As part of a National Science Foundation (NSF) internship, Jessica Jarratt is spending 10 weeks this summer sifting through sludge, or biosolids, the outgoing byproduct from the water purification process of wastewater treatment plants.
The freeze-dried thermally processed sludge is a cleaned-up version and not as, well, gross as some might imagine. And while it's not everyone's version of a dream experience, Jarratt, a rising senior at the University of Miami with a double major in marine science and chemistry, is excited to be researching in an area that fascinates her—the toxicity of microplastics in terrestrial environments.
Jarratt was selected for a Research Experiences for Undergraduate (REU) offered by the NSF and so joined a group of 10 or so undergraduates from colleges around the country this summer at the Virginia Institute of Marine Science (VIMS), the William & Mary graduate school for marine science located close to historic Yorktown. The NSF REU provides interns with a stipend, housing, and traveling expenses for the summer.
"There is significant research within marine environments, but a lack of knowledge of the microplastics in terrestrial environments," Jarratt explained. "By modifying similar methods from previous studies and applying it to biosolids, we're able to explore the health implications of biosolids when they are used as fertilizer and directly exposed to the food we consume."
The wastewater solid residue has a high concentration of nitrogen and phosphorous, some of the most important ingredients in fertilizer.
"So many people think, 'Oh, it's fertilizer, great,' but the reality is that there are other components of biosolids that are harmful to us. Considering that people are having plastics in all parts of their body, it's likely contributing to how we're being exposed to it."
For the REU, each student pursues a specific research project and is matched with faculty and other researchers who specialize on the topic.
As part of her major at the Rosenstiel School of Marine, Atmospheric, and Earth Science, Jarratt studies with associate professor Ali Pourmand, researching in his Neptune Isotope Laboratory. That isotope geochemistry research is close to, though not exactly, the area of emerging contaminants she's most drawn to explore.
At an internship last year with the Environmental Protection Agency (EPA) in Washington, D.C., Jarratt focused on environmental policy and generated a list of scientists who conduct the research she's most interested in. From that list, she contacted Robert C. Hale, who's done significant research on microplastics and organic pollutants.
"We had a lot of similar interests and it's exciting to find someone that does the research that I would be interested in conducting in graduate school," Jarratt said. "I'm more interested in the contaminant side of the wastewater, and he convinced me that I could explore different areas of microplastics research, not just on marine environments."
Hale told her about the REU opportunity at VIMS where he's based. Now she's benefiting from his direct mentorship.
"I'm really excited to be working under him. This is part of a larger EPA project, and I'm working on one of its subprojects, trying to find the best way to purify this really organic rich matrix and isolate the microplastics," she said.
Jarratt's interest in marine pollutants sparked in high school when she was assigned a history class project to analyze random contaminants in the Great Pacific Garbage Patch.
"I was fascinated, but never imagined that people made a career out of it, that it's very niche and random," she recalled. "I was always really interested in chemistry, so I came to Miami undeclared, then saw we could pursue marine science dual degrees through Rosenstiel. That ended up being the perfect combination for me because I now have the analytical chemistry skillset and understand the applications to marine environments."
Jarratt arrived in late May and will intern until early August. She's enjoying the camaraderie with other students, staying in the dorms during the week and is close to where she grew up in northern Virginia. She's benefited both academically and careerwise from her mentorship with Hale, and likewise from the science writing and resume writing seminars as part of the internship. While most of her time is spent in the lab, she's enjoyed the group field trips to the college's Eastern Shore Laboratory and will soon be voyaging on VIMS' research vessel similar to the University's F. G. Walton Smith.
Her final presentation research plan on "Purification Techniques for Improving the Determination and Characterization of Microplastics in Complex Wastewater Solids" will be submitted to the NSF and ideally developed into a more official paper.
Wastewater treatment plants purify water so it is drinkable and useable again but, in doing so, produce sludge that has a slew of microplastics in it, Jarratt explained.
"Our main objective is to introduce individual reagents such as enzyme cellulase or hydrogen peroxide to see which work best to degrade the plastics and then combine these steps to make our optimized protocol," she said. She plans to apply this procedure to other samples to tests its effectiveness without degrading the plastics.
"If microplastics remain in the sludge that is then applied to farms and soil, we are essentially reintroducing the plastics to the environment that eventually end up back in the oceans through runoff. It can be a very cyclical process," she said.
Jarratt plans to apply her experience and learning this summer to her honors thesis research at the University and to graduate in the spring of 2025. She'll participate in field work after graduation while she decides where to attend graduate school.
