Nanoplastics in vegetables threaten consumers

Nanoplastics in vegetables a health risk? Summary

• Nanoplastics have been found in edible part of vegetables for the first time
• Study shows 25% of plastics reached edible roots, and 10% shoots
• Nanoplastics can bypass the Casparian strip, a plant barrier
• Particles can enter the bloodstream, reaching human organs
• The experiment only lasted five days, and accumulation could theoretically be much greater over time

The dangers posed by microplastics is one of the most prevalent topics in food safety today. The plastics can migrate into food and then into humans, threatening health.

Now, a study has found nanoplastics (like microplastics but even smaller) in the edible part of vegetables for the first time.

This could pose significant health risks to consumers, as nanoplastics can be extremely dangerous.

What are nanoplastics?

We’ve all heard of microplastics, common as they are in both food and beverage products, and the fears of consumers.

Nanoplastics are their even smaller offspring. As many plastics can theoretically keep dividing indefinitely, microplastics are not the final stage of division. Some nanoplastics are as small as a millionth of a centimetre in diameter.

When plastic particles have divided enough times, and reached a small enough size, they’re known as nanoplastics.

Nanoplastics, unlike microplastics, are small enough to pass into the human bloodstream from the lungs or intestines, and reach the heart or brain, the cells, and even newborn babies during pregnancy. This makes them dangerous in a way that microplastics are not.

Nanoplastics in vegetables

Nanoplastics have been found in the edible part of vegetables for the first time.

A study, published in the journal Environmental Research, found that the particles have the ability to reach parts of vegetables they were not thought previously to be able to reach.

To explore this topic, the study exposed the non-fleshy roots of radishes to nanoplastics for five days.

Polystyrene nanoplastics were chosen due to being commonly found in agricultural soils.

In total, 4.4% of total exposure was retained by the radish after the experiment ended.

Of this exposure, around 25% was found in the edible roots, and 10% in the shoots. The exact measurements could not be determined due to analytical constraints.

The researchers used radiolabelling to track the plastic particles as they moved.

Why is the finding so significant?

Plants have a protective hydrophobic layer called the Casparian strip, which acts as a barrier, and should prevent nanoplastics from reaching the edible roots and shoot.

While nanoplastics have been shown to enter roots, they haven’t made it as far as the edible parts of the plant.

However, the study found that this is no longer always the case. Nanoplastics were indeed able to pass the barrier, accumulating in the edible roots and shoot. From there, they can pass on to anyone who consumes them.

The study does point out that while Polystyrene nanoplastics were able to cross this barrier, it does not necessarily mean that all nanoplastics can. Less hydrophobic particles, for example, might be stopped.

Nevertheless, the researchers believe that nanoplastics have the ability to enter other crops, such as lettuce, in the same way.

As only a five-day period was assessed, under normal conditions accumulation could be greater. The nanoplastics used have demonstrated the stability to last for several weeks.