University researchers investigate use of crops to remove subdivision contaminants

CULLOWHEE — Three Western Carolina University chemistry professors and their students are hoping to grow more than just a few ears of corn this summer in their small gardens in a Western North Carolina subdivision. They’re also seeking to harvest scientific evidence that could lead to a cost-effective method of removing contamination from the soil of a neighborhood that once housed a major commercial apple orchard.

The Barber Orchard subdivision near Waynesville has been the subject of a U.S. Environmental Protection Agency investigation and cleanup effort since 1999, after the discovery of soil and water contamination linked to the application of pesticides during the orchard’s heyday.

The EPA concluded an emergency removal project last year, extracting 31,500 tons of contaminated soil from 28 homesites, at a cost of approximately $4 million. EPA is now conducting studies to determine whether it will return to clean undeveloped lots and remaining yards.

Meanwhile, Western Carolina researchers are in the second year of a five-year project to determine whether Aphytoremediation — that is, remediation by plant processes — may prove a more cost-effective way of dealing with the problem. The professors believe that some plants can pull contaminants out of the soil through their root systems, and that application of certain types of chemical agents to the soil will accelerate the process.

Removal and replacement of contaminated soil typically costs between $30 to $300 per cubic meter of soil, the professors say, while phytoremediation may cost as little as 5 cents per cubic meter. The big unknown, the researchers say, is the length of time required for plant processes to cleanse the soil.

Funded by gifts of more than $100,000 from Blanton J. and Margaret S. Whitmire, WCU chemistry professors David Butcher, Cynthia Atterholt and Arthur Salido and their students have spent nearly a year sampling soil from the orchard and conducting experiments in on-campus laboratories and greenhouses. They recently returned to the housing development to begin planting their crops, and will tend their fields over the summer before returning to the laboratories to examine the plants to see if they have, indeed, absorbed significant amounts of contaminants.

“We are planting corn and mustard, which appear to be the most suitable candidates for phytoremediation of lead,” Butcher said. “Previous studies have demonstrated that brake ferns are effective for the removal of arsenic from contaminated soil, and we are investigating the use of these plants to remove lead, as well.”

Through a second study, the university researchers are conducting experiments to evaluate the safety of food gardening at Barber Orchard. “In this study, we plan to grow approximately 12 types of fruit and vegetables and analyze them for lead and arsenic,” Butcher said. “We suspect what we will find is that vine fruits and vegetables grown above the ground, such as tomatoes, will be fine for consumption. We’re less certain about the safety of root vegetables such as potatoes and carrots, and we’re curious as to what we’ll find in the leaf vegetables, such as lettuce.”

Blanton Whitmire, the retired St. Louis businessman who provided funding for the project with his wife, is no stranger to the worlds of chemistry and pesticides. He conceived in the early 1960s an innovative concept for the application of indoor insecticide, which is today widely regarded in the professional pest control industry as the most environmentally sound and effective method of applying insecticides indoors.

Members of the influential Whitmire family of Western North Carolina, Blanton and Margaret Whitmire also established the base for a $1 million endowed professorship in environmental sciences at Western through a gift of $666,000 in 1997.