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PubMed1990

Evaluation of occupational exposure to sulfur compounds in paper pulp kraft mills.

A study was carried out to provide a comprehensive profile of sulfur gas concentrations to which workers are exposed during the manufacture of paper pulp by the kraft process. Methods currently available--including colorimetric tubes, direct-reading monitors, and gas chromatographic methods--were compared. Gas chromatography is the only technique able to reliably measure individual sulfur gases. However, the necessity of using a gas sampling bag renders this technique inappropriate for personal monitoring. A strategy to evaluate occupational exposure was developed, based on fluctuations in workplace concentrations and the time profile of worker activities. In most samples, only three sulfur products were detected: dimethyl sulfide, methyl mercaptan, and hydrogen sulfide. Concentrations varied as a function of time and location and are correlated to process and equipment-operation variables. Using the proposed strategy, it was demonstrated that workers in the pulp and paper industry can be exposed to significant concentrations of sulfur compounds.

Chromatography, Gas↗
PubMed2006

A study of sorptive loss patterns for reduced sulfur compounds in the use of the bag sampling method.

In this work, the basic properties of the bag sampling method were examined and characterized in terms of recovery rate with respect to four reduced sulfur compounds (RSC) including H2S, CH3SH, DMS, and DMDS. For this comparative study, two types of calibration approaches were performed to evaluate the relative RSC loss due to bag sampling. As a reference calibration tool, a syringe dilution (SD) method was applied. The working standards prepared by diluting the primary standard in a gas-tight syringe (as a mixing chamber) were injected to the GC/PFPD through a loop-injection system to yield a background calibration information. In contrast, the target calibration was performed based on a bag dilution (BD) method. To this end, working standards for multiple calibration points were prepared by two different bag types (Tedlar bag (TB) and polyester bag (PB)). These standards were then drawn by the same syringe and injected into the GC/PFPD via loop. On the basis of these comparative analyses, both absolute and relative differences in RSC recovery rates (RR) were evaluated (e.g., comparison of wall-loss effect). The results indicate that TB has a mean RR of 87% for the four RSC with their values ranging from 82 (CH3SH) to 91% (DMDS). On the other hand, the results of PB generally exhibited slightly reduced RR with their mean values of 77% (range: 73% of H2S to 83% of DMS). The results of this study generally suggest that the losses of RSC samples, while inevitable with the bag sampling method, exhibit certain patterns between different RSCs and between different grab sampling materials.

Adsorption↗
PubMed2003

Catabolism of volatile sulfur compounds precursors by Brevibacterium linens and Geotrichum candidum, two microorganisms of the cheese ecosystem.

Two Brevibacterium linens strains and the cheese-ripening yeast Geotrichum candidum were compared with regard to their ability to produce volatile sulfur compounds (VSCs) from three different precursors namely L-methionine, 4-methylthio-2-oxobutyric acid (KMBA) and 4-methylthio-2-hydroxybutyric acid (HMBA). All microorganisms were able to convert these precursors to VSCs. However, although all were able to produce VSCs from L-methionine, only G. candidum accumulated KMBA when cultivated on this amino acid, contrary to B. linens suggesting that the transamination pathway is not active in this microorganism. Conversely, a L-methionine gamma-lyase activity--which catalyses the one step L-methionine to methanethiol (MTL) degradation route--was only found in B. linens strains. Several other enzymatic activities involved in the catabolism of the precursors tested were investigated. KMBA transiently accumulated in G. candidum cultures, and was then reduced to HMBA by a KMBA dehydrogenase (KDH) activity. This activity was not detected in B. linens. Despite no HMBA dehydrogenase (HDH) was found in G. candidum, a strong HMBA oxidase (HOX) activity was measured in this microorganism. This latter activity was weakly active in B. linens. KMBA and HMBA demethiolating activities were found in all the microorganisms. Our results illustrate the metabolic diversity between cheese-ripening microorganisms of the cheese ecosystem.

Brevibacterium↗
PubMed2004

Reduction of oral levels of volatile sulfur compounds (VSC) by professional toothcleaning and oral hygiene instruction in non-halitosis patients.

