The arsenic reported earlier this week in Charlotte's major drinking water source poses no health hazards, Mecklenburg County's water-quality chief says.
Rusty Rozzelle and Sam Perkins, the Catawba Riverkeeper Foundation's director of technical programs, talked to the community group We Love Mountain Island Lake at a Thursday night meeting.
The meeting followed publication Monday of a Duke University study that found arsenic in the discharge water that flows into the lake from the Riverbend power plant, and in lake sediment. Arsenic is, of course, toxic.
But Rozzelle told the group the arsenic is largely in sediment, not the lake water itself.
"There is no potential threat to the water supply downstream of the discharge pipe," he said. "We've never found any arsenic above the minimum detection limits, and to my knowledge no one else has either."
Charlotte-Mecklenburg Utilities tests Mountain Island water weekly with similar results, spokeswoman Karen Whichard said today. No arsenic is detected in treated water that flows to household taps, she said.
The Riverkeeper Foundation worked with Duke University to collect water and sediment samples for study. Perkins said contaminated "pore water" in sediment can be released into the water column during certain conditions, such as summer heat, or if the sediment is disturbed.
A more important question, Rozzelle said, is what will happen to Riverbend's ash ponds once Duke closes the c.-1929 plant by 2015. Rozzelle said Duke will have to submit a plan to permanently close the ponds, but hasn't yet.
"To me, the important thing is how it's closed," he said.