Less than a decade ago, water bottles contained a compound called BPA. When studies linked the compound to a number of behavioral and health problems, including ADHD, schizophrenia, obesity and diabetes, it was banned from human use in infant formula packaging, sippy cups, baby bottles and other plastic products.
In response to the danger, manufacturers began to use a similar compound called BPS. Water bottle labels carried the assurance that they were "BPA-Free." But despite the ban on BPA in water bottles and many other products, it is still used in some consumer products, such as receipt paper and canned foods.
Caroline Naso '16 and Judith Rosales Rivas '17 study the effects of BPA on tadpole brains with Professor of Biology Barbara Lom. Their work continued research initiated by Megan Garzón '14, who examined the effects of BPA on the region of the brain that synthesizes dopamine.
Garzón discovered that the region was smaller in tadpoles exposed to BPA than those that were not. Garzón's thesis about her work received the Johnston Thesis Award through the Center for Interdisciplinary Studies.
Naso and Rosales Rivas are investigating other possible effects of BPA and BPS on tadpoles.
Naso received a Davidson Research Initiative grant for summer 2015 to study BPA and estradiol, an estrogen hormone, as her senior biology thesis.
"BPA and estrogen are really similar. BPA kind of acts as an estrogen mimic," Naso said. "I was interested in how the two compounds affect a specific group of neurons in tadpole brains–neurons that use dopamine as their neurotransmitter."
The long hours Naso spends on her research sometimes lead to dead ends, but she insists that problem solving is part of the fun.
"I'm very interested in the science, and the enjoyable aspect of it is coming up with ideas that work," she said.
Rosales Rivas also worked with tadpoles and BPA in the Lom lab, but she compared the effects of BPA to BPS on the neurons that create dopamine.
"Manufacturers are not using BPA as a plasticizer any more, but some are using BPS," she said. "The problem is that very recent studies have demonstrated that BPS is sometimes as bad as, or worse than, BPA. We need to study these two together to come up with a healthier way to make plastics."
Rosales Rivas's also presented her independent study project as a neuroscience thesis. Her work examines two questions: First, do BPS and BPA actually affect dopamine neurons? Second, are these effects reversible?
Rosales Rivas exposed the tadpoles to different concentrations of BPA and BPS, and then examined dopamine-producing regions of their brains. She then exposed them to BPA and BPS, and returned them to a neutral solution before analyzing their brains.
The research is ongoing, and Rosales Rivas aims to learn as much as she can from her faculty mentor as the project evolves.
"She [Prof. Lom] is committed to reaching out to you wherever you are, and helping you advance from there," she said.
Rosales Rivas has also enjoyed conducting original research.
"I am the only one continuing this project," she said. "So it is a lot of responsibility, but really exciting."
Naso hopes to attend medical school, and Rosales Rivas aspires to be a neurologist's physician's assistant.