As a kid, William Dichtel developed two great lifelong loves — for swimming and science — that he has pursued with an abiding passion.
Now a Northwestern University chemistry professor, Dichtel, 43, swims in Lake Michigan almost every morning and holds a record for swimming the entire length of the Chicago shoreline.
And he has found a way to marry his passions, using science to discover better ways to remove toxic contaminants from water.
His latest discovery might prove to be a defining achievement. Dichtel and colleagues in his lab have come up with a simple, inexpensive method to destroy the harmful and ubiquitous contaminants called PFAS, known as “forever chemicals” because they don’t break down in the environment or the human body.
“The more I learned, the more I became concerned about these chemicals,” Dichtel says. “We have to address this quickly, at least in the context of drinking water.”
These chemicals have a wide range of uses, including waterproofing, firefighting and making nonstick pans.
Over more than half a century, though, they have become an environmental nightmare. They have leaked from landfills, factory sites and military bases to contaminate drinking water. That’s a big concern because they are believed to cause cancers and numerous other health problems.
Determined to find the “Achilles’ heel” of some of the most persistent and widespread harmful chemicals in the world, Dichtel, working with his former doctoral student Brittany Trang, led a study, recently published in the journal Science, which found that a combination of the widely used solvent dimethyl sulfoxide and sodium hydroxide — lye — heated to just above the boiling point of water can destroy many types of PFAS.
“It was so simple we can’t believe it was never known,” says Dichtel, who came to Northwestern six years ago. “PFAS manufacturing for the past 50 years has polluted the earth.”
PFAS is short for perfluoroalkyl and polyfluoroalkyl substances. There are more than 12,000 compounds in this class of chemicals. The first were introduced in the mid-20th century through products such as Teflon nonstick pans and Scotchgard fabric protection.
These chemicals are so widespread and seemingly indestructible that it’s estimated that nearly every person in the world has PFAS at some level in their bodies.
The chemicals are believed to increase the risk of developing prostate, kidney and testicular cancers. PFAS also have been linked to high cholesterol, a reduced ability to fight infections, low birth weight and developmental issues in children and other health problems.
Dichtel previously came up with a technology that can help clean PFAS from water.
But the problem, he says, is what to do with them once you do that. There aren’t any good options today to destroy the chemicals once they’re removed from water.
One commonly used method to try to destroy them has been to incinerate the chemicals at extremely high temperatures, as is done with some other types of hazardous waste. But there’s a danger in doing so that the process will also send PFAS into the air, spreading them anew. Citing that hazard, the U.S. Department of Defense announced a temporary halt earlier this year to incinerating the chemicals. Military bases have used vast amounts of PFAS firefighting foam for training exercises.
So the new findings that some PFAS can be destroyed with a process using readily available chemical materials has been greeted as highly promising.
Still, so far the research has shown only that this can be done in a lab. The next step will be to see whether the discovery can be done on a bigger scale.
Even then, Dichtel estimates that the process might work on about half of the total amount of forever chemicals that are now in use, not all of them.
The work that led to the discovery began in early 2020, when Trang, then a Ph.D. student working with Dichtel, had some success in early experiments to show the method could work to “decapitate” PFAS and then render the chemicals harmless.
Like Dichtel, Trang says she was “stunned that something so simple — that we should’ve known decades ago — worked.”
Northwestern has filed a patent on the technology and lists Dichtel and Trang as co-inventors of the process.
Trang says Dichtel encouraged her and other researchers to push ahead with finding a way to make the destruction of the chemicals possible, “recognizing the importance of it and the significance of it.”
In addition to PFAS, Dichtel and his research teams previously developed technology to remove multiple pollutants, including pesticides, industrial chemicals, pharmaceuticals and PFAS, from water. That research continues through the Dichtel Research Group at Northwestern.
Dichtel, a past MacArthur “genius grant” recipient, started a company, called CycloPure, to commercialize his technology.
He says the latest research on PFAS “was inspired by the need to destroy these compounds once we remove them from contaminated water. It’s a fundamentally new discovery from our prior work, but it does take inspiration from what we have been doing for a while.”
Environmental advocates have been pushing for a total ban on the use of PFAS, which also can be found in products including furniture, pizza boxes, microwave popcorn and dental floss.
“It’s promising, and we definitely need more research into these advanced destruction techniques,” says Tasha Stoiber, senior scientist for the Environmental Working Group, a Washington advocacy organization.
Still, Stoiber says manufacture of the chemicals needs to be eliminated altogether and that the U.S. government is “decades behind” on the dangers.
Dichtel agrees.
“Destruction will be important as we purify drinking water and do some types of environmental remediation,” he says. “Our discovery is not a free pass to keep using these compounds. We must dramatically curtail their use.”
Dichtel, who turns 44 Monday, grew up in Roanoke, Virginia. He graduated from a college prep school that had a senior class of just 29 students, and he was one of only three students in his Advanced Placement chemistry class.
By the start of his senior year, he’d already taken every science class his high school offered. So Jerry Maycock, an organic chemist who was a longtime instructor there, agreed to teach him one-on-one. Maycock, now retired, was impressed by how highly motivated Dichtel already was.
“He’s one of the best I ever had, and I had some really good students over the years,” Maycock says.
Dicthel went on to the Massachusetts Institute of Technology and then the University of California Berkeley. While doing post-doctoral work at UCLA and the California Institute of Technology, he was mentored by Nobel Prize-winning chemist Fraser Stoddart before joining Stoddart at Northwestern in 2016.
Dichtel’s mother Mary Lee was a nurse, and his father William was an ear, nose and throat doctor. His sister Laura is an endocrinologist and assistant professor at Harvard Medical School.
He and his wife Laura Nieder have two daughters: June, 12, and Cecilia, 10. Like her dad, June is a competitive swimmer.
He started swimming competitively in sixth grade. In high school, he swam distance events for the school’s swim team, earning five varsity letters.
Dichtel still swims, hitting Lake Michigan near his North Shore home six to seven mornings a week from May through late October. The rest of the year, he swims indoors.
He trained to swim the English Channel in June 2020, but the pandemic prevented him from traveling to England. So he decided to swim Lake Michigan that August instead and ended up setting a record, swimming the entire Chicago shoreline, going 42.1 kilometers in less than 12 and a half hours. He started on a Tuesday night and finished the following morning.
Dichtel hasn’t given up on swimming the English Channel. He plans to tackle that dream in about two years.
Brett Chase’s reporting on the environment and public health is made possible by a grant from The Chicago Community Trust.
