WCU researchers to investigate use of plants to remove orchard contaminants

CULLOWHEE — Three Western Carolina University chemistry professors have received a grant of more than $100,000 to determine if certain types of vegetation can be used to remove contamination from the soil at a Western North Carolina housing development that was once home to a major commercial apple orchard.

Through the project, funded by a gift from Blanton J. Whitmire, WCU chemistry professors David Butcher, Cynthia Atterholt and Arthur Salido hope to determine if such plants as corn, pea plants and Indian mustard will draw significant amounts of lead and arsenic from the soil through their root systems.

Butcher, Atterholt and Salido will conduct their research at the Barber Orchard subdivision near Waynesville, subject of a U.S. Environmental Protection Agency investigation and cleanup effort since 1999. The EPA recently concluded a six-month emergency removal project, extracting up to a foot of soil from homesites where levels of contamination were above “federal action levels.”

EPA officials are still trying to decide how to address the development’s other homesites, with yards containing contaminated soil below “federal action levels,” and numerous undeveloped lots. Even if EPA does decide to clean up the remaining yards and lots through its Superfund National Priority List system, it is expected to be several years before the long-term project is completed, officials say.

The Western Carolina chemistry professors believe that “phytoremediation” — that is, remediation by plant processes — may prove a more cost-effective way of dealing with such problems in the future.

“Removal and replacement of contaminated soil typically costs between $30 to $300 per cubic meter of soil,” Butcher said. “Phytoremediation, on the other hand, may cost as little as 5 cents per cubic meter. But the primary limitation of the technique is the length of time required for cleanup.”

By applying certain types of chemical agents, such as ethylenediaminetetraacetic acid, to the soil, scientists may be able to actually speed up the process by increasing the amount of lead and arsenic that accumulates in the plants, he said. The professors suspect that larger, faster growing vegetation with a higher “bio-mass” (corn, pea plants, Indian mustard, tobacco) will be more efficient than other types of herbage at drawing elements out of the soil and into the structure of the plant.

“The studies, to be conducted over five years, should allow us to determine which plants are most effective at removing lead arsenate from contaminated soils, and to see if phytoextraction is a viable remediation strategy in Barber Orchard and other sites,” Butcher said.

Working with undergraduate and graduate student assistants, the WCU professors will begin their research this fall by conducting soil sampling to determine which plants might be most effective in removing chemicals from the soils of Western North Carolina. They will analyze the chemical makeup of soil samples from orchard property and begin growing plants in that soil over the winter in on-campus biology laboratories and greenhouses. Based upon their findings, they will then begin planting various types of vegetation in the orchard in the spring.

Funding for the project was provided by St. Louis businessman Blanton J. Whitmire, a member of the influential Whitmire family of Western North Carolina. Whitmire and his wife, Margaret S. Whitmire, established the base for a $1 million endowed professorship in environmental sciences at Western through a gift of $666,000 in 1997. That donation was matched by $334,000 under a program initiated by the General Assembly to encourage private support of public institutions.

Jerry R. Miller, a geologist and teacher whose research into water quality issues has taken him around the world, joined WCU’s faculty last fall as the first Blanton J. Whitmire Distinguished Professor in Environmental Sciences.