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Surface water geochemical and isotopic variations in an area of accelerating Marcellus Shale gas development Full text
2014
Pelak, Adam J. | Sharma, Shikha
Water samples were collected from 50 streams in an area of accelerating shale gas development in the eastern U.S.A. The geochemical/isotopic characteristics show no correlation with the five categories of Marcellus Shale production. The sub-watersheds with the greatest density of Marcellus Shale development have also undergone extensive coal mining. Hence, geochemical/isotopic compositions were used to understand sources of salinity and effects of coal mining and shale gas development in the area. The data indicates that while some streams appear to be impacted by mine drainage; none appear to have received sustained contribution from deep brines or produced waters associated with shale gas production. However, it is important to note that our interpretations are based on one time synoptic base flow sampling of a few sampling stations and hence do account potential intermittent changes in chemistry that may result from major/minor spills or specific mine discharges on the surface water chemistry.
Show more [+] Less [-]Proinflammatory effects and oxidative stress within human bronchial epithelial cells exposed to atmospheric particulate matter (PM2.5 and PM>2.5) collected from Cotonou, Benin Full text
2014
Cachon, Boris Fresnel | Firmin, Stéphane | Verdin, Anthony | Ayi-Fanou, Lucie | Billet, Sylvain | Cazier, Fabrice | Martin, Perrine J. | Aissi, Faustin | Courcot, Dominique | Sanni, Ambaliou | Shirali, Pirouz
After particulate matter (PM) collection in Cotonou (Benin), a complete physicochemical characterization of PM2.5 and PM>2.5 was led. Then, their adverse health effects were evaluated by using in vitro culture of human lung cells. BEAS-2B (bronchial epithelial cells) were intoxicated during short-term exposure at increasing PM concentrations (1.5–96 μg/cm2) to determine global cytotoxicity. Hence, cells were exposed to 3 and 12 μg/cm2 to investigate the potential biological imbalance generated by PM toxicity. Our findings showed the ability of both PM to induce oxidative stress and to cause inflammatory cytokines/chemokines gene expression and secretion. Furthermore, PM were able to induce gene expression of enzymes involved in the xenobiotic metabolism pathway. Strong correlations between gene expression of metabolizing enzymes, proinflammatory responses and cell cycle alteration were found, as well as between proinflammatory responses and cell viability. Stress oxidant parameters were highly correlated with expression and protein secretion of inflammatory mediators.
Show more [+] Less [-]Analysis of petroleum contaminated soils by spectral modeling and pure response profile recovery of n-hexane Full text
2014
Chakraborty, Somsubhra | Weindorf, David C. | Li, Bin | Ali, Md Nasim | Majumdar, K. | Ray, D.P.
This pilot study compared penalized spline regression (PSR) and random forest (RF) regression using visible and near-infrared diffuse reflectance spectroscopy (VisNIR DRS) derived spectra of 164 petroleum contaminated soils after two different spectral pretreatments [first derivative (FD) and standard normal variate (SNV) followed by detrending] for rapid quantification of soil petroleum contamination. Additionally, a new analytical approach was proposed for the recovery of the pure spectral and concentration profiles of n-hexane present in the unresolved mixture of petroleum contaminated soils using multivariate curve resolution alternating least squares (MCR-ALS). The PSR model using FD spectra (r2 = 0.87, RMSE = 0.580 log10 mg kg−1, and residual prediction deviation = 2.78) outperformed all other models tested. Quantitative results obtained by MCR-ALS for n-hexane in presence of interferences (r2 = 0.65 and RMSE 0.261 log10 mg kg−1) were comparable to those obtained using FD (PSR) model. Furthermore, MCR ALS was able to recover pure spectra of n-hexane.
Show more [+] Less [-]Repeated phytoextraction of four metal-contaminated soils using the cadmium/zinc hyperaccumulator Sedum plumbizincicola Full text
2014
Li, Zhu | Wu, Longhua | Hu, Pengjie | Luo, Yongming | Zhang, Hao | Christie, Peter
A cadmium/zinc hyperaccumulator extracted metals from four contaminated soils over three years in a glasshouse experiment. Changes in plant metal uptake and soil total (aqua regia-extractable) and available metals were investigated. Plant Cd concentrations in a high-Cd acid soil and plant Zn concentrations in two acid soils decreased during repeated phytoextraction and were predicted by soil available metal concentrations. However, on repeated phytoextraction, plant Cd concentrations remained constant in lightly Cd-polluted acid soils, as did plant Cd and Zn in alkaline soils, although soil available metal concentrations decreased markedly. After phytoextraction acid soils showed much higher total metal removal efficiencies, indicating possible suitability of phytoextraction for acid soils. However, DGT-testing, which takes soil metal re-supply into consideration, showed substantial removal of available metal and distinct decreases in metal supply capacity in alkaline soils after phytoextraction, suggesting that a strategy based on lowering the bioavailable contaminant might be feasible.
