Effects of water accommodated fractions of crude oils and diesel on a suite of biomarkers in Atlantic cod (Gadus morhua)

Abstract

The aim of this study was to characterize concentration- and time-dependent responses in juvenile Atlantic cod (Gadus morhua) following exposure for one and three weeks to the water-soluble fraction (WAF) of three weathered oils: Arabian Light crude oil (ALC), North Sea crude oil (NSC) and ship-diesel. The sum of polycyclic aromatic hydrocarbons (PAH) in water was highest after one week of exposure and within environmentally relevant concentrations. PAH metabolites in bile confirmed exposure to and uptake of PAHs. Hepatic cytochrome P450 1A (CYP1A) gene expression (mRNA quantification) increased dramatically following exposure to all three oil types (fold-change up to 165) and there was a time lag between gene and protein expression. Hepatic CYP1A protein concentration and ethoxyresorufin-O-deethylase (EROD) activity were more variable among individuals and treatments than gene expression. EROD activity in liver and gills increased in fish exposed to WAF from the two crude oils, but not in fish exposed to WAF from diesel. Exposure to diesel appeared to induce oxidative stress to a greater extent than exposure to crude oils. Other biomarkers (glutathione S-transferases, acetylcholine esterase, vitellogenin) did not appear to respond to the exposure and hence did not discriminate among oils. Biomarker responses in cod after exposure to weathered crude oils and diesel suggested that the CYP1A system and oxidative stress markers have the highest potential for discriminating among different oil types and to monitor the environmental consequences of spills.

Effects of dietary crude oil exposure on molecular and physiological parameters related to lipid homeostasis in polar cod ( Boreogadus saida )

“…Dietary exposure to crude oil did not induce effects on the selected molecular endpoints related to vitellogenesis (vtg-β) and steroidogenesis (cyp19α1) in polar cod, which concurs with findings of other experimental studies on the effects of petroleum compounds in fish (Bilbao et al, 2010;Holth et al, 2014). The lack of effects might also be related to the low exposure levels used in the present experiment and to the fact that male and female individuals were differentially represented in each experimental group.…”

The effect of hydraulic flowback and produced water on gill morphology, oxidative stress and antioxidant response in rainbow trout (Oncorhynchus mykiss)

“…The oxidative stress tissue profiles observed here match tissue profiles in fish exposed to other oil-related contaminants (e.g. crude oil, diesel52). Importantly, these data also indicate that although salts alter antioxidant enzyme profiles, these effects do not appear to have consequences insofar as oxidative damage.…”

Diluted bitumen causes deformities and molecular responses indicative of oxidative stress in Japanese medaka embryos

“…Because production of cat, gpx, and gst can all be related to H 2 O 2 production and GSH content, elevated gsr synthesis in both WAF and CEWAF dilbit treatments suggested increased turnover and reduced availability of GSH compensating for oxidative stress, as noted in oil-exposed cod larvae (Olsvik et al, 2005). Although elevated levels of gst transcripts and protein activity in combination with similar changes in SOD, CAT, and GPx, are common in fish exposed to related products, such as oil sands process-affected water (OSPW) (He et al, 2012;Gagné et al, 2012), reduced GST activity has been also reported (Holth et al, 2014;Gagné et al, 2011), perhaps due to oxidative inactivation. In the present study, oxidative inactivation in CEWAFexposed medaka would be consistent with high concentrations of TPAH in exposure solutions, high exposure to PAH (also characterized by a strong cyp1a induction), and a high prevalence of BSD.…”