Characterization of unsubstituted and methylated polycyclic aromatic hydrocarbons in settled dust: Combination of instrumental analysis and in vitro reporter gene assays and implications for cancer risk assessment.

Concentrations of 34 unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) and AhR-mediated activities in settled dust samples were determined by a combination of gas chromatography-mass spectrometry and an in vitro reporter gene assay (PAH-CALUX). The levels of Σ34PAHs and bioassay-derived benzo[a]pyrene equivalents (CALUX BaP-EQs) were significantly higher in workplace dust from informal end-of-life vehicle dismantling workshops than in common house dust and road dust. In all the samples, the theoretical BaP-EQs of PAHs (calculated using PAH-CALUX relative potencies) accounted for 28 ± 19% of the CALUX BaP-EQs, suggesting significant contribution of aryl hydrocarbon receptor (AhR) agonists and/or mixture effects.

Emission of Dioxin-like Compounds and Flame Retardants from Commercial Facilities Handling Deca-BDE and Their Downstream Sewage Treatment Plants.

Commercial mixtures of decabromodiphenyl ether (deca-BDE), a brominated flame retardant, contain not only polybrominated diphenyl ethers (PBDEs, mainly BDE-209) as the main component but also dioxin-like compounds (DLCs) such as polybrominated dibenzofurans (PBDFs). Deca-BDE handling facilities (DHFs) and sewage treatment plants receiving effluent from DHFs are point sources of DLC and flame retardant (FR) pollution. Here, we examined their emission in Japan.

Validity of using a relative potency factor approach for the risk management of dioxin-like polychlorinated naphthalenes.

Here, we characterized the dioxin-like activities of 42 polychlorinated naphthalenes (PCNs) and 6 technical Halowax formulations by using the DR-CALUX (dioxin-responsive chemically activated luciferase expression) assay with rat hepatoma luciferase-expressing H4IIE cells. Of the 42 PCNs examined, 31 showed dioxin-like activities, for which the mass-based REP-EC (potency relative to that of 2,3,7,8-tetrachlorodibenzo-p-dioxin based on the 5% effective concentration determined from the dose-response curve for 2,3,7,8-TCDD) ranged from 0.00000012 to 0.

Separate screening of brominated and chlorinated dioxins in field samples using in vitro reporter gene assays with rat and mouse hepatoma cell lines.

In 2011, a joint World Health Organization (WHO) and United Nations Environment Programme expert panel recommended the use of the WHO toxicity equivalency factor (TEF) scheme for assessment of the human health risks of brominated dioxins which have different sources from chlorinated dioxins. Therefore, WHO toxic equivalents (TEQs) should be determined for both chlorinated and brominated dioxins. As alternative to the conventional but time-consuming dioxin analysis using gas chromatography high-resolution mass spectrometry, we have developed a screening method involving cleanup and separation of brominated dioxins from chlorinated dioxins in field samples and subsequent analysis by CALUX (chemically activated luciferase expression) assays which are in vitro reporter gene assays detecting dioxin-like compounds.

Dioxin-like activities, halogenated flame retardants, organophosphate esters and chlorinated paraffins in dust from Australia, the United Kingdom, Canada, Sweden and China.

The concentrations of organic flame retardants (FRs) and dioxin-like activities in dust collected from five countries were investigated. The correlations between the concentrations of the different groups of FRs and dioxin-like activities were examined. Chlorinated paraffins (CPs, C to C) were found in the highest concentration (median ∑CP 700 μg/g, range 280-4750 μg/g), followed by organophosphate esters (median ∑OPEs 56 μg/g, range 21-110 μg/g), halogenated flame retardants (median ∑HFRs 3.