Plastic in our plates: How microplastics invade plants and threaten global food security

Plants are quietly absorbing microplastics from soil and air, and those particles can work their way into our food and ecosystems, according to a new review by researchers at Nankai University in China. The study pulls together the latest evidence to show how plastic fragments and fibers enter plants through roots and leaves, how they travel and accumulate inside tissues, and what this means for crop health, soil microbes, and global food security.

A hidden plastic pipeline into plants

“People usually think of microplastics as a problem for oceans,” says lead author Hao Du of Nankai University. “Our work shows that terrestrial plants are also on the front line and may become an important gateway for plastics into land food webs.” Microplastics, defined as plastic particles smaller than 5 millimeters, now contaminate agricultural soils through plastic mulch, sewage sludge, fertilizers, irrigation water, landfills, and long-range atmospheric fallout. In some intensively farmed fields, residues of plastic mulch can reach hundreds of milligrams per kilogram of soil, while polyester pollution near factories can be even higher.​

Because plants form the base of most food chains, their ability to take up and store microplastics largely determines how far these particles can move through land ecosystems and into animals and humans. The review makes clear that plant–plastic interactions are very different from the way plants handle dissolved nutrients or heavy metals, and that the risks have been underestimated.​

How microplastics enter roots and leaves

The team describes several distinct pathways that allow microplastics and even smaller nanoplastics to infiltrate plant roots. Structural “cracks” that form when new lateral roots break through the main root can act as open doors, letting relatively large particles slip inside. In younger root zones where protective barriers are not fully developed, tiny plastic particles can move passively between cell walls, and the smallest nanoplastics can be actively pulled into living cells.​

Leaves, long thought to be nearly sealed off to solid particles, are also vulnerable. Microscopic plastic spheres and fragments deposited from the air can pass through open stomata tiny adjustable pores on the leaf surface or diffuse across the waxy cuticle. Laboratory and field studies in crops such as maize and lettuce have visualized plastic particles lodged in stomatal pores and distributed inside leaf tissues, confirming that foliage is a direct entry point for atmospheric microplastics.​

Damage to crops, soil life, and food production

Once inside, micro and nanoplastics can harm plants in multiple ways. They may stick to seeds and root hairs, blocking water and oxygen, slowing germination, and reducing early root growth. Smaller particles can penetrate deeper into tissues, disrupt ion channels and metabolism, and even clog stomata in leaves, lowering photosynthesis and biomass. Many experiments also show strong oxidative stress plants ramp up antioxidant enzymes but still accumulate markers of cell damage, and their normal sugar and protein balance is disturbed.​

The review warns that the danger is not just from the plastic backbone itself. Microplastics carry a cocktail of additives including plasticizers, antioxidants, UV stabilizers, flame retardants, colorants, and residual monomers, some of which can make up more than half of a product’s mass. These chemicals can leach into soil and plant tissues, further suppressing growth and photosynthesis and altering crop quality in species such as wheat, lettuce, and cucumber. Microplastics also reshape soil and leaf microbiomes, reducing beneficial fungi and bacteria, creating new niches for pathogens, and potentially enriching antibiotic resistance genes on plastic surfaces.​

At global scale, the review highlights a recent meta-analysis showing that microplastic pollution can reduce chlorophyll in major crops enough to translate into annual losses of roughly 110 to 360 million metric tons of rice, wheat, and maize, comparable to climate driven yield losses observed in past decades. The authors argue that microplastics should now be treated as a serious agricultural contaminant, not just a marine issue.​

From field and air to the dinner plate

The study also traces how plant contamination feeds into human exposure. Leafy vegetables grown outdoors have been found with plastic concentrations in the hundreds to thousands of nanograms per gram of dry weight, and calculations suggest that fruits and vegetables contribute a measurable but still modest share of people’s total dietary microplastic intake. Overall, humans appear to be exposed to far more microplastics than wildlife, reflecting higher pollution levels in cities and a wider mix of exposure routes through food, water, and air.​

Although current estimates suggest that fruit and vegetable consumption accounts for only a small percentage of overall microplastic exposure, the authors caution that inconsistent detection methods make direct comparisons difficult. What is clear, they say, is that the presence of plastics in crops adds another layer of concern to already stressed food systems and could interact with other pollutants such as heavy metals, pesticides, and antibiotics.​

Urgent questions and a call for better tools

Despite the mounting evidence, the review identifies major scientific blind spots. Researchers still do not know exactly where inside plants microplastics end up, in what forms they accumulate, or how much reaches edible tissues such as grains, fruits, and leaves. It is also unclear whether plants can chemically transform or degrade plastic polymers over time, or how they might shed absorbed particles back into soil and air through leaf fall and root exudates.​

Addressing these questions will require new analytical and imaging tools capable of tracking plastics and their additives inside living plants without relying on artificial fluorescent labels. The authors see promise in advanced mass spectrometry imaging and “spatial metabolomics” approaches that can map both plastic fragments and disrupted metabolic pathways at high resolution. “To truly assess the risks of microplastics in our food,” says corresponding author Lei Wang, “we need to see where they go, how they change, and what they do inside the plant, from root tip to dinner plate.”​

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Journal reference: Du H, Peng C, Li Y, Shi X, Liu C, et al. 2025. Absorption of microplastics by terrestrial plants and their ecological risk. New Contaminants 1: e003  

https://www.maxapress.com/article/doi/10.48130/newcontam-0025-0006  

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About the Journal:

New Contaminants is an open-access journal focusing on research related to emerging pollutants and their remediation.

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