Swimming banned at 4 Presque Isle beaches due to E. coli levels. What's the cause?

Eric Stofan and his family drove Wednesday from Pittsburgh to Erie to spend the day swimming at Presque Isle State Park.

Stofan had just set up chairs at Beach 8 when lifeguards notified him that swimming had just been banned at the popular beach due to high E. coli bacteria levels in the beachwater.

Swimming in water that contains high amounts of E. coli can cause skin infections and gastrointestinal illness, especially in children and people with weakened immune systems. E. coli is also a marker for other bacteria.

"We had gone to Beach 6 and they told us it wasn't open for swimming, but to come here," Stofan said as his wife, Amanda, and their 4-year-old daughter, Cora, searched for stones along the water's edge. "Then they tell us there's no swimming here, either."

Park officials, who were already dealing with a swimming restriction at Beach 6, said the additional restrictions came as a surprise. Now swimming is also prohibited at Beaches 3 and 8, and E. coli levels are too high to allow swimming at Beach 9, which has been unguarded in recent years.

The additional restrictions also seem to shoot down a main theory of why E. coli levels at Beach 6 started rising in late June, said Matthew Greene, park operations manager.

"We thought it might be due to beach nourishment, which had been done at Beach 6 just before we saw the spike," Greene said, referring to the practice of adding tons of sand to an existing beach. "But some of these other beaches haven't had any beach nourishment."

Sand is a known reservoir for E. coli. New beach sand isn't as packed down as existing sand, Greene said, and is more likely to be blown into the water due to high winds.

Members of Greene's staff, along with officials from the Erie County Department of Health and Regional Science Consortium, are searching for answers to the high E. coli levels.

They don't think it's due to an increase in bird feces at the beach, a frequent cause of high E. coli levels in beach water. Unusually high Lake Erie water temperatures are also not to blame, since they are around 73 degrees, which is normal for this time of year.

"We're looking into any possible causes, and it could be multiple sources leading to the increased numbers (sand replenishment, animal waste, sewer overflows, etc.)," said Breanna Adams, director of environmental health services for the county Health Department. "Because we are seeing the increased advisories and restrictions, we are working together to try to determine the cause."

One change that coincided with the increased E. coli levels is a new testing protocol, Greene said. The county Health Department and Regional Science Consortium started using the Colilert-18 test in late May.

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"We are looking at the potential cause of this, whether it's the sampling with the new testing protocol, or potentially some other kind of event that has happened in (Lake Erie) that has made these numbers spike," Greene said.

Adams said the Colilert-18 test is approved by the Environmental Protection Agency for regulatory beach sampling.

How these swimming restrictions are different

Park officials have dealt with multiple swimming restrictions in the past but these are different. Instead of being based on a single day's worth of sampling, these four restrictions rely on a 30-day geometric mean of test results.

The only other swimming restriction due to a high geometric mean that park officials can remember occurred at Beach 11. That restriction began Aug. 6, 2018 and lasted for the rest of the swimming season.

Now the park has four of these restrictions at the same time.

A restriction based on a daily sampling can be withdrawn the next day if E. coli levels decline enough, but one based on a 30-day geometric mean might require multiple days — or even weeks — of good results to be rescinded, Adams said.

"The geometric mean needs to be (a most probable number of) 126 or less. The sampling from June 27 at Beach 6 was 1,900 and we had other days around it that were in the 500s," Adams said. "Those are so high that you need multiple days of really low levels to get the mean down to where people can swim."

As of Wednesday, the geometric means were: Beach 3 (156.5), Beach 6 (201.5) and Beach 8 (162.2). Park officials did not provide a geometric mean for unguarded Beach 9.

Another way swimming could return to Beach 6 and the other beaches is when the high samples taken in late June and early July time out of the 30-day geometric mean and are replaced by more recent samples that are lower.

But that would likely be after Discover Presque Isle, the park's biggest event of the year. It occurs July 24-30 and Greene said it's important from a tourism perspective to have swimmable beaches that week.

"DPI brings in a boatload of people, and if we can't get Beaches 6 and 8 to an acceptable level for swimming, it will be a knock for us on the tourism side," Greene said. "The only other beach that can really take those kinds of crowds is Beach 11."

Swimming was permitted Thursday at Beaches 1, 10 and 11. Beach 1 had been unguarded this season until Wednesday's restrictions were announced.

Lifeguards had suggested to Stofan on Wednesday that he and his family could go to Beach 10 if they still wanted to swim. They decided to stay at Beach 8.

"The water is cold anyway, and my daughter is pretty happy throwing stones and building sand castles," Stofan said.

Contact David Bruce at dbruce@timesnews.com. Follow him on Twitter @ETNBruce.

This article originally appeared on Erie Times-News: High E. coli levels cause swim ban at 4 Presque Isle State Park beaches