SMITHS FALLS – The Town of Smiths Falls is continuing to monitor its historical compost site on County Road 43 after soil and groundwater tests revealed some exceedances in provincial standards.
Director of Public Works Paul McMunn presented the update to council during the Sept. 8 committee of the whole meeting. He outlined more than a year of soil, surface water, and groundwater sampling at the compost site, which for decades has been used by residents to drop off leaves, yard waste and brush.
The work has been carried out with St. Lawrence Testing, a Cornwall-based geotechnical firm, under oversight from Ontario’s Ministry of the Environment, Conservation and Parks (MECP).
“We have been very much engaged with the ministry throughout this whole process, and they’ve been great to deal with,” McMunn told council.
Sampling history at compost site
The town officially began soil testing at the compost site in March 2024. Five shallow pits were dug, with three showing elevated levels of cadmium, lead and zinc. A second round of sampling in December expanded testing to 10 additional pits. Half of those returned results above the stricter Table 2 standards, which apply in intake protection zones where municipal drinking water sources must be safeguarded.
n March 2025, surface water samples were collected during the spring melt from the creek that flows through the compost site toward the Rideau River. Tests for petroleum hydrocarbons, mercury, chromium-6 and other contaminants showed no detectable concentrations. Dissolved metals were within acceptable limits.
In late June and July, a total of eight boreholes were drilled through the bedrock to reach groundwater beneath the compost site. Results were generally within the provincial standards, except for one location where dissolved cobalt was measured at 7.3 micrograms per litre, nearly double the standard of 3.8.
“St. Lawrence Testing noted in their report that the cobalt exceedance could be a result of bedrock leaching into the groundwater and not from the compost site itself,” McMunn explained.
No impact on drinking water
Mayor Shawn Pankow asked about the potential risks to the town’s water system, given the compost site’s proximity to the municipal intake.
McMunn reassured council there is “no evidence to suggest the town’s drinking water is compromised” by the compost operation.
Surface water samples collected in March also showed no issues, he said. “We can unequivocally say that we have no suspicions of any compromise historically or currently today, or presumably in the future, that would compromise our water source.”
Chief Administrative Officer Malcolm Morris emphasized that all sampling has been done in close consultation with MECP. “The regulator is happy with what we’re doing on the site,” he said. “There is no threat emanating from the compost site, and we’re going to monitor it to make sure that threat doesn’t exist.”
Future monitoring of compost site
Currently, eight groundwater monitoring wells are now installed on the compost site. Annual groundwater testing will continue, with all results forwarded to the MECP. If results remain stable, the ministry could reduce the monitoring frequency in future years.
McMunn also addressed resident concerns through the mayor about whether contaminated material from Beckwith Street reconstruction was dumped at the compost site. He confirmed it was not. Contractors were required to remove and dispose of excavation material at approved locations.
Coun. Chris McGuire suggested the town provide a written report to supplement the verbal update. “This is a lot of information to process,” he said, noting a written version would also allow residents to access the findings if they missed the meeting.
Morris said staff could also prepare a concise summary report for a future meeting.
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