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."
Hernandez-Viezcas, 32, can be found doing his plant and nanoparticle research inside a nursery-like structure at UTEP.
"Nanoparticles are used in many things, and eventually also end up in our soil and water," Hernandez-Viezcas said.
The soybean-nanoparticle study was selected as one of the best papers for this year out of all 40 American Chemical Society journals.
Others who contributed to the study findings are UTEP doctoral chemistry student Cyren Rico; Jose Peralta-Videa, Ph.D., a UTEP chemistry research specialist; and scientists from the University of California, Santa Barbara.
University officials said the National Science Foundation, U.S. Environmental Protection Agency and the U.S. Department of Agriculture funded the study.
"Nanoparticle research is currently the most studied branch of science with the number of uses of nanoparticles in various fields," said Dr. Ananya Mandal, in an article published Friday by news-medical.net. "The particles have wide variety of potential applications in biomedical, optical and electronic fields."
Mandal said nanoparticles can range in size from 100 to 2,500 nanometers, and were used in the 9th century in Mesopotamia when artisans used these to generate a glittering effect on the surface of pots. A nanometer is a unit of measure that is equal to one billionth of a meter.
Some nanoparticles occur in nature, such as those produced by the friction of ocean waves or volcanoes. Others are manmade, such as those caused by vehicle emissions.
Mandal said in her article that some nanoparticles are used to detect proteins, to probe DNA structures, in MRI studies, in gene therapy and to destroy tumors with drugs or heat.
Other recent studies show that UTEP scientists are making their mark on the scientific world:
-- Journal of Exposure Science and Environmental Epidemiology published "Ultrafine particle levels at an international port of entry between the U.S. and Mexico: Exposure implications for users, workers, and neighbors," based on a recent study led by researcher Hector Olvera about air pollution from certain kinds of nanoparticles at the Bridge of Americas. -- Dr. Igor C. Almeida, a biological sciences professor, and Alexandre F. Marques, a postdoctoral researcher, developed a vaccine that can protect against the potentially mortal chagas disease. More work is needed before the vaccine is usable by humans.
Roberto Osegueda, Ph.D., vice president for research and sponsored projects, said the university has succeeded in attracting grant money and gifted researchers who, along with others, are conducting top-notch work.
"Research expenditures have risen steadily over the past decade, laying the groundwork for UTEP now to be ranked second in federal research expenditures in the UT System and second among Emerging Tier One institutions in the state," Osegueda said.
"UTEP's success in attracting external funding provides opportunities for UTEP students to learn by participating in research that makes a difference.
"Most UTEP students work while attending school, and on-campus positions in research labs have proven an effective means of expanding student income, promoting deeper learning, strengthening retention and graduation, reducing time to degree, increasing first-generation student confidence and motivation to purse graduate degrees, and improving job placement and career success."
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