Environmental induction of CYP1A-, CYP2M1- and CYP2K1-like proteins in tropical fish species by produced formation water on the northwest shelf of Australia

Normal operation of oil well platforms results in the discharge of “produced formation water” (PFW). The expression of CYP1A, CYP2M1- and 2K1-like proteins was examined for use as possible biomarkers of PFW exposure. A pilot study at the Harriet A production platform, on the Northwest Shelf of Australia, had indicated that PFW contamination possibly contributes to induction of CYP1A- and 2K1/2M1-like proteins in Gold-Spotted Trevally (Carangoides fulvoguttatus). In a subsequent caged fish study in the same location, Stripey seaperch (Lutjanus carponotatus) were caught at a clean site, then distributed to three caging sites: A (near-field), B (far-field) and C (a non-impacted reference site). Fish were sampled at time T = 0, 3 and 10 days. Significant increases of CYP1A, one CYP2K1- and two CYP2M1-like proteins were noted at Site A at T = 10. For another CYP2K1-like protein, a significant increase was observed at Site A only at T = 3. Prevailing winds changed between days 6 and 8 of sampling, moving the surface water plume directly west, possibly impacting in situ PFW exposure. The results indicate that tropical fish CYP1A protein is sensitive to PFW exposure. Importantly, statistically significant environmental induction of both CYP2M1- and CYP2K1-like proteins in tropical fish due to PFW exposure had not previously been described and CYP2 family induction may represent possible new biomarkers (other than CYP1A) of PFW exposure. In addition, the novel fraction-specific response of CYP2K-like proteins requires further verification but offers promise for improved monitoring of sub-lethal responses in marine organisms. (Supported by Australian Institute of Marine Science, Apache Energy Ltd. and the Environmental Toxicology Research Program at The University of Mississippi).