LEILA FADEL, HOST:
In Minnesota, scientists have launched what's believed to be the first statewide effort to measure PFAS in the air. PFAS, called forever chemicals, are found in all sorts of products from nonstick cookware to cosmetics. They don't break down in the environment, and studies link some of them to health risks like cancer, high cholesterol and liver damage. Kirsti Marohn with Minnesota Public Radio reports that this new effort uses a simple tool easily found in nature.
KIRSTI MAROHN, BYLINE: Scientists routinely find the human-made chemicals known as PFAS in soil and water near sources like manufacturing plants, landfills and airports. But Summer Streets, a research scientist at the Minnesota Pollution Control Agency, says sometimes the chemicals show up more mysteriously in remote areas.
SUMMER STREETS: There's no obvious local source. Where is that PFAS coming from? It's probably coming from an atmospheric deposition.
MAROHN: That means contaminants in the atmosphere settled to the earth as deposits in rain, snow or dust. Streets says understanding PFAS in the air is key to knowing how the chemicals move around in the environment and how they end up in lakes, rivers and fish.
STREETS: That air pathway is really important for moving PFAS all around the environment, not just in Minnesota, but globally.
MAROHN: But traditional air monitoring equipment is expensive and would be difficult to deploy statewide, especially in remote areas. Then, Streets heard about research in North Carolina that used pine needles to study PFAS around a chemical plant.
STREETS: I thought, wouldn't this be cool? Can we do this statewide?
MAROHN: She recruited volunteers to collect pine needles across Minnesota.
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MAROHN: Abby Wacker and her 9-year-old son, George, are two of the citizen scientists who volunteered to help. They pulled on plastic gloves to show how they collected pine needle samples.
ABBY WACKER: OK, this one is yours. I think you have one of mine (laughter).
MAROHN: Then George stuffs handfuls of pine needles into a Ziploc bag his mom holds open.
GEORGE: Not the whole branch, but the tip of it. We kind of fill up the whole bag.
WACKER: Then we went all the way around the tree at eye level.
MAROHN: They wear gloves so any PFAS on their skin won't taint the samples. And since PFAS are also used in clothing to make it resist water or stains...
WACKER: We had to make sure that the clothes that we were wearing had been washed at least six times so that we weren't wearing brand-new clothes that could contaminate our sample.
MAROHN: It turns out that pine needles make surprisingly good air monitors. They have a waxy surface that contaminants easily stick to. Lead scientist Streets says in the lab, researchers will test the needles for 75 different PFAS compounds.
STREETS: We should be able to kind of lay that out on a map and look for hotspots, possibly, if we're seeing an area where certain PFAS are very elevated. Does that mean there might be a source there that we could track down and work with?
MAROHN: Researchers also will compare the new samples with old pine needles from a natural history museum that were collected long before forever chemicals were invented.
STREETS: When did we see certain PFAS arrive on the scene? Maybe when was the first time we started really seeing PFAS out in the wider environment away from manufacturing? There's all sorts of interesting things that we can learn from that.
MAROHN: And the volunteers now understand more about PFAS and can share that knowledge. George Wacker already gave a report to his fourth-grade class about forever chemicals. His mom, Abby, says she hopes their work helps scientists better understand PFAS and pinpoint places where their exposure to people can be reduced.
For NPR News, I'm Kirsti Marohn in Buffalo, Minnesota.
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