Plants Accumulate Nanoplastics Primarily in their Roots, Not Shoots

Plastic nanoparticles collect primarily in the roots rather than the shoots, according to a new study aiming at assessing how plants take up plastic nanoparticles from the soil. The researchers that devised the approach to trace the nanoparticles utilized compounds known as lanthanide chelates, and they suggest it could be a versatile way to study the interactions between nano plastics and plants.

Plastic elements can be seen in the water, in our food, and even on the peaks of mountains. Nano plastics, the tiniest of these particles, are regarded to be more dangerous to life because their small size allows them to permeate cell membranes.

Because the continuous large-scale manufacture of plastics implies that nanoplastic concentrations are likely to rise, it's critical to understand their environmental impact as well as the possible risk to human health.

Scientists need to be able to track how nano plastics aggregate and migrate through the plant's structure since they can interact with plants in a variety of ways. While numerous researchers have looked into how to plant protoplasts - cells that have had their walls removed – take up nano-plastics, the mechanisms for nano plastic uptake and translocation across large-scale plant structures are still unknown. Quantitative data on how quickly plants absorb nanoparticles and then transmit them is particularly scarce.

Studies on Lettuce & Wheat

Researchers lead by Yongming Luo of the Chinese Academy of Sciences investigated how two crops, lettuce and wheat, absorbed 200-nm-diameter polystyrene particles doped with a europium chelate, Eu- diketonate, in the current study.

Polystyrene is one of the most widely used polymers in the world, and it's used in food packaging as well as as a "soil conditioner" to assist soil surfaces to stay stable and retain moisture. Organic fertilizers, sewage sludge, and wastewater have all been found to contain it.

Luo and colleagues produced their lettuce and wheat in hydroponic cultures and on sandy soil to imitate varied environmental conditions. Using an inductively coupled plasma mass spectrometry approach, they were able to quantify the doped polystyrene particles in the plants. Because europium is a highly rare element that does not naturally occur in plants, each signal they recorded is a particle that the plant has absorbed. They also used background-free time-resolved fluorescence imaging to visualize the particles, and scanning electron microscopy to confirm their presence.

The researchers hope to use this methodology in the microcosm or mesocosm tests to improve the sensitivity of their nano plastic tracing and detection methods, according to their findings published in Nature Nanotechnology.

"Because of the complicated environmental circumstances and the presence of a large number of (micro)organisms," team member Lianzhen Li tells Physics World, "we need to closely monitor potential lanthanide leaching from the particles in the systems we analyzed."

(Source: Physics World)