Assessing accumulation and biliary excretion of naphthenic acids in yellow perch exposed to oil sands-affected waters.

Naphthenic acids are known to be the most prevalent group of organic compounds in oil sands tailings-associated waters. Yellow perch (Perca flavescens) were exposed for four months to oil sands-influenced waters in two experimental systems located on an oil sands lease 30 km north of Fort McMurray Alberta: the Demonstration Pond, containing oil sands tailings capped with natural surface water, and the South Bison Pond, integrating lean oil sands. Yellow perch were also sampled from three lakes: Mildred Lake that receives water from the Athabasca River, Sucker Lake, at the edge of oil sands extraction activity, and Kimowin Lake, a distant reference site.

Physiological effects and tissue residues from exposure of leopard frogs to commercial naphthenic acids.

Naphthenic acids (NAs) have been cited as one of the main causes of the toxicity related to oil sands process-affected materials and have recently been measured in biological tissues (fish). However, adverse effects have not been a consistent finding in toxicology studies on vertebrates. This study set out to determine two factors: 1) whether exposure to commercial NAs (Refined Merichem) resulted in detectable tissue residues in native amphibians (northern leopard frogs, Lithobates pipiens), and 2) whether such exposure would produce clinical or subclinical toxicity.

Fathead minnow (Pimephales promelas) reproduction is impaired when exposed to a naphthenic acid extract.

Previous studies have demonstrated that oil sands process-affected water (OSPW) impairs the reproduction of fish and that naphthenic acids (NAs), a natural constituent of oil sands, are suspected of being responsible. This study evaluates the potential impact of NAs on the reproduction of adult fathead minnows (Pimephales promelas) under laboratory conditions. Fathead minnows exposed to a 10 mg/l naphthenic acid extract (NAE) for 21 days spawned fewer eggs and males had reduced expression of secondary sexual characteristics.

Blinded taste panel evaluations to determine if fish from near the oil sands are preferred less than fish from other locations in Alberta, Canada.

The oil sands industry is rapidly expanding surface mining and bitumen extraction operations near the Athabasca River in northeastern Alberta, Canada. There are anecdotal comments that the fish from the Athabasca River have an off-taste, implying that the oil sands operations are the cause. This study was done to determine if the taste of wild fishes caught near the Athabasca oil sands was less preferred than the taste of fishes collected from two other river basins in Alberta.

Distribution of naphthenic acids in tissues of laboratory-exposed fish and in wild fishes from near the Athabasca oil sands in Alberta, Canada.

Naphthenic acids, which have a variety of commercial applications, occur naturally in conventional crude oil and in highly biodegraded petroleum such as that found in the Athabasca oil sands in Alberta, Canada. Oil sands extraction is done using a caustic aqueous extraction process. The alkaline pH releases the naphthenic acids from the oil sands and dissolves them into water as their soluble naphthenate forms, which are anionic surfactants.

Fathead minnow (Pimephales promelas) reproduction is impaired in aged oil sands process-affected waters.

Large volumes of fluid tailings are generated during the extraction of bitumen from oil sands. As part of their reclamation plan, oil sands operators in Alberta propose to transfer these fluid tailings to end pit lakes and, over time, these are expected to develop lake habitats with productive capabilities comparable to natural lakes in the region. This study evaluates the potential impact of various oil sands process-affected waters (OSPW) on the reproduction of adult fathead minnow (Pimephales promelas) under laboratory conditions.

Naphthenic acids and other acid-extractables in water samples from Alberta: what is being measured?

There is increasing international interest in naphthenic acids (NAs, classical formula C(n)H(2n+Z)O(2)) found in the oil sands from Alberta, Canada and in petroleum from around the world. The complexity of NAs poses major analytical challenges for their quantification and characterization. We used ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS) to probe the make up of NAs from various sources by searching for peaks corresponding to the formula C(n)H(2n+Z)O(x), for combinations of n=8 to 30, Z=0 to -12, and x=2 to 5.

Odor detection thresholds of naphthenic acids from commercial sources and oil sands process-affected water.

Naphthenic acids (NAs) occur naturally in various petroleums and in oil sands tailings waters and have been implicated as potential fish tainting compounds. In this study, trained sensory panels and the general population from a university were used to determine the odor detection thresholds of two commercial NAs preparations (Acros and Merichem) and of NAs extracted from an oil sands experimental reclamation pond (Pond 9). Using the three-alternative forced choice method, a concentration series of NAs were presented to the sensory panels in phosphate buffer (pH 8) and in steamed fish (Sander vitreus).

Comparison of GC-MS and FTIR methods for quantifying naphthenic acids in water samples.

The extraction of bitumen from the oil sands in Canada releases toxic naphthenic acids into the process-affected waters. The development of an ideal analytical method for quantifying naphthenic acids (general formula C(n)H(2n+Z)O(2)) has been impeded by the complexity of these mixtures and the challenges of differentiating naphthenic acids from other naturally-occurring organic acids. The oil sands industry standard FTIR method was compared with a newly-developed GC-MS method.

Estimating naphthenic acids concentrations in laboratory-exposed fish and in fish from the wild.

Naphthenic acids (NAs) are the most water-soluble organic components found in the Athabasca oil sands in Alberta, Canada, and these acids are released into aqueous tailing waters as a result of bitumen extraction. Although the toxicity of NAs to fish is well known, there has been no method available to estimate NAs concentrations in fish. This paper describes a newly developed analytical method using single ion monitoring gas chromatography-mass spectrometry (GC-MS) to measure NAs in fish, down to concentrations of approximately 0.

Aerobic biodegradation of 2,2'-dithiodibenzoic acid produced from dibenzothiophene metabolites.

Dibenzothiophene is a sulfur heterocycle found in crude oils and coal. The biodegradation of dibenzothiophene through the Kodama pathway by Pseudomonas sp. strain BT1d leads to the formation of three disulfides: 2-oxo-2-(2-thiophenyl)ethanoic acid disulfide, 2-oxo-2-(2-thiophenyl)ethanoic acid-2-benzoic acid disulfide, and 2,2'-dithiodibenzoic acid.