Aquatic fate of fish tainting compounds in the Athabasca River

• Main Authors: Taylor, B., Hamilton, H., Westlake, D., Wallace, R., Foght, J., Hrudey, S.
• Format: Report
• Language: English
• Published: 1987
• Subjects: Naphthenates; RMD L-86; Water Quality; Oil Sands; Tar Sands; Hydrocarbons; RMD; Alberta; Athabasca River; Fish Tainting
• Online Access: https://era.library.ualberta.ca/items/5da26000-ddc9-405b-8b5c-5cb2824ebf4d; https://doi.org/10.7939/R3W66997D

This report investigates the relationship between certain hydrocarbons that are present naturally, or could be introduced due to surface oil sands mining and upgrading activities, and their potential bioaccumulation and tainting of the commercial fishery in the Athabasca River. This includes defining the contaminants of concern, reviewing their bioavailability and bioconcentration properties and consideration of their persistence in the aquatic environment of the Athabasca River. A water management approach for setting ambient surface water objectives and effluent standards for fish tainting compounds is discussed within the context of basin-wide water resource planning. The scientific literature regarding petroleum related compounds that could cause off-flavour in fish is often confused and contradictory. This results from inconsistent testing protocols and lack of analytical precision. However, it is generally concluded that low molecular weight compounds, i.e., dibenzothiophenes, naphthenic acids, mercaptans and methylated naphthalenes are petroleum related compounds which can taint fish. Phenolics are also of concern. Detailed chemical characterization of wastewaters originating from oil sands extraction is lacking. Those data which are available indicate that the general composition of the wastewaters is the same as the raw bitumen, but relative concentrations are drastically altered. The oil in natural bitumen deposits is deficient in water-soluble components, saturated hydrocarbons (n-paraffins) and low molecular weight aromatic compounds, while being enriched in asphaltenic and nitrogen-, sulfur-, and oxygen-containing compounds (NSO compounds). The process effluents (e.g., upgrading wastewaters and tailings pond discharge) resemble more the synthetic crude than the parent bitumen, being enriched in aromatic and alipathic compounds, including those which have the potential to taint fish flesh. Cross comparison between compounds known to taint fish and those which could exist in oil sand wastewaters ...