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A new study highlights a surprising lens for tracking pollution trends over centuries: preserved plants and animals housed at natural history museums around the world. According to Shane DuBay, a researcher at The University of Texas at Arlington, these specimens contain valuable environmental data that can help scientists reconstruct pollution trends spanning more than 200 years.

"We often lack the historical pollution data needed to understand the links between environmental contamination and long-term health effects, such as cancer, asthma, cognitive disorders and premature birth," said Dr. DuBay, an assistant professor of biology at UT Arlington and lead author of the study in the Proceedings of the National Academy of Sciences.

"By leveraging museum specimens, we can reconstruct environmental conditions from over a century ago and assess how pollution has impacted different communities."

The study suggests that museum collections serve as environmental archives, preserving traces of pollutants from the time and place where the organisms lived. By examining bird feathers, fish tissues and other biological materials, researchers can detect metals, airborne particulates and other pollutants from long before formal environmental monitoring systems existed.

One striking example from the study compares two field sparrow specimens collected 90 years apart, 1906 and 1996, in the U.S. Manufacturing Belt—also known as the Rust Belt—a region with historically heavy industrial activity. The 1906 specimen was coated in black carbon particulate from coal burning, while the 1996 sparrow showed no such deposits. This visible difference shows how pollution levels can shift over time.

In addition to tracking pollution trends, historical contamination data may also contribute to better understanding the long-term environmental effects on human health. By comparing pollutant levels found in preserved specimens to medical and demographic records, scientists can gain insights into exposure risks across different time periods and locations.

"We've always had gaps in historical pollution data," said DuBay, whose co-authors include researchers from the University of Michigan, University of Chicago, University of Wisconsin–Stevens Point and Yale University. "These specimens offer a new way to fill those gaps and better understand how pollutants persist in the environment."

While these specimens open new avenues for environmental research, challenges remain. Natural history specimens were often collected for various purposes, which means they don't always provide consistent geographic coverage. Additionally, measuring pollution in these specimens can require advanced techniques, some of which may be destructive to the samples.

Despite these hurdles, the authors emphasize that museum collections hold untapped potential for environmental studies. Expanding research efforts and fostering interdisciplinary collaborations could yield valuable insights into pollution's historical footprint—and its long-term effects on ecosystems and human health.

"This study underscores the importance of natural history collections—not just for understanding biodiversity, but for examining environmental changes over time," added DuBay. "By studying these specimens, we can improve our understanding of pollution trends and their broader impacts."