Researchers at a university in Italy have discovered microplastics in a large range of fresh produce items.

The study - carried out at the University of Catania and published in the Environmental Research journal - discovered that apples and carrots had the highest levels of plastic particles in them.

Researchers that microplastics in the ocean get picked up into the clouds, then they fall back to earth in rain, where they are sucked up by the roots of plants.

Fruits were more highly contaminated than vegetables, likely because fruit trees are older with deeper, more established root systems, they said.

Although the scientists found fewer plastic particles in fruits and vegetables studied than in the water from a plastic bottle, they still described their findings as cause for “considerable concern”.

“Based on the results obtained it is urgent important to perform toxicological and epidemiological studies to investigate for the possible effects of microplastics on human health,” the study warns.

Another study published in Nature Sustainability from researchers in China and the Netherlands showed that microplastics can be absorbed by the roots of lettuce and wheat crops, and transported to the edible parts above ground.