Toxicological Risks of Selected Flame-Retardant Chemicals (2000) / Chapter Skim
Currently Skimming:
4 Hexabromocyclododecane
4 Hexabromocyclododecane
Pages 53-71
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 53... ...
OCCURRENCE AND USE HBCDis a solid, white powder that is used as a flame retardant additive for thermoplastic polymers. Its principal use is in expanded polystyrene foams and other styrene resins.
|
From page 54... ...
, rats exposed dermally to a high dose of HBCD in saline experienced diarrhea and slight weight loss. This finding indicates that at least some absorption occurs via the dermal route.
|
From page 55... ...
'In this section, the subcommittee reviewed the data on toxicity of HBCD, including the toxicity assessment prepared by the U.S. Consumer Product Safety Commission (Hatlelid 1999)
|
From page 56... ...
(l 994) reported positive sensitization reactions in guinea pig maximization tests using HBCD induction concentrations of 5% for inkadermal injection and 25% for topical application, and HBCD topical challenge concentrations up to 5%.
|
From page 57... ...
Systemic Effects No data on oral exposures to HBCD were located for humans. Several studies reported that a single oral dose of 10 g/kg in rats produced hypoactivity, diarrhea, and matted hair, while a single oral dose of 5 g/kg had no effects and this dose was identified as a no-observed-adverse-effects level (NOAEL)
|
From page 59... ...
Using this study, a LOAEL of ~ % (equivalent to 900 mg/kg-~) for HBCD was identified, based on markedly increased absolute and relative liver weights and thyroid follicular hyperplasia.
|
From page 60... ...
Absolute liver weight was statistically increased in high-dose mates and in midand high-dose females, while relative liver weights were increased in the midand high-dose mates and in Tow-, mid-, and high-dose females. These increased liver weights were not, however, accompanied by related histopathological or serum chemistry changes.
|
From page 61... ...
Six dams from each dose group were delivered naturally, and the growth of each fetus was observed. There was a slight, but significant decrease in maternal food intake and a significant increase in maternal liver weight in the INTO group (magnitude of these changes was not reported)
|
From page 62... ...
Since no correlation was observed between the dosage and incidence of neoplastic changes in the liver in mate mice, the study authors concluded there was no evidence of carcinogenicity. Other Systemic Effects No studies were identified that examined immunological or neurological effects following oral exposure to HBCD.
|
From page 63... ...
The lack of information on systemic effects from subchronic or chronic dermal exposure to HBCD precludes the derivation of an RfD based on dermal toxicity data. However, the oral RiD was used in this risk assessment in place of the dermal RED as the best estimate of internal dose from dermal exposure (derivation of the oral RfD is presented below)
|
From page 64... ...
was selected as the NOAEL because the more subtle changes in liver weight and histology at this dose level are not considered to be adverse effects. An uncertainty factor of 3,000 was applied (l 0 for extrapolation from rats to humans, 10 for intraspecies variation, 10 for extrapolation from subchronic to chronic duration, and 3 to account for database deficiencies including lack of a two-generation reproductive study and a developmental toxicity study in a second species)
|
From page 65... ...
The potential carcinogenicity of HBCD in humans cannot be determined based on inadequate data for an assessment of carcinogenicity via the dermal, inhalation, or oral routes. EXPOSURE ASSESSMENT AND RISK CHARACTERIZATION Noncancer Assessment Dermal Exposure The assessment of noncancer risk for the dermal route of exposure is based on the scenario described in Chapter 3.
|
From page 66... ...
The hazard index of 6.67 x 10- indicates that HBCD used as an upholstery fabric flame retardant is not likely to pose a noncancer risk via the dermal exposure route. Inhalation Exposure Particles Inhalation exposure to HBCD in the particulate phase was calculated using the scenario described in Chapter 3 .
|
From page 67... ...
This indicates that under the worst-case exposure scenario, HBCD, used as an upholstery flame retardant, is not likely to pose noncancer risk via inhalation of HBCD in the particulate phase. Vapors In addition to the possibility of release of HBCD in particles worn from upholstery fabric, the subcommittee considered the possibility of its release by
|
From page 68... ...
results in a hazard index of 5 x 10~3, indicating that under the worst-case scenario, exposure to HBCD, used as an upholstery-fabric flame retardant, is not likely to pose a noncancer risk via the inhalation route, when exposures occur in the vapor phase. Oral Exposure The assessment of the noncancer risk for the oral exposure route is based on the scenario described in Chapter 3.
|
From page 69... ...
WIL- 186004. Sponsored by Chemical Manufacturers Association, Brominated Flame Retardant Industry Panel, Arlington, VA.
|
From page 70... ...
439C-104. Sponsor: Chemical Manufacturers Association, Brominated Flame Retardant Industry Panel, Arlington, VA.
|
From page 71... ...
439C-117. Sponsored by Chemical Manufacturers Association, Brominated Flame Retardant Industry Panel, Arlington, VA.
|
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.