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The odor problem caused by the decay of aquatic plants is widespread in many freshwater lakes. In this study, the spatial distributions of seven taste and odor (T&O) compounds (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, 2-methylisoborneol, geosmin, β-cyclocitral, and β-ionone) in the sediments and overlying water of the east of Taihu Lake were investigated. The effects of plant and physico-chemical parameters on the release of T&O compounds were also analyzed. The results showed that high concentrations of T&O compounds were detected in the area where Eichhornia crassipes was flourishing. Volatile organic sulfur compounds were not found in the water source area, which was not covered by aquatic plants. High plant biomass and aquiculture activities might increase the release of the taste and odor compounds. The correlation between the concentrations of odorous compounds and nutrients in the sediment was also analyzed. The production of odorants was positively correlated with the nitrogen, and they may migrate from sediment to overlying water. The result suggested that controlling the plant density and aquaculture activities could reduce the release of odorous compounds.

The presence of Hydrogen sulfide, Methane, Volatile Organic Compounds (VOCs), and other odorous compounds in the ambient air is the root cause of the offensive odor emitting from the MSW dumping yard. Composition features and health risks associated with odor emissions concentrations in MSW dumping yards. This paper aims to provide an overview of research on health problems due to their composition, ecological impacts, and potential health risks of volatile organic compounds (VOCs) and to examine the relationship between VOC exposure and chronic illnesses in humans and the environment. In this study, a comprehensive investigation of VOC odor emission from an urban MSW dumping site has been performed. The VOC odor sample was analyzed using the GC-MS technique. The maximum VOCs concentration reported is due to tert - butylbenzene at 1.41μg.m-3 and the minimum is due to Sec-butylbenzene at 0.07 μg.m-3. Scientific databases, including Google Scholar, California Office of Environmental Health Hazard Assessment (OEHHA), and US EPA (Integrated Risk Information System (IRIS), were searched extensively using a bibliographic technique, in addition to a case study on MSW dumping yard workers. The findings of epidemiologic and experimental research, the emission of odors as a result of volatile organic compounds (VOCs) can cause a variety of non-cancerous health effects that are linked to abnormal functioning of the body’s vital organs, including the nervous and coronary, and pulmonary systems. It can also have minimal impact on the environment by causing global warming and ozone layer depletion. The odor emissions from the dumpsite pose both carcinogenic and noncarcinogenic risks to the health of the individuals participating in the dumping yard. As a result of these results, it is important to manage odor emissions (VOCs) during composting and take steps to reduce their negative effects on the environment and public health.

Taste and odor (T&O) compounds are frequently reported during black blooms, however, their production mechanisms and influencing factors are far from clear. In this study, laboratory simulation experiment was carried out to investigate the formation processes of T&O compounds under the influences of temperature, cyanobacteria biomass and their combined effects. The decay of cyanobacteria blooms caused increased T&O compounds loading to water. Results showed the maximum dimethyl sulfide (DMS) release concentration was observed at 35°C compared with that at 25 and 30°C. DMS release concentration under cyanobacteria biomass of 25000 g/m3 demonstrated the highest production, whereas the minimum DMS production were obtained under 7500 g/m3. Similar patterns were observed for dimethyl disulfide, dimethyl trisulfide, β-cyclocitral and β-ionone production. Therefore, higher temperature and higher cyanobacteria biomass can enhance the concentration of T&O compounds. Furthermore, there were synergistic effects of cyanobacteria biomass and temperature on the production of T&O compounds.

