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结果 731-740 的 1,545
Variation of Antioxidant Activity in Dreissena polymorpha Specimens Exposed to 2,2′,4,4′,5,6′-Hexa BDE (BDE-154) 全文
2012
Parolini, Marco | Pedriali, Alessandra | Binelli, Andrea
We evaluated the imbalance of the oxidative status in zebra mussel (Dreissena polymorpha) specimens exposed for 96 h to environmentally relevant concentrations (0.1, 0.5, and 1 μg/L) of the 2,2′,4,4′,5,6′-hexa BDE (BDE-154). The activities of three antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and the phase II detoxifying enzyme glutathione S-transferase (GST), were measured in the cytosolic fraction from a pool of zebra mussels. Significant variations in the activity of each single enzyme were noticed at each treatment, indicating that exposure to BDE-154 was able to impair the oxidative status of treated bivalves through the increase of reactive oxygen species. In detail, SOD and GPx were significantly induced, while CAT and GST were depressed with respect to the baseline levels. These data have confirmed that the raise of oxidative stress is the main cause of the BDE-154-induced genetic damage observed in a previous study on the zebra mussel.
显示更多 [+] 显示较少 [-]Chelating–Ultrafiltration Treatment of Some Heavy Metal Ions in Aqueous Solutions by Crosslinking Carboxymethyl Modified Cornstarch 全文
2012
Wang, Ting | Song, Ye | Li, Bin | Zhou, Xiaoguang
Crosslinking carboxymethyl starch (CCMS) powder of degree of substitution (DS) 0.43–0.59 was prepared by the process of two steps of alkali addition synthesis. The technique of powder coupling with ultrafiltration was used to absorb Cu2+, Zn2+, Ni2+, Pb2+, and Cd2+ from aqueous solutions. FTIR was used to demonstrate the successfully grafting of carboxymethyl groups, and the technique of microwave plasma torch atomic emission spectrometer was applied in rapid determination of the aforementioned heavy metals ions. The results revealed that the removal sequence of heavy metal ions followed the order of Pb2+>Cu2+>Cd2+>Zn2+>Ni2+. By assistant of diethylene triamine penlaacetic acid, the quaternary system of Pb2+/Ni 2+/Cd2+/Cu2+ mixture solution could have the ideal separation. Besides, the influence of pH, ζ potential, DS value, and membranes molecular weight cut-off on removal of 20 mg L−1 Pb2+ or Ni2+ was also investigated.
显示更多 [+] 显示较少 [-]Environmental Monitoring Using Electrical Resistivity Tomography (ERT) in the Subsoil of Three Former Petrol Stations in SE of Spain 全文
2012
Rosales, Rosa Ma | Martínez-Pagan, Pedro | Faz, Angel | Moreno-Cornejo, Jennifer
Electrical resistivity tomography (2D ERT) is a powerful tool for the diagnosis of the subsoil state and to pursue an environmental monitoring in time to detect and follow a temporal evolution of plumes in hydrocarbon-contaminated soils. In situ, 2D ERT was conducted to investigate the electrical properties of the subsoil in three petrol stations in Murcia semiarid Region (SE Spain), which have been active for many years, in order to look for anomalous areas that could be related to the presence of a non-aqueous phase liquid (NAPL) contaminant plume in the subsoil. A total of 18 ERT profiles in wet and dry season were conducted to study the seasonal effects in the resistivity values of the subsoil. Dipole–dipole array was set up to make the soil diagnosis, achieving a good vertical and lateral resistivity distributions for the sites investigated. Interpretations obtained from ERT pseudo-sections, after a processing and inversion data process with PROSYS II and RES2DINV software, show delimited highly resistive regions above 2,000 Ω·m at 2 m deep related to the underground storage tanks (USTs) position and the filling ports and anomalous resistivity areas where boreholes and further GC–FID determination in soil samples have been done. No significant differences have been found between results obtained in dry and wet seasons. Thus, the geo-electrical non-destructive technique ERT is presented as a tool to delineate the USTs positions and to point out anomaly in the subsoil that could contain NAPL, helping to design sampling strategies, saving cost and time.
