Low Levels Of Hydrogen Sulfide Research Articles

Variability in Background Urinary Concentrations of the Hydrogen Sulfide Biomarker Thiosulfate.

Hydrogen sulfide is a toxic gas at high concentrations but has recently attracted attention as a naturally produced gaseous signaling molecule in various tissues of the human body, playing key physiological roles at low nanomolar concentrations. This has wide implications for chronic exposure to this gas in air at low levels far below toxicity. Thiosulfate is the currently used biomarker for exposure to hydrogen sulfide via inhalation but has been mainly employed for acute exposure. It is unknown how background thiosulfate concentrations vary on an intraindividual and interindividual basis in humans at normal ambient hydrogen sulfide levels (<1 μg m-3), which is key for the interpretation of its levels as biomarker for low-level hydrogen sulfide exposure. In the current work, the variability in thiosulfate urinary excretion in a total of 168 urine samples collected from eight volunteers over a period of 8 weeks was investigated. The determination of thiosulfate in urine was carried out by UHPLC-MS/MS. The total average concentration ± SD was 16 ± 6 μM (n = 168). Average urinary thiosulfate concentrations in the studied volunteers were within the range of 10-20 μM, but it was found that urinary thiosulfate can show significant day-to-day and week-to-week variability in some individuals (up to 10-fold), despite adjusting for urine specific gravity. In light of the presented variability data and previous studies about the lack of consistent response of thiosulfate to low levels of hydrogen sulfide inhalation exposure, and based on a review of the biochemistry of the production of thiosulfate and its various biological sources, it can be argued that thiosulfate might not be suitable as a biomarker for chronic environmental exposure to low levels of hydrogen sulfide via inhalation.

Endogenous H2S production deficiencies lead to impaired renal erythropoietin production.

Patients suffering from chronic kidney disease (CKD) experience a number of associated comorbidities, including anemia. Relative deficiency in renal erythropoietin (EPO) production is thought to be a primary cause of anemia. Interestingly, CKD patients display low levels of hydrogen sulfide (H2S), an endogenously derived renal oxygen sensor. Previous in vitro experiments have revealed that H2S-deficient renal cell lines produce less EPO than wild-type renal cell lines during hypoxia. We postulated that H2S might be a primary mediator of EPO synthesis during hypoxia, which was tested using an in vivo murine model of whole-body hypoxia and in clinical samples obtained from CKD patients. Following a 72-hour period of hypoxia (11% O2), partial H2S knockout mice (lacking the H2S biosynthetic enzyme cystathionine γ-lyase [CSE]) displayed lower levels of hemoglobin, EPO and cystathionine-β-synthase (CBS) (another H2S biosynthetic enzyme) compared to wild-type mice, all of which was rescued by exogenous H2S supplementation. We also found that anemic CKD patients requiring exogenous EPO exhibited lower urinary thiosulfate levels compared to non-anemic CKD patients of similar CKD classification. Together, our results confirm an interplay between the actions of H2S during hypoxia and EPO production.

Caenorhabditis elegans HIF-1 Is Broadly Required for Survival in Hydrogen Sulfide.

Hydrogen sulfide is common in the environment, and is also endogenously produced by animal cells. Although hydrogen sulfide is often toxic, exposure to low levels of hydrogen sulfide improves outcomes in a variety of mammalian models of ischemia-reperfusion injury. In Caenorhabditis elegans, the initial transcriptional response to hydrogen sulfide depends on the hif-1 transcription factor, and hif-1 mutant animals die when exposed to hydrogen sulfide. In this study, we use rescue experiments to identify tissues in which hif-1 is required to survive exposure to hydrogen sulfide. We find that expression of hif-1 from the unc-14 promoter is sufficient to survive hydrogen sulfide. Although unc-14 is generally considered to be a pan-neuronal promoter, we show that it is active in many nonneuronal cells as well. Using other promoters, we show that pan-neuronal expression of hif-1 is not sufficient to survive exposure to hydrogen sulfide. Our data suggest that hif-1 is required in many different tissues to direct the essential response to hydrogen sulfide.

