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Mapping Methane and Carbon Dioxide Concentrations and δ13C Values in the Atmosphere of Two Australian Coal Seam Gas Fields
2014
Maher, Damien T. | Santos, Isaac R. | Tait, Douglas R.
Fugitive greenhouse gas emissions from unconventional gas extraction processes (e.g. shale gas, tight gas and coal bed methane/coal seam gas) are poorly understood due in part to the extensive area over which these emissions may occur. We apply a rapid qualitative approach for source assessment at the scale of a large gas field. A mobile cavity ring down spectrometer (Picarro G2201-i) was used to provide real-time, high-precision methane and carbon dioxide concentration and carbon isotope ratios (δ¹³C), allowing for “on the fly” decision making and therefore an efficient and dynamic surveying approach. The system was used to map the atmosphere of a production coal seam gas (CSG) field (Tara region, Australia), an area containing pre-production “exploration” CSG wells (Casino, Australia), and various other potential CO₂and CH₄sources (i.e. wetlands, sewage treatment plants, landfills, urban areas and bushfires). Results showed a widespread enrichment of both CH₄(up to 6.89 ppm) and CO₂(up to 541 ppm) within the production gas field, compared to outside. The CH₄and CO₂δ¹³C source values showed distinct differences within and outside the production field, indicating a CH₄source within the production field that has a δ¹³C signature comparable to the regional CSG. While this study demonstrates how the method can be used to qualitatively assess the location and source of emissions, integration with atmospheric models may allow for quantitative assessment of emissions. The distinct patterns observed within the CSG field demonstrates the need to fully quantify the atmospheric flux of natural and anthropogenic, point and diffuse sources of greenhouse gases from individual Australian gas fields before and after production commences.
Afficher plus [+] Moins [-]Heavy Metal Content of Soils and Plum Orchards in an Uncontaminated Area
2014
Bošković-Rakočević, Ljiljana | Milivojević, Jelena | Milošević, Tomo | Paunović, Gorica
Research was conducted to assess metal contamination of soils and fruits and evaluate potential human health risks. Heavy metal concentrations (Fe, Mn, Cu, Zn, Cd and Pb) in plum orchard soils were below maximum permissible concentration. Igₑₒshowed that soils were uncontaminated (Igₑₒ<0 for Fe and Mn) and uncontaminated to moderately contaminated (I gₑₒ for Cu, Zn, Pb and Cd ranged from 1.20–0.57, 1.32–0.98, 2.97–0.88 and 1.26–0.58, respectively). Fruit Zn, Cu, Mn, Pb and Cd concentrations were within maximum permissible concentration in foods in Serbia. Only Fe levels were above maximum permissible concentration at most locations. The soil-to-fruit transfer factor (TF) showed large differences between metals. TF for Cd and Pb was 0.0, for Mn 0.007–0.030 and for Zn 0.04–0.09, indicating no potential risk to human health, whereas TF for Fe and Cu was high, i.e. 0.30–1.51 and 0.33–1.69, respectively, suggesting that plum can accumulate Fe and Cu.
Afficher plus [+] Moins [-]Long-term Aerosol Characteristics over Eastern, Southeastern, and South Coalfield Regions in India
2014
Soni, Kirti | Kapoor, Sangeeta | Parmar, Kulwinder Singh
Natural and anthropogenic aerosols over coal mines regions in India play a significant role in influencing the regional radiation budget, causing climate implications to the overall hydrological cycle of India. In the reference of regional climate change and air quality, we discuss aerosol optical depth (AOD) variability and long-term trends (from Mar 2000–Dec 2012) over eastern, southeast, and south coalfield regions in India. The present work analyses the variations and trends in aerosol loading using Terra-MODIS (Moderate-Resolution Imaging Spectroradiometer) AOD₅₅₀data in the period 2000–2012. Overall, an increasing trend in AOD₅₅₀has been observed over all regions namely Raniganj (7.31 %) in eastern and Korba (5.0 %) in southeast, and Godavari Valley (32 %) in the south coalfield region in India. This increasing trend predominantly owes to a constant increase in the seasonal/monthly averaged AOD during the winter (Dec–Feb) and post-monsoon (Oct–Nov) seasons dominated by anthropogenic emissions. In contrast, a decreasing trend is observed during pre-monsoon (Mar–May) season over eastern coalfield region (−13 %), while at south coalfield region (44 %) and southeastern coalfield region (0.8 %), increasing trends are observed. Similarly, increasing trends is observed over all regions in monsoon (Jun–Sep) months. Furthermore, the values of Hurst exponent, fractal dimension, and predictability index for AODs are 0.5, 1.5, and 0, respectively suggesting that the AODs in all sites follow the Brownian time series motion (true random walk). High AOD values (0.59 ± 0.21) are observed over eastern region Raniganj.
