First they thought it was a bacteria called sphaerotilus.
Now they're saying it might be phiothrix instead.
Although opinions differ as to the composition of the gooey slimeballs that angered Savannah River fishermen a few weeks ago, environmental authorities and corporate scientists agree that the bacterial slime is harmless.
But they're still not sure why it appeared in such quantities in the river a few miles downstream from New Savannah Bluff Lock and Dam.
"We know there's some growth out there, but the question is whether or not it has any significance," said Mike Creason, wastewater unit coordinator for Georgia's Environmental Protection Division.
EPD began studying the whitish goo -- tentatively identified as sphaerotilus -- in mid-January, after anglers complained of a buildup of the substance near International Paper Company's wastewater discharge.
Nehl Aldridge, International paper's environmental health and safety manager, said scientists at the plant believe the substance to be a different bacteria -- called phiothrix.
"Either way, it's certainly not anything that would cause infection or problems in humans," he said.
One theory is that higher-than-usual levels of bacteria appeared in the river last month because of a combination of weather factors, he said.
"The bacteria is, we think, growing in the river because of a unique combination of circumstances that were occurring back in the fall," he said. "The temperatures were high; the water levels were low; and we had extreme periods of sun."
Those conditions, he added, could have contributed to an outbreak of the bacteria.
"We will continue monitoring this, but we haven't found a whole lot of the stuff since the (January) reports," he said. "River conditions have returned to more normal; it's been colder; and we've had more rain."
EPD, meanwhile, will continue to monitor the situation.
International Paper has permits to release 44,478 pounds per day of oxygen-demanding wastes and 74,283 pounds per day of suspended solids into the Savannah River, according to EPD. In all, the plant discharges about 45 million gallons per day of treated wastes into the river.
Throughout the investigation, the company's wastewater has been in compliance with its state permit, Mr. Creason said.
"There were no violations, but if it turns out they are causing a problem, we'll have to re-examine their permit."
Reach Robert Pavey at (706) 868-1222, Ext. 119.