By Shannon BrennanThe Lynchburg News & AdvanceFields in Appomattox County where sewage has been spread do not show elevated levels of heavy metals, according to a study done by Sweet Briar College students.
David Orvos, an environmental studies professor, said students found very similar levels of arsenic, copper, zinc, nickel and lead in both control samples and land that had been treated with sludge, also called biosolids.
Students Shannon Smith, Medora Hackler and Rachel Chilton, who just graduated May 1, did the legwork for the study in the fall of 2003. With permission from the landowners, the students tested farmland both northwest and southeast of the Town of Appomattox that had been spread at least six months before.
Hackler said they were surprised with some findings.
"Arsenic was higher at the control site," she said.
Orvos said the students actually found that levels of lead, arsenic, and nickel at the control sites were higher than anticipated, though still within levels accepted by the Environmental Protection Agency.
They speculate that those metals may have been in the soil as a result of atmospheric deposition, perhaps from smokestacks out of state. That will require further research, Orvos said.
"We're not sure where it's coming from," he said.
The students, who also tested raw samples of sludge, found higher levels of copper and zinc in the sludge than on both the control and test sites. The metals may have been diluted in the soil, Orvos said.
The students also tested for bacteria.
"We could not find e. coli in the samples," Orvos said, adding that either they weren't there or they just didn't show up. But neither did they find any type of coliform bacteria, which live in the digestive tracts of warm-blooded animals. That's not surprising, Orvos said, because such bacteria rarely live outside their hosts for any length of time.
Orvos, who has studied biosolids since the early 1990s for both the state of Massachusetts and the pharmaceuticals industry, said a lot is known about the waste, but a lot remains unknown.
Not enough is known about either viruses or pharmaceuticals, he said. While Orvos said he would expect to see wastewater treatment workers sick if viruses were a problem, it's unknown how long viruses might survive past treatment.
"The jury's still out on that one," he said. "It's a concern."
Likewise, all kinds of pharmaceuticals have been found in surface water and wastewater, including beta-blockers, triclosan and antidepressants. And while the concentrations are generally low, it's unclear what the long-term accumulative effects might be.
"We're not sure what small amounts do during multiyear periods," Orvos said.
Still, Orvos has used biosolids on his own lawn, and sees their value as fertilizer.
"Really the main issue for a lot of people is odor," he said, noting that biosolids can stink for up to two months every time it rains.
His main concern is animals grazing on sludge-treated lands and the impact on the food chain. While the EPA says the risk is acceptable, Orvos said the government organization has a political agenda.
"I don't always trust the EPA," he said.
When it comes to disposal of treated human waste there are really only three choices.
"You either burn it, landfill it or you spread it," Orvos said.
Prior to the 1980s, New York City used to dump it in the ocean, he noted. That's no longer legal.
"I tell my students if you want to make a million dollars overnight, figure out what to do with biosolids," Orvos said.
Contact Shannon Brennan at
sbrennan@newsadvance.com or (434) 385-5561. For Sweet Briar media inquiries, please contact Shannon Wells, media relations coordinator, at (434) 381-6388 or
swells@sbc.edu.
