Michigan’s beach testing faster but expansion uncertain
Harrison Township — Michigan’s effort to provide faster and more reliable testing of the waters at its beaches began in earnest this summer and has shown promising early results.
But it’s unclear when or if the new technology will be expanded to all Michigan beaches as the state’s main water testing mechanism — a move that could drastically reduce the number of days swimming areas are closed due to contamination by E. coli.
The closures can wreak havoc with summer destinations such as the Lake St. Clair Metropark, whose popular beach area was closed more than 1-in-3 days over the summer because of more rainfall than usual that overwhelmed local stormwater systems.
For the past two swimming seasons, the beach in Harrison Township has been a proving ground for water testing. Macomb County health officials have continued to sample the water for E. coli using the decades-old approach of growing bacteria in a laboratory. That process can take days to return a result, leaving some beaches closed until follow-up testing and processing are complete.
By contrast, the new testing method, called quantitative polymerase chain reaction, identifies whether water is contaminated by essentially amplifying the DNA traces found in water samples instead of waiting for cultures to grow. In just hours, it can reveal the presence of E. coli in a water sample.
The testing program at Lake St. Clair Metropark during the last two years has taken results from both methods and compared them for consistency. From Memorial Day through the end of September this year, results between the two sampling methods showed agreement 90 percent of the time. In 2014, the figure was 95 percent.
This past summer, the state expanded the new testing to 10 more locations around Michigan.
“We are getting very encouraging results. ..,” said David Szlag, an associate professor of environmental science at Oakland University who runs the testing program at Lake St. Clair Metropark. “It shows some progress — that we’ll be able to have nearly real-time testing.”
But when officials will be comfortable enough with the new testing method to use it exclusively is still in doubt. It could have a big impact on summer destinations around the state that are handcuffed by the current testing protocols.
Shannon Briggs, a toxicologist who heads the state’s beach monitoring program in the Department of Environmental Quality, said more steps need to be taken before Michigan’s swimming destinations can turn to the new DNA-based method as the standard testing procedure.
“Whenever a new method comes along, it’s exciting and we want to use it,” Briggs said. “We also want to confirm that the results are making sense.”
The DEQ is still collecting testing results from the other 10 sites, she said. To switch to the testing method, Michigan must meet the application criteria set by the U.S. Environmental Protection Agency that include demonstrating the method is viable and creating criteria under the new method for beach closings.
Expansion would require more state funding that is not yet earmarked by the Legislature. The pilot programs for quantitative polymerase chain reaction are now funded in part through federal grants.
A switch to faster testing would likely benefit places such as Lake St. Clair Metropark, which was forced to close its beach/swimming area 47 days between Memorial Day and the end of September. Officials with Macomb County’s Health Department said Mother Nature was the biggest factor in a season when more than twice as many closures were reported as any other year since 2010.
“I would say 2015 was a predominantly wet season...,” said Bill Ridella, director of Macomb’s Health Department. Large amounts of rainfall, particularly in short periods of time, can overwhelm local stormwater and wastewater infrastructure. That can lead to E. coli reaching public waters and beaches being shut down.
But due to the schedule used in the old bacteria-based testing, it can leave beaches closed longer than necessary.
“(Macomb County) comes out and samples on Monday and Wednesday, and it takes roughly a day to get the results back,” Szlag said. “If they sample on a Wednesday, and the (E. coli) reading is high, then the beach is not going to be retested until Monday. And we won’t have those results back until Tuesday.”
In such a scenario, the water at the beach may have been safe for swimming as early as Thursday — 24 hours after the problematic samples were taken. But the beach would not be cleared to reopen until five days later.
“We need to be able to do this smarter,” Szlag said.