Pratt Trailblazers: Heileen Hsu-Kim

When someone is invited to the White House to meet the president of the United States, it generally signals they’ve reached the pinnacle of their career. But when professor and aquatic geochemist Heileen Hsu-Kim shook the hand of President Barack Obama in 2012, she was just getting started.

Hsu-Kim, the Yoh Family Professor of Civil and Environmental Engineering at Duke, had been recognized for her pioneering work into understanding how mercury changes in the environment to become bioavailable to organisms in the food chain.

As her expertise in mercury contamination and transport deepened, her sights shifted further afield to the rainforests of Madre de Dio, Peru. There, small-scale mining outfits were using mercury to separate gold from soil.

When mercury enters the water supply, microorganisms in the sediment transform it into methylmercury, which is highly toxic. That compound eventually winds up in the fish that local people eat. In collaboration with colleagues at the Nicholas School of the Environment, Hsu-Kim led a multi-year project in the region to identify, quantify and mitigate the resulting exposures for the people who live and work there.

But the impacts of Hsu-Kim’s work hit close to home, too. In the Southeast, coal ash spills have had devastating effects on the environmental quality of local waterways. Hsu-Kim has made it a focus to understand exactly how toxins like selenium and arsenic leach into the environment—but also how to make coal ash wastes a useful resource for metals and minerals needed for clean energy and low-carbon materials.

“Oftentimes, virgin materials are desirable because they’re high quality,” said Hsu-Kim. “I’d like to see a different approach—the default mindset should be, ‘What can we find that would be thrown away anyway?’ We should engineer around those waste streams.”