显示更多 [+] 显示较少 [-]Evaluation of Premature Mortality Caused by Exposure to PM2.5 and Ozone in East Asia: 2000, 2005, 2020 全文
2012
Nawahda, Amin | Yamashita, Ken | Ōhara, Toshimasa | Kurokawa, Junichi | Yamaji, Kazuyo
The aim of this study is to assess the premature mortality risks caused by exposure to particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) and ozone elevated concentrations for the years 2000, 2005, and 2020 in East Asia. The spatial distributions and temporal variations of PM2.5 and ozone concentrations are simulated using the Models-3 Community Multiscale Air Quality Modeling System coupled with the Regional Emission Inventory in Asia. The premature mortality risks caused by exposure to PM2.5 and ozone are calculated based on a relative risk (RR) value of 1.04 (95 % confidence interval (CI): 1.01â1.08) for PM2.5 concentrations above the annual mean limit of 10 μg mâ3 taken from the World Health OrganizationâAir Quality Guideline and based on a RR value of 1.003 (95 % CI: 1.001â1.004) for ozone concentration above 35 ppb of the SOMO35 index (the sum of ozone daily maximum 8-h mean concentrations above 35 ppb). We demonstrate one of the implications of the policy making in the area of environmental atmospheric management in East Asia by highlighting the annual premature mortalities associated with exposure to PM2.5 concentrations that just meet an annual mean concentration of 10 μg mâ3, as well as ozone concentrations that have a daily zero SOMO35 index in vulnerable places. Our results point to a growing health risk that may endanger human life in East Asia. We find that the effect of PM2.5 on human health is greater than the effect of ozone for the age group of 30 years and above. We estimate the corresponding premature mortality due to the effects of both ozone and PM2.5 in East Asia for the years 2000 and 2005 to be around 316,000 and 520,000 cases, respectively. For future scenarios of the year 2020, policy succeed case, reference, and policy failed case, the estimated annual premature mortality rates are 451,000, 649,000, and 1,035,000 respectively.
显示更多 [+] 显示较少 [-]Monitoring of Aerosol and Fallout Radioactivity in Belgrade After the Fukushima Reactors Accident 全文
2012
Nikolic, Jelena | Pantelic, Gordana | Todorovic, Dragana | Janković, Marija | Savkovic, Maja Eremić
After the accident in Fukushima reactors, a daily monitoring programme was initiated in two laboratories in Belgrade, one at the Vinčа Institute for Nuclear Sciences and the other at Institute for Occupational Health Karajovic. Samples of aerosol and fallout, as well as the random samples of food and water, were collected and analysed, using gross alpha/beta and gamma spectrometry, in order to establish the presence of traces of isotopes indicating Fukushima fallout. Gamma spectrometry measurement of these samples showed clear evidence of fission products ¹³¹I, ¹³⁴Cs and ¹³⁷Cs wtihin 2 weeks after the accident. The activity diminished with time due to dispersion in air and, in case of ¹³¹I, short half-life.
显示更多 [+] 显示较少 [-]Evaluating Methane Oxidation Efficiencies in Experimental Landfill Biocovers by Mass Balance and Carbon Stable Isotopes 全文
2012
Capanema, Marlon A. | Cabral, Alexandre R.
Biocovers are an alternative for mitigating fugitive and residual emissions of methane from landfills. In this study, we evaluated the performance of two experimental passive methane oxidation biocovers (PMOBs) constructed within the existing final cover of the St-Nicéphore landfill (Quebec, Canada). The biocovers were fed in a controlled manner with raw biogas and surface fluxes were obtained using static chambers. This enabled calculating mass balances of CH₄ and oxidation efficiencies (f ₒ_MB). Most of the time, f ₒ_MB ≥ 92 % were obtained for loadings as high as 818 g CH₄ m⁻² day⁻¹ (PMOB-2) and 290 g CH₄ m⁻² day⁻¹ (PMOB-3B). The lowest efficiencies (f ₒ_MB = 45.5 % and 34.0 %, respectively) were obtained during cold days (air temperature ~0 °C). Efficiencies were also calculated using stable isotopes (f ₒ_SI); the highest f ₒ_SI were 66.4 % for PMOB-2 and 87.3 % for PMOB-3B; whereas the lowest were 18.8 % and 23.1 %, respectively. However, f ₒ_SI values reflect CH₄ oxidation up to a depth of 0.10 m, which may partly explain the difference in regards to mass balance-derived efficiencies. Indeed, it is expected that a significant fraction of the total CH₄ oxidation occurs within the zone near the surface, where there is greater O₂ availability. The influence of the values of fractionation factors α ₒₓ and α ₜᵣₐₙₛ were also evaluated in this paper.
显示更多 [+] 显示较少 [-]Nitrate and Phosphate Leaching under Turfgrass Fertilized with a Squid-based Organic Fertilizer 全文
2012
Fetter, Joseph C. | Brown, Rebecca N. | Görres, Josef H. | Lee, Chong | Amador, José A.
