Personal exposure to HBCDs and its degradation products via ingestion of indoor dust

Personal exposures via ingestion of indoor dust to alpha-, beta-, and gamma-hexabromocyclododecanes (HBCDs) and the degradation products (pentabromocyclododecenes (PBCDs) and tetrabromocyclododecadienes (TBCDs)) were estimated for 21 UK adults. Under an average dust ingestion scenario, personal exposures ranged from 4.5 to 1851 ng Sigma HBCDs day(-1); while the range under a high dust ingestion scenario was I I to 4630 ng Sigma HBCDs day(-1). On average, personal exposure to Sigma HBCDs via dust ingestion in this study was 35% alpha-, 11% beta-. and 54% gamma-HBCD. However, while exposure to beta-HBCD (4-18% of Sigma HBCDs) was relatively consistent with the proportion of this diastereomer in the HBCD commercial formulation; exposures to alpha- and gamma-isomers (11-58% and 29-82% of Sigma HBCDs respectively) showed substantial variation from the commercial formulation pattern. Personal exposures to Sigma TBCDs (median = 0.2 ng day(-1) under an average dust ingestion scenario) and Sigma PBCDs (1.4 ng day(-1)) were significantly lower (p < 0.05) than for Sigma HBCDs (48 ng day(-1)). Despite this, the exposure of one participant to Sigma PBCDs exceeded the exposure to Sigma HBCDs received by 85% of the other participants. On average, house dust provided the major contribution to personal exposure via dust ingestion to all target compounds due to the large time fraction spent in houses. In contrast, although participants spent less time in cars than in offices, car dust Makes a higher average contribution (17%) to Sigma HBCDs exposure than office dust (13%). (C) 2009 Elsevier Ltd. All rights reserved.