Since January, Boothbay Harbor Sewer District plant operator Michael Hills has collected two 250 mL wastewater samples twice a week to monitor COVID-19 levels. Boothbay Harbor is one of two Maine sites participating in the federal study. The other is the Rockland wastewater plant.

For researchers, the data is closely tied to more traditional tracking methods: the number of daily COVID-19 cases and hospitalizations. But the wastewater samples provide data other sources do not. Dana Bushman is a Maine Center for Disease Control medical epidemiologist. “Wastewater surveys often correlate with other methods, but it is a leading indicator and often shows up four to six days before individual clinic cases appear,” she said. “That’s how we know about the virus spread. People may or may not have symptoms, but we track the genetic marker of the SARS-CoV-2 strand.” 

Bushman tracks data from both the federal and state studies. She said the data has followed a similar path. In January, Maine CDC had just registered a record of 46,000-plus COVID-19 positive cases, followed by a reduction this spring. “The data is a snapshot in time,” Bushman said. “In September, there was another spike before leveling off.”

The U.S. Environmental Protection Agency is monitoring results of the federal study. In a November email to participants, the EPA reported testing had three goals. The first is developing optimal sampling strategies for wastewater monitoring networks for detection of emerging pandemic pathogens. The second is developing and testing a framework for adapting wastewater monitoring. The strategies are based on characteristics of the pathogen, its infection, transmission processes, and target populations. The third is using data from these partnerships to produce reports and maps used for external-facing dashboards and more detailed analyses for decision-makers.

The study’s expected results are three-fold. “This project is expected to result in a transmission forecasting model for wastewater monitoring, and a tested hierarchical system for sentinel site identification, and a secure platform for data storage and analysis,” wrote Director of Wastewater Surveillance Anna Mehrotra, Ph.d in the email.

BHSD Superintendent Chris Higgins doesn’t know why Boothbay Harbor was picked for the federal study. The federal CDC contacted him in December 2021 about participating. “I thought it was a really good idea. Nobody really knows what’s going on here other than what data comes out of the Maine CDC,” he said.

In the beginning samples were sent to to LuminUltra Technologies in Miami for analysis. Samples are now sent to Biobot Analytics in Cambridge, Massachusetts. 

Higgins said the wastewater study runs until March 2023. He doesn’t know if the district will renew participating in the program.