Solutions for Troubled Waters

Lake Michigan is often thought of as the crown jewel of Northwestern. As large as an inland sea, its waters are ever-shifting: They can sit as still as glass on a calm spring day, or crash onto the painted rocks during summer thunderstorms, or collect into ice sculptures along the Clark Street Beach in subzero winters.

The lake is a draw for students and professors alike, whether for exercise — professor Will Dichtel is known to swim in the cool waters — or just for daily contemplation.

But this immense body of fresh water, whose shimmering beauty convinced Northwestern’s  founders that this was the place to build the University, has been under threat since the early 20th century.

The Great Lakes, the second-largest source of surface fresh water in the world and the source of drinking water for more than 48 million people in the U.S. and Canada, have undergone substantial changes over the past 200 years of human activity. Development, agriculture, infrastructure and industry have left the lake bottoms laced with legacy contaminants and toxins. More recent threats include invasive species such as zebra and quagga mussels, microplastic pollution and algae blooms.

Infographic by Heads of State

Now the Great Lakes region faces another imminent challenge: climate change. A new report by Midwestern and Canadian scientists and experts details how climate change could affect the Great Lakes and threaten public health, fish and wildlife, water quality, and the regional economy.

“We are already seeing the effects of climate change on Great Lakes cities,” says Northwestern civil and environmental engineering professor Aaron Packman, an expert in water scarcity, water management and urban flooding who helped write the report. “One example is the recent severe flooding in the Midwest, which is associated with changing weather patterns in the winter and early spring. These events discharge sewage and fertilizer into the Great Lakes. Flooding is very damaging to vulnerable communities in cities like Chicago.”

The report highlights the impact of climate change on the 34 million people who live in the Great Lakes area and lays out several problems, including lower quality of drinking water, extreme weather and decreased crop yields.

While it can be easy to be pessimistic, Northwestern researchers say these challenges can be solved. Through partnerships, new technologies, startup businesses, public policy roles, and as legal advocates, Northwestern faculty, students and alumni are keeping water resources like the Great Lakes clean and sustainable.

Packman is one of several Northwestern professors looking for innovative, cost-effective ways to tackle water issues. Chemistry professor Will Dichtel has created a polymer that, when placed in water, binds and eliminates PFOA, a human-made chemical that was used to manufacture Teflon and Scotchgard. Kimberly Gray ’78, a civil and environmental engineering professor, is helping develop a new membrane covered with a thin polyelectrolyte film that could be used in drinking water treatment. Water security, both in Chicago and worldwide, is the focus of anthropology assistant professor Sera Young’s research. And Julius Lucks, a chemical and biological engineer (and Young’s husband), is creating a new class of smart diagnostics to cheaply and quickly assess water quality.

“Water is life,” Packman says. “We all need water to live. So if you drink water, you should probably care about what exactly is in your water, make sure that you have enough water, and make sure that we have a sustainable supply of water.”

Finding ways to deliver clean and safe water sometimes has origins in unlikely places.

Chemist Will Dichtel is an open-water swimmer who isn’t afraid to traverse Lake Michigan’s summer waves, but he wasn’t focused on the extent of industrial pollutants circulating in the Great Lakes until he began to think about making new materials from sustainable sources. In his lab at Northwestern, Dichtel develops specially designed polymers that can do everything from store electricity to clean up water by taking advantage of the open space these materials have at the molecular level.

Will Dichtel, Robert L. Letsinger Professor of Chemistry

A few years ago, he and his research group began to study cyclodextrin, a sugar derived from corn, which is made from molecules shaped like tiny cups. It turns out those cups are the right size to bind and trap many pollutants found in water, including bisphenol-A (BPA) and pesticides. “It’s a lock-and-key fit,” says Dichtel, the Robert L. Letsinger Professor of Chemistry.

The first material he created from cyclodextrin in 2015 trapped hundreds of these pollutants found in water, but it did not trap pollutants that represent a growing concern: perfluorinated alkyl substances (PFASs), including eight-carbon derivatives known as PFOA and PFOS. These human-made chemicals have been used in industrial processes for the past 70 years. 

Even small amounts of PFASs and related chemicals are highly toxic and do not break down naturally, meaning every bit that found its way into the environment remains there. The Environmental Protection Agency’s advisory limit for these chemicals in drinking water is 70 parts per trillion, which is equal to one teaspoon in 14 Olympic-size swimming pools. Many experts think even this level is too high, and more stringent limits are being implemented by individual states.

Dichtel and his group modified their cyclodextrin polymer to bind PFOAs and other related chemicals. Now, when placed in water, the material binds the pollutant and eliminates it to below 10 parts per trillion, which is in line with the lower advisory limits introduced by Michigan, California and other affected states.

Using machine-learning algorithms, the group is fine-tuning the material for other pollutants and will continue to tweak them as new chemical pollutants are discovered.

Dichtel and his group are also beginning to develop next-generation membranes that could potentially remove dissolved salt from seawater in a much more efficient manner. “Our ultimate goal is to make materials that can make water cleaner and safer and ensure our water security long-term,” he says.

In 2016 Dichtel co-founded the materials startup CycloPure to bring his PFOA-binding materials to market. The company’s research and development lab in Skokie, Ill., is working to scale up production while reducing costs. The company hopes to launch its first PFOA-binding product later this year.

Dichtel says the company has been making great strides in developing products for both municipal water treatment facilities and household consumers.

“We want consumers to have peace of mind, a line of defense between the water coming into their homes and the water they put into their bodies,” he says.