AQUATIC TASTE AND ODOR: A PRIMARY SIGNAL OF DRINKING-WATER INTEGRITY

Abstract

Aquatic taste and odor (T/O) is rarely produced by toxic contaminants or pathogens; nevertheless, it has major negative impacts on the public and the drinking-water industry. Consumers use T/O as a primary measure of drinking water safety, yet this criterion is poorly understood, and its origins and triggers often go untraced. Much surface-water T/O is produced by the increased production of volatile organic compounds (VOCs) by algae. These chemicals can be symptomatic of short-term problems with source, treatment, or distribution systems. At a broader level, they can signify fundamental changes in aquatic ecosystems induced by human activity. T/O varies in chemistry, intensity, and production patterns among different algal taxa, and is often linked with excessive algal growth and/or the invasion of noxious species. Some VOCs may signal the presence of potentially toxic algae and/or other associated water quality issues. Traditionally, T/O has been linked with the widespread eutrophication of many surface waters; however, there has been a recent growth in the number of T/O events reported in oligo-mesotrophic systems, for example, the Glenmore Reservoir (Calgary AB) and the Laurentian Great Lakes. From a management and public perspective, therefore, it is vitally important to monitor T/O, and to continue to work toward a better understanding of the proximal and the ultimate causes—which VOCs and algae species are involved. In the short term, odor events could be anticipated and water treatment optimized. In the long term, this approach would contribute toward more a robust management of this resource through remedial or preventative measures.

The author acknowledges the funding and support provided by NSERC, Environment Canada and the Research Consortium, the Saint Lawrence River Institute, and the City of Calgary Glenmore Waterworks. I thank the many colleagues who have collaborated on the different research projects, notably Brian Brownlee, Trevor Satchwill, Murray Charlton, Jeff Ridal, Beryl Zaitlin, Todd Howell, Erica Hargesheimer, Jaime Dixon, Ed McCauley, and Tom Murphy, and technical personnel who provided valuable assistance: D. Settles, G. MacKinnis, T. Mamone, J. Milne, and L. Janzen.