NEW SHOREHAM, R.I. (WPRI) ─ Dylan Chase was shocked when the results of Block Island’s wastewater tests for the Fourth of July weekend came back.
Since May, he had been sending frozen samples of the town’s sewage to Massachusetts-based Biobot Analytics to see if there were any traces of coronavirus. For weeks, the answer had been no.
That changed after Independence Day.
“When I saw that there was an estimation of 10 cases, it’s all of sudden like, you hear about COVID-19, you don’t see it, but now here it is, it’s at your back door,” he said. “It’s kind of like seeing Big Foot.”
Chase is the superintendent of the New Shoreham Water Pollution Control Facility. He heard about Biobot’s pro bono testing back in April. The company offered free, biweekly testing to the town throughout June, but the island is now paying the company $1,200 per test.
Since the first positive test on July 5, the town’s wastewater has tested positive for the virus three times, even when there weren’t any new cases reported through traditional testing.
Chase said while wastewater testing cannot precisely tell him how many people on the island are positive for COVID-19, it can tell him that it’s there.
“Best-case scenario is using this as a canary in a coal mine,” he said.
Angelo Liberti of the Rhode Island Department of Environmental Management said research indicates wastewater testing may be able to predict a future spike in cases.
“The inactive virus in the wastewater sample seems to track cases of infection that occur four to seven days after those wastewater samples,” he said.
But he said the science isn’t perfect, especially with a turnaround time that often matches or exceeds that time frame.
“So there was some conversation about how useful is it if by the time you get it back, it’s no longer predictive,” he said.
Liberti said the Environmental Protection Agency and Centers for Disease Control and Prevention are currently studying how to best preserve samples and how to interpret the results of these tests. He said they’re planning to issue standard methodologies for researchers to follow.
He said the DEM has been in conversions with the Rhode Island Department of Health and four of the larger wastewater plants in the state to discuss the potential for expanding this kind of testing.
Joseph Wendelken, a spokesperson for the Department of Health, said they are following the science and having conversations to determine if sewage testing will benefit the state’s response.
“However, we still have a lot more to learn about wastewater and COVID-19, and there are complexities to the way that wastewater gets collected that present challenges,” Wendelken wrote in an email. “But again, we’re watching the science and are open to anything that helps us better understand COVID-19 rates at the community level.”
While this type of testing has been used in other parts of the country and the world to look for other disease or even pharmaceuticals in wastewater, Chase and Liberti agree it holds a lot of potential.
“Wastewater epidemiology is the future,” Chase said.