Two women wearing white hard hats, yellow safety vests, and blue latex gloves scrape at a soil sample.

Hidden Helpers: Pittsburgh鈥檚 Industrial Past Might Hold the Key to a Cleaner Future

By Amy Pavlak Laird Email Amy Pavlak Laird

Heidi Opdyke

Pittsburgh has reinvented itself from a steel powerhouse to a hub for health care and education. But the city鈥檚 industrial past left a hidden legacy: toxic compounds like benzene and toluene in the soil. While most life can鈥檛 survive such a contamination, some microbes adapted to use the pollutants as food.听

Now, scientists at 好色先生TV are exploring whether these microbes can help clean up what the steel industry left behind.听

鈥淲e鈥檙e taking advantage of the fact that, over generations, ecology and evolution have potentially already done a lot of the work for us in enriching microbes that might be able to assist us in doing more complete remediation,鈥� said Catherine Armbruster, assistant professor of biological sciences and a microbial ecologist. 鈥淎nd Pittsburgh is definitely the place for this project.鈥澨�

With a $250,000 grant from the Richard King Mellon Foundation, Armbruster and her team are searching for answers at Hazelwood Green, a former steel coking site.听


Western Pennsylvania is dotted with more than 250 brownfields 鈥� former industrial sites where hazardous pollutants linger. Conventional cleanup methods often involve digging up contaminated soil and burying it elsewhere. That鈥檚 what was done at Hazelwood Green, transforming the former steel site into a safe, thriving hub. Today, it hosts research centers for CMU and the University of Pittsburgh, with more development underway. The remediation, however, took years and cost tens of millions of dollars.听

Armbruster鈥檚 team is betting on a different strategy. Their project aims to harness brownfield bacteria鈥檚 innate abilities to do a less costly and more complete environmental cleanup.听

But first, she must find the bacteria that break down the most common pollutants located at these sites. It鈥檚 a daunting task. Just a teaspoon of soil teems with billions of bacteria and other microorganisms.听

鈥淪cience is in a place now where we have the technology to sequence entire microbial communities,鈥� Armbruster said. 鈥淎nd then we can use that genomic data to identify which bacterial species are there and predict whether they have the metabolisms we care about the most.鈥澨�

Digging Deep听

On a cold, rainy day in March, Armbruster headed to Hazelwood Green to collect soil samples. The ground was hard, but luckily she didn鈥檛 have to do any shoveling. With the funding from the Richard King Mellon Foundation, Armbruster brought in a GeoProbe, a machine designed to collect soil samples at up to 50 feet.听

A man in a yellow vest and hardhat kneels in front of a piece of machinery that is digging deep in the soil.
Jacob Stimson inspects the GeoProbe, a machine designed to collect soil samples at up to 50 feet.
Latex glove-covered hands scoop soil from a long tube into a plastic test tube.
Soil collected by the GeoProbe is transferred to a vial for transport to the Armbruster lab.

Once the soil makes it back to the lab, Armbruster has assembled an interdisciplinary team to isolate the bacteria, extract its genetic sequences, comb through the vast amounts of genomic data to identify which microbes can break down the hazardous pollutants common to brownfields, and track what the break-down products become.听

鈥淚 feel CMU is the right place for a project like this. The students have the interests and the aptitude to tackle these challenges,鈥� Armbruster said.听

Marcus Lopez, a senior studying biological sciences and environmental and sustainability studies, is leading the effort to extract the bacteria from the soil along with research scientist Mara Kessler and undergraduate Charlie Stanczak. Using traditional wet lab techniques, like spinning down the soil/liquid mixture in a centrifuge, siphoning off the liquid and adding it to petri dishes, the team will monitor for bacterial growth. Once the bacterial colonies start growing, they鈥檒l isolate different strains and send them off for genomic analysis.听

Meanwhile, Ethan Chen, a student in the M.S. in Automated Science program, is spearheading the effort to automate as much of the process as possible. And June Qu, a student in the M.S. in Quantitative Biology and Bioinformatics program, is using computational methods to comb through the vast amounts of genomic data extracted from the bacteria in the soil. Her goal is to identify which microbes carry the genetic machinery to break down chemicals like benzene, toluene, ethylbenzene, and xylene. To find these needles in the haystack, she鈥檚 developing a computational tool tailored to these genes.听

鈥淚n addition to soil samples from Hazelwood Green, I鈥檓 gathering more data from oil-contaminated sites and contaminated groundwater from different parts of the world. I鈥檓 running my tool on all this data to fine tune it a little bit more to decrease the number of false positives and increase the sensitivity of detecting these genes,鈥� Qu said.听

Once Armbruster鈥檚 team has isolated microbes from Hazelwood Green and screened them in the lab to see how well they break down pollutants, they鈥檒l hand them off to environmental chemist Carrie McDonough. An associate professor in the Department of Chemistry, McDonough will use high-resolution chemical analysis to track what the pollutants become once they are broken down.听

鈥淲e want to transform these hazardous compounds, but we want to know what we鈥檙e making during that process. For that, we absolutely needed a chemist, which is where Dr. McDonough comes in,鈥� Armbruster said.听

Preliminary results from the first group of soil samples from Hazelwood Green, some from the surface and some from deep in the ground, suggest that each site harbors a distinct microbial community, and that more contaminated samples had more bacteria that could degrade benzene, toluene, ethylbenzene, xylene and polycyclic aromatic hydrocarbons.听

Seven people wearing hard hats and safety vests stand in front of a digging machine in an empty lot of dirt
The team on site at Hazelwood Green, from left to right: June Qu, Mara Kessler, Betsy Lewis, Catherine Armbruster, Jacob Stimson, Anthony Tedesco and Charlie Stanczak.

Education with Impact听

The grant is also fostering STEM learning and empowering students to tackle local environmental challenges. The project will connect local high school teachers and students with CMU鈥檚 Pre-College program in Computational Biology and the Summer Academy for Math and Science. Each summer, about 160 students, including five recruited from Pittsburgh-area high schools, will study the Hazelwood Green site, analyze microbial communities, and gain experience in metagenomics and automated biology.听

鈥淚鈥檓 excited about this project because it鈥檚 local and culturally relevant to community stakeholders,鈥� said Michael Young, associate dean for community engagement and associate professor of mathematical sciences. 鈥淢y goal, particularly with students who might come from underserved schools or school districts, is very simple: I want them to learn new things and I want them to have a good experience. Academic and scientific rewards will be reaped later.鈥澨�

If successful, this work could turn Pittsburgh鈥檚 industrial past into a model for sustainable cleanup 鈥� and inspire the next generation of scientists.