We all know to avoid touching or eating oil (the fossil fuel variety that is). But after a coastal oil spill, avoiding oil can be difficult if you live near the sea or rely on it for protein or your livelihood. Some seafood-eaters may ingest oil by mistake, and cleanup workers will inhale and touch it. In those cases, what harm can small amounts of oil do? There isn’t a straightforward answer to this question because scientists don’t know for sure. Once inside a person's cells, oil molecules may affect gene expression—the process by which DNA is copied to regulate the creation of proteins in the body. It could interfere with how cells communicate with one another, how the immune system reacts to invaders, or how cells develop and change.
Alexis Temkin is one of the scientists investigating this question. She is a PhD student at the Medical University of South Carolina, where she looks at how chemicals, like those released into the Gulf of Mexico during the Deepwater Horizon oil spill, can have an impact on human health. Working in the field of marine biomedicine is a perfect blend of her interests in marine biology and medicine.
How did you become interested in this research?
I’ve always been a science person and, when I was little, I could often be found exploring the beach and any organisms I discovered there. I went to Connecticut College for my undergrad and majored in biology there. They have classes for molecular biology and marine science, and I had trouble choosing between the two. I ended up studying abroad in Australia, and that was the first time I’d heard of marine biomedicine, specifically marine natural products and how they can be used as different drugs.
After college, while working in an epigenetics lab (where they study how non-genetic factors influence gene expression) at Columbia University, I became interested in how the environment can affect human health. In graduate school, I wanted to bring my two interests together. The Medical University of South Carolina has a marine biomedicine and environmental sciences program, which was perfect for me. They did exactly the research I wanted to do, looking at the molecular effects of environmental contaminants in a variety of organisms (humans, alligators, dolphins, etc.) and how they may impact disease development.
What chemicals are you studying that can impact human health?
Broadly, we study endocrine disruptors, a class of chemicals that interferes with the body's hormone systems by mimicking or blocking normal hormones. Specifically, we’re interested in a type of endocrine disruptor known as obesogens, which can impact the development of obesity. We are trying to identify obesogens and other endocrine disruptors in oil and dispersants (like Corexit) to better understand the impacts of oil spills on human health. Other researchers in our group at the Medical University of South Carolina are also looking at other endocrine disruptors found in consumer products, such as the common plastic additives BPA and phthalates.
What links are you exploring between the Deepwater Horizon oil spill and human health? How do you see the impact?
We're interested in how oil-spill related chemicals or compounds—like a specific oil molecule or DOSS (dioctyl sodium sulfosuccinate), a main component in the dispersant Corexit—can trigger or interrupt normal processes inside human cells. People have many types of cells that serve specialized functions—brain cells, heart cells, eggs, sperm, to name a few—all of which develop from the same basic stem cells. I am studying how stem cells develop into different types of cells, specifically fat cells, and how exposure to chemicals can alter this process. Even small changes in how frequently or how well these cellular processes work could mean big changes for bodily functions and health.
We do our work on a variety of cultured human cells, exposing them to chemical mixtures or isolated molecules in the lab. We do a type of experiment where you expose cells to the chemicals or compounds we’re interested in and determine if they affect cellular processes like fat development or estrogen signaling. Because cellular processes are microscopic and complex, we engineered the cells to produce light if a chemical induces any changes in the cell. We can then measure and quantify the amount of light produced by these cells. It’s a fast way to see if the chemicals cause an effect we’re interested in. Then we follow up on those chemicals in more detailed and complex experiments to figure out what changes they made and what the broader health impacts might be.
From these experiments, we identified DOSS as a molecule that can influence fat development and increase the production of fat cells in culture. DOSS is widely known for its toxic effects on cells and organisms, but this is a totally different response that we weren’t really expecting—making it extremely exciting!
How can oil from a deep-water spill come to interact with humans?
The two biggest populations that could come in contact with oil or dispersant are high seafood consumers and oil spill cleanup workers. It might be very specific populations that we need to be concerned with, especially in terms of DOSS exposure.
With something like DOSS (and other chemicals), chronic low-dose exposure may have more of an impact than a single large exposure. There is a certain class of compounds called persistent organic pollutants that can build up and stay in your system. DOSS is not one of those; it’s metabolized and excreted relatively rapidly. The hypothesis behind compounds like DOSS is that, if you are exposed to it again and again, it remains in your system long enough to elicit an effect. However we don’t yet know the actual concentrations required to have an effect.
How can results from this project be used to protect human health?
First off, DOSS is not only used in dispersants but also found in other consumer products. So our research addresses the question of other routes of exposure beyond oil spills. DOSS is commonly used as a laxative (Colace, docusate) and often prescribed to pregnant women, so we are studying this exposed population. This kind of research is really interesting because it can shed light on other ways that human health may be affected.
Secondly, some scientists are trying to develop safer dispersants. We worked with these researchers and tested one of their new dispersant mixtures that doesn’t contain DOSS, and saw no biological activity in our experiments. In this way, our work can help develop safer dispersants that don't have these endocrine-disrupting effects that we were potentially seeing with DOSS. Similarly, identifying endocrine disruptors that are found in oil or dispersant and in other consumer products can help people avoid those items. There are a lot of really good consumer databases out there that contain information for the public.
Editor’s note: The research mentioned here related to oil and dispersant impacts is funded by the Gulf of Mexico Research Initiative.The Ocean Portal receives support from the Gulf of Mexico Research Initiative (GoMRI) to develop and share stories about GoMRI and oil spill science. GoMRI is a 10-year independent research program established to study the effect, and the potential associated impact, of hydrocarbon releases on the environment and public health, as well as to develop improved spill mitigation, oil detection, characterization and remediation technologies. For more information, visit http://gulfresearchinitiative.org/.