Toxicity screening of crude-oil fractions using luciferase-based reporter gene assays for Atlantic cod ( Gadus morhua) receptors.

Crude oil and its water accommodated fraction (WAF) are complex mixtures where toxicity mainly has been associated with polycyclic aromatic hydrocarbons (PAHs). However less is known regarding the toxicity of the other constituents of crude oil. This study investigates the toxicity pathways of specific chemical fractions of WAF using a library of reporter gene assays developed for Atlantic cod receptors. Five different fractions were assessed (saturates, monoaromatic hydrocarbons, naphthalene, polycyclic aromatic hydrocarbons, and resins), as well as the complete WAF extract. Reporter gene assays with receptors linked to detoxification pathways (aryl hydrocarbon receptor, pregnane X receptor), energy metabolism (peroxisome proliferator-activated receptor), and reproduction (estrogen receptor) were used. Ultimately, this in vitro approach will help identify toxicity mechanisms of chemical components of crude-oil, which may be linked to adverse outcomes such as reproductive success, fitness, and survival.