Collaborative Research: Identification and Characterization of Petrogenic Compounds that Persist in Aquatic Environments

Crude oil and petroleum spills contaminate soil, surface water, and groundwater. Crude oil is made up of many different molecules, and when oil is released into the environment, microbes in the soil and water degrade and change the structure of these molecules. These biologically transformed oil molecules are collectively called “oxygen-containing organic compounds” (OCOCs).

Although OCOCs are not yet regulated in the USA, these compounds are of emerging concern because they are known to harm human and ecological health. The goal of this project is to determine how OCOCs form from crude oil spills in the environment and how this process affects their persistence in contaminated groundwater. To achieve this goal, microbial degradation experiments will be conducted to evaluate OCOC formation and breakdown with different crude oil types under various environmental conditions.

Data gathered from experiments and from a historic oil spill site will be used to build a reactive transport model that predicts the environmental persistence and behavior of OCOCs in oil-contaminated groundwater plumes. This work benefits society by providing stakeholders with information needed to assess the human and ecological health risk of OCOCs at contaminated sites.

Training of early career investigators and graduate and undergraduate students will increase scientific literacy and enhance workforce development.

Petroleum-contaminated groundwater contains a mixture of natural dissolved organic matter (DOM), dissolved petroleum hydrocarbons, and OCOCs in the form of polar metabolites or hydrocarbon oxidation products. The OCOCs are contaminants of emerging concern because they harm aquatic flora and fauna but are not well characterized by traditional analytical methods.

The overarching goal of this project is to link OCOCs to their petroleum source, and to assess intrinsic and extrinsic controls on their environmental persistence. This work combines experimental and field-collected data to constrain a reactive transport model for simulating the natural attenuation and distribution of OCOCs. Petroleum-contaminated groundwater will be collected along a plume transect from a historic oil spill to recover microbial communities for experiments and inform modeling efforts.

Specific objectives include: i) determining the chemical variability of OCOCs among parent oil types and between anaerobic and aerobic biodegradation conditions, ii) evaluating whether biological “priming” of native DOM alters the OCOC molecular signatures, and iii) predicting the environmental persistence of OCOCs in an oil-contaminated aquifer. Microbial degradation of specific OCOC molecular signatures will be assessed using ultrahigh resolution mass spectrometry, Fourier-transform infrared spectroscopy, and optical proxies.

Successful completion of this research will provide information necessary for stakeholders to address and mitigate the human and ecological health risks associated with OCOCs.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.