Cabbage and Spinach Found to Harbor Microplastics in Their Leaves

In the sprawling city of Tianjin, the leaves of trees and vegetables like cabbage and spinach have been quietly soaking up a modern menace: nano- and micro-particles of polyethylene terephthalate (PET) and polystyrene from the air. The closer these plants grew to a synthetic textile factory, the more plastic they amassed—but even in parks, university grounds, and greenhouses, hundreds of nanograms per gram of dry leaf mass were detected. This unsettling discovery, detailed in Nature, spans both open fields and sheltered plots.

Lab experiments have long hinted at plants’ knack for sipping nanoplastics—particles tinier than 1,000 nanometers—through their roots from tainted soil. The toll is real: in cress, gene expression tied to stress and oxygen defense falters, root tips morph, and plant mass dwindles. Lettuce, too, has shown it can gulp microplastics from the air, with leaves hoarding 1.5 × 10³ to 1.2 × 10⁴ micrograms of polystyrene per gram in controlled tests. Yet how these findings stack up against the wilder, less polluted outdoors has remained a question mark.

Enter Ye Li and his team from Nankai University, who set out to bridge that gap. They probed the leaves of 12 tree species and leafy veggies across Tianjin’s varied landscapes—near dacron factories, a landfill, a park, and a campus. To zero in on internal buildup, they scrubbed leaf surfaces clean, then peered inside with confocal laser scanning microscopy and atomic force microscopy paired with infrared spectroscopy. Gas and liquid mass spectrometry crunched the numbers.

Every tree leaf bore the mark: PET up to 6.1 × 10⁴ nanograms per gram of dry weight, polystyrene up to 1.24 × 10⁴. PET peaked near the factory, polystyrene by the dump, but even in “cleaner” zones like the campus, levels hit hundreds of nanograms. Older leaves, seasoned by six months, sopped up more than their youthful kin.

Nine vegetable types—cabbage varieties, celery, spinach—told a similar tale. Open-ground crops held up to 8.70 × 10³ nanograms of PET per gram, while greenhouse greens clocked in at 2.31 × 10³. A lab-grown corn trial in fouled air showed leaves snagging 0.079 percent of airborne microplastics, peaking within 10 days. Soil-to-root-to-stem transfer? Just five days.

Polystyrene nanoparticles turned up in corn’s stomata, mesophyll, and intercellular gaps, reaching vascular stem tissue and trichomes by day 10. It’s a stark warning: microplastic-laden air and soil threaten food security and whisper of a creeping handover through nature’s food chains.

Humans aren’t spared. Beyond crops, microplastics lurk in seafood—damaging fish gills, as seen in Japanese medaka. Even infants can’t dodge it: bottle-fed babies swallow 1.5 million particles daily, outpacing adults by thirteenfold. From field to fork, the plastic age leaves its trace.