Ability of humans to smell geosmin, 2-MIB and nonadienal in indoor air when using contaminated drinking water

Abstract

The most common compounds responsible for off flavours are geosmin, 2-MIB, and nonadienal which are poorly removed by conventional water treatment operations and hence result in customer complaints. Because these odourants are moderately volatile and have very low odour threshold values, it is necessary to determine their concentrations in air when water is used indoors. If the detectable aqueous concentrations for these odourants are known, the utilities may take action to treat their water at times when the concentration of the raw water exceeds the threshold concentration. To predict the concentration in the shower stall and bathroom air after showering, recently published Henry's law constants for the selected odourants and a model developed to determine the volatilization of the odourous compounds by applying two-resistance theory were used. Then the results were compared with the odour threshold concentration data to determine under which conditions the odourants become detectable. For parameters representing a typical bathroom and shower stall setting, the results showed that the odourants become detectable when the aqueous concentration of geosmin and nonadienal exceed 10 ng/L at 42 degrees C. As the aqueous concentration increases, geosmin and nonadienal become detectable at lower temperatures, however 2-MIB is only detectable above 20 ng/L and at 42 degrees C.

Microbial Production of the Off-Flavor Geosmin in Tilapia Production in Brazilian Water Reservoirs: Importance of Bacteria in the Intestine and Other Fish-Associated Environments

“…Several TOCs produced by microorganisms have been identified in fish flesh, e.g., terpenes (Podduturi et al, 2017), but the most commonly known TOC in fish is the earthy smelling terpenoid geosmin (Guttman and van Rijn, 2008; Houle et al, 2011). Due to the low detection threshold of geosmin (<5 ng⋅L –1 in water and <250 ng⋅kg –1 in fish tissue) by human senses (Omür-Ozbek et al, 2007; Petersen et al, 2011), even small amounts of geosmin in aquaculture-raised fish may cause a negative consumer preference and impact the value of fish products. Tainted fish can be depurated in clean, geosmin-free water, but this procedure requires additional handling and costs (Robertson et al, 2006).…”

Gender Differences in Electroencephalographic Activity in Response to the Earthy Odorants Geosmin and 2-Methylisoborneol

“…The odor threshold concentrations for geosmin and 2-methylisoborneol can range from 4 to 20 ng/L [6]. Humans can smell these odor molecules at very low concentrations (<10 parts per trillion) in water [7]. Many people like the odor of soil mixed with rain because it brings a lot of nostalgic memories.…”

Rapid Phenotypic and Metabolomic Domestication of Wild Penicillium Molds on Cheese

“…Geosmin is widely recognized for contributing a musty aroma to environmental and food samples and is produced by both bacteria and fungi, including Penicillium (30–32). It has a very low odor threshold, meaning that even small amounts of geosmin produced by Penicillium can be perceived as strong aromas (33). The loss of geosmin production could be the major driver of the perceived loss of musty aromas in domesticated Penicillium strains.…”