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Tetrabromobisphenol A and hexabromocyclododecane flame retardants in infant–mother paired serum samples, and their relationships with thyroid hormones and environmental factors
2014
Kim, Ŭn-jung | Oh, Jeong-Eun
The concentrations of tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs), and their correlations with thyroid hormones, were investigated in sera from 26 infants with congenital hypothyroidism, 12 healthy infants, and their mothers. The analyte concentrations were not significantly different in the two infant groups. Polybrominated diphenyl ethers (measured in a previous study) were the dominant brominated flame retardants, contributing 42–87% of the total, and HBCDs contributed 5–18%. TBBPA concentrations were 2–5 times higher in the infants than in the mothers. The TBBPA concentrations decreased dramatically with age for 2–3 months after birth, which might be caused by its relatively high maternal transfer rate, short half-life, and fast excretion. Significant correlations were found between mothers and infants in the TBBPA and HBCD concentrations, implying that maternal transfer was important. TBBPA correlated weakly with thyroid hormones, showing a positive relationship with FT4 but a negative relationship with T3.
Show more [+] Less [-]Exposure to air pollutants and mortality in hypertensive patients according to demography: A 10 year case-crossover study
2014
Wong, Martin C.S. | Tam, Wilson W.S. | Wang, Harry H.X. | Lao, X.Q. | Zhang, Daisy Dexing | Chan, Sky W.M. | Kwan, Mandy W.M. | Fan, Carmen K.M. | Cheung, Clement S.K. | Tong, Ellen L.H. | Cheung, N.T. | Tse, L.A. | Yu, Ignatius T.S.
This study evaluated whether short term exposures to NO2, O3, particulate matter <10 mm in diameter (PM10) were associated with higher risk of mortality. A total of 223,287 hypertensive patients attended public health-care services and newly prescribed at least 1 antihypertensive agent were followed-up for up to 5 years. A time-stratified, bi-directional case-crossover design was adopted. For all-cause mortality, significant positive associations were observed for NO2 and PM10 at lag 0–3 days per 10 μg/m3 increase in concentration (excess risks 1.187%–2.501%). Significant positive associations were found for O3 at lag 1 and 2 days and the excess risks were 1.654% and 1.207%, respectively. We found similarly positive associations between these pollutants and respiratory disease mortality. These results were significant among those aged ≥65 years and in cold seasons only. Older hypertensive patients are susceptible to all-cause and respiratory disease-specific deaths from these air pollutants in cold weather.
Show more [+] Less [-]Environmental hazards from natural hydrocarbons seepage: Integrated classification of risk from sediment chemistry, bioavailability and biomarkers responses in sentinel species
2014
Benedetti, Maura | Gorbi, Stefania | Fattorini, Daniele | D'Errico, Giuseppe | Piva, Francesco | Pacitti, Davide | Regoli, Francesco
Potential effects of natural emissions of hydrocarbons in the marine environment have been poorly investigated. In this study, a multidisciplinary weight of evidence (WOE) study was carried out on a shallow seepage, integrating sediment chemistry with bioavailability and onset of subcellular responses (biomarkers) in caged eels and mussels. Results from different lines of evidence (LOEs) were elaborated within a quantitative WOE model which, based on logical flowcharts, provide synthetic indices of hazard for each LOE, before their integration in a quantitative risk assessment.Evaluations of different LOEs were not always in accordance and their overall elaboration summarized as Moderate the risk in the seepage area. This study provided first evidence of biological effects in organisms exposed to natural hydrocarbon emissions, confirming the limit of chemical characterization as stand-alone criteria for environmental quality assessment and the utility of multidisciplinary investigations to determine the good environmental status as required by Environmental Directives.
