Summer 2015 – GoMRI Researcher Interview with Dr. Darrell Sparks
– August 26, 2015
(From Summer 2015 Newsletter) Dr. Darrell Sparks from Mississippi State University answered a few questions about his RFP-II project, Characterizing the Composition and Biogeochemical Behavior of Dispersants and Their Transformation Products in Gulf of Mexico Coastal Ecosystems.
1. Thank you so much for talking with us! Tell us a bit about your research. What are the goals of your project?
My project focuses on the fate of the dispersant (Corexit) used in the cleanup efforts of the Deepwater Horizon oil spill. I am working in collaboration with Duke University and Stony Brook University. We are investigating the toxicity, sorption behavior, and metabolism chemistry of the dispersant.
2. What are you learning about the fate of the dispersant? What methods are you using to carry out this research?
One of the studies we have completed is a biodegradability study of Corexit 9500 in seawater. This study revealed that some of the components of the dispersant degrade quite rapidly (within days), while other components (such as DOSS) are more persistent. In our projects, we use a variety of analytical techniques. For example, we have used comet and EROD assays for toxicity studies and high performance liquid chromatography with tandem mass spectrometry for dispersant characterization and detection.
3. What are some of the most significant or exciting findings so far in your work?
We have been screening seafood collected from the Gulf of Mexico for DOSS (a major component of Corexit) as well as its metabolites. It has been interesting to see what types of seafood seem to be more prevalent at containing these compounds.
4. What types of seafood have you been focusing on? What types seem to be impacted the most? The least?
We have tested fish, oysters, crab, and shrimp. Oysters and fish test positive* (in the part-per-billion range) for DOSS more often than crab and shrimp. However, one of the metabolites of DOSS has been found in crab.
5. What is your background and how did you get involved in this kind of work?
My background is in Chemical Engineering and I am an Assistant Professor in the Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology at Mississippi State University. I also have an appointment with the Mississippi State Chemical Laboratory, which was involved in testing seafood immediately after the oil spill to determine safety for human consumption.
6. Can you tell us more about your collaborations with your fellow GoMRI researchers from Duke University and Stony Brook University?
The collaboration includes Drs. Anne McElroy and Bruce Brownawell of Stony Brook and Dr. Lee Ferguson of Duke University. Each member of our collaboration has a different focus area while maintaining the overall objective of better understanding the fate of dispersants. Dr. McElroy’s emphasis is on toxicity, while Dr. Brownawell studies the sorption of dispersant components in sediments. Dr. Ferguson’s group at Duke has made great progress in being able to better characterize dispersant components, and my area focuses detecting dispersants in seafood. Without a doubt, it has been a team effort.
6. If funding were not an issue, what would you add to your project?
We would add more metabolites to our study as well as expand the scope of our toxicity studies.