Chemical and microbial characteristics of municipal drinking water supply systems in the Canadian Arctic

Drinking water in the vast Arctic Canadian territory of Nunavut is obtained from surface water that is transferred to man-made or natural reservoirs, before being treated (chlorinated) and distributed to customers either by trucks delivering to a water tank inside buildings or through a heated distribution system. We studied the chemical and microbial drinking water quality from source to tap in three small (Coral Harbour, Pond Inlet and Pangnirtung) and one larger (Iqaluit) community. Generally, both the source and drinking water was of excellent microbiological quality, containing Escherichia coli levels of <1 MPN/100 mL with a few exceptions, and absence of selected pathogenic bacteria and protists. Tap water in households receiving trucked water contained less than the recommended 0.2 mg/mL of free chlorine, while piped drinking water in Iqaluit was compliant with Health Canada guidelines for chlorine residuals. Issues with premise plumbing were identified as the tap water in several individual households and/or buildings in the four communities contained manganese (Mn), copper (Cu), iron (Fe) and/or lead (Pb) concentrations above Health Canada guideline values for the aesthetic (Mn, Cu and Fe) and health (Pb) objectives. This study showed that the municipal drinking water supply in Nunavut is generally safe. However, our results point to the need for better control of the chlorine residual to prevent microbial regrowth in drinking water tanks in buildings on the trucked water service and strategies to replace problematic premise plumbing.