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

Abstract

Drinking water in the vast Arctic Canadian territory of Nunavut is sourced from surface water lakes or rivers and transferred to man-made or natural reservoirs. The raw water is at a minimum treated by chlorination and distributed to customers either by trucks delivering to a water storage tank inside buildings or through a piped distribution system. The objective of this study was to characterize the chemical and microbial drinking water quality from source to tap in three hamlets (Coral Harbour, Pond Inlet and Pangnirtung-each has a population of <2000) on trucked service, and in Iqaluit (population ~6700), which uses a combination of trucked and piped water conveyance. Generally, the source and drinking water was of satisfactory microbial quality, containing Escherichia coli levels of <1 MPN/100 mL with a few exceptions, and selected pathogenic bacteria and parasites were below detection limits using quantitative polymerase chain reaction (qPCR) methods. Tap water in households receiving trucked water contained less than the recommended 0.2 mg/L of free chlorine, while piped drinking water in Iqaluit complied with Health Canada guidelines for residual chlorine (i.e. >0.2 mg/L free chlorine). Some 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. Corrosion of components of the drinking water distribution system (household storage tanks, premise plumbing) could be contributing to Pb, Cu and Fe levels, as the source water in three of the four communities had low alkalinity. The results point to the need for robust disinfection, which may include secondary disinfection or point-of-use disinfection, to prevent microbial risks in drinking water tanks in buildings and ultimately at the tap.

Source Water Characteristics and Building-specific Factors Influence Corrosion and Point of Use Water Quality in a Decentralized Arctic Drinking Water System

“…A previous study in Nunavut detected >0.1 μg L –1 of lead in flushed drinking water samples collected in Pond Inlet . In February 2019, Health Canada released a new health-based MAC guideline of 5 μg L –1 for lead in drinking water based on an RDT sample or a sample gathered after 30 min of stagnation .…”

“…Concerns about energy, food, and materials security, including drinking water quantity and safety, are well documented in Nunavut and Canada’s other Arctic jurisdictions. − Many Arctic communities employ trucked drinking water systems because it is difficult to install southern-style piped distribution systems in areas underlain by permafrost. Water is gathered from a surface water source, treated, pumped into trucks, and distributed to individual buildings, where it is stored in indoor cisterns until it is required by users.…”

“…Most peer-reviewed water quality studies that have been conducted in Nunavut to date have focused on microbiological water quality parameters. ,, Metals, organics, and particulate matter can also affect the aesthetic quality of water at the tap and potentially increase the risk of negative health-related outcomes related to drinking water. Daley et al measured physical and chemical parameters in addition to biological parameters in four Nunavut communities, including Pond Inlet. The researchers detected metal concentrations above Canadian aesthetic (iron) and health guidelines (lead, copper, and manganese) in some buildings in Pond Inlet and in three other communities in Nunavut.…”

Climate Change and Enteric Infections in the Canadian Arctic: Do We Know What’s on the Horizon?

“…Similarly, in a study by Daley et al (2016) that sampled other sites in the Arctic (Coral Harbour, Pond Inlet, and Pangnirtung), there were low levels of fecal coliforms and none of the specific pathogens were detected (e.g., Campylobacter jejuni, Cryptosporidium parvum, Giardia lamblia, etc.) [56]. However, the occurrence of enteric pathogens in surface water is notoriously variable over time and conditions.…”

Health risk related to the presence of metals in drinking water from different types of sources

“…It provides qualitative and quantitative characteristics as well as information on potential negative effects on human health which may occur over a short or long period of time as a result of exposure to harmful substances (De Miguel et al 2007, Kicińska 2016c). Most often, substances detrimental to human health are those found in daily diet or in the environment as the ingestion route is the major, although not the only, route of exposure (Kicińska, 2016b; 2018; Bi et al , 2018; Daley et al , 2018). In the case of contaminants found in water there are three exposure routes: ingestion of contaminated water; dermal route, namely contact of skin with contaminated water (e.g.…”