OCENA METOD MONITORINGU STĘŻEŃ SIARKOWODORU W POWIETRZU

The development of different branches of industry and a growing fossil fuels minming results in a considerable emission of by-products. Major air pollutants are: CO, CO2, SO2, SO3, H2S, nitrogen oxides, as well as compounds of an organic arigin. The main aspects of this paper is to review and evaluate methods used for monitoring of hydrogen sulfide in the air. Different instrumental techniques were discussed, electrochemical, chromatographic and spectrophotometric (wet and dry), to select the method most suitable for monitoring low levels of hydrogen sulfide, close to its odor threshold. Based on the literature review the method for H2S determination in the air, involving absorption in aqueous zinc acetate and reaction with N,N-dimethylo-p-phenylodiamine and FeCl3, has been selected and preliminary verified. The adopted method allows for routine measurements of low concentration of hydrogen sulfide, close to its odor threshold in workplaces and ambient air.

Evaluation of Portable Single-Gas Monitors for the Detection of Low Levels of Hydrogen Sulfide and Sulfur Dioxide in Petroleum Industry Environments

Many portable single-gas monitors are used for the detection of low concentrations of hydrogen sulfide (H2S) and sulfur dioxide (SO2) in the workplace. With the recent lowering of the H2S and SO2 ACGIH® threshold limit value (TLV®) the ability of these devices to selectively respond to these new lower levels is not well documented in petroleum industry environments, which often have potential interfering gases and vapors present as well as varying environmental conditions. Tests were carried out to measure the ability of various monitors with their respective sensors to correctly quantify and respond to H2S and SO2 in a simulated petroleum industry environment. This included the identification of selected interference effects and estimation of the reliable lower limit of detection for real workplace environments. None of the H2S monitors responded at 0.1 times the new TLV (0.1 ppm), only some of them responded at the new TLV concentration (1 ppm), and all the monitors exposed to five times the new TLV (5 ppm) responded with reasonable accuracy. There was generally little effect of interferent gases and vapors on the H2S monitors. None of the SO2 monitors responded at 0.1 and 1 times the new TLV (0.025 ppm and 0.25 ppm) concentrations, and all but one of them exposed to five times the new TLV (1.25 ppm) responded. There was much greater cross-sensitivity to interferents at the tested concentrations with the SO2 monitors, which responded to six out of eight of the interferents tested. Results demonstrate that these monitors cannot reliably alarm and measure H2S or SO2 concentrations at the new TLVs with an acceptable degree of accuracy. However, these monitors are designed to alarm as a safety device; these results do not change this important function.

Right Under Our Noses: the Direct Detection of Low Levels of Hydrogen Sulfide

Right Under Our Noses: the Direct Detection of Low Levels of Hydrogen Sulfide

Low Levels of Hydrogen Sulfide in the Blood of Diabetes Patients and Streptozotocin-Treated Rats Causes Vascular Inflammation?

Hydrogen sulfide (H(2)S) is emerging as a physiological neuromodulator as well as a smooth muscle relaxant. We submit the first evidence that blood H(2)S levels are significantly lower in fasting blood obtained from type 2 diabetes patients compared with age-matched healthy subjects, and in streptozotocin-treated diabetic rats compared with control Sprague-Dawley rats. We further observed that supplementation with H(2)S or an endogenous precursor of H(2)S (l-cysteine) in culture medium prevents IL-8 and MCP-1 secretion in high-glucose-treated human U937 monocytes. These first observations led to the hypothesis that lower blood H(2)S levels may contribute to the vascular inflammation seen in diabetes.

Catalytic Performance and Deactivation of Precipitated Iron Catalyst for Selective Oxidation of Hydrogen Sulfide to Elemental Sulfur in the Waste Gas Streams from Coal Gasification

The selective oxidation of hydrogen sulfide to elemental sulfur, using a commercial, precipitated silica promoted ferric oxide based catalyst, was investigated in laboratory and pilot-plant reactors. Low levels of hydrogen sulfide (1-3 vol%) can be readily removed, but a continuous slow decrease in catalyst activity was apparent. X-ray photoelectron spectroscopy showed that the loss of activity was due to the formation of ferrous sulfate, which is known to be less active than the ferric oxide. In addition, studies using a model feed showed that the propene and HCN impurities in the plant feed stocks also act as potent catalyst poisons.

