Acute Exposure Guideline Levels for Selected Airborne Chemicals Volume 4 (2004) / Chapter Skim
Currently Skimming:
Appendix 5: Uranium Hexafluoride: Acute Exposure Guideline Levels
Appendix 5: Uranium Hexafluoride: Acute Exposure Guideline Levels
Pages 250-291
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 250... ...
It is one of the most highly soluble industrial uranium compounds and, when airborne, hydrolyzes immediately on contact with water to form hydrofluoric acid (HF) and uranyl fluoride (UO2F2)
|
From page 251... ...
1986~. To obtain protective AEGL values in the absence of an empirically derived, chemical-specific scaling exponent, temporal scaling was performed using n = 3 when extrapolating to shorter time points and n = 1 when extrapolating to longer time points.
|
From page 252... ...
It may present both chemical and radiological hazards. It is one ofthe most highly soluble industrial uranium compounds and, when airborne, hydrolyzes rapidly on contact with water to form hydrofluoric acid (HF)
|
From page 253... ...
The predominant concern from acute exposure to soluble uranium compounds is chemical toxicity. However, depending on the degree of enrichment, radiologic toxicity might also be important.
|
From page 254... ...
Case Reports On September 2, 1944, an accidental UFO release occurred at a Manhattan Engineering District pilot plant located at the Philadelphia naval shipyard (Kathren and Moore 1986~. A weld ruptured in a 2.4 m x 0.2 m cylinder containing gaseous UFO, causing the cylinder to act as a rocket.
|
From page 255... ...
The 38-y follow-up medical and health physics exams of two of the seriously injured workers revealed no detectable uranium deposition and no findings attributable to uranium exposure (Kathren and Moore 1986; Moore and Kathren 1985~. Another accident occurred on January 4,1986, at a uranium conversion facility in Gore, Oklahoma (Nuclear Regulatory Commission 1986~.
|
From page 256... ...
and were given oral sodium bicarbonate to enhance uranium excretion, and three were transferred to another hospital for observation and treatment of potential lung damage from HF exposure. Of the eight employees who returned to spray water on the fumes, one was in the group transferred to another hospital with serious respiratory symptoms, and five were hospitalized for more than 1 ~ (including the individual with HF burns)
|
From page 257... ...
2.3. Developmental and Reproductive Toxicity No information concerning developmental and reproductive toxicity in humans following acute inhalation exposure to UFO was located.
|
From page 258... ...
2.6. Summary Case reports from human accidental exposures to UFO indicate that acute toxicity is chemical, not radiologic, in nature and is due to the hydrolysis products, hydrogen fluoride (HF)
|
From page 259... ...
Six 1 -min samples were taken during the 10 min period and analyzed for concentration using a ferrocyanide acetic acid chemical method. Upon removal from the chamber, all animals were gasping for breath; severe irritation of the nasal passages and conjunctivitis was also observed and persisted for a period of several hours.
|
From page 260... ...
Cumulative uranium excretion over 6 ~ in the feces ranged from 59% to 81% of the inhaled dose. With a soluble uranium compound such as UFO, one might have expected predominately urinary excretion (especially given that fecal excretion typically accounts for less than 1% of excretion of soluble uranium compounds after inhalation expo
|
From page 261... ...
; however, it is likely that the rats trapped the particles in the nasopharyngeal region and swallowed them. Urine bioassays indicated renal injury at all exposure durations (Tables 5-4, 5-5, and 5-6~.
|
From page 262... ...
However, animals that died during or shortly after exposure had congestion, acute inflammation, and focal degeneration ofthe upper respiratory tract. The tracheas, bronchi, and lungs exhibited acute inflammation with epithelial degeneration, acute bronchial inflammation, and acute pulmonary edema and inflammation, respectively.
|
From page 263... ...
Six 1-min samples were taken during the 10-min period and were analyzed for concentration using a ferrocyanide acetic acid chemical method. Upon removal from the chamber, all animals were gasping for breath; severe irritation of the nasal passages, conjunctivitis, and closed, encrusted eyes were also observed and persisted in survivors for a period of several hours.
|
From page 264... ...
