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.

Simultaneous removal of multiple odorants from source water suffering from septic and musty odors: Verification in a full-scale water treatment plant with ozonation

“…And, the species responsible for the production of geosmin needs further study. The aldehyde compounds, including hexanal, heptanal, nonanal and decanal, were mainly associated with algal metabolites (Yasuhara and Fuwa, 1982;Watson, 2004;Zhang et al, 2013).…”

“…Several nitrogen containing compounds including pyrazine, tetramethyl-pyrazine, pyridine, thiazole and 2-nitro-phenol, which may be associated with the stinky/fishy/sour/medicinal like odors (Watson, 2004) example, Pandey reported that pyridine was detected in waste gas emissions with unpleasant fishy odor (Pandey et al, 2007). Thiazole was an important flavor compound in food fields with unpleasant smell (Mahattanatawee et al, 2007).…”

“…The thioethers, including DEDS and DMDS, have been reported as typical septic odorants in drinking water (Watson, 2004;Yang et al, 2008), which were associated with bio-industry (Hwang et al, 1995;Smet and Van Langenhove, 1998) and swine operation processes (Schiffman et al, 2001). Bis(2-chloroisopropyl) ether, as a septic odorant, has been discovered in drinking water contaminated by industrial outfall (Kleopfer and Fairless, 1972;Steltenpohl and Graczova, 2008).…”

Simultaneous assessments of occurrence, ecological, human health, and organoleptic hazards for 77 VOCs in typical drinking water sources from 5 major river basins, China

“…Volatile organic compounds (VOCs), one contaminant group of concern, could be originated from photochemical and microbial activities (Fink, 2007;Watson, 2004) and introduced to the aquatic environment by emission and combustion (Liu and Zhou, 2011). Halogenated hydrocarbons used to be thought as the most frequently detected VOCs, followed by benzene, toluene, ethylbenzene and xylene (Chary and FernandezAlba, 2012;Ma et al, 2014), thus they were known as common VOCs (Niri et al, 2008).…”

Source-water odor during winter in the Yellow River area of China: Occurrence and diagnosis

“…Chrysophyta, Cryptophyta, and diatoms were the dominant algae during winter. Some members in these phyla, including Dinobryon, Cryptomonas, Asterionella, Melosira, Synedra, and Cyclotella, reportedly contain high intracellular unsaturated and polyunsaturated fatty acids associated with fishy/oily/cucumber odors in water (Watson, 2004). It could be speculated that the fishy odors in the Yellow River might be associated with the presence of these species.…”