Tracing Nanoparticle Transformations in Soybean Plants

February 2013 SSRL Science Summary by Lori Ann White, SLAC Office of Communications

Tricolor µ-XRF maps (red = Zn, green = Ca, blue = K) of soybean plant grown in ZnO NPs shows accumulation in a) pod, b) stem and c) nodule. d) Full-field transmission X-ray microscopic image (30 nm resolution) depicts Zn precipitates in the soybean pod. [larger image]

The global production of engineered nanoparticles (ENPs) is currently a trillion-dollar industry, with nanoparticles now found in products ranging from sunscreen, gas sensors and pigments (ZnO ENPs), to catalysts for internal combustion and oil cracking processes (cerium-based ENPs). While their benefits in such products are known, much is yet to be determined regarding their fate, transport, and toxicity in the environment, including the implications of the potential storage of these ENPs or their biotransformed products in the edible and reproductive organs of crop plants.

Scientists from the University of Texas El Paso, UC Santa Barbara, ESRF and SSRL studied ENP uptake in soybean plants (Glycine max). Their report on the chemical forms of Ce and Zn within various parts of the soybean, as well as the potential for transfer of the ENPs into the food chain, appeared in a recent issue of ACS Nano. The team used X-ray imaging and spectroscopy to analyze soybean plants grown to maturity in ZnO and CeO₂ ENP-impacted soils. They found Zn in several areas of the plant, with XANES spectra suggesting that Zn ENPs in soy are transformed, with the Zn probably binding to organic acids such as citrate. The team also found that the Ce taken up by the plant persisted as CeO₂ ENPs.

These results suggest that CeO₂ ENPs can reach the food chain and the next soybean plant generation, with potential health implications.

 

Primary Citation

J. A. Hernandez-Viezcas, H. Castillo-Michel, J. C. Andrews, M. Cotte, C. Rico, J. R. Peralta-Videa,Y. Ge, J. H. Priester, P. A. Holden, and J. L. Gardea-Torresdey, "In Situ Synchrotron X-ray Fluorescence Mapping and Speciation of CeO₂ and ZnO Nanoparticles in Soil Cultivated Soybean (Glycine max)", ACS Nano (2013), [doi: 10.1021/nn305196q]

Related Links

• Science Highlight – HTML  /  PDF
• X-rays reveal uptake of nanoparticles by soya bean crops - ESRF News Release

Contacts

Jorge L. Gardea-Torresdey, University of Texas at El Paso
Joy C. Andrews, Stanford Synchrotron Radiation Lightsource
Jose A. Hernandez-Viezcas, University of Texas at El Paso