Show more [+] Less [-]Improvement of aerosol optical properties modeling over Eastern Asia with MODIS AOD assimilation in a global non-hydrostatic icosahedral aerosol transport model
2014
Dai, Tie | Schutgens, Nick A.J. | Gotō, Daisuke | Shi, Guangyu | Nakajima, Teruyuki
A new global aerosol assimilation system adopting a more complex icosahedral grid configuration is developed. Sensitivity tests for the assimilation system are performed utilizing satellite retrieved aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS), and the results over Eastern Asia are analyzed. The assimilated results are validated through independent Aerosol Robotic Network (AERONET) observations. Our results reveal that the ensemble and local patch sizes have little effect on the assimilation performance, whereas the ensemble perturbation method has the largest effect. Assimilation leads to significantly positive effect on the simulated AOD field, improving agreement with all of the 12 AERONET sites over the Eastern Asia based on both the correlation coefficient and the root mean square difference (assimilation efficiency). Meanwhile, better agreement of the Ångström Exponent (AE) field is achieved for 8 of the 12 sites due to the assimilation of AOD only.
Show more [+] Less [-]Modelling segregation effects of heterogeneous emissions on ozone levels in idealised urban street canyons: Using photochemical box models
2014
Zhong, Jian | Cai, Xiao-Ming | Bloss, William James
Air quality models include representations of pollutant emissions, which necessarily entail spatial averaging to reflect the model grid size; such averaging may result in significant uncertainties and/or systematic biases in the model output. This study investigates such uncertainties, considering ozone concentrations in idealised street canyons within the urban canopy. A photochemical model with grid-averaged emissions of street canyons is compared with a multiple-box model considering each canyon independently. The results reveal that the averaged, ‘one-box’ model may significantly underestimate true (independent canyon mean) ozone concentrations for typical urban areas, and that the performance of the averaged model is improved for more ‘green’ and/or less trafficked areas. Our findings also suggest that the trends of 2005–2020 in emissions, in isolation, reduce the error inherent in the averaged-emissions treatment. These new findings may be used to evaluate uncertainties in modelled urban ozone concentrations when grid-averaged emissions are adopted.
Show more [+] Less [-]Concentrations of polycyclic aromatic hydrocarbons (PAHs) and azaarenes in runoff from coal-tar- and asphalt-sealcoated pavement
2014
Mahler, Barbara J. | Van Metre, Peter C. | Foreman, William T.
Coal-tar-based sealcoat, used extensively on parking lots and driveways in North America, is a potent source of PAHs. We investigated how concentrations and assemblages of PAHs and azaarenes in runoff from pavement newly sealed with coal-tar-based (CT) or asphalt-based (AS) sealcoat changed over time. Samples of simulated runoff were collected from pavement 5 h to 111 d following application of AS or CT sealcoat. Concentrations of the sum of 16 PAHs (median concentrations of 328 and 35 μg/L for CT and AS runoff, respectively) in runoff varied relatively little, but rapid decreases in concentrations of azaarenes and low molecular weight PAHs were offset by increases in high molecular weight PAHs. The results demonstrate that runoff from CT-sealcoated pavement, in particular, continues to contain elevated concentrations of PAHs long after a 24-h curing time, with implications for the fate, transport, and ecotoxicological effects of contaminants in runoff from CT-sealcoated pavement.
Show more [+] Less [-]Species-dependent effects of biochar amendment on bioaccumulation of atrazine in earthworms
2014
Wang, Fang | Ji, Rong | Jiang, Zhongwei | Chen, Wei
We observed that at a contamination level of 4.25 mg-atrazine/kg-soil, the biota–soil accumulation factor (BSAF) for the anecic M. guillelmi is approximately 5 times that for the epigeic E. foetida. This is attributable to the fact that bio-uptake by E. foetida is mainly through dermal absorption, whereas bio-uptake by M. guillelmi is largely affected by the gut processes, through which the physical grinding and surfactant-like materials facilitate the desorption of atrazine from soil. Strikingly, biochar amendment resulted in much greater reduction in BSAF for M. guillelmi than for E. foetida. At a biochar dose of 0.5% (wt:wt) the difference in BSAF between the two species became much smaller, and at a dose of 2% no statistical difference was observed. A likely explanation is that gut processes by M. guillelmi were much less effective in extracting atrazine from the biochar (the predominant phase wherein atrazine resided) than from soil particles.
