A framework for better understanding drinking-water quality in small community of Happy Valley-Goose Bay, Southern Labrador: Implications for optimization and protection of the municipality supplied water
This research project was driven by the recurring complaints and concerns voiced in the media by residents living in the Valley area of the community of Happy Valley-Goose Bay, Labrador. Drinking water in this town is supplied by two water treatment plants (a municipality treatment plant and a DND treatment plant), which use raw water from two different sources groundwater from multiple wells versus surface water from Spring Gulch brook) and use two different processes of drinking-water treatment. In fact, the drinking water supplied in the Valley area has a unique distribution arrangement. To meet demand, the Valley area is served by a blend of treated waters from a storage reservoir (Sandhill reservoir), which is fed by both water treatment plants. Most of the time, treated water from the municipal treatment plant dominates in the mixture. As water travels through the distribution system and household plumbing, specific reactions can occur either in the water itself and/or at the solid–liquid interface at the pipe walls; this is strongly influenced by the physical and chemical characteristics of the water. These reactions can introduce undesirable chemical compounds and/or favor the growth of bacteria in the drinking water, causing the deterioration of the quality of water reaching the consumer taps. In the distribution system in general, these chemical constituents and bacteria may pose potential threats to health or the water’s aesthetic qualities (smell, taste or appearance). Drinking water should be not only safe, but also palatable.
The focus of this research is on the Valley area of Town. The main objectives were to: (i) evaluate the physical parameters and the concentrations of chemical constituents of groundwater and surface water (Spring Gulch) sources and municipally supplied water in the distributions systems; and (ii) investigate the effects of treatment conditions, distribution arrangements, and seasonal and spatial variations on the quality of drinking water. The ultimate purpose is to assist the municipality in providing safe and aesthetically pleasing water at consumers’ taps. In addition, stable isotope geochemistry was used to assess the importance of precipitation (rain or snow) for groundwater recharge and to investigate the relationships between the groundwater, Spring Gulch and the Churchill River.
The report with the project results can be found here: http://www.mun.ca/harriscentre/reports/Fonkwe_14-15_Water.pdf
This research provides crucial information not only on the quality of drinking water sources, but also on the variability of water quality at consumer’s taps. It is intended help the municipality administrators and plant operators to develop and implement strategies for managing water quality across the distribution systems and ultimately, providing safe, aesthetically pleasant tap water. Moreover, this study provides sound baseline information on groundwater geochemical evolution to foster the sustainable management of fresh groundwater resources in coastal quifers.
As demonstrated by our statistical analysis of consumer perceptions of tap water quality in October 2014, the results presented here also highlights some possible misconceptions of the appropriate authorities as to the extent of the chemical safety and aesthetic problems of water reaching consumer taps (which are site- specific and differ from house to house), and possible ways they can be addressed. Mitigation strategies should be evaluated and implemented at the municipal treatment plant to reduce the formation of trihalomethanes (THMs) (and other chlorination disinfection by-products), as well as to combat water corrosiveness and hardness. Furthermore, the municipality’s decision to add fluoride to drinking water might warrant a re-examination and systematic review, giving the low levels of naturally-occurring fluoride in groundwater source. In the meantime, the appropriate authorities should encourage residents to test their tap water for Pb (and other metals) by a certified laboratory, especially in houses built before 1990, but even in newer houses with plastic pipes and brass faucets and other plumbing fixtures. Location-specific testing is necessary because the results of this study indicate that Pb comes from materials in the houses’ plumbing, not in the town's water distribution pipes, and the composition of plumbing materials varies from house to house. Moreover, residents should be encouraged to use topical fluoride (e.g. fluoridated toothpaste, varnish, gel or mouth rinse) or other measures to promote dental health, as recommended by the Canadian Dental Association.