Comparing human exposure to emerging and legacy flame retardants from the indoor environment and diet with concentrations measured in serum Enrique Cequier a,b, ⁎, Rosa Maria Marcé b , Georg Becher a,c , Cathrine Thomsen a a Department of Exposure and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway b Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain c Department of Chemistry, University of Oslo, Norway abstract article info Article history: Received 2 July 2014 Accepted 1 October 2014 Available online xxxx Keywords: Dietary exposure Emerging flame retardant Indoor Polybrominated diphenyl ether Blood Dust This study investigates associations between serum concentrations of emerging and legacy halogenated flame retardants (HFRs) in 46 Norwegian women and measured indoor air and dust concentrations of the HFRs as well as detailed information on diet and household factors. Hexabromobenzene (median 0.03ng/g lipid) and Dechlorane 602 (median 0.18 ng/g lipid) were detected in about 50% of the samples and Dechlorane Plus syn (median 0.45 ng/g lipid) and anti (median 0.85 ng/g lipid) in more than 78%. The most abundant polybrominated diphenyl ethers were 2,2′,4,4′,5,5′-hexabromodiphenyl ether (BDE-153; median 0.82 ng/g lipid) and 2,2′,4,4′- tetrabromodiphenyl ether (BDE-47; median 0.49 ng/g lipid) detected in more than 70% of the samples. In the bivariate analysis, no consistent associations were observed between the biomonitoring data and measured concentrations in indoor air and dust. On the other hand, consumption of specific food items (mainly lamb/mut- ton and margarine) correlated significantly with more than two HFR serum concentrations, while this was not the case for household factors (electronic appliances). Only the significant bivariate associations with diet were confirmed by multivariate linear regression analyses, which might indicate a higher contribution from food compared to the indoor environment to the variation of the body burden of these HFRs. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Halogenated flame retardants (HFRs) are a group of chemicals used to provide fire resistance to a wide variety of consumer goods. The occurrence of the most frequently used HFRs, such as polybrominated diphenyl ethers (PBDEs) and 1,2,5,6,9,10-hexabromocyclododecane (HBCDD), has been recently detected in humans (Jakobsson et al., 2012; Rawn et al., 2014), even after they have been phased-out due to their toxic effects in animals, and reported associations between human body burden of HFRs and adverse health effects (Darnerud, 2008; Marvin et al., 2011; Turyk et al., 2008; Herbstman et al., 2010; Eskenazi et al., 2013). After the ban of these chemicals, other HFRs, such as hexabromobenzene (HBB) and dechloranes, have been increas- ingly detected in humans (Brasseur et al., 2014; Cequier et al., 2013; Ren et al., 2009). These new or “emerging” HFRs have similar physico- chemical properties as the former flame retardants (FRs) and thus, they are also potentially hazardous for the environment and human health. The most studied sources of human exposure to HFRs are house dust and diet. The content of HFRs in dust may vary geographical- ly due to different fire regulations and uses in different countries. In Europe, some studies suggest that exposure from house dust is lower than from the diet (Harrad et al., 2004; Roosens et al., 2009). However, in countries where indoor environments are highly contaminated, like the U.S.A., dust ingestion was estimated to account for 82% of the overall PBDE intakes in a modelling study (Lorber, 2008). This has been exper- imentally supported by later studies (Johnson et al., 2010; Stapleton et al., 2012; Watkins et al., 2011, 2012), which showed significant asso- ciations between concentrations of PBDEs in dust and in serum from the general population. The contamination of indoor dust has been surveyed to evaluate exposure to emerging and legacy HFRs through ingestion of dust (Cequier et al., 2014; Dodson et al., 2012). Nonetheless, most other studies have not found any significant associations between exposure to PBDEs from indoor dust and levels in human serum (Fromme et al., 2009; Imm et al., 2009; Roosens et al., 2009; Zheng et al., 2011). There is increasing awareness of short term exposures in micro-environments with high contamination of HFRs like in cars (Harrad et al., 2008). Such exposures could explain the lack of associa- tions between human biomarkers and house dust. On the other hand, the exposure to HFRs through diet is more likely because HFRs are lipophilic and tend to bioaccumulate in the food web. Diet has been reported as a significant source of human exposure to PBDEs (Fraser et al., 2009; Knutsen et al., 2008). Two studies from Scan- dinavia assessing the impact of fish consumption (Sjödin et al., 2000; Environment International 74 (2015) 54–59 ⁎ Corresponding author. E-mail address: enrique.cequier@fhi.no (E. Cequier). http://dx.doi.org/10.1016/j.envint.2014.10.003 0160-4120/© 2014 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Environment International journal homepage: www.elsevier.com/locate/envint