Afficher plus [+] Moins [-]The Effects of Urbanization on Runoff Pollutant Concentrations, Loadings and Their Seasonal Patterns Under Cold Climate
2014
Valtanen, Marjo | Sillanpää, Nora | Setälä, Heikki
The effects of urbanization on runoff pollutant concentrations and pollutant loading were studied in three urban catchments of varying imperviousness and land use type in the city of Lahti, Finland. Imperviousness of the catchments were 19 % (“Low”), 62 % (“Intermediate”) and 89 % (“High”). During the 2-year study period, runoff quantity was measured continuously and samples were taken for water quality analysis. Besides imperviousness, land use type strongly affected pollutant concentrations: differences in total phosphorus (tot-P), Al, Cr, Zn and Pb concentrations were observed especially between the city centre catchments (High and Intermediate) and the residential catchment (Low), while total suspended solids (TSS), total nitrogen (tot-N), Mn, Co, Ni and Cu concentrations increased with increasing imperviousness. As for pollutant loads, imperviousness was strongly related to TSS, tot-P, Al, Mn, Zn, Cr, Co, Ni and Cu export. The effects of urbanization on runoff quality were season dependent: urbanization increased runoff volumes and, hence, pollutant loads, especially during warm seasons. Still, highest pollutant export in the catchments occurred during spring. Nevertheless, the warm period produced comparable loads to spring at the city centre catchments. Pollutant concentrations, especially in the city centre catchments, exceeded thresholds set for surface waters, indicating a need for runoff treatment in water quality protection.
Afficher plus [+] Moins [-]Isolation and Characterization of Cadmium- and Arsenic-Absorbing Bacteria for Bioremediation
2014
Bhakta, Jatindra N. | Munekage, Y. | Ohnishi, K. | Jana, B. B. | Balcazar, J. L.
The contamination of hazardous metal(loid) is one of the serious environmental and human health risks. This study isolated a total of 40 cadmium (Cd)- and arsenic (As)-resistant bacterial isolates from coastal sediments by pour plate technique using tryptic soy agar supplemented with Cd or As (50 mg l⁻¹) for use as metal(loid) bioremediation agents. Out of 40, 4 isolates, RCd3, RCd6, RAs7, and RAs10, showed a relatively higher growth rate in Cd- or As-supplemented culture media which were selected for further study. The selected isolates showed a high minimum inhibitory concentration (60–400 mg l⁻¹for Cd and 400–2200 mg l⁻¹for As), which demonstrated their remarkable Cd and As resistance capabilities. The metal(loid) removal efficiencies (0.032–0.268 μg Cd h⁻¹ mg⁻¹and 0.0003–0.0172 μg As h⁻¹ mg⁻¹[wet weight cell]) of selected isolates indicated their greater magnitude in absorbing Cd compared to As from water. Phylogenetic analysis of the 16S rDNA sequences revealed that isolates RCd3, RCd6, RAs7, and RAs10 were closely related to Acinetobacter brisouii, Pseudomonas abietaniphila, Exiguobacterium aestuarii, and Planococcus rifietoensis, respectively. Because of high Cd and As resistance and removal efficiency, the selected isolates can survive in a high metal(loid)-contaminated environment and could be a potential tool for bioremediation of high metal(loid)-contaminated effluents to protect the aquatic environment.
Afficher plus [+] Moins [-]Short-Term Impacts of Frangula alnus Litter on Forest Soil Properties
2014
Stokdyk, Joel P. | Herrman, Kyle S.
Effects of invasive plants on soil properties and microbial communities have been observed, but the mechanisms driving change are less obvious. The objective of this study was to determine the short-term impacts of litter from the invasive shrub Frangula alnus on soil properties and soil microorganims. In situ soil rings (6-cm diameter by 7-cm deep) received the following aqueous treatments: deionized water, dextrose, cellulose, Quercus alba leaf extract, and F. alnus leaf extract (n = 7) and were sampled 1, 2, and 4 weeks after additions were made. Microbial biomass carbon did not respond differently to treatments containing carbon (C) sources at any sampling period, suggesting that C quality had little impact on microbial abundance at this site. However, in weeks 1 and 2, soil treated with F. alnus had significantly higher total extractable nitrogen (N) than the control, dextrose, cellulose, and Q. alba extract (all comparisons for both weeks p < 0.001). We suspect that the increase in extractable N in the F. alnus-treated soil was due to enhanced N mineralization. In addition, changes to the microbial biomass C-to-N ratio in the F. alnus-treated soil indicated that microbial function had been altered. Overall, results from this study suggest that F. alnus leaf litter has the capacity to alter soil properties and microbial function by stimulating N mineralization.