Consumer demand for cleaned squid generates a substantial amount of waste that must be properly disposed of, creating an economic burden on processors. A potential solution to this problem involves converting squid by-products into an organic fertilizer, for which there is growing demand. Because fertilizer application to lawns can increase the risk of nutrient contamination of groundwater, we quantified leaching of NO3–N and PO4–P from perennial ryegrass turf (Lolium perenne L.) amended with two types of fertilizer: squid-based (SQ) and synthetic (SY). Field plots were established on an Enfield silt loam, and liquid (L) and granular (G) fertilizer formulations of squid and synthetic fertilizers were applied at 0, 48, 146, and 292 kg N ha−1 year−1. Levels of NO3–N and PO4–P in soil pore water from a depth of 60 cm were determined periodically during the growing season in 2008 and 2009. Pore water NO3–N levels were not significantly different among fertilizer type or formulation within an application rate throughout the course of the study. The concentration of NO3–N remained below the maximum contaminant level (MCL) of 10 mg L−1 until midSeptember 2009, when values above the MCL were observed for SQG at all application rates, and for SYL at the high application rate. Annual mass losses of NO3–N were below the estimated inputs (10 kg N ha−1 year−1) from atmospheric deposition except for the SQG and SYL treatments applied at 292 kg N ha−1 year−1, which had losses of 13.2 and 14.9 kg N ha−1 year−1, respectively. Pore water PO4–P levels ranged from 0 to 1.5 mg P L−1 and were not significantly different among fertilizer type or formulation within an application rate. Our results indicate that N and P losses from turf amended with squid-based fertilizer do not differ from those amended with synthetic fertilizers or unfertilized turf. Although organic in nature, squid-based fertilizer does not appear to be more—or less—environmentally benign than synthetic fertilizers.
显示更多 [+] 显示较少 [-]Multiparameter Quantitative Optimization in the Synthesis of a Novel Coagulant Derived from Tannin Extracts for Water Treatment 全文
2012
Beltrán-Heredia, Jesus | Sánchez-Martín, Jesus | Martín-García, Leticia
A novel tannin-based coagulant has been synthesized at lab scale. A multiparameter optimization was performed on the production process, and up to five variables were studied according to the response surface methodology in a face-centered design of experiments which included two temperatures, two pH levels, and the reaction time in the chemical process. The coagulant involved diethanolamine, formaldehyde, and a tannin extract from Acacia mearnsii de Wild. The results revealed an average optimum combination for dye and surfactant removal which was able to remove either Alizarin Violet 3R and sodium dodecylbenzene sulfonate efficiently from water effluents.
显示更多 [+] 显示较少 [-]Can a Single and Unique Cu Soil Quality Standard be Valid for Different Mediterranean Agricultural Soils under an Accumulator Crop? 全文
2012
Recatalá, L. | Sacristán, D. | Arbelo, C. | Sánchez, J.
Can a Single and Unique Cu Soil Quality Standard be Valid for Different Mediterranean Agricultural Soils under an Accumulator Crop? 全文
2012
Recatalá, L. | Sacristán, D. | Arbelo, C. | Sánchez, J.
The validity of the soil quality standard for copper (Cu) established by the Spanish legislation (Spanish Royal Decree 9/2005) is evaluated in representative agricultural Mediterranean soils under an accumulator crop (Lactuca sativa L. var. Romaine cv. Long Green), considering both the effect of the metal on crop growth (biomass production) and its accumulation in the edible part of the plant. For saline soils, such a soil quality standard seems not to be valid taking into account both of the aspects evaluated. For non-saline soils, the soil quality standard also seems not to be valid since, considering the metal accumulation in the edible part of the plant, the soil quality standard should be above such standard; but considering the productivity function of soil (biomass production), the standard should be much below, meaning that this function is being greatly affected by the presence of high concentrations of Cu. The soil quality standard for each soil considered should correspond to a value between its respective EC50 and EC10 values (effective concentrations of added Cu causing 50% and 10% inhibition on the biomass production), depending on the politicians and/or farmers' compromise with yield production and, therefore, with soil productivity. These threshold values were greater for the soil having more organic matter and clay content, showing that Cu toxicity also depends on these properties. Further research in other agricultural areas of the region would improve the basis for proposing adequate soil quality standards as highlighted by the European Thematic Strategy for Soil Protection.
显示更多 [+] 显示较少 [-]Can a single and unique Cu soil quality standard be valid for different mediterranean agricultural soils under an accumulator crop? 全文
2012
Recatalá Boix, Luis | Sacristán Moraga, Daniel | Arbelo, C. | Sánchez, J.
