Detection & Toxicity of Hydrocarbon Oxidation

FY 2022 | 3 – Inform | 22-10-09

Detection & Toxicity of Hydrocarbon Oxidation

GRF Harsha, University of New Orleans
Contract Term: 04/01/22 - 03/31/24
Award: $30,000

The goal of this project is to study the formation and toxicity of the petroleum-derived
dissolved compounds, known as hydrocarbon oxidation products, that are formed through the
photodegradation of spilled crude oil, marine diesel, and heating oil in Cook Inlet. This
research is crucial due to the relevance and risks associated with the oil and gas industry in
Alaska. Specifically, Cook Inlet is of particular interest due to its diverse ecosystem,
populous areas, commercial fishing, tourism and new lease sales for petroleum production. A
potential oil spill event in Cook Inlet could have devasting effects. In order to study the
effects of an oil spill, it is essential to understand the contaminate in question: oil. The
chemical composition of oil is incredibly diverse and complex, containing tens-hundreds of
thousands of organic compounds, making the detection and effects of an oil spill extremely
challenging. Spilled oil in aquatic environments can undergo and oxidative photodegradation
from solar radiation, forming hydrocarbon oxidation products (HOPs). HOPs are ubiquitous
in aquatic environments due their increased solubility in water that allow them to diffuse
vastly and greatly. Detection of HOPs is extremely difficult with conventional analytical
techniques such as gas chromatography and liquid chromatography due to HOPs residing in
an unresolved complex mixture. Ultrahigh-resolution mass spectrometry and fluorescence
excitation-emission matrix spectroscopy can be used in tandem to characterize HOPs through
molecular-level composition and optical properties. Studying the effects of HOPs is crucial
due to the possibility of photo-enhanced toxicity of oil. The toxicity of HOPs can be studied
with exposure studies to early life stage Pacific herring (Clupea pallasii) embryos. Pacific
herring are a species of interest in Cook Inlet due to their ability to be commercially fished.
Further understanding of toxicity can be understood by using a biochemical assay measure 7-
ethoxy-resorufin-O-deethylase activity.
The formation of HOPs in Cook Inlet through the photodegradation of spilled oil can be
studied through laboratory simulations of spilled oil with Cook Inlet environmental
conditions. Ultrahigh-resolution mass spectrometry and fluoresce excitation-emission matrix
spectroscopy can be employed to characterize the HOPs formed in the laboratory
simulations. Finally, the HOPs formed in laboratory simulations can be used to expose
Pacific herring embryos and analyzed by 7-ethoxy-resorufin-O-deethylase activity assay. The
toxicity tests can uncover important toxicological endpoints of HOPs.
This project aligns with OSRI’s mission of supporting research, education, and projects
that improve understanding and response to oil spills in Arctic and Subarctic environments.
This study will address a knowledge gap that persists, HOPs, that can be used to understand
and respond to oil spills more effectively. OSRI’s goal area of understand is aligned with this
project that is studying degradation and toxicity, which are focus areas of OSRI. The second
goal area, respond, aligns with health and safety risks and detection of HOPs that can be
utilized in response efforts. Inform connects to the proposed project because the key findings
of the study will be submitted to a peer-reviewed journal and presented at conferences.
Finally, partner is utilized in this project that includes heavy collaborative aspects and
possibility of future projects with OSRI and the Prince William Sound Regional Citizens’
Advisory Council. The proposed project greatly aligns and connects with the mission
statement and research areas set forth by OSRI.