Museum specimens preserve traces of pollution from centuries ago

In a quiet corner of a museum, behind glass or inside drawers, sit creatures long departed from the wild. A bird collected from a soot-covered forest in the early 1900s. A fish caught from a river that no longer runs clear. These specimens, once seen mainly as records of biodiversity, are now being reinterpreted.

The specimens carry the fingerprint of the environments from which they came. This includes not just the climate and ecology but also the pollution, hidden in feathers, scales, bones and skin.

A recent study has highlighted this unexpected role. The researchers discovered that preserved plants and animals in natural history museums serve as powerful tools for understanding pollution over time.

These preserved organisms hold clues about environmental contamination, and offer a rare glimpse into ecosystems that existed more than two centuries ago.

Museum specimens and pollution data

We treat pollution as a modern issue. Smog, chemical waste and microplastics dominate headlines today. But the environmental degradation caused by industry and human expansion stretches back much further.

The problem is that monitoring systems did not exist in the past. That means we do not have continuous data on how pollution levels have changed or how they impacted communities.

“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, assistant professor of biology at UT Arlington and lead author of the study.

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

This historical gap limits our ability to connect environmental data with public health trends. Knowing when certain pollutants appeared or peaked could provide critical context for rising disease rates, childhood asthma or even regional disparities in birth outcomes.

That is why museum collections are so valuable. They allow researchers to go back in time using biology as a record-keeper.

A record of shifting pollution levels

Dr. DuBay and his team have shown that biological specimens contain more than DNA or taxonomy. These samples preserve traces of airborne and waterborne pollutants.

The researchers analyzed items such as feathers and fish tissues and discovered that they still carry metals and particulates from their original environments, even if they were collected more than 100 years ago.

Before the rise of environmental science, no one thought to measure mercury in fish or airborne lead in birds. But the creatures that lived through those times did absorb such substances. By studying the specimens now, scientists can reconstruct long-term pollution timelines.

One compelling case involved two field sparrow specimens from the U.S. Rust Belt. One was collected in 1906, the other in 1996.

The 1906 bird had visible black carbon deposits, the result of coal-based pollution. In contrast, the 1996 bird had clean feathers, showing how pollution levels had changed.

Patterns of chronic illness

DuBay and his colleagues believe these museum archives can do more than map trends. They can help link historical pollution exposure to human health outcomes.

If researchers compare pollution levels in specimens to local medical records, they might reveal patterns of chronic illness, cognitive issues or premature births that are tied to environmental exposures.

“We’ve always had gaps in historical pollution data,” said DuBay. “These specimens offer a new way to fill those gaps and better understand how pollutants persist in the environment.”

This line of inquiry adds depth to both environmental and medical studies. It could explain why certain communities experienced health disparities for decades. It could also expose how long certain pollutants linger in an ecosystem even after being banned or regulated.

Specimens for pollution analysis

Of course, turning a 19th-century bird or fish into a source of chemical data is not easy. These specimens were not originally collected for pollution analysis.

Many were part of projects that documented species distributions, or collected for museums and educational displays. This makes the data uneven. Some regions are well-represented, while others have few or no samples.

Also, the techniques required to detect trace pollutants in feathers, bones or scales can be highly advanced. Some even risk damaging the original specimen. That is a heavy cost when dealing with irreplaceable archives.

Scientists must strike a balance between extracting useful data and preserving the sample’s integrity.

Still, the field is advancing. Less invasive methods are being developed. And interdisciplinary teams are working together to share techniques, data and insights.

Specimens reveal pollution’s impacts

Despite these challenges, the authors of the study believe there is vast, untapped potential. Natural history museums can serve as long-term archives of human impact on the planet. They are no longer just about biodiversity. They are about environmental change.

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

In a way, these specimens offer a bridge between the past and present. They let us ask: What was in the air when this bird lived? What was present in this fish’s river? The answers could reshape how we view the legacy of industrialization, regulation and recovery.

As researchers continue unlocking the secrets of these long-preserved organisms, one thing becomes clear: the past still speaks. We just need to know where to listen.

Experts from the University of Michigan, University of Chicago, University of Wisconsin–Stevens Point, and Yale University also contributed to the research.

The study is published in the journal Proceedings of the National Academy of Sciences.

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