The March 21 issue of Science--the world's leading journal of original scientific research, global news, and commentary--features an invited review article about this research co-authored by Donald L. Sparks, S. Hallock du Pont Chair of Plant and Soil Sciences and the director of the Center for Critical Zone Research at UD.
The article, “Nanominerals, Mineral Nanoparticles, and Earth Systems,” originated with a group convened by the National Science Foundation, the Nanogeosciences Working Group, which includes Sparks. The lead author, Michael F. Hochella Jr. of the Center for NanoBioEarth, Department of Geosciences at Virginia Tech, serves on the external advisory board for UD's Center for Critical Zone Research and the external advisory board for the Delaware Experimental Program to Stimulate Competitive Research (EPSCoR).
“NSF was seeking guidance on the frontier areas of research in regards to nanogeosciences and wanted to know what types of questions still needed to be answered as they develop funding priorities and opportunities,” Sparks said.
“We know that there are lots of natural nanoparticles in the environment,” Sparks said. “Here at UD, we often study particles in the soil that can be nanosized--for example, certain clay minerals, iron oxides, manganese oxides and how they react with metals and nutrients. Only in the last few years has nanoparticles research come to the forefront of the science world, with a push to understand the fate and reactivity of both natural and manufactured nanoparticles.”
The research featured in the article looks at particles that are 10s of nanometers in size, the very smallest of the nanoparticles.
“The structure of the minerals changes as they get smaller," Sparks said. "Reactivity is affected and the rates of reaction of the nanoparticles with metals and microbes have been observed to be much faster than with larger particles. It raises questions that we don't yet have all of the answers to in regards to how these reaction rates affect the fate and transport of contaminants in the environment."
Researchers continue to study how nanoparticles and their changing properties have the potential to either positively or negatively affect environmental quality and human health. Nanoparticles are able to influence the movement of heavy metals, radionuclides and atmospheric particles. Of great interest to UD's Department of Plant and Soil Sciences is how nanoparticles influence the transport of metals and toxins in the soil.
“Atmospheric nanoparticles can travel long distances through wind currents," Sparks said. "We don't yet fully understand what these particles contain or what they may bind or bind to. Are they attached to other things, like microbes? Do they have an impact on global climate change? How do they impact air quality and human health? We want to raise awareness of these particles beyond the scientific world.”
Nanoparticle research at UD spans many disciplines, ranging from environmental science and materials science to chemistry and engineering. One of the themes of the new Delaware EPSCoR proposal is the study of the interactions and transport of nanoparticles, as well as larger particles, with metals, microbes and nutrients.
The article can be viewed online at [http://www.sciencemag.org/cgi/content/full/319/5870/1631].
Article by Katy O'Connell
Photo by Duane Perry