Indoor dust has been acknowledged as a major source of flame retardants (FRs) and dust ingestion is considered a major route of exposure for humans. In the present study, we investigated the presence of PBDEs and alternative FRs such as emerging halogenated FRs (EHFRs) and organophosphate flame retardants (PFRs) in indoor dust samples from British and Norwegian houses as well as British stores and offices. BDE209 was the most abundant PBDE congener with median concentrations of 4700ngg and 3400ngg in UK occupational and house dust, respectively, 30 and 20 fold higher than in Norwegian house dust. Monomeric PFRs (m-PFRs), including triphenyl phosphate (TPHP), tris(chloropropyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) dominated all the studied environments. To the best of our knowledge, this is the first report of isodecyldiphenyl phosphate (iDPP) and trixylenyl phosphate (TXP) in indoor environments. iDPP was the most abundant oligomeric PFR (o-PFR) in all dust samples, with median concentrations one order of magnitude higher than TXP and bisphenol A bis(diphenyl phosphate (BDP). iDPP and TXP worst-case scenario exposures for British workers during an 8h exposure in the occupational environment were equal to 34 and 1.4ngkgbwday, respectively. The worst-case scenario for BDE209 estimated exposure for British toddlers (820ngkgbwday) did not exceeded the proposed reference dose (RfD) (7000ngkgbwday), while exposures for sum of m-PFRs (Σm-PFRs) in British toddlers and adults (17,900 and 785ngkgbwday respectively) were an order of magnitude higher than for Norwegian toddlers and adults (1600 and 70ngkgbwday).
Phthalate esters (PEs) are plasticiser additives imparting durability, elasticity and flexibility to consumer products. The low migration stability of PEs along with their ubiquitous character and adverse health effects to humans and especially children has resulted in their classification as major indoor contaminants. This study assesses inhalation exposure to PEs via indoor dust using an in vitro inhalation bioaccessibility test (i.e. uptake) for of dimethyl phthalate (DMP), diethyl phthalate (DEP) and di-(2-ethylhexyl) phthalate (DEHP) and the alternative non phthalate plasticisers bis(2-ethylhexyl) terephthalate (DEHT) and cyclohexane-1,2-dicarboxylic acid diisononyl ester (DINCH), exposure. Using artificial lung fluids, which mimicktwo distinctively different pulmonary environments, namely artificial lysosomal fluid (ALF, pH = 4.5) representing the fluid that inhaled particles would contact after phagocytosis by alveolar and interstitial macrophages within the lung and Gamble's solution (pH = 7.4), the fluid for deep dust deposition within the pulmonary environment. Low molecular weight (MW) PEs such as DMP and DEP were highly bioaccessible (> 75 %) in both artificial pulmonary media, whereas highly hydrophobic compounds such as DEHP, DINCH and DEHT were < 5 % bioaccessible via the lung. Our findings show that the in vitro pulmonary uptake of PEs is primarily governed by their hydrophobicity and water solubility, highlighting thus the need for the establishment of a unified and biologically relevant inhalation bioaccessibility test format, employed within the risk assessment framework for volatile and semi-volatile organic pollutants.
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