Arsenic in the Water
Arsenic – a poison – is naturally occurring in groundwater around the world. In higher concentrations (like 50-100 micrograms per litre), there is evidence of adverse effects, but those are nowhere near the concentrations we are seeing in our water. The World Health Organization, the federal guideline under Health Canada, and the Ontario Drinking Water Quality Standards all have the standard of 10μg/L (10 micrograms per litre). Most of Mono’s wells are compliant with this limit, although the Island Lake water supply in some tests has gotten up to 9μg/L. Under Ontario rules, reaching “Half-Maximum Acceptable Concentration” (so 5μg/L) triggers more monitoring, reporting and doing something about it. Options include:
- Treat the water to remove the arsenic
- Drill new wells and connect the Island Lake Drinking Water System to the Cardinal Woods Drinking Water System
- Connect the Island Lake Drinking Water System to a neighbouring municipality’s water system
Council decided against removing the arsenic because it takes a lot more water to get arsenic out of water, which puts more strain on the amount of water available to folks. This option would also cost more over the long run.
The current plan is to drill new wells in the Klondyke Gravel Pit and to connect the Island Lake and Cardinal Woods drinking water systems. The next steps will be to submit the report to the Ministry of the Environment, Conservation and Parks for review and comments.
To learn more, go to the Town of Mono’s site, get more information on arsenic around the world check out the World Health Organization’s page and if you are curious about how they could remove arsenic from water, read this.
christine sinclair for mono council 