A study by researchers at the University of Texas at El Paso discovered that potentially harmful minute particles used in cosmetics and other common substances are able to make their way into the food that people eat.
The news of this study follows other recent announcements by the university about the kind of cutting-edge research that is being conducted by UTEP scientists, and by Latino researchers in particular.
The researchers, led by Jose Gardea-Torresdey, chairman of the chemistry department and a distinguished academic, said they believe more study is needed to determine the effects of nanoparticles (fine particles) on human health, considering how they are able to migrate to the food supply.
Nano, the American
Chemical Society's journal, published an article in January about the study titled "Synchrotron X-ray Fluorescence Mapping and Speciation (Cerium dioxide) and (Zinc oxide) Nanoparticles in Soil Cultivated Soybean."
Jose Hernandez-Viezcas, a doctoral student at the university, is credited with making the key part of the discovery.
"To our knowledge, this is the first report on the presence of cerium dioxide and zinc oxide compounds in the reproductive/edible portion of the soybean plant grown in farm soil with (cerium dioxide) and (zinc oxide nanoparticles)," according to the Nano article.
UTEP researchers said the nanoparticles, which are used in cosmetics, lotions, sunscreens and other products, eventually go down the
drain, through municipal sewage treatment plants and end up in the sewage sludge that some farmers apply to crops as fertilizer.
A key question they tried to answer was whether such particles would break down once plants absorbed them, or if they remained as a metal oxide nanoparticle, which could have harmful effects on humans when consumed.
"Once engineered (man-made) nanoparticles enter the food chain, this is an accumulative process. Today's tolerable levels can become dangerous tomorrow," Gardea-Torresdey said. "This is why it is important to study not only whether man-made nanoparticles can be taken up from soil, but also how they are biotransformed in the plants."
Gardea-Torresdey's previous studies showed that cerium oxide nanoparticles in soybeans stunted their growth, reduced yield, and affected their nitrogen fixation rate.
The research using soybean plants found that cerium dioxide -- which is used in sunscreens and oil refining -- remained intact (did not break down into nontoxic forms) when it was absorbed by the plant, and was transferred all the way into the edible soybean grains.
Zinc oxide, which is used in sunscreens and cosmetics, also transferred to the soybean grain, but had broken down to a nontoxic form.
To track the routes of the nanoparticles within the plants, the researchers used intense X-ray beams from the SLAC National Accelerator Laboratory's Stanford Synchrotron Radiation Lightsource, and the European Synchrotron Radiation Facility in Grenoble, France.
The X-rays also helped to reveal whether the nanoparticles were chemically transformed in the process.
"It's too soon to say that the nanoparticles that caused DNA damage to the plant can harm us if we consume the edible plants," said Hernandez-Viezcas, a native of Chihuahua City, who expects to complete his Ph.D. at UTEP this year. "That's why we need more research."
