State officials now say that treatments used to kill algae in order to improve Anderson County’s drinking water may have caused the deaths of thousands of fish in Lake Hartwell.
The South Carolina Department of Natural Resources told the Anderson Independent-Mail that it’s investigating the fish kill. But a Clemson researcher said the evidence seems to indicate the fish became trapped when crews used algaecides to kill the blooms blamed for the moldy taste and odor of Anderson Regional Water Systems water. Crews from the environmental company Synterra had applied the hydrogen peroxide treatment and copper-based algaecide to more than 160 acres of the lake last week.
Clemson aquatic ecology professor John Rodgers said most of the dead fish were shad and other small baitfish, along with a few carp. Rodgers said the crews had used an airboat to stir up the water and chase fish out of coves before applying the algaecide. However, he added that it appeared the dead fish had hidden under manmade docks and became trapped once the chemicals were in the water.
“If fish are holding on structures… essentially using the structures as cover and refusing to move… those are the ones that get trapped,” Rodgers told South Carolina Radio Network. He noted that few fish were found in coves that did not have docks or other structures.
Anderson Regional Water System first alerted the public about the kill in a statement earlier this week, saying “Fish are typically safe during algaecide treatments and are generally not as sensitive as the targeted algae. Extreme care was taken to apply the algaecides directly to the algae on the lake bottom and to avoid contacting fish.” The utility insisted the chemical treatments were too low in concentration to be a threat to humans.
DNR Capt. Bob McCullough told the Independent Mail that an estimated 4,000 to 6,000 fish were killed by the algaecide. He said his agency and DHEC are investigating how much chemicals were put into the lake.
ARWS has been trying to reduce algae blooms in Lake Hartwell after residents complained the water is nearly undrinkable due to bad taste and smell. The agency is not commenting beyond the statement issued this week, which said Synterra had gotten the necessary permits and the algaecide followed manufacturer guidelines.
A Corps of Engineers spokesman told the Independent-Mail that the overall impact of the fish kill was likely small, as millions of shad are estimated to live in the lake.
Rodgers said he believes the kill was a one-time event, as any future algaecide use would be on a much lower scale — preventing new algae growth rather than killing existing blooms.