Relative Significance of Indoor Exposure

The previous section demonstrates clearly that concentrations of the POPs under consideration in this chapter are markedly higher in indoor air and dust than those detected in the corresponding matrices (air and soil respectively) outdoors. It is therefore pertinent to evaluate the significance of human exposure that arises from such indoor contamination relative to dietary exposure. 

Additionally, there is the crucial consideration of the extent to which such external exposure translates into internal exposure or body burden. To date, there is only one paper that makes a definitive link between indoor contamination (specifically of dust) and body burden for PBDEs (Wu et ah, 2007). While there are few data relating to such bioavailability issues for indoor air and dust, the situation is not appreciably less certain than for dietary exposure. An important recent study (Huwe et al, 2008) has compared the bioavailability of PBDEs administered to rats in both indoor dust and in corn oil. While there was considerable congener-specific variation in uptake, there were no significant differences in uptake for a given congener regardless of whether it was administered in dust or corn oil. 

Given this evidence of similar availability of PBDEs associated with dust and diet. Table 7.9 summarises data on how contamination of indoor dust (and air) contributes to UK estimates of external human exposure to BFRs relative to dietary exposures. It is apparent 

Study location matrix number of samples (Reference) Statistical parameter/ BER a-HBCD /3-HBCD Y-HBCD XHBCDs TBBP-A BDE-47 BDE-99 Xtri-hexa- BDE-209 BDEs  

Birmingham, UK outdoor air n = 5 (HBCDs and TBBP-A), 110 (tri-hexa-BDEs) (Abdallah, Harrad, and Covaci, 2008 Harrad and Hunter, 2006) 

---