W9 PM Residual Oil and its Effects
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in 339-340

(SPR-1117-832569) Induction of CYP1A in rainbow trout from bioavailable Exxon Valdez oil: fifteen years and still counting.

Springman, K¹, Short, J², Lindeberg, M², Khan, C³, Larsen, M², Hodson, P³, Rice, S², ¹ University of California, Davis, Davis, California, USA² NOAA/NMFS Auke Bay Laboratory, Juneau, Alaska, USA³ Queen's University, Kingston, Ontario, Canada

ABSTRACT- Assessing complex mixture toxicity by summing their concentrations may not be sufficiently realistic to evaluate or predict the consequences of exposure. An effective alternative involves the modification of a well-documented form of mimetic chemistry, the semi-permeable membrane device (SPMD), and the exposure of test animals to its contents. This method allows the evaluation of the effects of those bioavailable compounds present, including those whose analysis is difficult with their breakdown products and metabolites, as encountered in situ. This approach facilitates an evaluation of toxicity for each sample and site as a unit. We evaluated the CYP1A induction potential found in intertidal areas in Prince William Sound, some of which were oiled in 1989 from the Exxon Valdez oil spill, using SPMDs. The SPMDs were deployed for the standard 28-day deployment period, processed, and the extracts injected in juvenile rainbow trout (Oncorhynchus mykiss) which were sacrificed after 2 or 7 days, the livers excised and examined with the ethoxyresorufin-o-deethylase (EROD) bioassay. The results demonstrate that even after fifteen years, there is enough bioavailable oil in formerly oiled intertidal habitats of Prince William Sound to elicit a marked induction of CYP1A. The induction potential from oiled sites are comparable to those from a boat harbor (hot control), and are significantly elevated above environmental controls from sites that were not oiled. These results indicate that oil bioavailability is real, and can be evaluated with this technique.

Key words: residual oil, biological effects, bioavailability, semipermeable membrane device (SPMD)