Acute Exposure Guideline Levels for Selected Airborne Chemicals Volume 15 (2013) / Chapter Skim
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4 tert-Octyl Mercaptan Acute Exposure Guideline Levels
4 tert-Octyl Mercaptan Acute Exposure Guideline Levels
Pages 99-129
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From page 99... ...
Both the document and the AEGL values were then reviewed by the National Research Council (NRC) Committee on Acute Exposure Guideline Levels.
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From page 100... ...
AEGL-3 values were based on a 4-h BMCL05 (benchmark concentration, 95% confidence limit with 5% response) value for tert-octyl mercaptan of 11.5 ppm, calculated from combined data on female rats (Temple University 1982)
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From page 101... ...
Values were scaled across time using the equation Cn × t = k, where default values of n = 3 when extrapolating to shorter durations and n = 1 when extrapolating to longer durations were used to derive values protective of human health (NRC 2001)
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From page 102... ...
mg/m3) female rats (Temple University 1982)
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From page 103... ...
Clinical signs included respiratory stimulation, followed by CNS stimulation initially characterized by a "threshold effect" consisting of localized minimal convulsive movements in the form of repeated facial and ear twitches. Seizures were observed at all concentrations; the severity, frequency, and latency period for the onset of seizures were concentration related.
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From page 104... ...
; all dead within 2 h, 45 min LC50 51 ppm (46.5-54.5 ppm) BMCL05 31.8 ppm BMC01 34.4 ppm Abbreviations: BMC01, benchmark concentration with 1% response; BMCL05, benchmark concentration, 95% lower confidence limit with 5% response; LC50, lethal concentration, 50% lethality.
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From page 105... ...
BMCL05 52 ppm 11.3 ppm 4.8 ppm BMC01 59.7 ppm 13.8 ppm 4.6 ppm Abbreviations: BMC01, benchmark concentration with 1% response; BMCL05, benchmark concentration, 95% lower confidence limit with 5% response; LC50, lethal concentration, 50% lethality. Source: Temple University 1982.
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From page 106... ...
Mortality 12 ± 0.6 1/10 14 ± 0.5 3/10 17 ± 1.4 5/10 18 ± 0.7 10/10 19 ± 1.7 10/10 LC50 17 ppm (15-19 ppm) BMCL05 10.1 ppm BMC01 10.7 ppm Abbreviations: BMC01, benchmark concentration with 1% response; BMCL05, benchmark concentration, 95% lower confidence limit with 5% response; LC50, lethal concentration, 50% lethality.
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From page 107... ...
BMC01 65.9 ppm 21.5 ppm * Abbreviations: BMC01, benchmark concentration with 1% response; BMCL05, benchmark concentration, 95% lower confidence limit with 5% response; LC50, lethal concentration, 50% lethality.
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From page 108... ...
. Rat data suggest that females are much more sensitive to tert-octyl mercaptan than males; calculated 4-h LC50 values were 59 ppm for male rats and 17 ppm for female rats in one study (Temple University 1982)
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From page 109... ...
. However, data suggest that tert-octyl mercaptan acts differently because an initial effect of CNS stimulation is observed.
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From page 110... ...
DATA ANALYSIS FOR AEGL-1 5.1. Human Data Relevant to AEGL-1 No human data on tert-octyl mercaptan relevant deriving AEGL-1 values were available.
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From page 111... ...
DATA ANALYSIS FOR AEGL-2 6.1. Human Data Relevant to AEGL-2 No human data on tert-octyl mercaptan relevant to deriving of AEGL-2 values were found.
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From page 112... ...
, and a slightly higher concentration of 12 ppm caused clinical signs (tremors and clonic convulsions) in 90% and mortality in 10% of the female rats (Temple University 1982)
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From page 113... ...
. An interspecies uncertainty factor of 3 was applied because the limited data suggest no difference in species sensitivity between rats and mice (the 4-h LC50 is 51 ppm for male rats and 47 ppm for male mice [Fairchild and Stokinger 1958]
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From page 114... ...
AEGL-2 values were derived by dividing the AEGL-3 values by 3, and the AEGL-3 values were based on a threshold for lethality in female rats (BMCL05)
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From page 115... ...
101 TO-68, Acute Toxicity Studies, October 9, 1970. Submitted to EPA by Elf Atochem North America, King of Prussia, PA, with Cover Letter Dated 08/13/92.
