Study shows nanoplastics can leap from plants to insects to fish

plastic fish
— chaiyapruek youprasert /

Polystyrene and PVC nanoparticles have been found in the flesh of roaches after these fish ate fly larvae that had fed on lettuce growing in soil contaminated with these particles.

Particles capable of moving up the food chain

If it was already established that these tiny particles suspended in water could be absorbed by fish, then consumed by humans, new work shows that nanoplastics can enter the food chain by another route: by passing from soil to plants, then to insects and fish.

Researchers at the University of Eastern Finland started by growing lettuces in soil containing 250-nanometer-wide polystyrene and polyvinyl chloride (PVC) particles, chosen because of the abundance of such plastics in the environment.

After 14 days, the plants were harvested and used to feed black soldier fly larvae (Hermetia illucens), constituting an important source of protein for animal feed. After five days, the larvae were in turn fed to freshwater roach for the same duration. Some of the lettuce plants, larvae and fish were then dissected and examined by scanning electron microscopy.

— chayanuphol /

The team found that both types of nanoparticles were first taken up by plant roots and then accumulated in their leaves. When the latter were consumed by the larvae, the nanoplastics contaminated the organism of the insects, persisting there even after having been able to empty the contents of their digestive tract over a period of 24 hours. These nanoparticles then passed from the larvae to the fish, where they were found mainly in the liver, but also in the gills and intestinal tissues.

A potential health risk for herbivores and humans

It should be noted that neither the lettuce, nor the larvae, nor the fish presented adverse reactions following the absorption/ingestion of the nanoparticles. However, other studies have suggested that they can pick up pathogens from polluted environments and then transmit them to plants or animals.

These experiments show that nanoplastics can be absorbed by lettuce and move up the food chain “says Fazel Monikh, lead author of the study, published in the journal NanoToday. ” This indicates that the presence of tiny plastic particles in soil could be associated with a potential health risk to herbivores and humans if these findings prove generalizable to other plants, crops and contexts.. »

In mid-July, Dutch researchers had detected microplastics in the meat, milk and blood of farm animals.

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