Afficher plus [+] Moins [-]Validation of Radiochemical Method for the Determination of ⁹⁰Sr in Environmental Samples
2014
Sarap, Nataša B. | Janković, Marija M. | Pantelić, Gordana K.
The proposed and validated method for determination of ⁹⁰Sr content in environmental samples (water, soil and plant) is based on the radiochemical analytical separation of ⁹⁰Y from the sample and measuring its activity after the establishment of radioactive equilibrium with ⁹⁰Sr. Validation is the confirmation by examination and provision of objective evidence that they meet the individual requirements stipulated for a specific use. Validation of method was done based on the blank samples for water by adding ⁹⁰Sr known activity and using reference materials of soil (IAEA-326) and plant (IAEA-330). Content of ⁹⁰Sr in environmental samples was determined by α/β low level proportional counter. The accuracy and the precision of the applied method are confirmed and the method is validated and can be used for determination of ⁹⁰Sr in environmental samples. On the other hand, participations in interlaboratory comparisons are confirmed that the adequacy of the validated method is ensured.
Afficher plus [+] Moins [-]Comment: Pilot-Scale Test for a Phosphate Treatment Using Sulfate-Coated Zeolite at a Sewage Disposal Facility by Jae-Woo Choi, Kyu-Sang Kwon, Soonjae Lee, Byungryul An, Seok-Won Hong, Sang-Hyup Lee
2014
Unuabonah, Emmanuel I. | Oladoja, Nurudeen A.
The article, Pilot-Scale Test for a Phosphate Treatment Using Sulfate-Coated Zeolite at a Sewage Disposal Facility by Jae-Woo Choi, Kyu-Sang Kwon, Soonjae Lee, Byungryul An, Seok-Won Hong, Sang-Hyup Lee, is replete with some fundamental scientific flaws which have the potential to misinform readers. This comment seek to correct these flaws.
Afficher plus [+] Moins [-]Assessment of Lead Contamination in Peatlands Using Field Portable XRF
2014
Shuttleworth, E. L. | Evans, M. G. | Hutchinson, S. M. | Rothwell, J. J.
Ombrotrophic peatlands are highly sensitive to atmospheric heavy metal deposition. Previous attempts to quantify peatland lead pollution have been undertaken using the inventory approach. However, there can be significant within-site spatial heterogeneity in lead concentrations, highlighting the need for multiple samples to properly quantify lead storage. Field portable x-ray fluorescence (FPXRF) continues to gain acceptance in the study of contaminated soil, but has not thus far been used to assess peatland lead contamination. This study compares lead concentrations in surface peat samples from the South Pennines (UK) derived using (a) FPXRF in the field, (b) FPXRF in the lab on dried samples and (c) ICP-OES analysis. FPXRF field and lab data are directly comparable when field measurements are corrected for water content, both can be easily used to estimate acid extractable lead using regression equations. This study is a successful demonstration of FPXRF as a tool for a time- and cost-effective means of determining the lead content of contaminated peatlands, which will allow rapid landscape scale reconnaissance, core logging, surface surveys and sediment tracing.
Afficher plus [+] Moins [-]Fluorescence Characterization of Natural Organic Matter at a Northern Ontario Wastewater Treatment Plant
2014
Riopel, Rémi | Caron, François | Siemann, Stefan
The fate of colored natural organic matter (CNOM) was investigated for a period of 16 months at a municipal wastewater treatment plant of a mid-sized city in Northern Ontario, Canada, using fluorescence spectroscopy. Our objectives were to assess the changes of CNOM at the inlet and outlet of the plant and to determine if these changes were correlated with parameters routinely measured at the plant. The fluorescence signals were spectrally resolved into humic-like, fulvic-like, and protein-like components using a parallel factor analysis (PARAFAC) routine. We found that the signals of the CNOM components in the raw sewage had protein-like characteristics, followed by fulvic-like and humic-like characteristics. Conversely, after treatment, the CNOM signals were dominated by fulvic-like components, followed by approximately equal signals of humic-like and protein-like components. The fluorescence signals were, on average, ∼60 % lower in the effluent for the protein-like components and ∼28 % lower for the humic-like components, suggesting a decomposition of these CNOM materials. The fluorescence signals showed a small apparent increase of fulvic-like components, by ∼4 %, suggesting that the material showing this signal is recalcitrant to decomposition, or it could be potentially produced in the process. We found weak but statistically significant correlations (R ² > 0.3) between the total fluorescence signals and total carbon (TC), the flow rate through the plant, and rainfall in the raw sewage. Similarly, correlations were found between protein-like fluorescence of the protein-like components and total Kjeldahl nitrogen (TKN) and ammonium at the effluent (R ² > 0.3).
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