Blog by Accountant+ Kallie Val-Zehan Desruisseaux.
What would the accountant of the Oldman Watershed Council (OWC) write about in her blog debut? A national program for sampling surface and groundwater for pesticides, of course!
In addition to crunching the numbers for OWC, in 2023 and 2024 I took 97 water samples upstream and downstream of Lethbridge as part of a Canada-wide pilot project. This program, led by Health Canada’s Pest Management Regulatory Agency (PMRA), was done to develop a water monitoring framework, in which many small partner organizations take water samples for Health Canada to test and analyze. Partners in the pilot ranged from provincial organizations to local groups like OWC, as well as members of Indigenous communities across Canada.
Join me for a walkthrough of what the seasons of sampling looked like, and how this program has given us new insight into the quality of the Oldman River!
Selecting sampling sites
PMRA chose sampling locations near areas of intensive agricultural use, sites with easy access to the river, or places previously sampled for pesticides and other chemicals.
Our sample sites along the river up and downstream of Lethbridge made the cut: a lot of the land surrounding the city is used for agriculture, including a variety of crops and livestock. The land is also used for industry (think alternative energy development, industrial developments, and business parks) and recreation, with this beautiful part of southern Alberta offering many ways to enjoy nature.
So because Lethbridge is downstream of intensive agriculture and is an urban city, PMRA decided that our two sites were appropriate to be included for this water monitoring pilot project, and off we went. Check out some of the other sampling sites here:
PMRA pilot program surface water sites. Map: Government of Canada
The OWC’s contribution to the PMRA program was to collect surface water samples from the Oldman River at two points: north (downstream) of Lethbridge at Pavan Park, and south-west (upstream) of Lethbridge at Popson Park. The first time I went to these locations to collect samples I was briefly confused by the way the water was flowing: isn’t north “up” and south “down”? As it turns out, water doesn’t care about our map directions, and I quickly realized which way was upstream and which was downstream. The sample bottles made it to the Health Canada pesticide laboratory in Ottawa for testing safe and sound (and correctly labelled).
Sampling sites upstream of Lethbridge at Popson Park and downstream at Pavan Park.
What’s in the jar?
Collecting the actual samples was fairly simple. Wearing gloves over clean hands, I collected water from the river in prepared glass jars. The jars were pre-sanitized and free of contaminants to ensure accurate samples. I also took a second set of samples in plastic jars, which were specifically tested for glyphosate, a type of herbicide. Then I measured river conditions, including temperature, pH, and conductivity (how well water carries an electrical current), using a specialized probe. Finally, I took photos of the river and surrounding area throughout the sampling period. It was fascinating to see how the sites changed across the seasons.
Popson Park, Sept. 15, 2023. Photo: Kallie Val-Zehan Desruisseaux
Popson Park, June 18, 2024. Photo: Kallie Val-Zehan Desruisseaux
One thing I especially enjoyed about the sampling process was the drive down into the hills and coulees, and meeting the local people and dogs out enjoying the parks. In summer, I saw folks canoeing, tubing, and even sitting in camping chairs in the river, cooling off on hot days. And thanks to PMRA’s analysis, we now know more about what exactly is in that water.
Pavan Park, October 30, 2023 - Kallie Val-Zehan Desruisseaux
Pavan Park, June 11, 2024. Photo by Kallie Val-Zehan Desruisseaux
And the results are…
Results from the pesticide monitoring program are now available, and I’m happy to report that all samples from the two locations in Lethbridge came back with pesticide levels below established government guidelines.
We collected 97 samples in total, and each was tested for 205 different chemicals. These included herbicides, insecticides, fungicides, antimicrobial substances, plant growth regulators (chemicals used to modify plant growth), acaricides (used to control ticks and mites), and more. The results show that while pesticides are being used in areas upstream of Lethbridge and within the city, they are not accumulating in the river at higher-than-expected levels. You can check out the data from the monitoring program here.
Let’s keep this success going
In your garden and yard, you can be a good watershed steward by avoiding pesticides and chemical yard products, which can be carried in runoff directly into waterways. There are many safer alternatives that are better for the health of our rivers—learn more about alternatives to pesticides here. If you must use pesticides, use them safely and correctly, and follow the specific instructions for products you use.
For landowners, consider leaving a buffer of natural vegetation along the banks of any creeks or waterways on your property. Natural vegetation helps filter sediments and pollutants from runoff before they reach flowing water.
Humans, plants, animals, fungi, microbes, and all other beings rely on the Oldman River to survive and thrive. Clean, healthy water is essential to a healthy ecosystem, so it’s encouraging news for everyone who enjoys the Oldman River that pesticide levels are below established guidelines. Let’s keep it that way.
Like all OWC’s blogs, this post was written by a real live human, without the use of generative AI.
