How toxic are the oils left over from the 2010 Deepwater Horizon oil spill?
By: Amanda Herzog, REU intern
My name is Amanda Herzog and this summer I am working in Dr. Christoph Aeppli’s lab at the Bigelow Laboratory for Ocean Sciences. My experience in this ten-week summer undergraduate research program is made possible through the National Science Foundation and the Gulf of Mexico Research Initiative. My project focuses on the composition and toxicity of oil samples collected at different time points following the 2010 Deepwater Horizon oil spill. As the second largest marine spill in US history, the spill started on April 20, 2010, lasted for 87 days, and released nearly 5 million barrels of oil from the Macondo Well into the Gulf of Mexico. This had large effects on wildlife, fisheries, and marine habitats, many of which scientists are still trying to better understand. In my lab this summer we are interested in seeing how the toxicity of oil changes as oil “weathers” in the environment. We do this by comparing oil samples that we collected at various time points following the spill. Our most recent samples are oil soaked sands (“sand patties”), which we collected just a few weeks ago on Alabama beaches. Walking along these beaches I quickly realized that there is still plenty of oil still present, but the question is: is it something we should be concerned about?
My mentor, Christoph Aeppli, his lab technician, Sam Katz and I took a two-day trip at the end of June to the beaches of Florida and Alabama to collect recent oil samples. We visited three different beaches in search of sand patties (pictured below), which range in size from a few millimeters to a few centimeters long. These sand patties contain roughly 90% sand and 10% oil. If you’re not consciously looking for them they may just look like rocks, but once you pick them up you can see that they are embedded with sand, can easily be broken, they feel sticky and smell faintly of oil.
Our first two stops were at Perdido Key Beaches in Pensacola, Florida. These locations were fairly populated with people enjoying the beautiful beaches. We spent about two hours at this location but found no sand patties at all. As we walked along the beaches searching in the sand and the surf in bright purple gloves, lugging a bag full of mason jars behind us, many beach goers were curious as to what we were up to and were very interested in talking to us. Some locals were aware of the sand patties while other people we talked to were surprised that six years after this spill, oil is still present and washing up on beaches.
Continuing our road trip and crossing into Alabama, we stopped at a beach in Gulf Shores. There, we found our first sand patty lying right on the beach! Our luck didn’t last too long on this beach however as we did not continue to find many sand patties in the few hours we spent there.
Fort Morgan Beach in Alabama was our third and most successful stop. This beach was far less populated with people compared to the other two beaches, which may have helped our search for samples. It was sort of like a treasure hunt as we found plenty of sand patties by walking along the beach above and at the tide line, as well as in the surf. What I found particularly interesting was that on this beautiful beach, home to many types of wildlife, there are more than 4,000 oil platforms out in the Gulf of Mexico, and at this beach you could see about a dozen massive oil rigs in the distance.
After two days of walking over ten miles on the beach in 90-degree weather we were ready to return to the mild temperatures of Maine. Overall it was a very successful trip, we came back with lots of samples as well as sunburns! Now back at the lab, we will extract out the oil from the sand patties. We then analyze the chemical composition of the sand patties and measure their toxicity using different bioassays to determine whether weathered oil is a concern in the environment.
About the Blogger:
Amanda Herzog is a rising senior at Wheaton College in Norton, Massachusetts, and is from South Salem, New York. Amanda is an environmental science major concentrating in chemistry with a minor in dance. She hopes to pursue a career in environmental chemistry.