PURPOSE: The aim of the study was to determine the longitudinal effect of an oral hygiene program on oral levels of volatile sulfur compounds (VSC). MATERIALS AND METHODS: The study subjects were randomly selected from patients attending a student course in operative dentistry and from staff members of our dental clinic. The test group (n = 30) received an oral hygiene training including professional toothcleaning (PTC), oral hygiene instruction, and motivation. The control group (n = 10) received no particular treatment. None of the subjects suffered from bad breath nor performed regular tongue cleaning. At baseline, immediately after PTC, one week, and four weeks thereafter we measured the oral hygiene status by means of the papillary bleeding index (PBI) and the oral concentrations of VSC by using a portable sulfide monitor (Halimeter). RESULTS: Immediately after PTC, as well as one week, and four weeks after entering the program the PBI and the VSC-levels were significantly decreased as compared to the baseline values and the control group. VSCs were decreased by 34.9% (+/- 6.3) after PTC, 33.2% (+/- 7.1) one week, and 27.9% (+/- 5.8) four weeks thereafter. CONCLUSION: The present study shows that in a group of patients without bad breath, an oral hygiene training program including professional toothcleaning, motivation and instruction of self-applied oral hygiene procedures is capable of reducing both papillary bleeding and oral levels of VSC Halimeter readings over the observation period of four weeks.

Adult↗
PubMed1982

Volatile sulfur compounds responsible for an offensive odor of the flat-head, Calliurichthys doryssus.

1. The volatiles of a flat-head, Calliurichthys doryssus, which gives out a characteristic offensive odor in living time, were analyzed by gas chromatography. 2. A large quantity of volatile sulfur compounds was detected in the flat-head; of which methyl mercaptan and/or dimethyl disulfide were judged to be responsible for the offensive odor. 3. The contents of methyl mercaptan and dimethyl disulfide were much higher in skin than in muscle and viscera.

Animals↗
PubMed2005

Quantitative detection of volatile sulfur compound- producing microorganisms in oral specimens using real-time PCR.

OBJECTIVE: It is well-known that some periodontopathic bacteria, especially Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia (formerly Bacteroides forsythus or Tan. forsythensis), and Treponema denticola, actively produce volatile sulfur compounds (VSCs), such as H2S and CH3SH. We previously reported a qualitative relationship between periodontopathic bacteria and VSCs; however, a quantitative analysis of periodontopathic bacteria in oral specimens is required for further characterization of the relationship between oral bacteria and VSCs. In this study, we report a real-time polymerase chain reaction (PCR) method for the quantitative analysis of VSC-producing bacteria in oral specimens. SUBJECTS AND METHODS: Specimens were collected from 22 patients who visited the Preventive Dentistry and Breath Odor Clinic of Kyushu Dental College. A real-time PCR assay using the TaqMan system, based on the 5'-3' exonuclease activity of Taq polymerase, was employed for the quantitative analysis of periodontopathic bacteria that produce VSCs. RESULTS: Using real-time PCR, we performed a quantitative analysis of P. gingivalis, F. nucleatum, Tan. forsythia, and T. denticola in the saliva, on the tongue coat, and in the subgingival plaque of patients with oral malodor. CONCLUSION: Real-time PCR using the TaqMan system can be used for the quantitative analysis of VSC-producing oral bacteria.

Adult↗
PubMed2001

Effectiveness of mechanical tongue cleaning on oral levels of volatile sulfur compounds.

