文摘
α-, β-, and γ-hexabromocyclododecane diastereomers (HBCDs) were measured in house dust from Birmingham, UK (n = 31, median concentration = 730 ng ΣHBCDs g−1); Amarillo/Austin, TX (n = 13, 390 ng g−1); and Toronto, Canada (n = 8, 640 ng g−1). Concentrations in dust (n = 6, 650 ng g−1) from UK offices were within the range for UK homes. Concentrations from each country were statistically indistinguishable. In one UK house dust sample, 110,000 ng g−1 was recorded−the highest recorded in indoor dust to date. While upper bound average UK dietary exposures for adults and toddlers, respectively, are 413 and 240 ng ΣHBCDs day−1, UK adults and toddlers daily ingesting, respectively, 50 and 200 mg of dust contaminated at the 95th percentile concentration are exposed, respectively, to 1100 and 4400 ng ΣHBCDs day−1. Normalized to body weight, this high-end exposure scenario estimate for toddlers is within the range reported elsewhere for occupationally exposed adults. While in commercial formulations γ-HBCD predominates (>80%), α-HBCD in dust constitutes 14−67% of ΣHBCDs (average 32%). Hence the predominance of the α-diastereomer in humans may arise partly from dust ingestion, and not solely to in vivo metabolism (when α-HBCD is formed from bioisomerization of other diastereomers), or dietary exposure (where α-HBCD predominates in most foodstuffs).