Acute Exposure Guideline Levels for Selected Airborne Chemicals Volume 9 (2010) / Chapter Skim
Currently Skimming:
4 Hydrogen Sulfide
4 Hydrogen Sulfide
Pages 173-218
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 173... ...
Both the document and the AEGL values were then reviewed by the National Research Council (NRC) Committee on Acute Exposure Guideline Levels.
|
From page 174... ...
The 30-min experimental value was scaled to the 10min and 1-, 4-, and 8-h time points by using the concentration-exposure duration relationship, C4.4 × t = k, where C is concentration, t is time, and k is a constant. The exponent 4.4 was derived from rat lethality data ranging from 10-min to 6-h exposures.
|
From page 175... ...
An intraspecies uncertainty factor of 3 was applied to account for sensitive individuals. The intraspecies uncertainty factor of 3 is considered sufficient because applying the default uncertainty factor of 10 would result in a total uncertainty factor of 30, which would yield AEGL-2 values inconsistent with the total database for H2S.
|
From page 176... ...
TABLE 4-1 Summary of AEGL Values for Hydrogen Sulfide End Point Classification 10 min 30 min 1h 4h 8h (Reference) AEGL-1 0.75 ppm 0.60 ppm 0.51 ppm 0.36 ppm 0.33 ppm Headache in (Nondisabling)
|
From page 177... ...
Occupational Safety and Health Administration records, there were 80 fatalities in 57 H2S incidents from 1984 to 1994 (Fuller and Suruda 2000)
|
From page 178... ...
Autopsy showed massive liquid manure pulmonary aspiration in two individuals and fulminant pulmonary edema without manure aspiration in the third. "Increased heart-blood sulfide levels" indicated significant H2S exposure.
|
From page 179... ...
Artificial respiration is appropriate in victims with depressed or absent breathing, as are supportive steps to combat development of pulmonary edema (Gosselin et al.
|
From page 180... ...
. It was also stated that, as a provisional rule, it appears that when an unpleasant odor reaches approximately 5 times its odor threshold concentration, the mean concentration for complaints of odor annoyance is attained.
|
From page 181... ...
. Many objectionable odor sources have been implicated in asthma attacks, annoyance, and behavioral modifications and include municipal odors (landfills, sewage treatment plants)
|
From page 182... ...
. Although H2S concentrations have been reported in these studies, the populations were also exposed to relatively high concentrations of other malodorous sulfur compounds such as sulfur dioxide and mercaptans.
|
From page 183... ...
/min. Hydrogen sulfide concentration was monitored continuously with a sulfur dioxide analyzer connected to a converter that transformed H2S into sulfur dioxide at 840°C.
|
From page 184... ...
after H2S exposure compared with controls. Muscle lactate and lactic acid dehydrogenase were not affected in women and cytochrome oxidase increased 23% (n.s.)
|
From page 185... ...
Muscle cytochrome oxidase decreased by 16% in men, whereas it increased by 11% in women after exposure to H2S. None of the subjects reported adverse health effects after H2S exposure.
|
From page 186... ...
Several reports suggest that neurologic effects may persist in survivors of severe H2S poisonings. Some reports hypothesize that odors, such as the rotten egg smell associated with H2S, may trigger asthma attacks and other health effects; however, it is uncertain whether a toxicologic mechanism or a nontoxicologic odor-related mechanism is involved.
|
From page 187... ...
Rats exposed to H2S exhibited dyspnea characterized by exaggerated abnormal, audible respiration and had frothy fluid from the nose and mouth during exposure. Pulmonary edema was evident in exposed rats at necropsy.
|
From page 188... ...
Exposure Duration Reference Rat Mouse 10 min 835 1,160 Zwart et al. 1990 30 min 726 800 Zwart et al.
|
From page 189... ...
increased protein concentration and LDH activity were found in lung lavage fluid from animals exposed to 300 ppm. Exposure to H2S at 300 ppm produced significant (p < 0.01)
|
From page 190... ...
Rats exposed to H2S at 10 and 100 ppm exhibited concentration-related reductions in cytochrome c oxidase activity in lung (p < 0.05) mitochondria.
|
From page 191... ...
Lung sulfide concentrations increased during exposure and returned to baseline levels within 15 min after exposure to 400 ppm, and lung sulfide metabolite concentrations transiently increased immediately after the end of exposure. Decreased cytochrome oxidase activities were noted in the olfactory epithelium at 30, 80, 200, and 400 ppm.
|
From page 192... ...
