For the first time, microplastics have surfaced in historic soil samples, a discovery that’s shaking up traditional preservation methods of archaeological finds.
A University of York-led team, in the United Kingdom, uncovered microplastics buried over seven meters (23 feet) deep, in layers dating back to the first or second century CE. These were initially dug up in the ’80s, the researchers noted last Friday.
The research pinpointed 16 different microplastic types within both modern and decades-old soil samples, the team detailed.
Microplastics, tiny fragments no bigger than five millimeters (about a sesame seed’s size), are born when big plastics degrade or wear down. They’ve been a hot topic recently, especially since their usage in beauty products was common until circa 2020, the study’s authors mention.
The environmental and human health impacts of microplastics are well-known concerns. Yet, this study hints they might also revolutionize archaeology.
The recent trend of preserving archaeological sites as they are could be challenged, as microplastic pollution might taint the scientific worth of these relics.
“We’re facing a crucial point—it’s clear now, microplastics are in what we assumed were untouched archaeological layers, including those archived back in the late ’80s,” Professor John Schofield, from University of York’s archaeology department, said.
“We’ve seen plastics polluting our oceans and rivers. Now, they’re invading our historical legacy, adding toxic substances. We’re keen to understand how this affects the evidence’s integrity and its national significance,” he added.
David Jennings, York Archaeology’s CEO, expressed why microplastic pollution is troubling.
“Our most intact relics—like York’s Viking relics at Coppergate—stayed undisturbed in a wet, oxygen-free setting for millennia, which preserved them remarkably,” he stated.
“Microplastics, though, can alter the soil’s chemistry, potentially bringing in elements that make the organic materials decay. If true, in situ preservation might not be the best route forward.”
The findings appear in the journal Science of the Total Environment.