BACKGROUND: Mechanical tongue cleaning may be an effective method for decreasing oral levels of volatile sulfur compounds, or VSC, and oral malodor. The authors conducted a study to compare the effectiveness of a specially designed tongue cleaner (One Drop Only Tongue Cleaner, One Drop Only, Berlin), a tongue scraper and a toothbrush in reducing oral VSC levels. METHODS: In this balanced, crossover study, 30 subjects had four morning appointments each with a waiting period of one week between appointments. At each appointment, a dental professional performed a single standardized tongue cleaning procedure using one of the cleaning tools. The authors monitored the subjects' oral VSC values using a portable sulfide monitor until their baseline VSC values were reached. RESULTS: The baseline values showed no significant difference between the three groups. The tongue cleaner and the tongue scraper (42 percent and 40 percent, respectively) reduced oral VSC levels more than the toothbrush (33 percent) did. Reduced VSC values could be detected significantly longer after using the tongue cleaner than after using the tongue scraper or the toothbrush. The authors, however, could not detect a significant VSC reduction for more than 30 minutes in any of the subjects. CONCLUSIONS AND CLINICAL IMPLICATIONS: The tongue cleaner, a combination brush and scraper, was slightly more effective in reducing oral VSC levels than were the tongue scraper and a regular toothbrush. Because of the limited duration of the effect, however, the clinical efficacy on the reduction of oral malodor remains questionable.

Analysis of Variance↗
PubMed2006

Influence of anxiety on the production of oral volatile sulfur compounds.

Since many patients complain about halitosis without there being any clinical evidence of its cause, psychological symptoms have been pointed out as halitosis-inducing factors. The aim of this study was to evaluate the influence of anxiety on the production of volatile sulfur compounds (VSC). Seventeen undergraduate men in good oral and general health participated in this study, after approval by the ethics committee. The volunteers were requested to refrain from toothbrushing, using mouth rinse and eating on the experimental day. Before presenting the anxiogenic condition, the volunteer was asked to fill out the Beck Anxiety Inventory questionnaire, to check whether he had been exposed to stressors during the previous week. The Video-Recorded Stroop Color-Word Test (VRSCWT) was used to elicit anxiety. The VSC (halimeter), blood pressure, heart rate and salivary flow measurements were taken before and after the VRSCWT. The volunteers presented a minimal or slight level of anxiety before the test. There was an increase in the oral concentration of VSC, Systolic Blood Pressure and of heart rate (p < 0.05) after the VRSCWT, and no changes in the salivary flow. The results of the present study showed that the anxiogenic condition (VRSCWT) induced increases in VSC concentration, which might contribute to halitosis.

Adult↗
PubMed2002

[Levels of volatile sulfur compounds and the analysis of related factors in oral cavities of 384 health subjects in Chengdu].

OBJECTIVE: The purpose of the study was to investigate the prevalence of oral malodor in a group of health cohorts in Chengdu, China by using different diagnostic methods. METHODS: Volatile sulfur compounds (VSCs) level was evaluated by using Halimeter. The organoleptic score and tongue coating index were also evaluated. A questionnaire interview was conducted at the same time. RESULTS: There were 21.61% subjects whose oral VSCs level were more than 300 ppb. No significant difference was found between male and female for the VSCs values. The subjects with malodor (score > or = 6) evaluated by organoleptic score were 28.91%, and the difference between the male and female was significant (P < 0.05). Further, a significant correlation could be detected between the VSCs level, organoleptic score and tongue coating index (P < 0.05). CONCLUSION: The study indicates that nearly one of fourth people suffer from oral malodor. Malodor has significant correlation with tongue coating, so cleaning of tongue dorsum is very important to reduce oral malodor.

Adult↗
PubMed2004

Clinical comparison of a new manual toothbrush on breath volatile sulfur compounds.

