Hydrogen sulfide levels

Reliable evaluation of the potential for human exposure to hydrogen sulfide depends in part on the reliability of supporting analytical data from environmental samples and biological specimens. In reviewing data on hydrogen sulfide levels monitored or estimated in the environment, it should also be noted that the amount of chemical identified analytically is not necessarily equivalent to the amount that is bioavailable. 

An air monitoring study at a waste-water treatment plant in Australia found time-averaged hydrogen sulfide levels of 1-2 ppm near the primary clarifiers and inlet structure, and levels <1 ppm at various other locations in the 10-hectare plant site (Koe 1985). 

Hydrogen sulfide levels in air on some NPL sites ranged from 0.9 to 808 ppm (HazDat 1997). Data on ambient air concentrations at all NPL sites were not available, however. 

There are no known studies which hydrogen sulfide levels were measured in the blood or other tissues of children. It is not clear whether hydrogen sulfide can be transferred from mother to fetus although there is limited evidence that women occupationally exposed to hydrogen sulfide have a higher rate of spontaneous abortions (Hemminki and Niemi 1982 Xu et al. 1998). 

Fresh and frozen human tissue samples obtained from brain, liver, and kidney have been analyzed for hydrogen sulfide levels by sulfide-derived methylene blue determination using ion-interaction reversed-phase HPLC (Mitchell et al. 1993). This method can quantify nmol/g levels of sulfide. Gas dialysis/ion chromatography with ECD has been utilized for measurement of sulfide in brain tissue with 95-100% recovery (Goodwin et al. 1989). 

Koe LCC. 1985. Ambient hydrogen sulfide levels at a wastewater treatment plant. Environmental Monitoring and Assessment 5 101-108. 

Siegel SM, Penny P, Siegel BZ, et al. 1986. Atmospheric hydrogen sulfide levels at the Sulfur Bay Wildlife area, Lake Rotorua, New Zealand. Water Air Soil Pollut 28 385-391. 

Although there is no ASTM specification for gasoline mercaptan or hydrogen sulfide levels, a copper corrosion specification does exist. Since mercaptans and hydrogen sulfide attack copper and copper-containing alloys such as brass and bronze, it is important to minimize fuel mercaptans and hydrogen sulfide concentrations. 

Four samples of sulfur from four different condensers were obtained from the Petrogas plant in Balzac, Alberta. At the plant the hydrogen sulfide level varied from 168 to 18.5 ppm. Table I indicates that substantially lower values were obtained in the laboratory before the samples had been remelted. A further reduction occurred as a result of remelting and storage. 

Pezeshki, S. R., R. D. DeLaune, and S. Z. Pan. 1991. Relationship of soil hydrogen sulfide level to net carbon assimilation of Panicum hemitomon and Spartina patens. Vegetation 95 159-166. 

In general, chemical processes are able to meet the regulated hydrogen sulfide levels with little difficulty. However, they suffer from the fact that, in general, a material that will react satisfactorily with hydrogen snlfide will also react with CO2. 

Acetylene manufactured from hydrocarbon feedstock is inherently free from phosphine, arsine, and hydrogen sulfide. However, phosphine, arsine, and hydrogen sulfide levels in acetylene produced from a water/calcium carbide reaction are not routinely checked by the acetylene producer (due to the noncritical nature of the use—welding and cutting). These purity levels traditionally have been based on the calcium carbide producers raw material information. 

A mixture of dibenzothiophene in white oil was hydrodesulfurized over a wide range of reaction conditions, varying temperature, pressure, space velocity, and hydrogen sulfide level. 

Dissolved oxygen probes should not normally be inserted directly into the process stream, but fitted into a small flow chamber connected to a side stream or a process fluid off-take point. Proprietary kits may be used for the rapid on-site determination of oxygen, carbon dioxide, and hydrogen sulfide levels in aqueous process fluids. 

The first HTS catalysts were reported to operate for about two years before replacement was required. As production techniques were developed, however, catalyst lives improved so that by 1940, lives of more than 14 years were regularly achieved. There were few poisons which affected the catalyst performance although sulfirr, which was the most common impurity in early plants, did sulfide the magnetite. This reaction was, nevertheless, reversible. If hydrogen sulfide levels exceeded about 300 ppm, sulfided catalysts could not be regenerated... 

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