Inside a freezer in North Central High School’s Institute of Science and Technology sits a tray of extracted DNA that junior Hanna Faught can’t bring herself to discard.
“For these, I just really don’t want to throw them out ,” Faught said, as her lab partner, senior Meilin Scott, laughed nearby.
Inside those tubes are tiny samples of DNA from soil collected from the city of Spokane’s sewer drains, DNA that has now degraded to a point to be of little use in future research. The pair recently won first place at the Washington State Science and Engineering Fair for their work trying to eliminate a pervasive pollutant in that soil: polychlorinated biphenyls, or PCBs.
“We’re trying to see if we can use microorganisms to degrade the PCBs, versus using chemicals or simply moving them,” said Scott.
The students, who first met each other in the same Girl Scout troop, worked with North Central science teacher Dan Shay, the teacher of the year recipient at the state science and engineering fair. They also built upon research begun by previous North Central students Rachel Harwood, Nick Heimbigner, Sandra Thang and Alyssa Toney, as well as the Spokane Lands Council.
The resulting paper’s findings are promising. Three bacteria types were identified as worthy of future study in breaking down the rigid carbon-chlorine bonds that give the manmade chemical and presumed carcinogen its long life. Though production of PCBs was prohibited in the United States in 1978, the chemical remains in soil, water and the air, and has prompted debate about discharge standards of wastewater into the Spokane River.
Breaking down the compounds in soil has the potential to address the problem on a greater scale, said Scott.
“It’s a more natural method,” she said. “All of our ecosystem is connected. So, if the PCBs are in the soil, then they’re also in the water or the air.”
If the project, which also sought to see whether the introduction of additional nitrogen into the soil would help the PCB degradation process, can be scaled up successfully, it could show ways to treat contamination at the source and avoid the costly removal efforts currently used for such dirty dirt.
Soil contaminated with PCBs above a certain level is usually moved to a landfill, or if it’s contaminated but not at levels requiring cleanup may be used as fill material beneath a building.
All that does is move the problem, it doesn’t solve it, Shay said.
“We are getting rid of it,” he said. “It’s measurably gone. We’re getting 80% reduction, and that’s consistently.”
How the students determine that involves pans of dirt, a freezer that is of similar build and quality that is now being used to house COVID-19 vaccines and DNA sequencing machines, all housed on North Central’s campus. The school has been partnering with Mike Petersen, formerly of the Lands Council, and consultant Les Stephens to collect the samples and design future studies.
Stephens said the collaboration with North Central and their state-of-the-art genomics equipment represented a perfect pairing to address soil contamination in Spokane. The city was already collecting soil from within its storm drains during the summer months to prevent PCBs from leaching into the water, a process that includes giant vacuum trucks that suck up debris for drying and eventual disposal.
“Once I went into the high school and saw the lab, I thought this is perfect,” Stephens, who originally worked with Heimbigner and Harwood, said. “Those two students at the time had done all this research. You could see they’re motivated.”
They’re also doing the same work as biochemists seeking advanced degrees.
“It’s like graduate-level college work being done in a high school,” said Petersen.
Over the past year, that’s meant some early wake-up calls so that Faught and Scott could even get into the lab and perform work during the pandemic. The pair would often arrive at North Central at 6 a.m. to perform DNA extraction, then return home for their coursework during the day.
The process of extraction took months, and Faught – who plans to return next year to continue work on the project – said it’s fortified her confidence now working with the high-tech machinery.
“The last few times I’ve tried to sequence, it’s failed,” she said. “But I really don’t feel discouraged about it anymore. I just restart it.”
Those moments, of learning through failure and seeking fellow students’ help when something seems hard rather than simply asking for the answer, are what brings Shay pride as a teacher. A mantra posted in the classroom encourages students to fail fast, so that they can move on to the next possible solution.
“At this level, when we’re solving problems, it really feels like we’re solving them together,” Shay said. “I don’t have any of the answers, and these students become a lot more like colleagues in how we think about problems.”
Petersen said he’s been in talks with both the city of Spokane and Kaiser Aluminum to obtain additional contaminated samples and hopes that future projects can be run outdoors so that students can look at fungi activity outside of the laboratory.
“The local fungi are really appropriate for this,” Petersen said. “What was lacking is it doesn’t have enough oxygen, nitrogen, to keep up those levels needed for bioremediation.”
That work will continue without Scott, who plans to attend Western Washington University in the fall and conduct undergraduate research on related problems that could be solved by fungi.
Scott said she’ll miss working with her partner, and in the North Central lab, after graduation, though.
“The award’s just kind of like a cherry on top,” Scott said. “Even if I walked out of the lab and knew that I didn’t get the results I wanted, I still was happy because I got to be in the lab.”
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