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From page 116... ...
116 Acute Exposure Guideline Levels Inc., King of Prussia, PA with Cover Letter Dated 12/23/91. EPA Document No.
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From page 117... ...
OTS0534950. Toxicity end point: 4-h threshold for lethality in female rats, BMCL05 of 11.5 ppm Time scaling: Cn × t = k (default values of n = 3 for extrapolating to shorter durations and n = 1 for extrapolating to longer durations)
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From page 118... ...
118 Acute Exposure Guideline Levels Uncertainty factors: 3 for interspecies differences 3 for intraspecies variability Modifying factor: Not applicable Calculations: 10-min AEGL-3: 2.3 ppm (30-min AEGL-3 value adopted)
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From page 119... ...
, September 17, 1982. Submitted to EPA by Atochem North America, Inc., King of Prussia, PA with Cover Letter Dated 12/23/91.
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From page 120... ...
Calculated 4-h LC50 values were 59 ppm for male rats and 17 ppm for female rats in one study (Temple University 1982) and 79 ppm for males and 24 ppm for females in another (Amoco 1979)
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From page 121... ...
is the cumulative normal distribution function Dependent variable = COLUMN2 Independent variable = COLUMN1 Slope parameter is restricted as slope >= 1 Total number of observations = 13 Total number of records with missing values = 0 Maximum number of iterations = 250 Relative Function Convergence has been set to: 1e-008 Parameter Convergence has been set to: 1e-008 User has chosen the log transformed model Default Initial (and Specified) Parameter Values Background = 0 Intercept = -2.865 Slope = 1.09606 Asymptotic Correlation Matrix of Parameter Estimates Background Intercept Background 1 -0.19 Intercept -0.19 1 (*
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From page 122... ...
No. Parameters Deviance Test DF P-value Full model -18.793 13 Fitted model -22.802 2 8.01802 11 0.7117 Reduced model -60.1424 1 82.6988 12 <0.0001 AIC: 49.6039 Goodness of Fit Scaled Estimated Dose Probability Expected Observed Size Residual 0.0000 0.1344 0.672 0 5 -0.881 7.0000 0.1344 0.672 0 5 -0.881 15.0000 0.1537 0.768 1 5 0.287 19.0000 0.9893 4.946 5 5 0.233 29.0000 1.0000 5.000 5 5 0.000 59.0000 1.0000 5.000 5 5 0.000 71.0000 1.0000 5.000 5 5 0.000 110.0000 1.0000 5.000 5 5 0.000 12.0000 0.1344 1.344 1 10 -0.319 14.0000 0.1349 1.349 3 10 1.528 17.0000 0.6502 6.502 5 10 -0.996 18.0000 0.9119 9.119 10 10 0.983 19.0000 0.9893 9.893 10 10 0.329 Chi-square = 6.19; DF = 11; P-value = 0.8602 Benchmark Dose Computation Specified effect = 0.05 Risk type = Extra risk Confidence level = 0.95 BMD = 15.3075 BMDL = 11.5133
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From page 123... ...
. Parameter Estimates Standard 95.0% Wald Confidence Interval Variable Estimate error Lower confidence limit Upper confidence limit Background 0.13443 0.0579167 0.0209153 0.247945 Intercept -50.7551 0.346663 -51.4345 -50.0756 Slope 18 NA NA: indicates that this parameter has hit a bound implied by some inequality constraint and thus has no standard error.
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From page 124... ...
No. Parameters Deviance Test DF P-value Full model -18.793 13 Fitted model -22.802 2 8.01802 11 0.7117 Reduced model -60.1424 1 82.6988 12 <0.0001 AIC: 49.6039 Goodness of Fit Scaled Estimated probDose ability Expected Observed Size Residual 0.0000 0.1344 0.672 0 5 -0.881 7.0000 0.1344 0.672 0 5 -0.881 15.0000 0.1537 0.768 1 5 0.287 19.0000 0.9893 4.946 5 5 0.233 29.0000 1.0000 5.000 5 5 0.000 59.0000 1.0000 5.000 5 5 0.000 71.0000 1.0000 5.000 5 5 0.000 110.0000 1.0000 5.000 5 5 0.000 12.0000 0.1344 1.344 1 10 -0.319 14.0000 0.1349 1.349 3 10 1.528 17.0000 0.6502 6.502 5 10 -0.996 18.0000 0.9119 9.119 10 10 0.983 19.0000 0.9893 9.893 10 10 0.329 Chi-square = 6.19; DF = 11; P-value = 0.8602
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From page 125... ...
tert-Octyl Mercaptan 125 Benchmark Dose Computation Specified effect = 0.01 Risk type = Extra risk Confidence level = 0.95 BMD = 14.7388 BMDL = 10.2853
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From page 126... ...
