COVID-19 is in Tacoma’s sewers. Testing them will prepare us for future outbreaks, scientists say
Scientists in Tacoma believe they’ve found a way to track COVID-19, and the answer lies in the sewer system.
Earlier this month, researchers at biotech nonprofit RAIN Incubator were given permission to test samples of raw sludge at Tacoma’s Central Wastewater Treatment Plant for the virus.
So far, they’ve tested about 40 samples at their lab in downtown Tacoma, and sure enough — COVID-19 was there.
“We found it,” said David Hirschberg, founder of RAIN Incubator. “So Tacoma tests positive for it. It doesn’t mean it’s infectious — it’s likely not. But it means it’s in our system.”
For research scientist Stanley Langevin, the results weren’t exactly surprising. Langevin knew traces of similar respiratory viruses have been found in fecal matter in the past.
“I had a hunch it would be in the sewers if it was frequently transmitted,” he said. “That’s why we looked.”
But proving it has unlocked a powerful tool — not only for tracking hot spots in the community but also as a warning system in the event of another outbreak.
“I have a feeling that as (COVID-19) goes away, it’s going to come back,” Langevin said. “If we can monitor this long term, I hypothesize we’ll be able to pick it up in the sewers before you see it in the hospital — and that is the value of this tool.”
Taking the sample
Hirschberg, who has a background in infectious disease, is the one who takes samples from Tacoma’s Wastewater Treatment Plant off Portland Avenue.
He brings a kit filled with vials, testing material and personal protective equipment.
When he arrives, he’s led by staff down a flight of stairs beneath noisy tanks holding wastewater that comes from sources like toilets, sinks and showers. The plant takes in more than 15 million gallons of flow per day, said Todd Sundvall, an operator at the plant.
Sundvall fishes out samples for Hirschberg to swab and dip into a substance that essentially “freezes” the sample in time. The whole process takes no more than 10 minutes.
Hirschberg returns to his labs at RAIN, where his team conducts a test to detect the virus through reverse transcription of RNA into DNA. Results are available within a couple of hours.
Hirschberg assures that the tests they’re using are not being taken away from people who are sick.
“The tests we use, although measuring the same thing, are not these CLIA (Clinical Laboratory Improvement Amendments) tests that you would find in a hospital. (Those tests) go through a certain rigor with the government,” he said.
Testing sewage for viruses isn’t a completely new idea, but it’s caught the attention of cities across the country amid the coronavirus pandemic.
Biotech startup Biobot Analytics, in partnership with researchers from MIT, Harvard and Brigham and Women’s Hospital, launched a COVID-19 sewage testing program to help governments track the virus in their communities.
A study by Massachusetts researchers has already found that coronavirus cases are being underreported, largely in part because many are asymptomatic and aren’t tested.
The city of Tacoma is joining in the Biobot effort, said Stuart Magoon, assistant division manager with the City of Tacoma’s Environmental Services Department.
“This is an emerging science, and we are working with David to see what we can learn,” Magoon said in an email. “Additionally, we are participating in a broader national study with Biobot in conjunction with MIT and others using protocols they are establishing to test sewage for SARS-CoV-2.”
Pierce County has also taken an interest in Hirschberg’s research and provided him with samples from the Chambers Creek Regional Wastewater Treatment Plant. The county has given him the green light to also obtain samples at the Cascadia Wastewater Treatment Plant at Tehaleh and the DuPont Pump Station, Pierce County spokesperson Erin Babbo said in an email.
Being prepared
The scientists at RAIN feel like continuing to test the area’s sewage, even after COVID-19 passes, is a good idea.
“It should be like an early warning system,” Hirschberg said. “We should be very alert now. So you could imagine in the future, if we had a surveillance system like this in place or a testing system, you would be able to detect when there’s a threat.”
The system also has the potential to show if certain areas of Tacoma are seeing more concentration of the virus than other areas, such as Hilltop or the North End.
If that can be determined, governments can better direct resources to service providers and hospitals.
The testing could be a “tripwire” for viruses, Hirschberg said.
“We have smoke alarms in our house, we have fire extinguishers,” he said. “These are all tools that we use in case of emergencies — and a smoke alarm is nothing but a sensor. So this is, in a sense, a biosensor that you would use to have an alarm go off to say, ‘There’s a potential threat in our system.’”
This story was originally published April 21, 2020 at 5:10 AM.