Show more [+] Less [-]Modelling segregation effects of heterogeneous emissions on ozone levels in idealised urban street canyons: Using photochemical box models Full text
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 [-]Hazard and risk of herbicides for marine microalgae Full text
2014
Sjollema, Sascha B. | MartínezGarcía, Gema | van der Geest, Harm G. | Kraak, Michiel H.S. | Booij, Petra | Vethaak, A Dick | Admiraal, Wim
Due to their specific effect on photosynthesis, herbicides pose a potential threat to coastal and estuarine microalgae. However, comprehensive understanding of the hazard and risk of these contaminants is currently lacking. Therefore the aim of the present study was to investigate the toxic effects of four ubiquitous herbicides (atrazine, diuron, Irgarol®1051 and isoproturon) and herbicide mixtures on marine microalgae. Using a Pulse Amplitude Modulation (PAM) fluorometry based bioassay we demonstrated a clear species and herbicide specific toxicity and showed that the current environmental legislation does not protect algae sufficiently against diuron and isoproturon. Although a low actual risk of herbicides in the field was demonstrated, monitoring data revealed that concentrations occasionally reach potential effect levels. Hence it cannot be excluded that herbicides contribute to observed changes in phytoplankton species composition in coastal waters, but this is likely to occur only occasionally.
Show more [+] Less [-]Effects of elevated temperature on the toxicity of copper and oxytetracycline in the marine model, Euplotes crassus: A climate change perspective Full text
2014
Gomiero, A. | Viarengo, A.
Trace metals and broad-spectrum antibiotic drugs are common environmental contaminants, the importance of which is increasing due to global climate change-related effects.In the present study, the biological model organism E. crassus was first acclimated to five temperatures, from 25 °C to 33 °C, followed by exposure to nominal concentrations of copper, the antibiotic model compound oxytetracycline and mixtures of both, at increasing thermal conditions. Variations of temperature-related toxicity were assessed by two high-level endpoint tests, survival and replication rates, and two sublethal parameters: endocytosis rate and lysosomal membrane stability. The selected toxicants presented opposite behaviours as the protozoa's survival rates increased following an increasing thermal gradient in the oxytetracycline-related treatments, and a decline of tolerance in metal-related treatments was observed. Results of tests combining binary mixtures of tested toxicants showed a complex pattern of responses.
Show more [+] Less [-]Can ammonia tolerance amongst lichen functional groups be explained by physiological responses? Full text
2014
Munzi, S. | Cruz, C. | Branquinho, C. | Pinho, P. | Leith, I.D. | Sheppard, L.J.
Ammonia (NH3) empirical critical levels for Europe were re-evaluated in 2009, based mainly on the ecological responses of lichen communities without acknowledging the physiological differences between oligotrophic and nitrophytic species. Here, we compare a nitrogen sensitive lichen (Evernia prunastri) with a nitrogen tolerant one (Xanthoria parietina), focussing on their physiological response (Fv/Fm) to short-term NH3 exposure and their frequency of occurrence along an NH3 field gradient. Both frequency and Fv/Fm of E. prunastri decreased abruptly above 3 μg m−3 NH3 suggesting direct adverse effects of NH3 on its photosynthetic performance. By contrast, X. parietina increased its frequency with NH3, despite showing decreased capacity of photosystem II above 50 μg m−3 NH3, suggesting that the ecological success of X. parietina at ammonia-rich sites might be related to indirect effects of increased nitrogen (NH3) availability. These results highlight the need to establish NH3 critical levels based on oligotrophic lichen species.
Show more [+] Less [-]Short-term exposure to dimethylformamide and the impact on digestive system disease: An outdoor study for volatile organic compound Full text
2014
Wang, Cui | Huang, Canke | Wei, Yumei | Zhu, Qi | Tian, Weili | Zhang, Qingyu
Occupational and experimental studies have revealed the organs most affected by dimethylformamide (DMF) are liver and gastrointestinal tract. However, few studies have focused on the potential effect of outdoor pollution of DMF. This study examined the health risk of hospitalization due to digestive system disease by time series studies in a case city Longwan, China. The urine metabolite of DMF was correlated well with DMF exposure concentration (EC). A 101.0-μg/m3 (interquartile range) increase in the two-day moving average of DMF EC was associated with a 1.10 (1.01 ˜ 1.20), 1.22 (1.10 ˜ 1.35), and 1.05 (0.90 ˜ 1.22) increase in hospitalization for total digestive system diseases, liver disease, and gastrointestinal tract disease, respectively. The exposure-dose response between DMF and the relative risk of liver disease was linear only below 350 μg/m3. These findings highlight a previously unrecognized health problem related to VOCs released into the outdoor environment.
Show more [+] Less [-]Passive sampling: An effective method for monitoring seasonal and spatial variability of dissolved hydrophobic organic contaminants and metals in the Danube river Full text
2014
Vrana, Branislav | Klučárová, Veronika | Benická, Eva | Abou-Mrad, Ninette | Amdany, Robert | Horáková, Soňa | Draxler, Astrid | Humer, Franko | Gans, Oliver
Application of passive samplers is demonstrated for assessment of temporal and spatial trends of dissolved polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and priority metals in the middle stretch of the Danube river. Free dissolved concentrations of PAHs, measured using SPMD samplers, ranged from 5 to 72 ng L−1. Dissolved PCBs in water were very low and they ranged from 5 to 16 pg L−1. Concentration of mercury, cadmium, lead and nickel, measured using DGT samplers, were relatively constant along the monitored Danube stretch and in the range <0.1, <1–20, 18–74, and 173–544 ng L−1, respectively. Concentrations of PAHs decreased with increasing temperature, which reflects the seasonality in emissions to water. This has an implication for the design of future monitoring programs aimed at assessment of long term trends. For such analysis time series should be constructed of data from samples collected always in the same season of the year.
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