The chemical PFECHS, commonly used in hydraulic fluid for airplanes, has recently been found within Great Lakes surface water and fish. Image via ThePublicDomain.net.
Researchers in Canada have discovered a hydraulic fluid used by planes within Great Lakes surface water and fish, according to a recent study.
For the first time perfluoroethylcyclohexanesulfonate, abbreviated as PFECHS, has been detected in surface water and also in predatory fish such as lake trout. What kind of health threat that represents for people and wildlife is unclear. Equally mysterious is how the chemical got into the water.
Derek Muir, head of the Priority Substances Exposure Section with Environment Canada, said he and the other researchers who contributed to the study believe wastewater plants are a possible source.
“Overall, the pattern looks like it’s related to the urban population around the lakes,” he said. “(Lake) Michigan is high, Erie is high and Ontario is high so we’re fairly confident in saying wastewater is a source. We’d like to know what specific kinds of industries or processes or releases might go into the wastewater plant and we just don’t know.”
Another possible source is the careless disposal of the chemical by companies that use it, said Anders Andren, a professor of environmental chemistry at the University of Wisconsin-Madison and director of the university’s Sea Grant Institute and Water Research Institute.
“Unfortunately, they change (the chemicals) every so often and have not been particularly careful at how they dispose of them, so we don’t know exactly but they must have been dumped in the watershed somewhere where they have leeched out into rivers,” he said.
Muir suspects PFECHS has been present in the Great Lakes for a while now – but was undetected by scientists who weren’t testing for it.
“To be more detailed about why that is, you should keep in mind that the perfluorinated chemicals were discovered in the Great Lakes about 10 years ago now, and so in a way everyone missed this group of chemicals,” he said. “They missed it because of the lack of appropriate methods to quantify or analyze it properly in environmental samples.”
The oversight illustrates a more fundamental point about commerical chemicals used about which people aren’t fully knowledgeable, Muir said.
“We don’t know if they’re in the environment because we don’t have methods to analyze it,” he said.
PFECHS belongs to a family of chemicals called perfluorinated chemicals. Each chemical bears similar qualities and is made up of similar compounds.
The length of time which PFECHS has been present is difficult to determine because the chemical, by nature, doesn’t break down easily, Andren said.
Another reason the chemical hasn’t been reported before is that it’s challenging to analyze, Andren said.
“You have to spend a lot of time in the laboratory extracting them from water, fish or sediments and cleaning things up. Purifying the extract, it’s a lengthy procedure takes for each sample takes several days to do.”
Another thing concerning scientists is how the chemical affects the fish it’s been found in – and the humans who eat them. They are studying the broader family of perfluorinated chemicals for clues. Unfortunately, even those impacts are uncertain.
“We know (perfluorinated chemicals) are toxic and they accumulate in fish tissues and presumably in human tissues from eating those fish, but (scientists) don’t know what the effects are,” Andren said.
Muir said all he and his fellow contributors to the study know about perfluorinated chemicals is that they aren’t acutely toxic – which to say there are no immediate apparent impacts. The impact from long-term exposure is unknown.
“You’re not going to get effects from exposures that are parts per trillion in lake water like these are,” he said. “If you feed fish a food with a certain amount, you wouldn’t get any effect that would knock them down or kill them. There’s other ways of talking about effects like long-terms effects in reproduction.”
Amy Babcock, a toxicologist with the Michigan Department of Environmental Quality, said she isn’t aware of any environmental effects or toxicity information specifically for PFECHS. To date, most of the research done on perfluorinated chemicals has been focused on other chemicals found in the environment and not PFECHS, she said.
Babcock said current research suggests that perfluorinated chemicals in general, not PFECHS specifically, are toxic.
“In laboratory animals, (other perfluorinated chemicals) caused liver damage and hormonal alterations … and caused liver and kidney damage,” she said. “There is no conclusive evidence that either chemical has caused illness in humans.”
PFECHS is commonly used in hydraulic fluids in aircraft brakes to keep them stable despite changing temperatures.
“(Planes) have a lot of brakes and lines full of braking fluid,” Andren said. “What happens is they try to improve the properties of the braking fluid because, as you might imagine, airplanes go from temperatures that are minus 70 degrees to almost 100 degrees.”
The chemical also coats metal inside hydraulic pumps to reduce wear, he said. “These brake lines will last a much longer time.”
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