Water experts warn some fish in Lake Wylie are only safe to eat in small amounts after largemouth bass taken from the lake tested positive for a cancer-causing compound.
South Carolina health officials announced Thursday largemouth bass from Lake Wylie and the Catawba River between the lake and Fishing Creek Reservoir should not be eaten more than once a week.
"People can still safely eat fish taken from the state's waters if they follow the fish consumption advisory guidelines," said David Wilson, chief of the state Department of Health and Environmental Control's Bureau of Water.
Public advisory signs will be posted at boat landings next month, Wilson said.
Sign Up and Save
Get six months of free digital access to The Herald
Also Thursday, North Carolina experts said no channel catfish should be eaten from Mountain Island Lake, the nearest upstream reservoir to Wylie.
The culprit is polychlorinated biphenyls, or PCBs, which test results released Thursday show exceed levels for unlimited safe consumption.
The chlorine-based, synthetic compound was banned in the 1970s after the Environmental Protection Agency linked it to "cancer, as well as a variety of other adverse health effects" on the immune, reproductive, nervous and endocrine systems.
The "blanket advice" statewide is for pregnant women, women who might become pregnant or children to avoid eating more than one meal of freshwater fish from any South Carolina lake each week, and avoid eating any fish under a consumption advisory.
DHEC spokesman Adam Myrick said the largemouth bass is the only species tested for PCBs in the latest round on Lake Wylie. So, he said, he can't be sure species such as channel catfish are any safer if they come out of Lake Wylie than from Mountain Island Lake.
Only largemouth bass were tested for elevated PCBs because they are a large predatory fish. The next step, Myrick said, is to test other species. He did not know when more testing will be done or on which fish.
"We're going to go where the data sends us," he said.
In late 2009, the EPA released data for 500 lakes nationwide. All lakes showed the presence of PCBs, despite the material not having been produced commercially in decades.
However, 17 percent of those lakes, including Lake Wateree downstream of Lake Wylie, exceeded federal water quality standards for PCBs.
South Carolina in May issued consumption advisories for Wateree, limiting largemouth bass to one meal per week, and both striped bass and blue catfish to one meal per month.
Chuck Gorman, director of the state's water monitoring, assessment and protection division, said in August that PCB levels in Wateree and Mountain Island Lake tests by the Catawba Riverkeeper Foundation were such a concern, the state needed to be "focusing more of our attention on the Catawba basin."
"It's quite alarming," Catawba Riverkeeper David Merryman said of Thursday's advisory, "not only for Lake Wylie but for the entire Catawba River basin in South Carolina.
"This is obviously a problem that has gone unchecked for quite some time."
Rock Hill professional angler Rusty White, who runs the fishingwithrusty.com website, said the PCB findings need perspective.
"Honestly, I don't think it really matters," he said. "If it was that high, they'd be saying don't eat it at all."
Catfish, crappie and light perch are "a whole different ballgame," White said, but the majority of bass anglers seldom, if ever, eat their catch.
"You have 98 percent of them out there who catch and release," White said. "And the other 2 percent who do eat the fish, they're not fishing that often.
"It's not like they're going to eat bass three or four times a week."
Past studies show smaller fish - such as bluegill and black crappie - usually have lower PCB levels than larger, predatory fish - like largemouth and striped bass.
"It's possible that a similar pattern will be found in the Catawba basin," Wilson said. "We will continue to collect additional species within the watershed and will update the advisory as needed."
According to DHEC, PCBs in fish tissue does not make the surrounding lake water unsafe for recreational uses such as wading, swimming, boating or handling fish.
What are PCBs?
Polychlorinated biphenyls are man-made compounds - banned in 1979 - that were often used in insulation, as fluids for electrical transformers and products like cutting oils and carbonless copy paper.
They remain a problem today because they do not break down easily in the environment.
PCBs have been shown to cause cancer, as well as a number of serious non-cancer health effects on the immune, reproductive, nervous and endocrine systems.
If pregnant women eat fish containing PCBs, their babies could suffer from lower birth weight, smaller head size, premature birth, developmental problems and learning disabilities.
PCBs build up over time in the fatty parts of the fish. They can also build up in your body if you eat fish contaminated with PCBs.
By cleaning or cooking fish to reduce fat, you can reduce the amount of PCBs you eat.
What to eat ... and not to eat
A "meal" in South Carolina is considered an 8-ounce portion of fish (uncooked), which is about the size of two decks of playing cards.
Largemouth bass from Lake Wylie or the Catawba River from Wylie to Fishing Creek Reservoir should be eaten no more than one meal a week.
Largemouth bass from Fishing Creek and Cedar Creek reservoirs should be eaten no more than one meal a month.
Largemouth bass from Lake Wateree should be eaten no more than one meal a week.
Blue catfish and striped bass from Lake Wateree should be eaten no more than one meal a month.
Do not eat channel catfish from Mountain Island Lake, which is between Charlotte and Lake Norman.
Do not eat largemouth bass from Mountain Island Lake if you are pregnant, nursing or you might become pregnant, or if you are a child younger than age 15.
Everyone else should eat no more than two meals a month of largemouth bass from Mountain Island Lake.
Want to know more?