Fish in Lake Calhoun found to have high levels of former 3M chemical
ECCO – On an overcast Tuesday morning, Billy Kaphaun of St. Louis Park cast a line into the channel connecting Lake Calhoun to Lake of the Isles.
It was two days before a May 10 town hall meeting brought state officials to nearby St. Mary’s Greek Orthodox Church, where they briefed area residents on the lakes¹ contamination with an industrial chemical and their plans to find a source.
Kaphaun, never taking his eyes off an orange bobber, said he¹d seen recent news reports warning anglers to limit their consumption of bluegill sunfish from the Chain of Lakes. Minnesota Pollution Control Agency tests showed Lake Calhoun bluegill fillets had relatively high concentrations of a former 3M chemical.
He remembered thinking: "What is this world coming to?"
Kaphaun said he rides his bike over to Lake Calhoun and fishes almost every day in the summer. But he eats only a few fish each season.
"There’s just too much garbage in the lake," he said, pointing out the plastic pop bottle bobbing near his feet.
"These people were out here fishing like two days ago," he said, "and they had a stringer full of fish and I told them [about the contamination]."
It was the first they¹d heard of the new fish consumption advisory. For his part, Kaphaun will avoid eating any fish he catches in the lake this summer.
"You see, the muskies and the northerns and stuff feed off [of] the bluegills and the sunnies," he said. "It’s common sense."
State officials plan to test Kaphaun’s hypothesis in coming months. Taking more fish samples is just one step in assessing the spread of perfluorochemicals, or PFCs, in state waters.
At the town hall meeting, Paul Hoff of the pollution control agency said PFCs pose new type of challenge for the agency. They may be more difficult to manage than mercury or polychlorinated biphenyls (PCBs), the pollutants of most concern to anglers.
Chemicals in the PFC family – including the perfluorooctane sulfonate (PFOS) found in Lake Calhoun bluegills – spread quickly and are extremely durable.
"This really is a different kind of persistent contaminant," Hoff said. "There’s no evidence that they really break down at all [in the environment]."
Finding a source
Hoff said PFOS was used in broad array of applications, from denture cleaner to firefighting foam to insecticides.
"It’s [in] everything from Scotchguard to shampoo," Hoff said.
3M used PFCs to make Scotchguard, Teflon and other products beginning in the late 1940s, but phased out their use by 2002. PFCs are still produced in other parts of the world, and their long shelf life ensures they¹ll remain in circulation for years, Hoff said.
Hoff said the pollution control agency was studying historical applications of the chemicals in the Lake Calhoun area. The agency also will examine how stormwater may carry PFCs into the water.
"The stormwater system we think has a role," Hoff said.
During the town hall meeting, Laura Solem, a pollution control agency toxicologist, displayed a map of Lake Calhoun showing a dozen or more bright green dots ringing its shore. Each marked a point where stormwater enters the lake.
Solem said Lake Calhoun has ³quite a large watershed,² draining not only nearby Minneapolis neighborhoods but also about half of St. Louis Park. The land in St. Louis Park includes both residential and industrial properties, she said.
In April, the pollution control agency took samples from several areas near the lake. By comparing the samples, the agency hopes to determine which land-use type – industrial or residential – is the source of PFOS.
Hoff said lab results from the samples would be ready in two to three months. The initial results will guide a follow-up study.
³We think we¹ll have some more information by mid-summer,² he said.
The pollution control agency will continue to test other urban lakes in the metro area, as well as outstate waters. Ongoing testing will also measure PFOS levels in various fish species.
Researchers want to determine if Lake Calhoun is a PFOS ‘hotspot,’ or if the contamination is typical of an urban lake, Hoff said.
They also hope to understand why bluegill sunfish show the highest concentrations of PFOS. It is the opposite for many contaminants, such as mercury and PCBs, which concentrate in larger fish, he said.
Patt McCann, a Minnesota Department of Health research scientist, assured audience members at the town hall meeting the Chain of Lakes was still safe for swimming and recreation during the testing period.
McCann said water from the hand pumps around Lake Calhoun was tested and showed no sign of PFCs. Those pumps draw from an aquifer about 150 feet below ground.
Minneapolis and St. Paul drinking water was also shown to be safe, she added.
In studies of laboratory animals, high concentrations of PFCs are associated with damage to the liver and other organs, developmental problems and, sometimes, cancer. There is still too little evidence to link PFCs to disease in humans, McCann said.
Still, those area residents who spoke at the town hall meeting expressed concern about the potential scope of the PFC problem.
ECCO resident Gary Farland asked if it wasn’t inevitable that levels of PFCs would continue to increase in the environment, given they don’t break down over time.
Hoff said it was.
"There are still large stockpiles being used up" around the world, he said.
John Stine, environmental health division director at the department of health, said the chemicals could also leech into area groundwater.
"If there are high concentration sources, migration of that water through the aquifers is very likely," Stine said.
Nancy Ward, who recently moved to the Lake Calhoun area, urged the state and city officials present to stay on top of the emerging PFC problem.
"This is really about life as we know it," Ward said. "We need to be looking a lot further down the line."