Odor issues occurring in drinking water have been a big challenge to face for water suppliers globally, which highly commend to develop quick or on-site odor detection tools for the management of odor problems. Olfactory sensors based on odor-binding proteins (OBPs) have been utilized to analyze pollutants in food and air samples, while their application for the detection of typical odor-causing compounds in drinking water is rarely reported, partly due to the lack of knowledge about the binding properties of odorants. In this study, the binding affinity and mechanism of human odor-binding protein OBP2a to 14 typical odorants in water were first assessed using fluorescent competitive binding assays and molecular docking techniques. The 14 odorants include 7 aldehydes, 2 terpenes, 2 thioethers, bis(2-chloro-1-methylethyl) ether (DCIP), 2-ethyl-4-methyl-1,3-dioxolane (2E4MDL), and 2-isobutyl-3-methoxypyrazine (IBMP). The results showed that OBP2a could bind to 9 odorants (Ki = 29.91 μmol/L–48.36 μmol/L), including IBMP, 2-MIB, and six aldehydes (hexanal, heptanal, benzaldehyde, 2-octenal, decanal, and β-cyclocitral), among which stronger binding affinity for aldehydes is observed (Ki = 29.91 μmol/L–43.87 μmol/L). Molecular docking confirmed that Lys112 and Phe97 are major amino acid residues involved in the binding of the most target odorants. To be specific, IBMP and aldehydes can form hydrogen bonds with Lys112; aromatic ring-containing odorants such as IBMP and benzaldehyde can also form pi–pi stacking with Phe97. The binding affinity of OBP2a to fatty aldehydes including hexanal, heptanal, 2-octenal, decanal, and β-cyclocitral increased with the increase of hydrophobicity of aldehydes. The valuable information to the binding of OBP2a to typical odorants in this study would provide a theoretical foundation for the development of OBP-based odor detection biosensors to achieve quick detection in drinking water, further helping the improvement of water treatment processes in the water industry.HighlightsOBP2a has a broad binding spectrum and binds preferentially to aldehydesLys112 and Phe97 are main amino acid residues involved in binding of 14 odorantsHydrogen bond contributes to the compact binding of OBP2a and aldehydesHydrophobicity of aldehydes affects significantly their binding affinity to OBP2a

The objective of this study was to establish a technique to predict the occurrence of algal bloom and the algal-derived taste and odor compounds 2-methylisoborneol (2-MIB) and geosmin using a three-dimensional (3D) model that could reflect the complex physical properties of a shallow reservoir. Water quality, phytoplankton, and taste and odor compounds monitoring was conducted at the Jinyang Reservoir in 2016. In June, there was a potential for a high concentration of 2-MIB (maximum 80 ng/L) to occur owing to the appearance of Pseudanabaena sp.; additionally, from July to August, there was potential for a high concentration of geosmin (maximum 108 ng/L) to occur, because of the presence of Anabaena sp. A 3D hydrodynamic model was coupled with an ecological model to predict cyanobacteria bloom and the presence of taste and odor compounds. Cyanobacteria producing either 2-MIB or geosmin were distinguished to enhance the accuracy of the modeled predictions. The results showed that the simulations of taste and odor compounds spatial distribution and occurrence time were realistic; however, the concentration of geosmin was overestimated when Microcystis sp. was blooming. The model can be used as a management tool to predict the occurrence of algal taste and odor compounds in reservoir systems and to inform decision-making processes concerning dam operation and water treatment.

Chinese mitten crab Eriocheir sinensis from the Songjiang district in Shanghai is popular among Chinese consumers due to its unique pleasant aroma. In this study, volatile compounds in four edible parts of steamed male E. sinensis were extracted by the monolithic material sorptive extraction method and analyzed by gas chromatography-mass spectrometry/olfactometry, the E-Nose technique, and sensory evaluation. Results showed that 2, 7, 7 and 10 important odor compounds (IOCs, odor intensity value ≥3) were determined in abdomen, claw, leg meat, and gonad parts, respectively. Among them, 2-ethylpyridine (fishy odor) was the only IOC in all four parts. Benzaldehyde (almond odor) and trimethylamine (fishy odor) were common to claw meat, leg meat, and gonad parts but not found as the IOCs in abdomen meat. Besides, 3-methyl-2-thiophenecarboxaldehyde (chocolate odor) and 2-acetylthiazole (roast meat odor) were the IOCs found exclusively in abdomen meat and gonad parts, respectively. There existed major differences between gonad parts and 3 types of crabmeat. Sensory evaluation results showed that meaty aroma was the prominent aroma of abdomen meat and claw meat. Leg meat had moderate aroma. Ammonia-like aroma, fishy aroma, grassy aroma, and fatty aroma were correlated with the gonads.

