Correlation between Atmospheric Boundary Layer Height and Polybrominated Diphenyl Ether Concentrations in Air

In this study, we aim to determine the correlation between the height of the atmospheric boundary layer (ABL) and the concentrations of polybrominated diphenyl ether (PBDE) congeners, in an effort to improve comprehension of the atmospheric behavior of PBDEs. We used the PBDE data in air (<i>n</i> = 298), which were measured by the Japan Ministry of Environment (JMOE) at 50 sites across Japan during the period 2009–2012. The height of the ABL, which directly affects the PBDE concentrations in the near-surface air, was estimated by employing data retrieved from the Japanese global reanalysis (JRA-55) database, using the parcel and Richardson number method. The ABL has shown a strong inverse relationship with BDE-47 and BDE-99 (<i>p</i> < 0.01). In contrast, there was less correlation between BDE-209 and the ABL (<i>p</i> = 0.258). These differing behaviors could be explained by differences in particle size distribution of PBDEs, where BDE-47 and BDE-99 are associated with gas phases and fine particles and BDE-209 is associated with coarse particles. To our knowledge, this paper represents the first large-scale analysis of correlations between the ABL and the concentrations of PBDEs in the air

Measurement of Vapor Pressures and Melting Properties of Five Polybrominated Aromatic Flame Retardants

While vapor pressure is among the most important properties used in the environmental fate assessment of organic contaminants, measured vapor pressures exist only for a few representatives of the group of novel brominated flame retardants (BFRs). To expand on this limited set of data, the vapor pressures of five BFRs1,2,4,5,-tetrabromo-dimethylbenzene (TBX), 1,2,3,4,5-pentabromo-6-methyl-benzene (PBT), 1,2,3,4,5-pentabromo-6-ethyl-benzene (PBEB), 2,3,4,5,6-pentabromo-phenol (PBP), and 1,3,5-tribromo-2­(2,3-dibromopropoxy)-benzene (TBP-DBPE)were measured in the temperature range 322.7–367.7 K with the gas saturation method. Enthalpies of sublimation or vaporization were determined from the slopes of semilogarithmic plots of measured vapor pressure against reciprocal temperature. The melting temperature and enthalpy of fusion were measured using differential scanning calorimetry. From these experimental data, the vapor pressures and subcooled liquid vapor pressures at 298.2 K, <i>p</i>_<i>i</i>° and <i>p</i>_<i>i</i>^°,sl, respectively, were derived and compared with values estimated using group contribution methods, polyparameter linear free energy relationships, as well as EPISuite, SPARC, and COSMOtherm. Depending on the method and compound, deviations between measured and estimated log­(<i>p</i>_<i>i</i>°) or log­(<i>p</i>_<i>i</i>^°,sl) values ranged from 8 to 77% of the measured values. The gas/particle partitioning behavior of the five BFRs was estimated using the measured <i>p</i>_<i>i</i>^°,sl values and the Junge–Pankow model. This estimation could account for the observed partitioning behavior of PBT and TBP-DBPE

Similarities in the Endocrine-Disrupting Potencies of Indoor Dust and Flame Retardants by Using Human Osteosarcoma (U2OS) Cell-Based Reporter Gene Assays

Indoor dust is a sink for many kinds of pollutants, including flame retardants (FRs), plasticizers, and their contaminants and degradation products. These pollutants can be migrated to indoor dust from household items such as televisions and computers. To reveal high-priority end points of and contaminant candidates in indoor dust, using CALUX reporter gene assays based on human osteosarcoma (U2OS) cell lines, we evaluated and characterized the endocrine-disrupting potencies of crude extracts of indoor dust collected from Japan (<i>n</i> = 8), the United States (<i>n</i> = 21), Vietnam (<i>n</i> = 10), the Philippines (<i>n</i> = 17), and Indonesia (<i>n</i> = 10) and for 23 selected FRs. The CALUX reporter gene assays used were specific for compounds interacting with the human androgen receptor (AR), estrogen receptor α (ERα), progesterone receptor (PR), glucocorticoid receptor (GR), and peroxisome proliferator-activated receptor γ2 (PPARγ2). Indoor dust extracts were agonistic to ERα, GR, and PPARγ2 and antagonistic against AR, PR, GR, and PPARγ2. In comparison, a majority of FRs was agonistic to ERα and PPARγ2 only, and some FRs demonstrated receptor-specific antagonism against all tested nuclear receptors. Hierarchical clustering clearly indicated that agonism of ERα and antagonism of AR and PR were common, frequently detected end points for indoor dust and tested FRs. Given our previous results regarding the concentrations of FRs in indoor dust and in light of our current results, candidate contributors to these effects include not only internationally controlled brominated FRs but also alternatives such as some phosphorus-containing FRs. In the context of indoor pollution, high-frequency effects of FRs such as agonism of ERα and antagonism of AR and PR are candidate high-priority end points for further investigation