A colorimetric response to hydrogen sulfide

Two simple Cu(II) chromophores [Cu(acac)(dmp)](NO 3) ( 1) and [Cu(acac)(dpph)](NO 3) ( 2) (acac = acetylacetone, dmp = 2,9-dimethyl-1,10-phenanthroline and dpph = 4,7-diphenyl-1,10-phenanthroline) have been synthesised and immobilized into a highly permeable polymer matrix and subsequently used in the optical detection of low levels of hydrogen sulfide (10 ppm) over a 2 min period. The system is responsive to a concentration one-tenth that quoted as being immediately dangerous to life and health (IDLH) value (100 ppm) by the National Institute for Occupational Safety and Health (NIOSH). The UV–vis spectral change is a consequence of the hydrogen sulfide gas reducing the Cu(II) to Cu(I) in the polymer matrix. A crystal structure of [Cu(acac)(dpph)](NO 3) ( 2) was obtained and will also be discussed.

The effect of molecular oxygen on sulfite reduction by Shewanella putrefaciens

Recently, Shewanella putrefaciens isolated from an industrial cooling water system has been shown to play a role in microbially influenced corrosion. In this study S. putrefaciens isolated from industrial cooling waters was shown to produce low levels of hydrogen sulfide from sulfite at dissolved oxygen concentrations up to 1.5 mg l −1 oxygen. Although oxygen is the preferred electron acceptor with the highest energy yield, some of the electrons were diverted to sulfite. When the starting inoculum was from a sulfite-reducing culture, the growth rate and oxygen depletion rate were lower compared to when the inoculum was from an aerobic culture that did not reduce sulfite, indicating that sulfite reduction occurred concurrently with oxygen reduction. The reduction of sulfite by S. putrefaciens under microaerophilic as well as anaerobic conditions points towards a more significant role of this species in microbially influenced corrosion when growing as a biofilm.

The effect of molecular oxygen on sulfite reduction byShewanella putrefaciens

Recently, Shewanella putrefaciens isolated from an industrial cooling water system has been shown to play a role in microbially influenced corrosion. In this study S. putrefaciens isolated from industrial cooling waters was shown to produce low levels of hydrogen sulfide from sulfite at dissolved oxygen concentrations up to 1.5 mg l−1 oxygen. Although oxygen is the preferred electron acceptor with the highest energy yield, some of the electrons were diverted to sulfite. When the starting inoculum was from a sulfite-reducing culture, the growth rate and oxygen depletion rate were lower compared to when the inoculum was from an aerobic culture that did not reduce sulfite, indicating that sulfite reduction occurred concurrently with oxygen reduction. The reduction of sulfite by S. putrefaciens under microaerophilic as well as anaerobic conditions points towards a more significant role of this species in microbially influenced corrosion when growing as a biofilm.

Design and development of a system to measure ambient levels of hydrogen sulfide and lower mercaptans from a mobile platform

Hydrogen sulfide and other reduced sulfur gases are released into the atmosphere during oil recovery operations. Little is quantitatively known concerning total sulfur flux due to these fugitive emissions. A mobile atmospheric research laboratory (MARL) was constructed to furnish facile, self contained access to oil field operations. An automated instrument that can continuously measure low levels of hydrogen sulfide with good time resolution (limit of detection 0.2 ppbv for a sampling time of 2.5 min) was developed and deployed on the MARL. Meteorological instrumentation and chemical instrumentation to monitor other gas and aerosol species along with information on meteorological conditions were also installed. Initial field data show a strong diurnal pattern of H 2S concentrations.

Growth and Development in the Rat during Sub-Chronic Exposure to Low Levels of Hydrogen Sulfide

The effects of low levels of hydrogen sulfide (H2S) on mammalian growth and development are unknown although it has long been postulated that H2S can inhibit critical developmental functions through the cleavage of disulfide bonds and chelation of essential metal ions. Gravid rat dams exposed to H2S (less than or equal to 75 PPM) from day 6 of gestation until day 21 postpartum (PP) demonstrated normal reproductive parameters until parturition. At parturition, however, delivery time was extended in a dose dependent manner with a maximum increase of 42% at 75 PPM. Maternal liver cholesterol content was elevated significantly on day 21 postpartum following exposure to 75 PPM H2S each day for 6 weeks. Pups which were exposed in utero and neonatally to day 21 postpartum developed with a subtle decrease in time of ear detachment and hair development and with no other observed change in growth and development through day 21 postpartum.

