Due to the nature of the Cook Inlet within southcentral Alaska and natural oil seeps, oil spills from vessels, municipal and industrial permitted discharges, and recent oil and gas lease sales, there exists a need to further understand the chemical fate of spilled oil and its effects on biological life. To address this need, laboratory simulations of Cook Inlet crude oil spills were conducted using artificial seawater and sunlight. Hydrocarbon oxidation products (HOPs) and their biological effects were characterized using ultra high performance liquid chromatography (UPLC) with orbitrap high resolution mass spectrometry and the aryl hydrocarbon receptor (AhR) chemically activated luciferase gene expression (CALUX) assay. Non-target UPLC-Orbitrap mass spectrometry analysis identified the oxidized polycyclic hydrocarbons phenanthrene quinone, anthraquinone, hydroxyanthraquinone, and 9-fluoreneone, along with 251 other HOPs that were in greater abundance in light exposed samples. These HOPs primarily contained one to three aromatic rings and one to three oxygen, consistent with photo-products of alkylated two to four ring polycyclic aromatic hydrocarbons (PAHs). The complex HOP mixture formed during photochemical weathering of Cook Inlet crude oil induced greater AhR activity than parent petroleum products solubilized in dark controls. These results show that a non-targeted analytical approach provides a comprehensive analysis of HOPs that highlights the complexity of the mixture and the limitations of targeted analyses for adequately monitoring HOPs in the environment. Furthermore, coupled AhR CALUX bioassays indicate that HOPs may pose a greater ecological risk than parent petroleum compounds.

USD: $133,673

2021-09-02 → 2023-12-31