Six 1-min samples were taken during the 10-min period and analyzed for concentration using a ferrocyanide acetic acid chemical method. Upon removal from the chamber, all animals were gasping for breath; severe irritation ofthe nasalpassages and conjunctivitis were also observed and persisted in survivors for a period of several hours.
|
From page 265... ...
Cumulative uranium excretion over 6 ~ in the feces was approximately 59°/O of the inhaled dose. With a soluble uranium compound such as UFO, one might have expected predominately urinary excretion; however, it is likely that the guinea pigs trapped the particles in the nasopharyngeal region and swallowed them.
|
From page 266... ...
No lung damage was noted in these dogs. Between 1 d and 3 d, kidneys TABLE 5-X Calculated LC50 Values for Animals Exposed to Uranium Hexafluoride Species Rat Rat Rat Rat Exposure Time (min)
|
From page 267... ...
3.6. Summary Rats and guinea pigs exposed to UFO for 2-10 min showed upper and lower respiratory tract irritation, pulmonary edema, and renal lesions.
|
From page 268... ...
SPECIAL CONSIDERATIONS 4.1. Metabolism and Disposition UFO and its hydrolysis products, hydrogen fluoride (HF)
|
From page 269... ...
at 24 mg/m3 for 6 in/d, 6 d/wk for 30 d; however, no renal effects were observed in rats similarly exposed at 7 mg/m3 (Stokinger 1949~. Renal tubular necrosis and congestion were reported in rats and guinea pigs exposed to HE (unreported
|
From page 270... ...
In the case of acute inhalation exposures to the soluble UFO, short-term radiotoxicity would be negligible compared with chemical toxicity, even in the case of highly enriched UFO (Just and Elmer 1984~. The United Nations Scientific Committee on the Effects of Atomic Radiation (UN SCEAR 1993)
|
From page 271... ...
4.6. Other Information In a previous attempt to assess the toxicity of UFO and its hydrolysis products to humans, four toxicologists were asked to use the available animal data to calculate levels for human health effects (Just and Elmer 1984; Just 1984~.
|
From page 272... ...
method was used to model absorbed uranium to the inhalation exposure concentration. The derived estimates are shown in Table 5-1 1.
|
From page 273... ...
5.2. Animal Data Relevant to AEGL-1 Effects observed from inhalation exposure to UFO in experimental an mats were more severe than those defined by AEGL-1.
|
From page 274... ...
6.2. Animal Data Relevant to AEGL-2 Two dogs exposed to UFO at 192-284 mg/m3 for 30 min to 1 h exhibited renal tubular pathology 6 ~ and 16 ~ post-exposure (Morrow et al.
|
From page 275... ...
275 o z o om om ~ ~ t ~ o Cal o corm in a)
|
From page 276... ...
1986~. To obtain protective AEGL values in the absence of an empirically derived, chemical-specific scaling exponent, temporal scaling was performed using n = 3 when extrapolating to shorter time points and n = 1 when extrapolating to longer time points.
|
From page 277... ...
7.2. Animal Data Relevant to AEGL-3 Well-conducted LC50 studies are available in rats, mice, and guinea pigs (Spiegel 1949; Leach et al.
|
From page 278... ...
X.2. Other Exposure Criteria The established exposure criteria for UFO or soluble uranium compounds are presented in Table 5-16.
|
From page 279... ...
The ERPG-2 for uranium hexafluoride is based on renal injury. The ERPG-3 is the maximum airborne concentration below which it is believed nearly all individuals could be exposed for up to 1 h without experiencing or developing life-threatening health effects.
|
From page 280... ...
eACGIH TLV-TWA (Threshold Limit Value-time-weighted average of the American Conference of Governmental Industrial Hygienists)
|
From page 281... ...
2001. Acute exposure guideline levels for hydrogen fluoride [interim draft 3, 7/2001]
|
From page 282... ...
1949. Toxicity following inhalation of fluorine and hydrogen fluoride.
|
From page 283... ...
10-min, 30-min, anc! l-h AEGL-I: AEGL = 1 .0 ppm 4 = 0.25 ppm; AEGL = 0.25 ppm x 14.4 = 3.6 mg/m3 Derivation of AEGL-2 Values Key study: Morrow et al., 1982 Toxicity end points: Renal pathology in dogs.
|
From page 284... ...
