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At least 19 recordsLinked to original sources

Oxidation of gas mixtures containing dimethyl sulfide, hydrogen sulfide, and methanethiol using a two-stage biotrickling filter.

A biofiltration technique was developed for removing a mixture of hydrogen sulfide (H2S), methanethiol (MeSH), and dimethyl sulfide (Me2S) from waste gases. Since H2S, especially at high concentrations, disturbs the removal of Me2S, two biotrickling filters with different microbes and operating pH levels were connected in series to create a two-stage system. Different loads of these gases were studied in order to determine their impact on the removal capacity of the system. The microbial consortia for these filters were enriched from the sludge of a Finnish refinery with bubbling H2S or Me2S. Acclimation for Me2S took 2 weeks, though no acclimation time was needed for the other gases. The first filter, at a pH of 2, removed most of the H2S and some of the MeSH and Me2S. The second filter, at a pH of approximately 6.5, removed the rest of the MeSH and most of the Me2S. The total maximum loads of the whole two-stage biotrickling filter were 1150 g/m3/day for H2S-S (suffix S indicates the results are counted as sulfur amounts), 879 g/m3/day for Me2S-S, and 66 g/m3/day for MeSH-S treated in a gas mixture. The average removal efficiencies for all gases tested were 99% or higher.

Air Pollutants, Occupational↗

Organic sulfur compounds resulting from the interaction of iron sulfide, hydrogen sulfide and carbon dioxide in an anaerobic aqueous environment.

The reaction of iron sulfide (FeS) with H2S in water, in presence of CO2 under anaerobic conditions was found to yield H2 and a variety of organic sulfur compounds, mainly thiols and small amounts of CS2 and dimethyldisulfide. The same compounds were produced when H2S was replaced by HCl, in the H2S-generating system FeS/HCl/CO2. The identification of the products was confirmed by GC-MS analyses and the incorporation of H2 in the organic sulfur compounds was demonstrated by experiments in which all hydrogen compounds were replaced by deuterium compounds. Generation of H2 and the synthesis of thiols were both dependent upon the relative abundance of FeS and HCl or H2S, i.e. the FeS/HCl- or FeS/H2S-proportions. Whether thiols or CS2 were formed as the main products depended also on the FeS/HCl-ratio: All conditions which create a H2 deficiency were found to initiate a proportional increase in the amount of CS2. The quantities of H2 and thiols generated depended on temperature: the production of H2 was significantly accelerated from 50 degrees C onward and thiol synthesis above 75 degrees C. The yield of thiols increased with the amount of FeS and HCl (H2S), given a certain FeS/HCl-ratio and a surplus of CO2. A deficiency of CO2 results in lower thiol synthesis. The end product, pyrite (FeS2), was found to appear as a silvery granular layer floating on the aqueous surface. The identity of the thiols was confirmed by mass spectrometry, and the reduction of CO2 demonstrated by the determination of deuterium incorporation with DCl and D2O. The described reactions can principally proceed under the conditions comparable to those obtaining around submarine hydrothermal vents, or the global situation about 4 billion years ago, before the dawn of life, and could replace the need for a reducing atmosphere on the primitive earth.

Anaerobiosis↗

Reduction of radiation sensitivity of dry bacterial spores with hydrogen sulfide.

Hydrogen sulfide redtuces the lethal effect of x-rays in dry spores by about 50 percent when given after irradiation, and by approximately 75 percent when present during irradiation. The first effect is the result of removal of radicals that are toxic when combined with oxygen; the second, the removcal of radicals that become toxic in the absence of oxygen. With these results we construct an explanation of the action of sulfhydryl compounds in protection against radiation damage.

Bacteria↗

Direct electrical measurement of the conversion of metal acetates to metal sulfides by hydrogen sulfide.

Copper acetate and related metal salt films react directly with hydrogen sulfide at room temperature to form metal sulfides, resulting in conductivity changes as large as 108. The observed changes in conductivity are related to the solubility product constant (Ksp) and the difference in conductivity between the metal salt and the resulting metal sulfide. A smaller Ksp indicates a more stable metal sulfide and, therefore, greater metal salt reactivity. Polyaniline nanofiber/metal salt composites were also examined and show metal sulfide conversion with changes in resistance up to 106. The direct electrical measurement of the conversion of metal salt to metal sulfide has the potential to be the basis of a new type of sensitive, thin-film chemical sensor.

Journal Article↗

Metabolism of S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine to hydrogen sulfide and the role of hydrogen sulfide in S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine-induced mitochondrial toxicity.

The nephrotoxic cysteine S-conjugate S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine (CTFC) is metabolized by kidney homogenates and subcellular fractions to pyruvate and a reactive thiol, which is cytotoxic and partially decomposes to yield hydrogen sulfide and thiosulfate. Although hydrogen sulfide is a potent mitochondrial poison, the mitochondrial toxicity of CTFC is not attributable to hydrogen sulfide formation, as shown by different sites of inhibition of mitochondrial respiration by CTFC and hydrogen sulfide. The efficient mitochondrial oxidation of hydrogen sulfide apparently serves to protect mitochondria against the toxic effects of hydrogen sulfide generated from CTFC.