The objective of this randomized, crossover study was to compare the effectiveness of a newly designed manual toothbrush (Colgate 360 degrees) to two commercially available manual toothbrushes (Oral-B Indicator and Oral-B CrossAction) and a battery-powered toothbrush (Crest SpinBrush PRO) for their ability to reduce overnight volatile sulfur compounds (VSC) associated with oral malodor. The study followed a four-period crossover design. Following a washout period, prospective subjects arrived at the testing facility without eating, drinking, or performing oral hygiene for baseline evaluation of breath VSC levels. For each phase of the study, subjects were given one of the test tooth-brushes and a tube of regular toothpaste to take home, and they were instructed to brush their teeth in their customary manner for 1 minute. When using the Colgate 360 degrees toothbrush, subjects were instructed to clean their tongue with the implement on the back of the brush head for 10 seconds. The following morning, subjects reported to the testing facility, again without performing oral hygiene, eating, or drinking, for the overnight evaluation. After a minimum 2-day washout period, subjects repeated the same regimen using the other toothbrushes. The levels of breath VSC were evaluated instrumentally using a gas chromatograph equipped with a flame photometric detector. Measurements were taken in duplicate and then averaged. The levels of VSC were expressed as parts per billion (ppb) in mouth air. Sixteen men and women completed the study. At baseline, the mean levels of VSC in mouth air for the 4 toothbrushes were 719.8 ppb+/-318.4 ppb, 592.8 ppb+/-264.6 ppb, 673.8 ppb+/-405.9 ppb, and 656.2 ppb+/-310.2 ppb for the Colgate 360 degrees, Oral-B Indicator, Crest SpinBrush PRO, and Oral-B CrossAction, respectively. Overnight, the mean breath VSC levels after using the four toothbrushes were lower than those observed at baseline. The respective mean levels of breath VSC were 266.5 ppb+/-269.9 ppb, 545.2 ppb+/-346.1 ppb, 567 ppb+/-335.7 ppb, and 554.6 ppb+/-398.4 ppb. Only the Colgate 360 degrees toothbrush provided a statistically significant reduction (P < .05) in breath VSC vs baseline. Additionally, the Colgate 360 degrees toothbrush was statistically significantly better (P < .05) than the three commercial toothbrushes in reducing breath VSC. Therefore, the results of this randomized, crossover clinical study indicate that a newly designed manual toothbrush with a tongue-cleaning implement on the back of the brush head was significantly more effective than three commercially available toothbrushes in reducing morning breath VSC associated with oral malodor.

Adult↗
PubMed2001

Investigation of the storage stability of selected volatile sulfur compounds in different sampling containers.

The suitability of various sample containers (i.e. standard Tedlar sample bags, black/clear layered Tedlar sample bags and Silcosteel sample cylinders) was examined for a gaseous multicomponent standard containing methylmercaptan, ethylmercaptan, dimethyl sulfide, ethylmethyl sulfide, 2-propylmercaptan, 1-propylmercaptan, 2-butylmercaptan, diethyl sulfide and 1-butylmercaptan (1 mg/m3 each in nitrogen). In the black/clear layered Tedlar sample bags, significant losses (up to 10% for methylmercaptan as the most critical component) were observed after 2 days, whereas in the standard Tedlar sample bags the recovery of methylmercaptan was approximately 90% even after 1 week. The Silcosteel sample cylinders were suitable for sampling of volatile sulfur compounds with respect to the stability of the analytes, but the recoveries exceeded 100% especially for the higher boiling compounds, which was attributed to enrichment effects on parts of the sampling system.

Kinetics↗
PubMed2005

Short-term and long-term effects of increasing temperatures on the stability and the production of volatile sulfur compounds in full-scale thermophilic anaerobic digesters.

This study compares the effect of a rapid increase of the digester temperature (from 54 degrees C to 58 degrees C in 2 weeks) with a slow increase (from 53.9 degrees C to 57.2 degrees C at a rate of 0.55 degrees C per month) on full-scale thermophilic anaerobic digestion at Hyperion Treatment Plant. The short-term test demonstrated that rapidly increasing the digester temperature caused elevated production of volatile sulfur compounds, most notably methyl mercaptan, but volatile solids destruction and methane production were not significantly affected. The increase of the volatile fatty acid to alkalinity ratio from 0.1 to over 0.3 indicated a transient change in digester biochemistry, which was reversed by lowering the temperature. In the long term-test, a slow increase of digester temperature, the production of hydrogen sulfide increased above temperatures of 56.1 degrees C, but was controlled by increased injection of ferrous chloride. Methyl mercaptan was detected in trace amounts at the highest temperature tested (57.2 degrees C). This test showed insignificant effects on other digestion parameters, although some temperature-independent changes were observed that could have been seasonal effects over the year that the long-term test lasted. Thus a slow temperature increase was preferable. This observation contrasts with previous results showing the desirability of a rapid temperature rise to first establish a thermophilic culture when converting from mesophilic operation. Further research is warranted on temperature limits and process changes to optimize thermophilic anaerobic digestion.

