New research finds that rainwater can be a source of PFAs chemicals.
PFAs, or perfluoroalkyl substances, are a family of chemicals found across the state and connected to health problems including cancer.
Researchers with the National Atmospheric Deposition Program, or N.A.D.P., tested 37 rainwater samples for PFAs. Those samples came predominantly from around the eastern US, including one sample from Michigan.
Martin Shafer is a researcher with the N.A.D.P. He said their study looked for 36 different PFAs compounds and found total levels close to 5 parts per trillion in some samples.
“In the rainfall we’re seeing levels that are not too far off from the water quality limits that have been proposed,” he said.
The EPA currently has a health advisory level of 70 parts per trillion but some states, including Michigan, are considering levels for some PFAs closer to 6.
“The concentrations are not insignificant. In terms of looking at sources of PFAs this atmospheric precipitation cannot be ignored,” Shafer said.
The Michigan sample had total PFAs levels of less than 1 part per trillion.
Shafer said more research will be needed to understand where the PFAs are coming from. He said one possibility is that some PFAs may be in the atmosphere itself.
“What is in the vapor in the air, what is in the particles in the air that the rain is washing out?”
Shafer said PFAs have been found in remote locations around the world indicating that atmospheric transportation is significant - and needs to be better understood.
“This is maybe a little bit of a wake up call that we need to pay more attention to the atmosphere as a mode of dissemination and ultimately of deposition to the surface.”