Toxicity of Photoproducts from Complex Organic Compounds on Early Life Stage Fish

FY 2023 | 1 – Understand | 23-10-11

Toxicity of Photoproducts from Complex Organic Compounds on Early Life Stage Fish

David Podgorski, University of New Orleans
Contract Term: 09/01/23 - 09/30/24
Award: $

Potentially toxic dissolved hydrocarbon oxidation products (HOPs) are of emerging concern
because they are understudied and unregulated. Results obtained by Harsha during his OSRI
Graduate Fellowship indicate that photochemically-derived HOPs in the absence of polycyclic
aromatic hydrocarbons (PAHs) are toxic to early life-stage Pacific herring at environmentally
relevant concentrations. This result is significant because it disproves the common perception that
PAHs are the sole driver of toxicity. However, HOPs are still a complex mixture, and we have no
way of determining which photoproducts are toxic. The goal work proposed in this study is to
obtain a fundamental understanding of the relationship between the chemical structure of
compounds in the unresolved complex (i.e., photoproduct formation) and their associated toxicity.
This work is made possible through a collaboration with colleagues at the University of Alberta
that synthesize mode “asphaltene” compounds (i.e., compounds in the unresolved complex
mixture) that are unavailable commercially. We will study the chemical composition of photo
products formed from model compounds with different fundamental starting structures and their
resulting toxicity. The information obtained from this study is a building block toward determining
the risk connected to the spill of different petroleum products and developing robust analytical
methods that can be used to quantify toxic HOPs for regulatory purposes.