The validity of the soil quality standard for copper (Cu) established by the Spanish legislation (Spanish Royal Decree 9/2005) is evaluated in representative agricultural Mediterranean soils under an accumulator crop (Lactuca sativa L. var. Romaine cv. Long Green), considering both the effect of the metal on crop growth (biomass production) and its accumulation in the edible part of the plant. For saline soils, such a soil quality standard seems not to be valid taking into account both of the aspects evaluated. For non-saline soils, the soil quality standard also seems not to be valid since, considering the metal accumulation in the edible part of the plant, the soil quality standard should be above such standard; but considering the productivity function of soil (biomass production), the standard should be much below, meaning that this function is being greatly affected by the presence of high concentrations of Cu. The soil quality standard for each soil considered should correspond to a value between its respective EC 50 and EC 10 values (effective concentrations of added Cu causing 50% and 10% inhibition on the biomass production), depending on the politicians and/or farmers' compromise with yield production and, therefore, with soil productivity. These threshold values were greater for the soil having more organic matter and clay content, showing that Cu toxicity also depends on these properties. Further research in other agricultural areas of the region would improve the basis for proposing adequate soil quality standards as highlighted by the European Thematic Strategy for Soil Protection. © Springer Science+Business Media B.V. 2011. | Peer Reviewed
显示更多 [+] 显示较少 [-]Treatment of Olive Oil Mill Wastewater by Silica–Alginate–Fungi Biocomposites 全文
2012
Duarte, Kátia R. | Freitas, Ana C. | Pereira, Ruth | Pinheiro, Jorge C. | Gonçalves, Fernando | Azaari, H. | El Azzouzi, Mohammed | Zrineh, Abdallah | Zaydoun, Souad | Duarte, Armando C. | Rocha-Santos, Teresa A. P.
Treatment of Olive Oil Mill Wastewater by Silica–Alginate–Fungi Biocomposites 全文
2012
Duarte, Kátia R. | Freitas, Ana C. | Pereira, Ruth | Pinheiro, Jorge C. | Gonçalves, Fernando | Azaari, H. | El Azzouzi, Mohammed | Zrineh, Abdallah | Zaydoun, Souad | Duarte, Armando C. | Rocha-Santos, Teresa A. P.
Olive oil mill wastewater (OMW) generates a wide variety of pollutants depending on the production process and other factors such as olive varieties and cultivation system. Efforts to mitigate the impact of these effluents in the environment have been made by developing more efficient treatment systems in terms of removal of chemical oxygen demand (COD), color, organic compounds, and toxicity. This study is the first that reports the potential of a treatment of OMW by biocomposites of silica–alginate–fungi (Pleurotus sajor caju and Trametes versicolor). The treatment by biocomposites can be considered as a three-step process responsible for the removal of the compounds: (1) adsorption of reactants on the monolithic structure and diffusion to the biological active sites, (2) biodegradation by the fungi, and (3) diffusion of the products resulting from the biodegradation. Both treatments tested showed potential capacity to remove organic compounds, color, COD, and toxicity. The T. versicolor biocomposites were the most effective and responsible for the reduction in color (from 38.4 to 44.9 %), COD (from 42.8 to 63.8 %), and total phenolic content (from 85.3 to 88.7 %) after 29 days of treatment. The toxicity reduction on Portuguese OMW was minimal, but the use of composites on the Moroccan OMW caused a 9.5- to 19-fold reduction in toxicity. Furthermore, the biocomposites showed potential for re-utilization for more 29 days of treatment.
显示更多 [+] 显示较少 [-]Treatment of olive oil mill wastewater by silica–alginate–fungi biocomposites 全文
2012
Duarte, Kátia R. | Freitas, Ana C. | Pereira, Ruth | Pinheiro, Jorge C. | Gonçalves, Fernando | Azaari, H. | El Azzouzi, Mohammed | Zrineh, Abdallah | Zaydoun, Souad | Duarte, Armando C. | Rocha-Santos, Teresa A. P.
Olive oil mill wastewater (OMW) generates a wide variety of pollutants depending on the production process and other factors such as olive varieties and cultivation system. Efforts to mitigate the impact of these effluents in the environment have been made by developing more efficient treatment systems in terms of removal of chemical oxygen demand (COD), color, organic compounds, and toxicity. This study is the first that reports the potential of a treatment of OMW by biocomposites of silica–alginate–fungi (Pleurotus sajor caju and Trametes versicolor). The treatment by biocomposites can be considered as a three-step process responsible for the removal of the compounds: (1) adsorption of reactants on the monolithic structure and diffusion to the biological active sites, (2) biodegradation by the fungi, and (3) diffusion of the products resulting from the biodegradation. Both treatments tested showed potential capacity to remove organic compounds, color, COD, and toxicity. The T. versicolor biocomposites were the most effective and responsible for the reduction in color (from 38.4 to 44.9 %), COD (from 42.8 to 63.8 %), and total phenolic content (from 85.3 to 88.7 %) after 29 days of treatment. The toxicity reduction on Portuguese OMW was minimal, but the use of composites on the Moroccan OMW caused a 9.5- to 19-fold reduction in toxicity. Furthermore, the biocomposites showed potential for re-utilization for more 29 days of treatment. | published
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