Hexabromocyclododecanes and tetrabromobisphenol-A in indoor air and dust in Birmingham, UK: Implications for human exposure

Hexabromocyclododecanes (alpha, beta, and gamma-HBCDs) and tetrabromobisphenol-A (THIP-A) were determined in indoor air from homes (n = 33; median concentrations Sigma HBCDs = 180 pg m(-3); TBBP-A = 15 pg m(-3)), offices (n = 25; 170; 11), public microenvironments; (n = 4; 900; 27) and outdoor air (n = 5; 37; 1). HBCDs and TBBP-A were also determined in dust from homes (n = 45; median concentrations Sigma HBCDs = 1300 ng g(-1); TBBP-A = 62 ng g(-1)), offices (n = 28; 760; 36), cars (n = 20; 13,000; 2), and public microenvironments (n = 4; 2700; 230). While Sigma HBCDs in car dust significantly exceeded (p < 0.05) those in homes and offices, TBBP-A in car dust was significantly lower (p < 0.05) than that in homes and offices. No significant differences were observed between Sigma HBCDs and TBBP-A in air or dust from homes and offices. Compared to dietary and inhalation exposures, dust ingestion constitutes an important pathway of exposure to HBCDs and TBBP-A for the UK population. Specifically, using average dust ingestion rates and concentrations in dust, dust ingestion constitutes for adults 34% (TBBP-A) and 24% (HBCDs) of overall exposure, and for toddlers 90% (TBBP-A) and 63% (HBCDs). Inhalation appears a minor exposure pathway to both HBCDs and TBBP-A. On average, dust is 33% alpha-, 11% beta-, and 56% gamma-HBCD, while air is 22% alpha-, 11 % beta-, and 65% gamma-HBCD.