Scientists have discovered that microscopic plastic particles can travel from soil into the edible parts of crops, marking the first time researchers have proven nanoplastics can contaminate our food supply at the source.
The University of Plymouth study used radishes to demonstrate that nanoplastics – some measuring just one millionth of a centimeter – can penetrate plant roots and accumulate in parts we consume. After five days of exposure, nearly 5% of plastic particles in the growing solution had been absorbed by the root systems, with about a quarter of those particles making their way into the edible portions.
“This is the first time a study has demonstrated nanoplastic particles could get beyond that barrier, with the potential for them to accumulate within plants and be passed on to anything that consumes them.”
The finding challenges what scientists thought they knew about how plants protect themselves from contamination. Plants have a natural filter called the Casparian strip within their roots, designed to block harmful particles from entering. Yet the study shows nanoplastics can breach this defense system.
A New Route to Human Exposure
The research team, led by Dr. Nathaniel Clark, placed radish plants in a hydroponic system where only the thin root fibers contacted a solution containing radioactively-tagged polystyrene nanoparticles. This careful setup ensured any particles found in the fleshy radish bulb or leaves had traveled through the plant’s internal systems rather than simply sticking to surfaces.
Results showed a clear distribution pattern: the highest concentrations remained in the root system, but significant amounts migrated upward. About 25% of accumulated particles reached the edible radish bulb, while 10% traveled all the way to the leaves.
The implications extend far beyond radishes. Professor Richard Thompson, who heads the university’s International Marine Litter Research Unit, noted the universal nature of the discovery.
“This work forms part of our growing understanding on accumulation, and the potentially harmful effects of micro- and nanoparticles on human health.”
From Lab Bench to Dinner Table
While the study used higher concentrations than typically found in the environment – necessary for detecting such tiny particles – the proof-of-principle demonstration raises concerns about widespread crop contamination. The researchers chose polystyrene because it ranks among the most common synthetic polymers detected in agricultural soils, stemming from packaging, insulation, and fishing gear that breaks down over time.
The five-day timeframe suggests contamination can occur relatively quickly. In commercial growing operations, crops often remain in the ground for weeks or months, potentially allowing greater accumulation over time.
The University of Plymouth has spent two decades documenting plastic pollution everywhere from ocean depths to Mount Everest’s slopes. This latest research adds the food supply to that growing list, though questions remain about long-term health impacts and contamination levels in actual farming conditions.
The study appears in the journal Environmental Research, adding scientific weight to growing concerns about plastic pollution’s reach into human food systems. As Clark observed, there’s no reason to believe this phenomenon is unique to radishes, suggesting nanoplastic absorption could be occurring in various crops grown worldwide.
Environmental Research: 10.1016/j.envres.2025.122687
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