Two scientists are publishing this week about a very worrying phenomenon: microplastics are capable of penetrating fruit and vegetables such as apples, carrots, and lettuce via their root system.
This up-until-now unknown phenomenon affects the very foundation of our lives: the food we consume. Microplastics are a potential public health problem.
Apples & Carrots most contaminated
Research by researcher Margherita Ferrante from the University of Catania, published in Environmental Research, shows that apples and carrots contain the most microplastics. Ferrante measured the number of microplastics below 10μm per gram. For apples, the average is 195,500 microplastics and for carrots 101,950 microplastics per gram. Ferrante estimates the daily intake (EDI Estimated Daily Intake) based on the recommended amounts of fruit that adults and children should eat for a healthy diet.
Absorbed with water
The second study, soon to be published in Nature Sustainability by professor Willie Peijnenburg (Leiden University), together with Dr. Lianzhen Li (Yantai Institute of Coastal Zone Research, China), shows that microplastics penetrate the roots of wheat and lettuce. Then, they move to the edible parts of the plant. That means that the harvested crops end up on our plate.
Plastic small enough for uptake by plants
For a long time, it was assumed that plastic particles were too large to penetrate plants’ tissue. New analysis techniques confirm the contrary. Microplastics were found in roots, stems, and leaves. There is relatively a lot of information available about microplastics in marine organisms, but little was known about the existence of microplastics in edible crops. The study by Peijnenburg assumes that in a dry and hot environment, where irrigation with treated wastewater is widespread, there is a higher chance that microplastics in the sub-micrometer (< 1 micrometer) range are included in cultivated plants.
Increasing amounts of Microplastics in the soil
Two years ago, researchers estimated that four to 23 times as much plastic ends up on land than in the sea. They pointed out the danger of harmful effects in the long term. The microplastics, which never biodegrade, end up in our agricultural land through plastic waste, which falls apart into ever smaller pieces. Another route is via sewage sludge from water treatment plants, which is often used as manure, as well as compost containing microplastics, or scraps of agricultural plastic. Two other sources concern the irrigation of fields with wastewater containing microplastics and microplastics carried by air. Because of all these causes, microplastics accumulate rapidly. Edible crops are thus, directly exposed to more and more microplastics.
Plastic Soup Foundation is very concerned about this and calls for more research.
Read our press release here.
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