Exposure to low levels of hydrogen sulfide elevates circulating glucose in maternal rats

Although the lethal effect of hydrogen sulfide (H2S) has long been known, the results of exposure to low levels of H2S have not been well documented. Rat dams and pups were exposed to low levels of H2S (less than or equal to 75 ppm) from d 1 of gestation until d 21 postpartum and analyzed for changes in circulating enzymatic activity and metabolites. Blood glucose was significantly elevated in maternal blood on d 21 postpartum at all exposure levels. This increase in glucose was accompanied by a possible decrease in serum triglyceride in the pups and in the dams on d 21 postpartum. There was no evidence of alterations in serum alkaline phosphatase, lactate dehydrogenase, or serum glutamate oxaloacetate transaminase.

Copper Corrosion Inhibition in Sour Hydrocarbon Fuels

Abstract The corrosion of copper in fuels containing low levels of hydrogen sulfide was investigated. The performance of several inhibitors was evaluated using the ASTM Standard D130-83 method. The...

A monitoring system for low levels of hydrogen sulfide in alkanolamine streams

To meet the needs in gas-sweetening processes for on-line monitoring of low levels of hydrogen sulfide in alkanolamine solutions, an on-line analysis system has been developed based on the measurement of the intense and broad ultraviolet (u.v.) absorption of the H 2S-amine bond. This system incorporates the following three features to provide the requird accuracy and reliability. To compensate for variation in sample background absorbance from additives and from degradation and corrosion products, a vacuum distillation step is used to strip out H 2S from a process sample to provide an H 2S-free “zero” standard. To compensate for the temperature sensitivity of the u.v. absorption of the H 2S-amine bond, close temperature control as well as a temperature-compensating circuit is provided. To handle sample streams often containing heavy loadings of fine and well-dispersed particulate matter, a special self-cleaning filtering system is used.

Mine timber economies

The toxicology of hydrogen sulfide (H2S) and sour gas on the eye has a long history beginning at least with Ramazzini's observations [Ramazzini B. Diseases of Workers—De Morbis Artificum Diatriba—1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc.; 1964. 98–99 pp.]. In contrast, a recent review by Alberta Health and Wellness (AHW Report) concluded that there is little evidence of eye irritation following short-term exposures to H2S at concentrations up to 100 ppm and that the H2S literature on the eye is a series of unsubstantiated claims reproduced in review articles dating back to the 1930s [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide: a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In this paper, we evaluated this claim through a historical review of the toxicology of the eye. Ramazzini noted the effects of sewer gas on the eye [Ramazzini B. Diseases of Workers—De Morbis Artificum Diatriba—1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc. 1964. 98–99 pp.]. Lehmann experimentally showed eye effects in men at 70–90 ppm H2S and also in animals [Lehmann K. Experimentalle Studien uber den Einfluss technisch und hygienisch wichtiger Gase und Dampfe auf den Organismus. Arch Hyg 1892;14:135–189]. In 1923, Sayers, Mitchell and Yant reported eye effects in animals and men at 50 ppm H2S. Barthelemy showed eye effects in animals and men at 20 ppm H2S [Barthelemy HL. Ten years' experience with industrial hygiene in connection with the manufacture of viscose rayon. J Ind Hyg Toxicol 1939;21:141–51]. Masure experimentally showed that H2S is the causative agent of eye impacts in animals and men [Masure R. La Keratoconjunctivite des filatures de viscose; etude clinique and experiementale. Rev Belge Pathol 1950;20:297–341]. Michal upon microscopic examination of the rat's cornea, found nuclear pyknosis, edema and separation of cells in the eye following exposures for 3 h at 36 ppm H2S [Michal FV. Eye lesions caused by hydrogen sulfide. Cesk Ophthalmol 1950;6;5–8]. In 1975, in Alberta, irreversible eye damage and photophobia were experimentally produced in calves exposed to 20 ppm H2S for 1 week [Nordstrom GA. A study of calf response of ammonia and hydrogen sulfide gases. Thesis, University of Alberta, Department of Agricultural Engineering, Edmonton Alberta; 1975, 218 pp.]. Alberta Environmental Centre documented clinical irritation of the eye at 40 ppm H2S in 6 hours in rats [Alberta Environmental Centre. Morphological observations in rats exposed for six hours to an atmosphere of 0, 56, or 420 mg/m3 hydrogen sulfide. AECV86-A1. Alberta Environmental Centre, Vegreville, Alberta; 1986b. 28 pp.]. In two sour gas blow-outs in Alberta, in the early 1980s, eye injury was documented in humans and animals at 0.5 ppm H2S. Community studies in the United States, Europe and New Zealand suggest that acute exposure to 25 ppb H2S is the lowest concentration to irritate the eyes; with chronic exposure, serious eye effects are suggested. In contrast to the conclusion, all of the studies, except one, cited in the AHW Report indicate toxic effects on the eye below 100 ppm H2S [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide (H2S): a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In addition, the AHW Report (2002) mis-presented two studies as ‘clinical studies’, claiming they reported no evidence of eye effects in humans from 2 and 30 ppm H2S for 30–40 minutes [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide (H2S): a technical review, Alberta Health and Wellness, October 2002, 81pp.].