Show more [+] Less [-]An integrated evaluation of molecular marker indices and linear alkylbenzenes (LABs) to measure sewage input in a subtropical estuary (Babitonga Bay, Brazil)
2014
Martins, César C. | Cabral, Ana Caroline | Barbosa-Cintra, Scheyla C.T. | Dauner, Ana Lúcia L. | Souza, Fernanda M.
Babitonga Bay is a South Atlantic estuary with significant ecological function; it is part of the last remaining areas of mangrove communities in the Southern Hemisphere. The aim of this study was to determine the spatial distribution of the faecal sterols and linear alkylbenzenes (LABs) in surface sediments and to perform an integrated evaluation of several molecular marker indices to assess the sewage contamination status in the study area. The highest observed concentrations of faecal sterols (coprostanol + epicoprostanol) and LABs were 6.65 μg g−1 and 413.3 ng g−1, respectively. Several faecal sterol indices were calculated and correlated with coprostanol levels; these analyses showed that the index limits presented in the current literature could underestimate the sewage contamination in this study area. For the overall estuarine system, a low sewage impact may be assumed based on the low total mass inventories calculated for coprostanol (between 1.4% and 4.8%).
Show more [+] Less [-]Metal pollution in a contaminated bay: Relationship between metal geochemical fractionation in sediments and accumulation in a polychaete
2014
Fan, Wenhong | Xu, Zhizhen | Wang, Wen-Xiong
Jinzhou Bay in Northern China has been seriously contaminated with metals due to the impacts of smelting activities. In this study, we investigated the relationship between metal accumulation in a deposit-feeding polychaete Neanthes japonica and metal concentration and geochemical fractionation (Cd, Cu, Pb, Zn and Ni) in sediments of Jinzhou Bay. Compared with the historical data, metals in the more mobile geochemical fraction (exchangeable and carbonate fractions) were gradually partitioned into the more stable fraction (Fe–Mn oxides) over time. Metal concentration and geochemical fractionation in sediment significantly affected metal bioavailability and accumulation in polychaetes, except for Ni. Metal accumulation in polychaetes was significantly influenced by Fe or Mn content, and to a lesser degree by organic matter. Prediction of metal bioaccumulation in polychaetes was greatly improved by normalizing metal concentrations to Mn content in sediment. The geochemical fractionation of metals in sediments including the exchangeable, organic matter and Fe–Mn oxides were important in controlling the sediment metal bioavailability to polychaetes.
Show more [+] Less [-]Interactions between biomass-burning aerosols and clouds over Southeast Asia: Current status, challenges, and perspectives
2014
Lin, Neng-Huei | Sayer, Andrew M. | Wang, Shengxiang | Loftus, Adrian M. | Hsiao, Ta-Chih | Sheu, Guey-Rong | Hsu, N Christina | Tsay, Si-Chee | Chantara, Somporn
The interactions between aerosols, clouds, and precipitation remain among the largest sources of uncertainty in the Earth's energy budget. Biomass-burning aerosols are a key feature of the global aerosol system, with significant annually-repeating fires in several parts of the world, including Southeast Asia (SEA). SEA in particular provides a “natural laboratory” for these studies, as smoke travels from source regions downwind in which it is coupled to persistent stratocumulus decks. However, SEA has been under-exploited for these studies. This review summarizes previous related field campaigns in SEA, with a focus on the ongoing Seven South East Asian Studies (7-SEAS) and results from the most recent BASELInE deployment. Progress from remote sensing and modeling studies, along with the challenges faced for these studies, are also discussed. We suggest that improvements to our knowledge of these aerosol/cloud effects require the synergistic use of field measurements with remote sensing and modeling tools.
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