Very-short- (vSCCPs, C 6–9 ), short- (SCCPs, C 10–13 ), medium- (MCCPs, C 14–17 ), and long-chain chlorinated paraffins (LCCPs, C >17 ) were analyzed in indoor air and dust collected from the living rooms and personal 24 h air of 61 adults from a Norwegian cohort. Relatively volatile CPs, i.e., vSCCPs and SCCPs, showed a greater tendency to partition from settled indoor dust to paired stationary indoor air from the same living rooms than MCCPs and LCCPs, with median logarithmic dust–air partition ratios of 1.3, 2.9, 4.1, and 5.4, respectively. Using the stationary indoor air and settled indoor dust concentrations, the combined median daily exposures to vSCCPs, SCCPs, MCCPs, and LCCPs were estimated to be 0.074, 2.7, 0.93, and 0.095 ng/kg bw/d, respectively. Inhalation was the predominant exposure pathway for vSCCPs (median 99%) and SCCPs (59%), while dust ingestion was the predominant exposure pathway for MCCPs (75%) and LCCPs (95%). The estimated inhalation exposure to total CPs was ∼ 5 times higher when the personal 24 h air results were used rather than the corresponding stationary indoor air results in 13 paired samples, indicating that exposure situations other than living rooms contributed significantly to the overall personal exposure. The 95 th percentile exposure for CPs did not exceed the reference dose.

In this study, we estimated human exposure to polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), and several emerging flame retardants (EFRs) via inhalation and dust ingestion. Sixty indoor stationary air samples, 13 personal air samples, and 60 settled dust samples were collected from a Norwegian cohort during winter 2013. PBDEs showed the highest median concentration in dust (1200 ng/g), followed by EFRs (730 ng/g) and HBCDDs (190 ng/g). The PBDE concentrations in dust were mainly driven by BDE-209 and those of EFRs by bis(2-ethylhexyl) tetrabromophthalate. EFRs predominated in stationary air samples, with 2-ethylhexyl 2,3,4,5-tetrabromobenzoate and 4-(1,2-dibromoethyl)-1,2-dibromocyclohexane having the highest median concentrations (150 and 25 pg/m (sum of α- and β-isomers), respectively). Different profiles and concentrations were observed in personal air samples compared to the corresponding stationary air samples. In relation to inhalation exposure, dust ingestion appears to be the major exposure pathway to FRs (median total exposure 230 pg/kg bw/d, accounting for more than 65% of the total exposure) for the Norwegian cohort. The calculated exposure due to air inhalation was substantially lower when the stationary air concentrations were used rather than personal air concentrations (43 pg/kg bw/d versus 130 pg/kg bw/d). This suggests that other exposure situations (such as outdoors or in offices) contributed significantly to the overall personal exposure, which cannot be included by using only a stationary air sampling technique. The median and 95th percentile exposures for all target FRs did not exceed the reference dose.

Up to 18000 ng of total chlorinated paraffins (CPs) was found in hand wipes of individual adult participants in a Norwegian cohort study ( n = 60), with a geometric mean (SD) value of 870 (2700) ng. The CPs covered a wide range of alkane chain lengths from C 7 to C 48 with variable chlorine substitution. Complex mixtures of very-short-chain (vSCCPs, C <10 ), short-chain (SCCPs, C 10–13 ), medium-chain (MCCPs, C 14–17 ), and long-chain (LCCPs, C >17 ) CPs were found, contributing on average 0.3%, 20%, 58%, and 22%, respectively, of the total CPs. Significant positive correlations were found between CP levels and factors related to the indoor environment and product use, including living in a house/apartment built before the ban of SCCPs, having a sofa, the number of TVs in the home, and owning a car, which mirrors CP usage as flame retardants and/or plasticizers in consumer products. Compared to previous studies of other organic contaminants in hand wipe samples from the same cohort, CPs were the most abundant flame retardants. This is the first report of CPs in hand wipes, and dermal exposure based on these data suggested that hand contact could be an important human exposure pathway for LCCPs.

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