As I post the results of the weekly pool testing for contamination, I have had a few questions. So perhaps it may be worthwhile to have a wider dialogue on this.
What Does the Test Look For?
It looks for bacterial contamination of the water. But in fact, only for two ‘bugs’ —known as coliforms and E.Coli. They are considered ‘indicator’ organisms. By and large coliforms are bacteria that break down sugars, and are of much less concern. E.coli are a specific bacteria found in the intestines of humans and other animals (including farming stock)and is excreted in feces. It is this bug that is of potential concern. Some strains of it are especially nasty, but fortunately these are rare. People may recall the Walkerton outbreak of a few years back—that was a particularly virulent strain. We do not test for the sub-types (strains) that are especially nasty. But our test would raise a signal, if there were potential issues.
How do these contaminants get into our creek?
Cedar Springs lies in a very fertile, rich agricultural area. The assumption is often made that rain sweeps off some of the waste products into the river systems.
How are the pool results obtained and expressed?
On a weekly basis during the summer, a sample of water from the beach area is taken, and plated out in a test-kit. This kit contains 96 ‘wells’ in which bugs in the water incubate. Over 24 hours the bugs react with a chemical in the ‘well’ to give a blue-ish-green colour for “coliforms” and a fluorescent glow (under a UV light) to wells positive for E.Coli. The number of positive wells gives a count of the number of bugs.
But the degree of ‘blue-green-ess’ varies. This, when read by eye (as opposed to a colorimetric analyser), may lead to a slight variation of opinion between people reading the results. Hence I report a range, from a lower limit to a higher limit, given in CFU’s which stands for Colony Forming Units—so each bug can form a ‘colony’—when grown in a petri dish.
There is far less variation about fluorescence. In fact, it is either there or it is not. Hence, there is only one number given for the E.Coli.
What is a safe level?
For swimming and recreation, figures now say, since 2018: “The new recreational water quality standard is a geometric mean concentration (minimum of five samples) of less than 200 E. coli per 100 milliliters, and a single-sample maximum concentration of less than 400 E. coli per 100 millilitres.” (https://www.watercanada.net/ont-ministry-of-health-changes-e-coli-measurement-standard-at-beaches/).
Why does the count vary weekly?
You will notice the count varies weekly. This is because of several potential factors: the rainfall prior to time of testing; the temperature; and degree of turbulence of the bottom of the creek. Thus the more rain there is, may ‘wash effluent’ down the creek. The more hot it is, the better the bugs like it and grow. Climate change definitely does not help!
Should one swim if the levels are above government recommended limits?
This is a personal choice. But, the important thing is not to drink it—or ‘inhale’ as President Clinton might have it. Symptoms of actual ‘infection’ might include: fever, abdominal cramps, and diarrhea. Vulnerable populations include: the elderly, children, and those who are immunocompromised. All I can say is that I choose to swim despite relatively high counts. I try to avoid mats of soil-algae-other materials (I prefer to think of these as those rather than the possible alternatives… although this does not influence me as to drinking it—I do not).
Is the ‘wishing well’ water tested?
This is tested once a month during the summer months and is historically, very clean. The process used to test this is the free, official Ministry laboratory testing. The last counts for years, including this year, have shown no growth of coliforms, and no growth of E.coli.
I hope this helps you consider what is going on! But—at the end of the day—it is generally safe, and generally wonderful to enjoy the water at Cedar Springs Beach! Just don’t drink the stuff!
Haresh Kirpalani – Environment