E. coli at Mactaquac Beach more than double acceptable levels last weekend

E. colilevelsat MactaquacBeach near Fredericton were more than double what they should've been last Friday, forcing a no swimming advisory that lasted the weekend,New Brunswick's acting deputy chief medical officer of health says.

Dr.CristinMueckesaidlevelsof the bacteria between 800/100 mLand 1,000/100 mL were well over the threshold. Anything under 400 is considered safe for swimming, she said.

• E. coli keeps weekend swimmers at Mactaquac Beach out of the water

"Water results fromMactaquacBeach showed levels exceeding the guidelines for Canadian recreational water qualityfor E. coli," she said. "Based on that information, I issued a no swimming advisory for the beach."

Historically, Muecke said, the beach has seen results under 100.

"This was unusual," she said of the much higher levels. "Sometimes that means there was an issue with the sampling process."

Muecke saidwater samples are taken at intervals along MactaquacBeach, and testing was done about a week prior to the no swimming advisory.

When the high results turned up, she immediatelyobtained two re-samples, she said, and when thebacteria returned to their typical levels, the beach was reopened Monday.

"The frequency of sampling moving forward is dependent, in part, on the risk assessment for each beach," she said. "What you may find is there's slight variation, depending on the beach."

Direct cause unclear

Mueckesaid there were several possible reasons why levels of E. coli, which are bacteria found in the intestines of humans and other animals, could be elevated in the water.

They include bird contamination, storm water runoff and the inadvertentdischarge of sewage from boats.

The good news is, based on sampling records, this doesn't seem to be a typical result forMactaquacBeach.- Cristin Muecke, acting deputy chief medical officer

"We have to look at all the possibilities, anywhere from there being an issue at the lab level, to the sampling process to the actual water itself," she said.

When visiting a popular beach, Muecke said, it's important to watch for advisoriesabout swimming.

She said public health will be looking into the source of what caused E. colilevels to change and expects to keep an eye on it over the summer.

"The good news is, based on sampling records, this doesn't seem to be a typical result forMactaquacBeach."