With nanotechnology on the rise and seen as the great next advance for technology, there is still a lot of room for research. Tiny nanoparticles are found in nature. However, the past few years have seen an explosion of potential applications. Nanoparticles are being synthesized for many different products, from electronics to cosmetics. While the myriad benefits of these particles are increasingly appealing, the consequences are poorly understood. Many critics advocate a slower approach to incorporating nanoparticles in products, so there is time to look at unexpected side effects.

A new study in the Journal of Environmental Monitoring has focused on plants and nanoparticles. It marks the first experimental results showing that plants can incorporate these tiny particles into their tissues. The implications are far-ranging. Once accumulated in plant tissue, nanoparticles may be able to enter the food chain.

One concern is that certain compounds may have different properties when in a tiny form. In particular, a smaller concentration of nanoparticles may deliver similar impacts as large amounts of conventional molecules. Another possibility is that microscopic particles are more easily transported, so that they become a respiratory hazard. Existing research has shown that nanoparticles in vehicle emissions are responsible for health problems in humans.

Pumpkin plants were grown hydroponically. Iron oxide, or magnetite, nanoparticles were added to the growth medium. After 20 days, plants were harvested and dried. The resulting material was placed in a magnetometer to detect uptake of any iron oxide. The instrument uses low-frequency radio waves to map the location of individual nanoparticles inside plant tissues. Scans showed that iron oxide nanoparticles were taken in by pumpkin plants, transported throughout the tissues, and accumulated.

Once taken up by plants, the question remains whether nanoparticles could then bioaccumulate when plants are eaten by animals. In addition, what happens when affected plants decompose is also a mystery.

Preliminary tests used lima bean plants, which demonstrated no absorption of nanoparticles. The results suggest that different plants have correspondingly different uptake potential with nanoparticles. In addition, while pumpkins grown in aqueous solutions could incorporate particles, plants grown in sand showed much less uptake, while those in soil had none at all. So the growth medium is also a key factor when considering nanoparticle accumulation. Additional experiments are planned to explore the mechanisms behind nanoparticle absorption.

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