284 ACUTE EXPOSURE GUIDELINE LEVELS Uncertainty factors: 3 for interspecies variability 3 for intraspecies variability 10-min AEGL-2: C3 x 0.167 h = 3,53S,944 mg/m3 h C3 = 21191281 mg/m3 C= 276.7 mg/m3 10-min AEGL-2 = 276.7/10 = 27.7 mg/m3 30-min AEGL-2: C3 x 0.5 h = 3,53S,944 mg/m3 h C3 = 7,077,888 mg/m3 C = 192 mg/m3 30-min AEGL-2 = 192/10 = 19.2 mg/m3 I-h AEGL-2: C~ x 1 h = 96 mg/m3 h C~ = 96 mg/m3 C= 96 mg/m3 1-h AEGL-2 = 96/10 = 9.6 mg/m3 4-h AEGL-2: C~ x 4 h = 96 mg/m3 h C~=24 mg/m3 C= 24 mg/m3 4-h AEGL-2 = 24/10 = 2.4 mg/m3 8-h AEGL-2: C~ x ~ h = 96 mg/m3 h C~ = 12 mg/m3 C = 12 mg/m3 R-h AE(lL-2 Derivation of AEGL-3 Values Key study: Leach et al. 1984 = 12/10 = 1.2 mg/m3 Toxicity end point: Estimated 1-h threshold for death in rats (one-third the LC50)
|
From page 285... ...
URANIUM HEXAFLUORIDE Uncertainty factors: 3 for interspecies variability 3 for intraspecies variability 10-minAEGL-3: Cat x 0.167 h= 365 mg/m3 h C= 2,165.6 mg/m3 10-min AEGL-3 = 2,165.6/10 = 216 mg/m3 30-min AEGL-3: Cat x 0.5 h = 365 mg/m3 h C= 730 mg/m3 30-min AEGL-3 = 730/10 = 73 mg/m3 I-h AEGL-3: Cat x 1 h = 365 mg/m3 h Cut = 49 mg/m3 h C= 364 mg/m3 1-h AEGL-3 =364/10 = 36.4 mg/m3 4-h AEGL-3: Cat x 4 h = 365 mg/m3 h C= 90 mg/m3 4-h AEGL-3 = 90/10 = 9.0 mg/m3 8-h AEGL-3: C~ x ~ h = 365 mg/m3 h C= 45.6 mg/m3 S-h AEGL-3 = 45.6/10 = 4.5 mg/m3 285
|
From page 286... ...
2001. Acute exposure guideline levels for hydrogen fluoride [interim draft 3,7/2001]
|
From page 287... ...
Data quality: Data appropriate for AEGL-1 derivation were not available for UFO. Therefore, AEGL-1 values for UFO were approximated from the AEGL1 values for HF, a known hydrolysis product and a likely source of respiratory irritation.
|
From page 288... ...
Interspecies: 3 Intraspecies: 3 Modifying factor: NA Animal to human dosimetric adjustment: None, insufficient data Time-scaling: To obtain conservative and protective AEGL values in the absence of an empirically derived, chemical-specific scaling exponent, temporal scaling was performed using the Cal x t = k equation where n = 3 when extrapolating to shorter time points and n = 1 when extrapolating to longer time points. (Although a chemical-specific exponent of 0.66 was derived from rat lethality data, the default values were utilized for timescaling AEGL-2 values because the end points for AEGL-2 [renal toxicity]
|
From page 289... ...
Modifying factor: Not applicable Animal to human dosimetric adjustment: Insufficient data Time-scaling: C~ x t = k where n = 1 on the basis of regression analysis of rat lethality data from experiments ranging in duration from 2 min to 1 h. Calculated value of n = 0.66 was rounded to n = 1 because limited data were used to derive n and the calculated value is below the range of a normal doseresponse curve (Leach et al.
|
From page 290... ...
The resulting concentration, 1 ppm, was used for the 10- and 30-min and 1-h, 4-h, and S-h AEGL-1. Summary of Key Study and Rationale Used in the Hydrogen Fluoride AEGL-1 Derivation (EPA 2001)
|
From page 291... ...
The 1 ppm concentration was reduced by a factor of 2 for the 4- and S-h exposure durations. Because there were no effects on respiratory parameters of healthy adults at concentrations that ranged up to 6.34 ppm in this study and up to S
|
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.