Charlotte officials said Friday they have detected another case of PCBs being dumped into wastewater in Mecklenburg County sometime between September and early March.
That is in addition to the PCBs found in water at a treatment plant in north Charlotte in early February, and ethanol-tainted water discovered at a south Charlotte treatment plant a few days later.
City officials also announced Charlotte-Mecklenburg police are offering a $10,000 reward for information in the PCB dumping.
In making the latest announcement, Charlotte-Mecklenburg Utilities Department spokesman Cam Coley stressed that the drinking water supply was not affected. The dumping took place in the wastewater system and involved low levels of contaminants, he said.
The discovery of polychlorinated biphenyls, or PCBs, was made during testing, Coley said.
While conducting intensive sampling and testing at all five wastewater plants, some samples of biosolids at McAlpine Creek wastewater Treatment Plant indicated low levels of PCB, Coley said.
He said the PCBs were found in some but not all of the samples taken at the McAlpine plant, near Carolinas Place Mall in Pineville, between last September and February.
At the time of the discovery of the contaminants at the Mallard Creek plant in early February, city officials said they didnt suspect anyone of trying to harm people. Rather, they suspected someone was trying to avoid paying the expensive fees for disposing of PCBs.
City officials said treatment plants are good at removing PCB from wastewater, and they said water leaving the plant showed PCB levels were well below government-set guidelines.
Coley said the Environmental Protection Agency, the N.C. Department of Environment and Natural Resources, and the S.C. Department of Health and Environmental Control have been notified of the findings. He said North Carolina officials also are still looking into the PCB dumping at the Mallard Creek plant.
The two plants feed different river systems.
wastewater from the Mallard Creek plant eventually flows into the Rocky River, and then into the Pee Dee River east of Charlotte.
Water from the McAlpine Creek plant eventually flows into the Catawba River, downstream from Lake Wylie in South Carolina.
PCBs are a toxic chemical and a family of chemical compounds that is a long-lived environmental contaminant.
Finding the source of dumping into the McAlpine Creek plant could be challenging. It is the biggest wastewater treatment plant in the CMUD system, and its service area stretches from Mint Hill to northwest Charlotte and then south to near the state line.
A multi-agency criminal task force, headed by the Charlotte-Mecklenburg police, is investigating the dumping, which is a violation of both state and federal law.
Anyone with information in the case is asked to contact Crime Stoppers, 704-334-1600.
Lyttle: 704-358-6107; Twitter: @slyttle