Here’s how DNA testing helps numerous beaches grapple high bacteria levels

It’s certainly been a summer suited for swimming, but numerous local beaches have been grappling with high bacteria, forcing swim advisories.

Here’s how the City of Orillia is now turning to DNA testing to identify the cause. While Orillia’s two beaches were open for swimming on Monday, that has often not been the case this summer.

• Swimming advisories issued for Oro-Medonte and Orillia beaches

“I don’t really even want to put my feet in the water with the number of warnings that are around here,” said one local to CTV News.

The city and local health unit issue swim advisories each time E. coli levels exceed 200 E. coli per 100 milliliters in Lake Couchiching Beach Park.

But the city has responded by taking a deep dive to try and understand what’s contaminating the waters of Couchiching Beach and Moose Beach, looking at not just the quantity of contamination but also where it’s coming from.

Greg Preston, Orillia director of environmental services, says, “There are four sources we’re looking at. One is seagulls, the next is geese, the next is dogs, and the last is humans, human waste.”

Staff have been taking DNA samples on three dry weather days and three wet weather days and getting them analyzed by water scientist Dr. Tom Edge. He says that, according to his initial findings, the contamination has been mostly coming from the sky.

Dr. Tom Edge says, “What we have found are DNA sequences of bacteria from the seagull gut and DNA from Canada geese as well. There’s no question that there’s bird fecal contamination at the beach that’s contributing to the E. coli.”

While the city has an $18,500 budget for the study, the Rescue Lake Simcoe Coalition fears that future costs could be even greater to keep Lake Couchiching clean.

The city says it will take several weeks to get the results back from their samples. Staff will then report their findings and make other recommendations to council.