Living with microplastics It seems like the new normal in our diet. We already see them in things as everyday as bottled water either tapbut also within our body as in breast milk or their own testicles. Now the researchers, who remain very focused on the food chain, have wanted analyze its presence in crops and it has made it clear that the problem is more serious than we thought.
The study. Published in the magazine Environmental Researchresearchers have used a technique of radiolabeling to demonstrate, for the first time quantitatively, that nanoplastics are not only absorbed by plants, but travel through them until they accumulate in the parts we eat. And the results, obtained with radishes, are a wake-up call to a very important food safety problem.
The marking. The main challenge of studying nanoplastics in biological tissues is to distinguish them from the organic material that surrounds them. To overcome this obstacle, a team of scientists from the University of Plymouth in the United Kingdom synthesized polystyrene nanoplastics and “marked” them with a radioactive isotope: lime. famous carbon-14.
In this way, it was possible to accurately monitor the movement of the plastic inside the plant. And precisely the material is more common in agricultural soils.
Design. The experiment was meticulously designed to avoid any type of surface contamination. For this, radishes were used due to their rapid growth and their large fleshy root (the edible part), which were introduced into a hydroponic system with a liquid nutrient solution instead of being in their normal habitat, which is soil.
This is where the key is: only the fine, non-fleshy roots were in contact with the water containing the nanoplastics. In this way, the edible part and the sprouts were never in contact with the contaminated medium.
From here, the radishes were left for five days to absorb the solution and subsequently analyzed to check if the nanoplastics (which emit radiation) had been absorbed and what path they would follow.
Results. After the passage of these five days, radioactivity was detected in all parts of the silver that had been exposed, demonstrating the absorption and transport of the nanoplastics. In total, the radishes managed to retain almost 5% of the nanoplastics that were in the water and of these, 65% remained in the non-fleshy roots (the entry point).
But the alarming thing comes when in the part that is edible, a concentration of 25.5% of the nanoplastics that the plant had absorbed and transported to this area was found. Even the buds and leaves, the furthest part, accumulated almost 10% of the total absorbed.
What does it mean. This finding demonstrates that polystyrene nanoplastics are capable of crossing the Caspary bandan impermeable layer of cells that functions as a protective barrier in the root of the plant, designed precisely to prevent the passage of unwanted substances into the vascular system. Once this barrier is overcome, the nanoplastics have free rein to distribute throughout the rest of the plant.
Why it is important. These results open a direct and quantifiable pathway for human exposure to nanoplastics through diet. Unlike animals, which have rapid excretion mechanisms (such as feces or urine) to eliminate part of the contaminants, plants lack these systems. This makes them potential “sinks” for nanoplastics, accumulating them throughout their lives.
And for humans, the fact that these particles are so small means that they can diffuse our biological barriers and enter the body to circulate through the bloodstream. Although the effects that these microplastics have on our body still remain to be known, something that is currently still being studied to know exactly their distribution throughout the body.
Future research should explore whether other types of plastics behave the same, how soil type affects absorption, and what happens in longer growing cycles. But the door has already been opened: smaller plastics are no longer just pollute our oceans and air, but they have found a way to silently sneak into our food, from the roots.
Images | Teslariu Mihai Marc Pell
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