126 Acute Exposure Guideline Levels APPENDIX D CATEGORY PLOT FOR tert-OCTYL MERCAPTAN Chemical Toxicity - TSD Animal Data Tert-Octyl Mercaptan 1000 100 No Effect Discomfort ppm 10 Disabling Partially Lethal AEGL-3 1 Lethal AEGL-2 0 0 60 120 180 240 300 360 420 480 Minutes FIGURE D-1 Category plot of toxicity data and AEGL values for tert-octyl mercaptan. The decimal point is lost on this log-scale plot.
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From page 127... ...
TABLE D-1 Data Used in Category Plot for tert-Octyl Mercaptan Source Species Sex No. Exposures ppm Minutes Category Effect AEGL-1 NR 10 AEGL AEGL-1 NR 30 AEGL AEGL-1 NR 60 AEGL AEGL-1 NR 240 AEGL AEGL-1 NR 480 AEGL AEGL-2 0.77 10 AEGL AEGL-2 0.77 30 AEGL AEGL-2 0.60 60 AEGL AEGL-2 0.40 240 AEGL AEGL-2 0.19 480 AEGL AEGL-3 2.3 10 AEGL AEGL-3 2.3 30 AEGL AEGL-3 1.8 60 AEGL AEGL-3 1.2 240 AEGL AEGL-3 0.58 480 AEGL Rat Male 1 38 240 2 Seizures Rat Male 1 40 240 PL Mortality 1/6; seizures Rat Male 1 44 240 PL Mortality 1/5; seizures Rat Male 1 55 240 PL Mortality 3/5; seizures Rat Male 1 64 240 3 Mortality 5/5; seizures Rat Male 1 78 240 3 Mortality 6/6; seizures (Continued)
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From page 128... ...
128 TABLE D-1 Continued Source Species Sex No. Exposures ppm Minutes Category Effect Rat Male 1 110 240 3 Mortality 6/6; seizures Rat Male/Female 1 7 240 0 No effects Rat Male/Female 1 15 240 PL Mortality: male 0/5; female 1/5 Rat Male/Female 1 19 240 PL Mortality: male 0/5; female 5/5 Rat Male/Female 1 29 240 PL Mortality: male 0/5; female 5/5 Rat Male/Female 1 59 240 PL Mortality: male 0/5; female 5/5 Rat Male/Female 1 71 240 PL Mortality: male 4/5; female 5/5 Rat Female 1 12 240 PL Mortality 1/10 Rat Female 1 14 240 PL Mortality 3/10 Rat Female 1 17 240 PL Mortality 5/10 Rat Female 1 18 240 3 Mortality 10/10 Rat Female 1 19 240 3 Mortality 10/10 Rat Male/Female 1 23 240 2 Convulsions Rat Male/Female 1 24 240 PL Mortality: male 0/5; female 1/5 Rat Male/Female 1 25 240 PL Mortality: male 0/5; female 5/5 Rat Male/Female 1 73 240 PL Mortality: male 0/5; female 5/5 Rat Male/Female 1 77 240 PL Mortality: male 4/5; female 5/5 Rat Male/Female 1 79 240 3 Mortality: male 5/5; female 5/5 Mouse Male 1 38 240 2 Seizures Mouse Male 1 40 240 PL Mortality 2/10 Mouse Male 1 44 240 PL Mortality 4/10
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From page 129... ...
Mouse Male 1 55 240 PL Mortality 9/10 Mouse Male 1 64 240 3 Mortality 10/10 Mouse Male 1 78 240 3 Mortality 10/10 Mouse Male 1 42 60 2 Convulsions Mouse Male 1 58 60 PL Mortality 2/5 Mouse Male 1 84 60 PL Mortality 4/5 Mouse Male 1 117 60 3 Mortality 5/5 Mouse Male 1 167 60 3 Mortality 5/5 For category: 0 = no effect, 1 = discomfort, 2 = disabling, 3 = lethal; PL = partially lethality.
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