Clinical signs included crustiness around the ear tags; crusty noses, eyes, and muzzles; redstained fur; swollen red ears; rales; lacrimation; and swollen muzzles and eyes. Decreased body weight gain and decreased brain weights were observed in highconcentration animals of both sexes.
|
From page 193... ...
decrease in food consumption was observed in F0 males only in the 80-ppm group during the first week of exposure. There were no deaths and no treatment-related adverse clinical signs in F0 males or females.
|
From page 194... ...
at 75 ppm in the cerebellum at postpartum days 7, 14, and 21 but significantly increased in the frontal cortex only at postpartum day 21. At 20 ppm, frontal cortex norepinephrine levels decreased compared with controls on days 14 and 21.
|
From page 195... ...
. Pulmonary edema and atelectasis developed in rats exposed to H2S at 300 ppm for 4 h (Green et al.
|
From page 196... ...
Although the signs of H2S poisoning are essentially identical to those of cyanide poisoning, H2S has a greater tendency to produce conjunctivitis and pulmonary edema (Smith 1996)
|
From page 197... ...
Rats pretreated with ethanol (0.33 or 0.66 gram per kilogram of body weight, intraperitoneally) 0.5 h before exposure to H2S at 790 to 800 ppm for a maximum of 20 min lost consciousness in 35% less time than rats exposed only to H2S (Beck et al 1979)
|
From page 198... ...
Thus, the value n = of 4.4, derived from rat lethality data from 10 min to 6 h (r2 = 0.92) , was selected for extrapolation of H2S response across time.
|
From page 199... ...
. For scaling the AEGL values for H2S across time, the empirically derived chemical-specific value of 4.4 (derived from rat lethality data ranging from 10-min to 6-h exposure durations; Figure 4-1)
|
From page 200... ...
The intraspecies uncertainty factor of 3 is sufficient because application of 10 yields AEGL-2 values inconsistent with the total database. AEGL-2 values derived with a total default uncertainty factor were less than the10-ppm concentration causing no effects in humans exercising to exhaustion (Bhambhani and Singh 1991; Bhambhani et al.
|
From page 201... ...
The intraspecies uncertainty factor of 3 is sufficient because application of the default 10 yields AEGL-3 values inconsistent with the total database. AEGL-3 values derived with a total default uncertainty factor were less than twice the concentration causing no effects in humans exercising to exhaustion (Bhambhani and Singh 1991; Bhambhani et al.
|
From page 202... ...
. The LOA represents the concentration above which it is predicted that more than half of the exposed population will experience at least a distinct odor intensity, and about 10% of the population will experience a strong odor intensity.
|
From page 203... ...
(AIHA 2001) : The ERPG-1 is the maximum airborne concentration below which it is believed nearly all individuals could be exposed for up to 1 h without experiencing other than mild, transient adverse health effects or without perceiving a clearly defined objectionable odor.
|
From page 204... ...
h TLV-STEL (Threshold Limit Value–short-term exposure limit, American Conference of Governmental Industrial Hygienists)
|
From page 205... ...
American Conference of Governmental Industrial Hygienists, Cincinnati, OH. ACGIH (American Conference of Governmental Industrial Hygienists)
|
From page 206... ...
for Hazardous Substances, December 2009. Agency for Toxic Substances and Disease Registry [online]
|
From page 207... ...
2002. Cytochrome oxidase inhibition induced by acute hydrogen sulfide inhala tion: Correlations with tissue sulfide concentrations in the rat brain, liver, lung and nasal epithelium.
|
From page 208... ...
1991. Cytotoxic effects of hydrogen sulfide on pulmonary alveolar macrophages in rats.
|
From page 209... ...
. NIOSH (National Institute for Occupational Safety and Health)
|
From page 210... ...
2001. Standing Operating Procedures for Developing Acute Exposure Guideline Levels for Hazardous Chemicals.
|
From page 211... ...
1981. Acute and subchronic toxicity studies of rats exposed to vapors of methyl mercap tan and other reduced-sulfur compounds.
|
From page 212... ...