Adaptation, Physiological↗
PubMed2000

A gas chromatography-quartz crystal microbalance for speciation of sulfur compounds in landfill gas.

A new method, based on separation with gas chromatography and detection with a quartz crystal microbalance, was used for the quantification of ethane-1-thiol, propane-1-thiol, ethyl methyl sulfide, propane-2-thiol, butane-2-thiol and butane-1-thiol. The analytical error, the analysis time and the general analytical performance are identical for gas chromatography-mass spectrometry (GC-MS) and gas chromatography-quartz crystal microbalance (GC-QCM). However, the GC-QCM method constitutes a low cost alternative to GC-MS for monitoring individual sulfur compounds in landfill gas. It is an easily assembled apparatus made with an injection device, a furnace, a column, a crystal cell and a quartz crystal.

Air Pollutants↗
PubMed2001

Mechanism of oxidation of inorganic sulfur compounds by thiosulfate-grown Thiobacillus thiooxidans.

Thiobacillus thiooxidans was grown at pH 5 on thiosulfate as an energy source, and the mechanism of oxidation of inorganic sulfur compounds was studied by the effect of inhibitors, stoichiometries of oxygen consumption and sulfur, sulfite, or tetrathionate accumulation, and cytochrome reduction by substrates. Both intact cells and cell-free extracts were used in the study. The results are consistent with the pathway with sulfur and sulfite as the key intermediates. Thiosulfate was oxidized after cleavage to sulfur and sulfite as intermediates at pH 5, the optimal growth pH on thiosulfate, but after initial condensation to tetrathionate at pH 2.3 where the organism failed to grow. N-Ethylmaleimide (NEM) inhibited sulfur oxidation directly and the oxidation of thiosulfate or tetrathionate indirectly. It did not inhibit the sulfite oxidation by cells, but inhibited any reduction of cell cytochromes by sulfur, thiosulfate, tetrathionate, and sulfite. NEM probably binds sulfhydryl groups, which are possibly essential in supplying electrons to initiate sulfur oxidation. 2-Heptyl-4-hydroxy-quinoline N-oxide (HQNO) inhibited the oxidation of sulfite directly and that of sulfur, thiosulfate, and tetrathionate indirectly. Uncouplers, carbonyl cyanide-m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNP), inhibited sulfite oxidation by cells, but not the oxidation by extracts, while HQNO inhibited both. It is proposed that HQNO inhibits the oxidation of sulfite at the cytochrome b site both in cells and extracts, but uncouplers inhibit the oxidation in cells only by collapsing the energized state of cells, delta muH+, required either for electron transfer from cytochrome c to b or for sulfite binding.

2,4-Dinitrophenol↗
PubMedDate not supplied

[An evaluation of acute effects of sulfur compounds for the human organism in natural gas fields emergencies (review)].

A trend towards a growing number of emergency situations at industrial enterprises has been recently traced throughout the world. The main reasons of such phenomenon are: a comprehensive use of highly dangerous technologies and materials; large-scale violations of the operational rules and norms; and an inadmissibly high wear-and-tear of the main production funds in economic branches with extra risk. The world experience is indicative of a high degree of danger related with exploiting the natural-gas fields with a high content of sulfur compounds. The occurrence of emergency situations in the mentioned fields is accompanied by development of acute and sub-acute toxic effects in the workers and population. It necessitated, recently, an elaboration of a concept of a relative safety, in view of an unfavorable impact produced by chemical substances in emergencies, and an elaboration of methods applicable to the evaluation of emergency regulations.

Accidents, Occupational↗
PubMed2006

Reduced sulfur compounds in gas from construction and demolition debris landfills.