Physiological effects of exposure to low concentrations of carbon monoxide

The toxicology of hydrogen sulfide (H2S) and sour gas on the eye has a long history beginning at least with Ramazzini's observations [Ramazzini B. Diseases of Workers—De Morbis Artificum Diatriba—1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc.; 1964. 98–99 pp.]. In contrast, a recent review by Alberta Health and Wellness (AHW Report) concluded that there is little evidence of eye irritation following short-term exposures to H2S at concentrations up to 100 ppm and that the H2S literature on the eye is a series of unsubstantiated claims reproduced in review articles dating back to the 1930s [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide: a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In this paper, we evaluated this claim through a historical review of the toxicology of the eye. Ramazzini noted the effects of sewer gas on the eye [Ramazzini B. Diseases of Workers—De Morbis Artificum Diatriba—1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc. 1964. 98–99 pp.]. Lehmann experimentally showed eye effects in men at 70–90 ppm H2S and also in animals [Lehmann K. Experimentalle Studien uber den Einfluss technisch und hygienisch wichtiger Gase und Dampfe auf den Organismus. Arch Hyg 1892;14:135–189]. In 1923, Sayers, Mitchell and Yant reported eye effects in animals and men at 50 ppm H2S. Barthelemy showed eye effects in animals and men at 20 ppm H2S [Barthelemy HL. Ten years' experience with industrial hygiene in connection with the manufacture of viscose rayon. J Ind Hyg Toxicol 1939;21:141–51]. Masure experimentally showed that H2S is the causative agent of eye impacts in animals and men [Masure R. La Keratoconjunctivite des filatures de viscose; etude clinique and experiementale. Rev Belge Pathol 1950;20:297–341]. Michal upon microscopic examination of the rat's cornea, found nuclear pyknosis, edema and separation of cells in the eye following exposures for 3 h at 36 ppm H2S [Michal FV. Eye lesions caused by hydrogen sulfide. Cesk Ophthalmol 1950;6;5–8]. In 1975, in Alberta, irreversible eye damage and photophobia were experimentally produced in calves exposed to 20 ppm H2S for 1 week [Nordstrom GA. A study of calf response of ammonia and hydrogen sulfide gases. Thesis, University of Alberta, Department of Agricultural Engineering, Edmonton Alberta; 1975, 218 pp.]. Alberta Environmental Centre documented clinical irritation of the eye at 40 ppm H2S in 6 hours in rats [Alberta Environmental Centre. Morphological observations in rats exposed for six hours to an atmosphere of 0, 56, or 420 mg/m3 hydrogen sulfide. AECV86-A1. Alberta Environmental Centre, Vegreville, Alberta; 1986b. 28 pp.]. In two sour gas blow-outs in Alberta, in the early 1980s, eye injury was documented in humans and animals at 0.5 ppm H2S. Community studies in the United States, Europe and New Zealand suggest that acute exposure to 25 ppb H2S is the lowest concentration to irritate the eyes; with chronic exposure, serious eye effects are suggested. In contrast to the conclusion, all of the studies, except one, cited in the AHW Report indicate toxic effects on the eye below 100 ppm H2S [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide (H2S): a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In addition, the AHW Report (2002) mis-presented two studies as ‘clinical studies’, claiming they reported no evidence of eye effects in humans from 2 and 30 ppm H2S for 30–40 minutes [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide (H2S): a technical review, Alberta Health and Wellness, October 2002, 81pp.].