Spatial Distribution and Air-Water Exchange of Organic Flame Retardents in the Lower Great Lakes

Organic flame retardants (OFRs) such as polybrominated diphenyl ethers (PBDEs) and novel halogenated flame retardants (NHFRs) are ubiquitous, persistent, and bioaccumulative contaminants that have been used in consumer goods to slow combustion. In this study, polyethylene passive samplers (PEs) were deployed throughout the lower Great Lakes (Lake Erie and Lake Ontario) to measure OFRs in air and water, calculate air–water exchange fluxes, and investigate spatial trends. Dissolved Σ12BDE was greatest in Lake Ontario near Toronto (18 pg/L), whereas gaseous Σ12BDE was greatest on the southern shoreline of Lake Erie (11 pg/m3). NHFRs were generally below detection limits. Air–water exchange was dominated by absorption of BDEs 47 and 99, ranging from −964 pg/m2/day to −30 pg/m2/day. Σ12BDE in air and water was significantly correlated with surrounding population density, suggesting that phased-out PBDEs continued to be emitted from population centers along the Great Lakes shoreline in 2012. Correlation with dissolved Σ12BDE was strongest when considering population within 25 km while correlation with gaseous Σ12BDE was strongest when using population within 3 km to the south of each site. Bayesian kriging was used to predict dissolved Σ12BDE over the lakes, illustrating the utility of relatively highly spatially resolved measurements in identifying potential hot spots for future study

Aryl hydrocarbon receptor-mediated activity of gas-phase ambient air derived from passive sampling and an \u3cem\u3ein vitro\u3c/em\u3e bioassay

The gaseous fraction of hydrophobic organic contaminants (HOCs) in ambient air appears to be responsible for a significant portion of aryl hydrocarbon receptor (AhR)‐mediated activity, but the majority of compounds contributing to this activity remain unidentified. This study investigated the use of polyethylene passive samplers (PEs) to isolate gaseous HOCs from ambient air for use in in vitro bioassays and to improve our understanding of the toxicological relevance of the gaseous fraction of ambient air in urban and residential environments. Concentrations of polycyclic aromatic hydrocarbons (PAHs) and organic flame retardants (OFRs) were measured in PE extracts. Extracts were also analyzed using an in vitro bioassay to measure AhR‐mediated activity. Bioassay‐derived benzo[a]pyrene (BaP) equivalents (BaP‐Eqbio), a measure of potency of HOC mixtures, were greatest in the downtown Cleveland area and lowest at rural/residential sites further from the city center. BaP‐Eqbio was weakly correlated with concentrations of 2‐ring alkyl/substituted PAHs and one organophosphate flame retardant, ethylhexyl diphenyl phosphate (EHDPP). Potency predicted based on literature‐derived induction equivalency factors (IEFs) explained only 2‐23% of the AhR‐mediated potency observed in bioassay experiments. This study suggests that health risks of gaseous ambient air pollution predicted using data from targeted chemical analysis may underestimate risks of exposure, most likely due to augmentation of potency by unmonitored chemicals in the mixture, and the lack of relevant IEFs for many targeted analytes

Estimation of Uncertainty in Air-­Water Exchange Flux 2 and Gross Volatilization Loss of PCBs: a Case Study 3 based on Passive Sampling in the Lower Great Lakes

Compared with dry and wet deposition fluxes, air–water exchange flux cannot be directly measured experimentally. Its model-based calculation contains considerable uncertainty because of the uncertainties in input parameters. To capture the inherent variability of air–water exchange flux of PCBs across the lower Great Lakes and to calculate their annual gross volatilization loss, 57 pairs of air and water samples from 19 sites across Lakes Erie and Ontario were collected using passive sampling technology during 2011–2012. Error propagation analysis and Monte Carlo simulation were applied to estimate uncertainty in the air–water exchange fluxes. Results from both methods were similar, but error propagation analysis estimated a smaller uncertainty than Monte Carlo simulation in cases of net deposition. Maximum likelihood estimations (MLE) of wind speed and air temperature were recommended to quantify the site-specific air–water exchange flux. An assumed 30–40% of relative uncertainty in overall air–water mass transfer velocity was confirmed. MLEs of volatilization fluxes of total PCBs across Lakes Erie and Ontario were 0.78 and 0.53 ng m–2 day–1, respectively, and gross volatilization losses of total PCBs over the whole lakes were 74 kg year–1 for Lake Erie and 63 kg year–1 for Lake Ontario. Mass balance analysis across Lake Ontario indicated that volatilization was the uppermost loss process of aqueous PCBs

