Abstract  1,2,5,6,9,10-Hexabromocyclododecane was evaluated for mutagenicity in vitro in the TA98, TA100, and TA1535 strains of Salmonella typhimurium, both in the presence and absence of Arochlor-induced rat liver S-9 metabolic activation. Bacterial cultures with and without metabolic activation were tested at concentrations of 0, 10, 100, 1000, and 10000 ug/plate; the test compound formed a precipitate at 10000 ug/plate, possibly affecting the accuracy of the test. The treatment did not increase the frequency of histidine revertants, either with or without metabolic activation, indicating that the test compound was not mutagenic in Salmonella under the conditions of this assay. Positive control treatment with 10 ug/plate beta- naphthylamine or 20 ug/plate 2-aminoanthracene produced the expected large increases in the frequency of histidine revertants. The document summarizes this study, and no further information is available regarding experimental method or results.

Abstract  IN VITRO MICROBIOLOGICAL MUTAGENICITY STUDIES OF FOUR CIBA-GEIGY CORPORATION COMPOUNDS (FINAL REPORT) WITH TEST DATA AND COVER LETTER

Abstract  This document presents the scope of the risk evaluation to be conducted for HBCD. If a hazard, exposure, condition of use or potentially exposed or susceptible subpopulation has not been discussed, EPA, at this point in time, is not intending to include it in the scope of the risk evaluation. As per the rulemaking, Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act (TSCA), with respect to conditions of use in conducting a risk evaluation under TSCA, EPA will first identify “circumstances” that constitute “conditions of use” for each chemical. While EPA interprets this as largely a factual determination—i.e., EPA is to determine whether a chemical substance is actually involved in one or more of the activities listed in the definition—the determination will inevitably involve the exercise of some discretion.

Abstract  Final report of an in vitro percutaneous absorption through human skin / The In Vitro Percutaneous Absorption of Radiolabelled Hexabromocyclododecane (HBCD) Through Human Skin

Abstract  Developmental health risks of chronical exposure to low doses of foodborne persistent organic pollutants (POP)are recognized but still largely uncharacterized. Juvenile female BALB/c mice exposed to either HBCD, CB-153 or TCDD at doses relevant to human dietary exposures (49.5 μg, 1.35 μg and 0.90 ng kg−1 bw−1 day−1, respectively) for 28 days displayed histopathological changes in liver (HBCD, CB-153, TCDD), thymus (HBCD, CB-153) and uterus (HBCD), reduced serum oestradiol 17β (E2) levels (HBCD), increased serum testosterone (T)levels (CB-153) and an increased T/E2 ratio (HBCD). Proteomics analysis of brain provided molecular support for the HBCD-induced reduction in E2. Neural gene expression analysis, confirmed effects on 18 out of 30 genes previously found to be affected after exposure to higher doses to the same pollutants. Our findings indicate that exposure to POP at low doses is associated with subtle, but toxicological relevant effects on post-natal development in female mice.