A private study of mercury in Olin Corp.'s Savannah River drainage canal found elevated levels similar to those identified in April in a high school student's science fair project.

"Their data, while somewhat lower in some instances, essentially corroborate our data," said Frank Carl, the executive director of Savannah Riverkeeper Inc., which assisted in the student's study.

The student, 16-year-old John S. Davidson Fine Arts Magnet School junior Lauren Smith, sampled sediment in the canal that links the 40-year-old chemical plant with the river's main channel.

She found mercury levels in the canal ranging from 36,000 to 62,000 parts per billion - many times over the National Oceanic and Atmospheric Administration's standard for mercury in stream sediment, which ranges from 5 to 51 parts per billion.

Olin hired a private firm, MACTECH Consulting, to conduct its own tests. The results included levels as low as 110 parts per billion and as high as 69,000 parts per billion, according to a copy of the study obtained by The Augusta Chronicle.

"Our concentrations, on average, were a little bit higher, but the proportions are about the same," said Dr. Carl, whose group has criticized Olin over what it calls an obsolete manufacturing process that uses mercury to manufacture chlorine.

Olin's permit from Georgia's Environmental Protection Division allows the discharge of small amounts of mercury into the river, according to state authorities.

Dr. Carl believes mercury levels in the drainage canal could threaten the nearby river and wants the area dredged.

"It is my opinion that most of the residual channel mercury and a considerable portion of the river mercury comes from their wastewater outfall," he said.

Olin's state permit allows it to dump 0.1 pound of mercury into the channel daily - or about 7 pounds annually, he said.

"That is still too much for the river to absorb."

Plant Manager David Blair said in an e-mail that mercury levels closest to the river are too low to affect the river but that higher levels farther from the river channel might warrant remediation.

Olin, he added, already is discussing possible cleanup options with state regulators who would have to approve and supervise any remediation in the area.

"Olin operations are well within compliance with its wastewater permit, discharging only one-third of what the government allows," Mr. Blair said. "We have steadily reduced the mercury concentration in our wastewater in recent years. Our total mercury emissions have gone down 87 percent since 1987."

Reach Rob Pavey at (706) 868-1222, ext. 119, or rob.pavey@augustachronicle.com.