Dissolved Organophosphate Esters and Polybrominated Diphenyl Ethers in Remote Marine Environments: Arctic Surface Water Distributions and Net Transport Through Fram Strait

Organophosphate esters (OPEs) have been found in remote environments at unexpectedly high concentrations, but very few measurements of OPE concentrations in seawater are available, and none are available in subsurface seawater. In this study, passive polyethylene samplers (PEs) deployed on deep-water moorings in the Fram Strait and in surface waters of Canadian Arctic lakes and coastal sites were analyzed for a suite of common OPEs. Total OPEs ( ∑11OPE) at deep-water sites were dominated by chlorinated OPEs, and ranged from 6.3 to 440 pg/L. Concentrations were similar in eastern and western Fram Strait. Chlorinated OPEs were also dominant in Canadian Arctic surface waters (mean concentration ranged from \u3c DL to 4400 pg/L), while nonhalogenated alkyl/aryl-substituted OPEs remained low (1.3–55 pg/L), possibly due to the greater long-range transport potential of chlorinated OPEs. Polybrominated diphenyl ethers (PBDEs) were found at much lower concentrations than OPEs

Damaging variants in FOXI3 cause microtia and craniofacial microsomia

Q1Q1Pacientes con Microtia y Microsomía craneofacialPurpose: Craniofacial microsomia (CFM) represents a spectrum of craniofacial malformations, ranging from isolated microtia with or without aural atresia to underdevelopment of the mandible, maxilla, orbit, facial soft tissue, and/or facial nerve. The genetic causes of CFM remain largely unknown. Methods: We performed genome sequencing and linkage analysis in patients and families with microtia and CFM of unknown genetic etiology. The functional consequences of damaging missense variants were evaluated through expression of wild-type and mutant proteins in vitro. Results: We studied a 5-generation kindred with microtia, identifying a missense variant in FOXI3 (p.Arg236Trp) as the cause of disease (logarithm of the odds = 3.33). We subsequently identified 6 individuals from 3 additional kindreds with microtia-CFM spectrum phenotypes harboring damaging variants in FOXI3, a regulator of ectodermal and neural crest development. Missense variants in the nuclear localization sequence were identified in cases with isolated microtia with aural atresia and found to affect subcellular localization of FOXI3. Loss of function variants were found in patients with microtia and mandibular hypoplasia (CFM), suggesting dosage sensitivity of FOXI3. Conclusion: Damaging variants in FOXI3 are the second most frequent genetic cause of CFM, causing 1% of all cases, including 13% of familial cases in our cohort.https://orcid.org/0000-0003-3822-7780https://orcid.org/0000-0002-0729-6866Revista Internacional - IndexadaA1N

Gaseous and Freely-Dissolved PCBs in the Lower Great Lakes based on Passive Sampling: Spatial Trends and Air-water Exchange

Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorinated biphenyls (PCBs) in the air and water of Lakes Erie and Ontario during 2011–2012. In view of differing physical characteristics and the impacts of historical contamination by PCBs within these lakes, spatial variation of PCB concentrations and air–water exchange across these lakes may be expected. Both lakes displayed statistically similar aqueous and atmospheric PCB concentrations. Total aqueous concentrations of 29 PCBs ranged from 1.5 pg L–1 in the open lake of Lake Erie (site E02) in 2011 spring to 105 pg L–1 in Niagara (site On05) in 2012 summer, while total atmospheric concentrations were 7.7–634 pg m–3 across both lakes. A west-to-east gradient was observed for aqueous PCBs in Lake Erie. River discharge and localized influences (e.g., sediment resuspension and regional alongshore transport) likely dominated spatial trends of aqueous PCBs in both lakes. Air–water exchange fluxes of Σ7PCBs ranged from −2.4 (±1.9) ng m–2 day–1 (deposition) in Sheffield (site E03) to 9.0 (±3.1) ng m–2 day–1 (volatilization) in Niagara (site On05). Net volatilization of PCBs was the primary trend across most sites and periods. Almost half of variation in air–water exchange fluxes was attributed to the difference in aqueous concentrations of PCBs. Uncertainty analysis in fugacity ratios and mass fluxes in air–water exchange of PCBs indicated that PCBs have reached or approached equilibrium only at the eastern Lake Erie and along the Canadian shore of Lake Ontario sites, where air–water exchange fluxes dominated atmospheric concentrations