Beach Closures

Why are the beaches closed?

 

OLYMPUS DIGITAL CAMERABeach closings are complex environmental issues with both public health and economic consequences. When bacteria levels at public beaches are found to be “unsafe” for human exposure, local municipal health departments may issue a “no swimming advisory”.

In accordance with the Guidelines for Canadian Recreational Water Quality, a beach is closed when the geometric mean of at least five samples exceeds 200 E.coli colony forming units (cfu) per 100 mL of water or if any individual sample concentration exceeds 400 E.coli cfu/100mL.

E.coli, along with other coliform bacteria, are “indicator” bacteria used to assess the potential public health risk following exposure to water. Their presence in surface waters is an indication of fecal contamination. While some indicator bacteria are known to pose a direct health risk to humans (for example some strains of E.coli are pathogenic), not all do. However, their presence in water may suggest the presence of harmful pathogens, such as Salmonella, Shigella, noraviruses, enteroviruses, Cryptosporidium, and Giardia, which can be found in both human and non-human sources of fecal pollution and are considered threats to human health.

Exposure to water-borne bacteria increases the risk of adverse health effects such as gastroenteritis, ear, eye and skin infections, and acute respiratory illness. The likelihood of contracting these symptoms increases with the concentration of pollution and length of exposure to polluted water.

High E.coli counts may be caused by stormwater runoff after heavy rain, overflows from combined sewers that carry untreated sewage and stormwater, sewage spills or leaking sewage pipes. Large bird populations have also been blamed for high E.coli counts. Consequently, beach closure signs during the summer are not unusual at the urban beaches in the Ottawa River watershed.

Beach closures are only one result of waterborne pathogens in our waters. These pathogens can also pose threats to our drinking water as well as to aquatic ecosystems and biodiversity.

Water Quality at Municipal Beaches

The cities of Ottawa and Gatineau post their monitoring data from official municipal beach sites.