What does it mean when a swim advisory is issued by the health unit?

On July 19, a swim advisory was issued for Port Sydney Beach – and was lifted on July 21 – that may have had you wondering what causes the Simcoe Muskoka District Health Unit (SMDHU) to issue a swim advisory in the first place. Doppler reached out to the SMDHU safe water project co-ordinator, Karen Kivilahti, to find out.

In the Huntsville area, the health unit monitors three public beaches: Hutcheson Beach, Port Sydney Beach and Dwight Beach. It decides which beaches to monitor based on several criteria, including being owned and operated by the municipality, plus signage, amenities, safety equipment and parking that would indicate it’s a public beach.

The health unit only samples the public beach area and selects areas where contamination is likely to be highest – near a creek, river or stormwater outfall or where there is a higher density of septic systems, for example. “We always want to sample where we think there might be contamination,” says Kivilahti. “We want to know what is happening.”

The samples are taken weekly at monitored beaches and are tested for E. coli. Swimming in water with elevated E. coli levels may increase your risk of developing minor skin, eye, ear, nose and throat infections and stomach disorders.

It takes about 24 hours for samples to be tested at the lab, and an advisory is immediately issued if E. coli levels exceed the national standard of 200 E. coli per 100 mL. If the level is between 100-200, the health unit will do a risk assessment and consider if the area has a history of elevated bacteria or if recent rain may have impacted the water quality. “We know that water quality changes quite quickly and because there is a 24-hour wait by the time we get our results, we want to be sure we are providing useful information,” says Kivilahti. “We don’t want to issue an advisory when it might not be necessary.”

She said that closures are rarely issued, and would be triggered by a catastrophic event like a raw sewage or toxic chemical spill.

If an advisory has been issued, the area will be resampled within one to two days.

This year’s heavy rains have impacted water quality, says Kivilahti. “Nine times out of ten it’s rain events that effect most of our beaches and there are a few that show a strong correlation with heavy winds that start to stir up the bacteria that’s in the sand and silt. We’ve seen three to four as many advisories this year (across the district) as we did in the same time period last year, but they don’t seem to be lasting as long.” Kivilahti added that the health unit will analyze the results at the end of the year to determine what weather factors might have contributed to the number and length of the advisories.

So what if you’re planning to swim in an area that’s not monitored for bacteria? “We know that heavy rainfall will wash whatever is on the surface – if there happens to be bird feces and dog feces – into the water. For 24 to 48 hours after a rainfall, bacteria levels could be higher. That’s one thing we want people to be aware of. It might be prudent to avoid ducking your head for 24 to 48 hours after a rainfall, and never swallow the water.”

Also note the cloudiness of the water. At waist height in what is typically clear water, if you can’t see your feet then chances are the bacteria levels will be higher.

Finally, be aware of beach sand. “That wonderful sand that’s right at the water’s edge that’s wet and perfect for making sand castles, that has way more bacteria in it than the water will,” says Kivilahti. “It’s really important for people to keep in mind when you’re picnicking to wash their hands or bring hand sanitizer with them.”

Watch local media for beach advisories, or check the SMDHU Beach Postings page here.

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