4.4 × 0.5 h = 10.27 ppm-h Modifying factor: 3, wide variability in complaints associated with the foul odor of H2S and the shallow concentration response at the relatively low concentrations that are consistent with definition of the AEGL-1 Calculations: C4.4 × 0.167 h = 10.27 ppm-h 10-min AEGL-1: C4.4 = 61.5 ppm C = 2.6 ppm 10-min AEGL-1 = 2.6/3 = 0.75 ppm C4.4 × 0.5 h = 10.27 ppm-h 30-min AEGL-1: C4.4 = 20.54 ppm C = 2.00 ppm 30-min AEGL-1 = 2.0/3 = 0.60 ppm C4.4 × 1 h = 10.27 ppm-h 1-h AEGL-1: C4.4 = 10.27 ppm C = 1.71 ppm 1-h AEGL-1 = 1.7/3 = 0.51 ppm C4.4 × 4 h = 10.27 ppm-h 4-h AEGL-1: C4.4 = 2.57 ppm C = 1.28 ppm 4-h AEGL-1 =1.28/3 = 0.36 ppm C4.4 × 8 h = 10.27 ppm-h 8-h AEGL-1: C4.4 = 1.28 ppm C = 1.06 ppm 8-h AEGL-1 = 1.06/3 = 0.33 ppm
|
From page 213... ...
1991; Khan et al. 1991 Toxicity end points: Minor perivascular edema present and significant increase in protein and LDH in lung lavage fluid.
|
From page 214... ...
214 Acute Exposure Guideline Levels Derivation of AEGL-3 Key study: MacEwen and Vernot 1972 Toxicity end point: Highest concentration causing no death after a 1-h exposure in rats C4.4 × t = k Scaling: (504 ppm) 4.4 × 1 h = 6.06 × 1011 ppm-h Uncertainty factors: 3 for interspecies variability 3 for intraspecies variability Calculations: C4.4 × 0.167 h = 6.06 × 1011 ppm-h 10-min AEGL-3: C4.4 = 3.63 × 1012 ppm C = 759.8 ppm 10-min AEGL-3 = 759.8/10 = 75.9 ppm C4.4 × 0.5 h = 6.06 ×1011 ppm-h 30-min AEGL-3: C4.4 = 1.21 × 1012 ppm C = 590.8 ppm 30-min AEGL-3 = 590.8/10 = 59.1 ppm C4.4 × 1 h = 6.06 × 1011 ppm-h 1-h AEGL-3: C4.4 = 6.06 × 1011 ppm C = 503.9 ppm 1-h AEGL-3 =503.9/10 = 50.4 ppm C4.4 × 4 h = 6.06 × 1011 ppm-h 4-h AEGL-3: C4.4 = 1.52 × 1011 ppm C = 366.7 ppm 4-h AEGL-3 =366.7/10 = 36.7 ppm C4.4 × 8 hr = 6.06 × 1011 ppm-h 8-h AEGL-3: C4.4 = 7.58 × 1010 ppm C = 312.8 ppm 8-h AEGL-3 = 312.8/10 = 31.3 ppm
|
From page 215... ...
; increased Raw (significant in 2/10) with no accompanying clinical signs or lung function effects End Point/Concentration/Rationale: headache/2 ppm Uncertainty Factors/Rationale: Interspecies 1: subjects were human Modifying Factor: 3 to account for the wide variability in complaints associated with the foul odor of H2S and the shallow concentration response at the relatively low concentrations that are consistent with definition of the AEGL-1 Animal to Human Dosimetric Adjustment: NA Time-Scaling: Cn × t = k, where n = 4.4; value derived from rat lethality data ranging from 10 min to 6 h.
|
From page 216... ...
(2) No-effect level for pulmonary alveolar macrophage viability/200 ppm Uncertainty Factors/Rationale: Interspecies 3: rat and mouse data suggest little interspecies variability Intraspecies 3: The intraspecies uncertainty factor of 3 is considered sufficient because application of the default uncertainty factor of 10 would result in a total uncertainty factor of 30, which would yield AEGL-2 values inconsistent with the total database.
|
From page 217... ...
End Point/Concentration/Rationale: Highest concentration causing no death in rats after a 1 h-exposure/504 ppm/threshold for death for 1-h exposure in rats. Effects: Concentration Mortality 400 ppm 0/10 504 ppm 0/10 635 ppm 1/10 800 ppm 9/10 Uncertainty Factors/Rationale: Total uncertainty factor: 10 Interspecies: 3 for rat and mouse data suggest little interspecies variability Intraspecies: 3 is considered sufficient because application of the default uncertainty factor of 10 would result in a total uncertainty factor of 30, which would yield AEGL-3 values inconsistent with the total database.
|
From page 218... ...
leading to an odor intensity (I) of distinct odor detection (I = 3)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.