Summer is the season for worrisome spikes in some bacteria

Escaping the summer heat at regional beaches and pools is an annual tradition. Unfortunately, the summer months are also a time where local favourite Westshore watering holes have elevated levels of bacteria like enterococci and e-coli.

Worries surrounding enterococci bacteria and swimming have grown in recent years due to their implications for public health. Enterococci are a type of bacteria commonly found in the intestines of humans and animals, and their presence in recreational waters like swimming pools, lakes, and beaches can indicate contamination by fecal matter. 

High levels of enterococci can increase swimmers’ risk of gastrointestinal illness or skin infections. This concern is particularly relevant during warmer months when water activities are more popular, increasing the potential for exposure. 

On June 7, Langford Lake joined four other Greater Victoria beaches that have received water quality warnings. These included advisories at Gorge Park, Ross Bay along Dallas Road and Esquimalt. On May 22, 2,300 enterococci were found at Gorge Park. They were also found on June 4 at two locations on Willows Beach in Oak Bay but not in the same critical numbers. 

Island Health says with respect to its beach monitoring program that, “monitoring and managing water quality are crucial to mitigate these risks, ensuring that recreational waters remain safe for everyone to enjoy without compromising their health.”

Enterococci organisms have characteristics used by health officials as an indicator for the presence of fecal contamination. When compared to e-coli, studies have shown that enterococci are somewhat more resistant to the disinfectants commonly used in the decontamination of drinking water when compared to e-coli. 

It’s not just a concern for humans. Enterococci can get into the blood, bile and urinary tracts of dogs and cause urinary tract infections (UTIs). 

Earlier this month, a closure announcement was made at Langford Lake for e-coli, when, at the time, there were 415 e-coli found in a 100 millilitre sample, a number slightly over the recommended limit of 400.

Each summer, Environmental Health Officers (EHOs) work with Island Health in the monitoring of water quality at public beaches around the CRD. Beach owners and operators are responsible for beach water sampling and maintaining a safe environment for public beach use. Where results indicate the water may be unsafe, beach advisories are posted by individual municipalities at the beach site.

The frequency of monitoring is based on usage, previous sample results and potential sources of contamination.

EHOs also inspect Westshore public and commercial pools, hot tubs, spray pads and wading pools like the Juan de Fuca Swimming Pool.

Monitoring for these bacteria is not new. The Ministry of Environment, Lands and Parks monitored the water quality at Langford Lake’s deepest point (15 metres) of the basin between 1973 and 1995. The Capital Regional District's Health Protection and Environmental Division collected fecal coliform samples from one bathing beach on the north side of the lake off Goldstream Avenue weekly.

Obeying signage and not swimming isn’t necessarily a fail safe against falling ill if you choose to go to a beach with a public health warning. Enterococci bacteria can also persist in beach sand. Researchers have found that high levels of the bacteria can persist in sand, sometimes higher than the nearby bathing water itself. 

So why is this bacteria in our waters? A number of factors are at play during the summer that impact bacteria concentrations. “Elevated bacteria levels may be due to a variety of factors, including water temperatures, tides, or stormwater (which can be affected by heavy rainfall events),” an Island Health spokesperson said in an email. 

As the summer goes on, consistently higher temperatures and reduced rainfall can interrupt water flow. The combination creates an environment that can encourage bacterial growth. With climate change, drought, and a longer span of hot weather, summer water stressors may increase the occurrence of these bacteria at local beaches. 

Conversely, heavy rainfall can cause stormwater runoff from agricultural parcels and sewer overflow that can also contribute to spikes in bacteria in lakes, rivers and streams.

Water sources that have shown high levels of bacteria are tested weekly—low results are tested monthly and those that have had moderate counts are tested on a bi-weekly basis. A current list of water advisories is available here. Advisories are lifted once authorities determine there is no more risk to swimmers—in this case when enterococci numbers are 35 or less. 

Around the same time last year, the water in Glen View Park in Langford tested high for e-coli. In 2013, the lake was closed to swimmers due to high levels of bacteria. The blame for that closure was attributed to the presence of a large number of Canada geese, notorious for fouling park lawn and shoreline.

The recommended approach to avoiding the bacteria is to check Island Health monitoring sites and watch for signage at local swimming spots.