Solutions to pollution

From water pollution to contaminated soil, research conducted by graduate students in the College of Agriculture and Natural Resources has attracted the attention of the scientific community. Here are two examples of what some of the College's top doctoral candidates are investigating. 

Mining metals with a microscope

Chances are that when David McNear looks at a flower, he's not just admiring its color or delicate petals. McNear is mining. Although he doesn't have a pick or a flashlight, he is searching for traces of minerals and metals.

A doctoral student in soil chemistry, McNear has spent the past three years researching how certain plants can be used to clean up polluted soil, especially in the beds of former refineries.

Leftover metal in the soil of these polluted sites is absorbed through a plant's roots and stored in its leaves. The theory is that if metal-absorbing plants can be better understood, they could be used to remedy ground pollution without extensive excavation and then could be harvested for their valuable metal contents.

McNear says he hopes his research will serve an additional purpose.

"There are some humanitarian applications for this technology, too," he says, explaining that many societies throughout the world suffer from a short supply of such necessary dietary minerals as zinc. If a plant, such as corn or wheat, could be bred to absorb zinc from the soil, the crop could offer a solution to malnutrition.

Before this can happen, however, researchers must explore a variety of issues, including the question of whether a plant that absorbs helpful substances might also absorb harmful ones.

In seeking to answer such questions, McNear's research focuses on Alyssum murale, a tiny, flowering plant that is native to northern Turkey and is capable of moving metal from the soil to its leaves. Unlike most plants that absorb nutrients more quickly when the soil is more acidic, alyssum is most efficient in neutral soil.

If McNear can determine just how this diminutive plant functions, he says, the knowledge could be applied to breeding the mechanism into a larger plant such as corn. Since metals are stored in the stalks and leaves of plants, the more biomass a species has, the more metal it can absorb.

"Right now, we're trying to understand alyssum, with the expectation that our results will enlighten us as to what's going on in other plants," McNear says.

Winning the water-quality wars

"Linking science, management and environmental policy together is important for agriculture," says Amy Shober, a doctoral candidate in soil chemistry whose research on water pollution has earned her national recognition and a $10,000 award.

Her research focuses on nonpoint surface water pollution by nutrients, particularly phosphorus. She is investigating the chemistry of phosphorus in soils amended with organic byproducts, such as animal manures and municipal biosolids. The loss of phosphorus from soils amended with these materials has led to many serious water-quality problems worldwide, such as algal blooms and fish kills.

Shober says her goal is to understand the basic chemical reactions of phosphorus in soils and aquatic sediments in order to develop best-management practices that allow beneficial agricultural use of these materials. She recently received one of 85 national awards from P.E.O. International, a nonprofit organization that recognizes women who are making an impact in their fields.

While her research still is in the early stages, Shober says she believes the study can help make agriculture sustainable and profitable for farmers, while helping to solve some serious water-quality problems.

"If we have a good scientific understanding of the reasons soil phosphorus is lost in runoff, we can design the practices farmers need to produce crops profitably and protect water quality," Shober says.

She is using the prize money for more research, including a recent visit to several universities in England and The Netherlands to share her findings and gain ideas from colleagues working on similar problems in Europe.

--Kaytie Dowling, AS '04