Animals↗

A fatal disaster case based on exposure to hydrogen sulfide--an estimation of the hydrogen sulfide concentration at the scene.

Four adult men fell into an artificial lake which was being used to raise flatfish, after a water pipe had been connected to a tube allowing seawater to flow into the lake. Forensic autopsies were carried out on three of the four men, who died soon after the incident. From autopsy findings, the cause of death was diagnosed to be suffocation after aspirating seawater in the three victims. To clarify why the men fell into the lake, a chemical analysis for hydrogen sulfide was carried out using the extractive alkylation technique combined with gas chromatography/mass spectrometry. The sulfide was detected as its derivative, bis(pentafluorobenzyl)sulfide, in body tissues taken from all the victims, and the concentration of hydrogen sulfide gas at the scene was estimated as having been nearly fatal.

Adult↗

[Single and complex effect of ammonia and hydrogen sulfide in the air on small laboratory animals (rats) under various environmental conditions 2. Effect of hydrogen sulfide alone and hydrogen sulfide with ammonia and dust].

The maximum tolerable concentrations per animal position of hydrogen sulphide alone (5 ppm) and with ammonia (5 ppm H2S; 30 ppm NH3) were established by model experiments under defined environmental conditions. The normal values of the contaminant gas combination were found to be acceptable even with additional dust load on the experimental animals. TGL 29084 should stipulate 5 ppm hydrogen sulphide as the new maximum concentration per animal position.

Ammonia↗

Twenty-foot fall averts fatality from massive hydrogen sulfide exposure.

Hydrogen sulfide is a colorless irritant and asphyxiant gas with a noxious odor of "rotten eggs." Acute hydrogen sulfide exposure may cause, depending on the level and duration of toxicity, symptoms ranging from mild mucous membrane irritation to permanent neurologic impairment and cardiopulmonary arrest. We present a case of an oil refinery worker exposed to a typically fatal concentration of hydrogen sulfide gas (>1000 ppm) while working on top of a 20-foot ladder. The "knockdown" effect of exposure to high concentrations of hydrogen sulfide caused him to lose consciousness and fall from the top of the ladder. He was transported to the Emergency Department as a major trauma victim. Ironically, this 20-foot fall saved his life and possibly those of the rescuers by immediately removing him from the source of the hydrogen sulfide. Treatment of hazardous materials incidents and the pathophysiology and treatment options for hydrogen sulfide poisoning are discussed.

Accidental Falls↗

Competition for Dimethyl Sulfide and Hydrogen Sulfide by Methylophaga sulfidovorans and Thiobacillus thioparus T5 in Continuous Cultures.

Pure and mixed cultures of Methylophaga sulfidovorans and Thiobacillus thioparus T5 were grown in continuous cultures on either dimethyl sulfide, dimethyl sulfide and H(inf2)S, or H(inf2)S and methanol. In pure cultures, M. sulfidovorans showed a lower affinity for sulfide than T. thioparus T5. Mixed cultures, grown on dimethyl sulfide, showed coexistence of both species. M. sulfidovorans fully converted dimethyl sulfide to thiosulfate, which was subsequently further oxidized to sulfate by T. thioparus T5. Mixed cultures supplied with sulfide and methanol showed that nearly all the sulfide was used by T. thioparus T5, as expected on the basis of the affinities for sulfide. The sulfide in mixed cultures supplied with dimethyl sulfide and H(inf2)S, however, was used by both bacteria. This result may be explained by the fact that the H(inf2)S-oxidizing capacity of M. sulfidovorans remains fully induced by intracellular H(inf2)S originating from dimethyl sulfide metabolism.

Journal Article↗

Co-worker fatalities from hydrogen sulfide.

BACKGROUND: Hydrogen sulfide is a colorless, odorless gas that may cause rapid loss of consciousness and respiratory depression without warning. It has produced toxicity in workers in numerous industries and occupations. METHODS: A review of the United States Bureau of Labor Statistics (USBLS) Census of Fatal Occupational Injuries (CFOI) for occupational deaths related to hydrogen sulfide from 1993 to 1999 was performed. RESULTS: Fifty-two workers died of hydrogen sulfide toxicity in this 7-year period. Deaths were most commonly reported in workers who were white (85%), male (98%), and in their first year of employment with the company (48%). Common industries included waste management, petroleum, and natural gas. In 21% of cases, a co-worker died simultaneously or in the attempt to save the workers. CONCLUSIONS: Hydrogen sulfide toxicity is uncommon, but potentially deadly. Toxicity is predominantly in new workers and co-worker fatalities occur in a significant minority of cases. Proper training and education on the warning signs of hydrogen sulfide toxicity may help reduce worker fatalities.

Adult↗