Fort McMurray, Alta., has gone methanogenic. Currently, about 60%-80% of the flux of gas across the surface of the tailings pond is methane. As well as adding to greenhouse gas emissions, the production of methane in the fine tailings zone of(More)
Naphthenic acids (NAs) are naturally occurring saturated linear and cyclic carboxylic acids found in petroleum, including the bitumen contained in the Athabasca Oil Sands deposit in Alberta, Canada. The processing of these oil sands leads to elevated concentrations of NAs, as well as increased salinity from produced waters as a result of ions leaching from(More)
Naphthenic acids are the most significant environmental contaminants resulting from petroleum extraction from oil sands deposits. In this study, a mixture of naphthenic acids isolated from Athabasca oil sands (AOS) tailings pond water was used in acute and subchronic toxicity tests with rodents, in order to assess potential risks posed to terrestrial(More)
Naphthenic acids are found in wastewaters from petroleum refineries and oil sands extraction plants. Currently, the concentrations of these toxic carboxylic acids are determined by extracting them into methylene chloride and measuring the absorption of the carboxyl group by Fourier-transform infrared (FTIR) spectroscopy. An improved HPLC method, that is(More)
Organic acids, similar in structure to naphthenic acids, have been associated with the acute toxicity of tailings produced by the oil sands industry in northeastern Alberta, Canada. Bacterial cultures enriched from oil sands tailings were found to utilize as their sole carbon source both a commercial mixture of naphthenic acids and a mixture of organic(More)