Emily Crawford’s findings could reframe how we think about the downstream effects of prescription drugs.
By Dave DeFusco, College of Arts and Sciences
Every day, millions of Americans rely on antidepressant medications to stabilize their moods and reclaim their lives. Up to 90% of the chemical remnants of these drugs — still biologically active — pass quietly through wastewater treatment systems and into rivers, lakes and streams.
What impact do these antidepressants have on these environments and the species that live there? That’s the provocative question that spurred the research being done by chemistry doctoral student Emily Crawford.
Crawford is pioneering a multidimensional approach to quantify antidepressants in North Carolina’s waterways and evaluate their molecular impacts on aquatic life. The project received a National Science Foundation’s Graduate Research Fellowship Program honorable mention.
“We know these drugs are essential for mental health,” she said. “But they’re also active in trace amounts, and our wastewater systems weren’t designed to catch them. So they persist in the environment — and fish and other aquatic species are exposed constantly.”
Widely prescribed antidepressants like sertraline and escitalopram have already been linked to behavioral and reproductive disruptions in aquatic organisms. But until now, little has been known about how these exposures might affect organisms at a molecular level.
That’s where Crawford’s research breaks new ground. After graduating from Georgia Tech with a 4.0 GPA and a string of scholarships —including the Zell Miller and Women in Sciences Grant — Crawford joined the lab of analytical chemist Erin Baker, associate professor in the UNC College of Arts and Science’s chemistry department.
Baker’s lab has built a strong reputation for studying so-called “forever chemicals” like PFAS. Crawford saw an opportunity to apply the lab’s sophisticated tools to something new: pharmaceuticals in the environment.
“I was really interested in how human behaviors interact with our environment and vice versa,” she said. “We realized that no one had ever used our specific platform to analyze antidepressants. That opened the door.”
Before Crawford could analyze anything in the wild, she had to build a reference library from the ground up — a meticulous and time-consuming process that catalogued the key properties of 55 different antidepressant compounds and their metabolites.
“It had never been done before on this platform,” she said. “These drugs are designed to break down in the body, and sometimes they were fragmenting in the instrument even when we didn’t want them to. It took a lot of optimization to keep them intact.”
She had another problem too: uncertainty. Would the pharmaceutical-grade standards she purchased from chemical suppliers be chemically identical to the forms showing up in real-world water samples? What about unknown degradation products?