DULUTH - Richard Melvin has been going to the beach every weekend since July 4th this summer, looking for the corona­virus.

Thankfully for swimmers, he hasn’t found it yet.

A new study has found no traces of SARS-CoV-2 — the virus that causes COVID-19 — in Lake Superior along several of Duluth’s popular beaches, including Park Point.

“Our test is not detecting the virus,” said Melvin, a researcher with the University of Minnesota Medical School Duluth Campus. “It’s either absent completely or below the level of detection.”

Melvin was quick to warn that crowded beaches still pose a threat of infection if strangers get too close to one another because the virus spreads mainly by air.

“Water is not a natural environment for the virus; it’s going to rapidly degrade,” he said. “But if you’re at a popular place with people, the risk is there.”

The Lake Superior beach testing is unique to the state and region and even to most of the country — Melvin knew of no other lakes being tested for the virus in Minnesota.

The state Pollution Control Agency isn’t testing surface waters for the virus, nor is the Minneapolis Park and Recreation Board.

“Outcomes from research the U does on corona­virus in water may inform what we do in the future,” said Rachael Crabb, water resources supervisor with the board.

Studies concluded early in the pandemic that the risk of transmission in bodies of water is extremely low, and Melvin said “water is water” when it came to testing Lake Superior vs. a smaller lake.

“Water has not been shown to be a significant source of infection,” Melvin said. “However, we want to provide clear, scientifically sound information that citizens, public officials and business owners can use to make informed decisions about water-related activities.”

Wastewater is being tested around the country to give early warning signs of an outbreak, something Melvin has been involved in locally. Earlier this month the Centers for Disease Control and Prevention said it would aid those efforts and create a national database “for use in summarizing and interpreting data for public health action.”

“Sewage testing has been successfully used as a method for early detection of other diseases, such as polio,” the CDC said. “SARS-CoV-2 can be shed in the feces of individuals with symptomatic or asymptomatic infection; therefore, waste­water surveillance can capture data on both types of infection.”

If it’s in wastewater, it could be in clean water, Melvin thought as he secured a $10,000 grant from the Minnesota Sea Grant to study Lake Superior beaches.

“Part of our hope is we could provide some reassurance we weren’t seeing it in high numbers in the water,” said Jesse Schomberg with Minnesota Sea Grant, a federally funded research program based in Duluth. “That doesn’t mean you should start throwing beach parties and being close to other people.”

Researchers collect water samples on the weekends when more people are in the water at eight different sites in Duluth, including Park Point, Brighton Beach and Leif Erikson Park. The same process used to test humans for COVID-19 is used to test the water.

“Some tests are set aside for research so it’s not dipping into the stream necessary for human testing,” Melvin said. “We look for the genetic presence of the virus, the same test we do on wastewater.”

Results will be posted at parkpointbeach.org.