In this study, the key odor-active compounds in the steamed meat of Coilia ectenes from Yangtze River were isolated by headspace monolithic material sorptive extraction and analyzed by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). A total of 49 volatile compounds were identified and quantified in the extract. The results of gas chromatography–olfactometry analysis combined with odor activity value showed that trimethylamine (fishy, ammonia-like), 3-methylbutanal (dark chocolate), decanal (green, oily), hexanal (green), (Z)-4-heptenal (fishy, boiled potato) and benzaldehyde (bitter almond) were the key odor-active compounds contributing primarily to the overall aroma of steamed Coilia ectenes meat. Among them, trimethylamine and (Z)-4-heptenal were the most potent odor-active compounds on the basis of their detection frequency at high odor intensities.

Although there are many chemical compounds present in wines, only a few of these compounds contribute to the sensory perception of wine flavor. This review focuses on the knowledge regarding varietal aroma compounds, which are among the compounds that are the greatest contributors to the overall aroma. These aroma compounds are found in grapes in the form of nonodorant precursors that, due to the metabolic activity of yeasts during fermentation, are transformed to aromas that are of great relevance in the sensory perception of wines. Due to the multiple interactions of varietal aromas with other types of aromas and other nonodorant components of the complex wine matrix, knowledge regarding the varietal aroma composition alone cannot adequately explain the contribution of these compounds to the overall wine flavor. These interactions and the associated effects on aroma volatility are currently being investigated. This review also provides an overview of recent developments in analytical techniques for varietal aroma identification, including methods used to identify the precursor compounds of varietal aromas, which are the greatest contributors to the overall aroma after the aforementioned yeast-mediated odor release.

The seasonal variations of taste and odor (T&O) compounds in western Lake Chaohu were evaluated from July to December 2013. High values were detected in particulate fractions, with peak values 28.25 ng/L for geosmin (GEO), 45.18 ng/L for dimethyltrisulfide (DMTS), 714.77 ng/L for β-cyclocitral, 11.23 ng/L for β-ionone in surface water, and 14.21 ng/L for GEO, 103.68 ng/L for DMTS, 11.97 ng/L for β-ionone in overlying water, all exceeding their odor thresholds. The maximum off-flavor concentrations in sediment ranged from 2010.76 ng/kg for GEO to 1.7 ng/kg for β-ionone. Positive correlations could be found not only between Anabaena and particulate GEO (r = 0.813, p  < 0.01), but also between Microcystis and total β-cyclocitral (r = 0.652, p  < 0.01) or β-ionone (r = 0.560, p  < 0.01) in surface water. TP, TN, PO 4 -P, Chl-a and organic matter contributed significantly to the variations of T&O compounds in water or sediment. The cause of the variations of T&O compounds was the accumulation and degradation of cyanobacteria in water rather than nutrient-rich sediment.

Humans can discriminate several million different colors and almost half a million different tones, but the number of discriminable olfactory stimuli remains unknown. The lay and scientific literature typically claims that humans can discriminate 10,000 odors, but this number has never been empirically validated. We determined the resolution of the human sense of smell by testing the capacity of humans to discriminate odor mixtures with varying numbers of shared components. On the basis of the results of psychophysical testing, we calculated that humans can discriminate at least 1 trillion olfactory stimuli. This is far more than previous estimates of distinguishable olfactory stimuli. It demonstrates that the human olfactory system, with its hundreds of different olfactory receptors, far outperforms the other senses in the number of physically different stimuli it can discriminate.