Ethoxyresorufin-O-deethylase (EROD) induction in rainbow trout exposed to diluted oil sand wastewater

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:242330

Verbeek, A ^[1]; Mackay, W ^[2]; Birkholz, D ^[3]

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1. Chemex Labs Alberta Inc., Edmonton, Alberta (Canada)
2. Univ. of Alberta, Edmonton, Alberta (Canada)
3. Enviro-Test Labs., Edmonton, Alberta (Canada)

Toxic industrial wastewaters, such as those from oil sands extraction, must be assessed for their potential sublethal effects before they can be safely disposed in the environment. The induction of ethoxyresorufin-O-deethylase activity was assessed as a potential bioindicator of sublethal stress in rainbow trout exposed to sublethal concentrations of oil sands tailings water. The mixed-function oxygenase system in rainbow trout responded rapidly following a definable concentration-response relationship; however, it proved to be a relatively insensitive indicator of sublethal exposure to oil sands tailings water. Increased activity and maximal induction, as a result of exposure to 0.3 and 0.6 times the LC{sub 50} (Toxic Units), occurred rapidly within 24 hours of exposure. The linearity of the relationship between the concentration of oil sands tailings pond water and ethoxyresorufin-O-deethylase activity, expressed by the following regression equation, In EROD = 3.68 (conc.) + 3.20, had an r{sup 2} value of 0.593. Maximal induction required 0.4--0.8 Toxic Units. The absolute level of maximal induction was only one-fifth to one-sixth of the potential induction as found in response to the positive control, 0.5 mg/kg {beta}-naphthoflavone (i.p.). The authors also present data that suggests that the different levels of induction observed in trout exposed to tailings pond water vs those injected with 0.5 mg/kg {beta}-naphthoflavone (i.p.) may be indicative of two different P450 isoforms, the CYP4Al isoform responding to the organic acidic surfactants in oil sands tailings pond water and the CYP1A1 isoform, the isoform generally associated with most xenobiotic transformation in fish, responding to {beta}-naphthoflavone.

• OSTI ID: 242330
• Report Number(s): CONF-9511137--; ISBN 1-880611-03-1
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL INDICATORS
BIOLOGICAL MARKERS
BIOLOGICAL STRESS
DOSE-RESPONSE RELATIONSHIPS
ENVIRONMENTAL IMPACTS
ENZYME INDUCTION
MIXED-FUNCTION OXIDASES
OIL SAND PROCESSING PLANTS
OIL SAND TAILINGS
ORGANIC ACIDS
OXIDOREDUCTASES
TOXICITY
TROUT
WASTE WATER
WATER POLLUTION