The biological conversion of sulfate from disposed gypsum drywall to hydrogen sulfide (H(2)S) in the anaerobic environment of a landfill results in odor problems and possible health concerns at many disposal facilities. To examine the extent and magnitude of such emissions, landfill gas samples from wells, soil vapor samples from the interface of the waste and cover soil, and ambient air samples, were collected from 10 construction and demolition (C&D) debris landfills in Florida and analyzed for H(2)S and other reduced sulfur compounds (RSC). H(2)S was detected in the well gas and soil vapor at all 10 sites. The concentrations in the ambient air above the surface of the landfill were much lower than those observed in the soil vapor, and no direct correlation was observed between the two sampling locations. Methyl mercaptan and carbonyl sulfide were the most frequently observed other RSC, though they occurred at smaller concentrations than H(2)S. This research confirmed the presence of H(2)S at C&D debris landfills. High concentrations of H(2)S may be a concern for employees working on the landfill site. These results indicate that workers should use proper personal protection at C&D debris landfills when involved in excavation, landfill gas collection, or confined spaces. The results indicate that H(2)S is sufficiently diluted in the atmosphere to not commonly pose acute health impacts for these landfill workers in normal working conditions. H(2)S concentrations were extremely variable with measurements occurring over a very large range (from less than 3 ppbv to 12,000 ppmv in the soil vapor and from less than 3 ppbv to 50 ppmv in ambient air). Possible reasons for the large intra- and inter-site variability observed include waste and soil heterogeneities, impact of weather conditions, and different site management practices.

Air Pollutants↗
PubMed2003

Effects of tongue and oral mucosa cleaning on oral Candida species and production of volatile sulfur compounds in the elderly in a nursing home.

The purpose of this study was to investigate the effects of oral care using simple tools and methods on the cleanliness of the oral cavity in the elderly. Enrolled were 84 elderly subjects with a mean (+/-S.D) age of 85.1+/-7.0 years in a nursing home. They were given tongue and oral mucosa cleaning (the oral care) after lunch every day or every other day for two consecutive weeks by the authors. The effect of the oral care was studied in terms of Candida scores in tongue coating, concentration of volatile sulfur compounds (VSC) which are the main causative substance of bad breath, and change in tongue coating scores. The above parameters were measured five times; just before the oral care program, weekly during, and at the end of the oral care program. The groups of patients, who were given the oral care, especially the group of patients cared with sponge brushes every day, showed a significant reduction in Candida scores but not in VSC concentration and tongue coating scores. The present method of oral care proved effective in cleaning the tongue and oral mucosa, and the Candida scores appeared to be a reliable indicator for evaluation. It is suggested that this way of oral care is simple, easy and useful not only for the elderly at a nursing home but for the house-bound elder people who will rapidly increase in the near future in Japan.

Aged↗
PubMed2003

Evaluation of solid-phase microextraction for time-weighted average sampling of volatile sulfur compounds at ppb concentrations.

The potential of solid-phase microextraction (SPME) for time-weighted average (TWA) sampling of volatile sulfur compounds in air at ppb concentrations was investigated. The target compounds (hydrogen sulfide, methanethiol (MeSH), ethanethiol (EtSH), dimethyl sulfide (Me2S), and dimethyl disulfide (Me2S2)) were extracted using SPME with a Carboxen-poly(dimethylsiloxane) fiber coating, and diffusion was controlled by keeping the fiber retracted within the needle of the sampling device. The effects of several important experimental variables (air velocity, direction of air flow, analyte concentration, humidity, temperature, extraction time) were studied. The uptake by the fiber was not affected by the direction of the air flow or the air velocity. The effects of concentration, humidity, temperature, and extraction time were examined in experiments with a central composite face design. The results showed that all or most of the investigated parameters had a significant impact on the uptake rates of H2S, MeSH, EtSH, and Me2S, which invalidated time-weighted average sampling of these compounds by SPME under the tested conditions. Moreover, reverse diffusion of H2S, MeSH, and EtSH occurred at 40% relative humidity. For Me2S2, the uptake rate had a variation of only 8% within the whole experimental domain, and the experimental value derived for the uptake rate was consistent with the theoretical value. This result was confirmed by comparative analyses of industrial samples by the standard addition method. Therefore, SPME appears to be a suitable technique for TWA sampling of Me2S2 using the Carboxen-poly(dimethylsiloxane) fiber coating. Finally, in an investigation of potential losses during storage of the fiber, no significant losses of the target compounds were detected after 3 days at -80 degrees C.

Journal Article↗