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991.
S.P. McGrath C. Micó J.L. Stroud S. Fozard 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3085-3094
Four plant species (oilseed rape, Brassica napus L.; red clover, Trifolium pratense L.; ryegrass, Lolium perenne L.; and tomato, Lycopersicon esculentum L.) were tested on ten soils varying widely in soil properties to assess molybdenum (Mo) toxicity. A larger range (66-fold-609-fold) of added Mo concentrations resulting in 50% inhibition of yield (ED50) was found among soils than among plant species (2-fold-38-fold), which illustrated that the soils differed widely in the expression of Mo toxicity. Toxicity thresholds based on soil solution Mo narrowed the variation among soils compared to thresholds based on added Mo concentrations. We conclude that plant bioavailability of Mo in soil depends on Mo solubility, but this alone did not decrease the variability in observed toxicity enough to be used in risk assessment and that other soil properties influencing Mo toxicity to plants need to be considered. 相似文献
992.
Syam S. Andra Konstantinos C. Makris Shahida Quazi Dibyendu Sarkar Rupali Datta Stephan B. H. Bach 《Environmental science and pollution research international》2010,17(5):1167-1173
Background, aim, and scope
Organoarsenical-containing animal feeds that promote growth and resistance to parasites are mostly excreted unchanged, ending up in nearby wastewater storage lagoons. Earlier work documented the partial transformation of organoarsenicals, such as, 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) to the more toxic inorganic arsenate [As(V)] and 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA). Unidentified roxarsone metabolites using liquid chromatography coupled to inductively coupled plasma mass spectrometry (LC/ICP-MS) were also inferred from the corresponding As mass balance. Earlier batch experiments in our laboratory suggested the presence of organometallic (Cu) complexes during relevant roxarsone degradation experiments. We hypothesized that organocopper compounds were complexed to roxarsone, mediating its degradation in field-collected swine wastewater samples from storage lagoons. The objective of this study was to investigate the role of organometallic (Cu) complexes during roxarsone degradation under aerobic conditions in swine wastewater suspensions, using electrospray ionization mass spectrometry (ES-MS). 相似文献993.
Jianling L. Xu Zhanhui H. Tang Jincheng C. Shang Yuanhui H. Zhao 《Environmental science and pollution research international》2010,17(5):1090-1097
Purpose
The environmental issues caused by the municipal solid waste disposal are becoming a worldwide concern.Methods
We studied the situations both domestically and abroad by the strategic environmental assessment (SEA) approach and also conducted comprehensive evaluations of garbage disposal in Changchun City.Results
On the basis of this study, we found that SEA is of great importance in the municipal solid waste disposal. Moreover, with the rapid socioeconomic development of Changchun City, municipal solid waste production increases on an annual basis, and thus, good waste management planning is of great significance.Conclusions
Considering the situation of the economic development of Changchun City, garbage disposal was handled mainly in the major sanitary landfills with appropriate use of incineration technology. This plan is environmentally friendly at a relatively high degree and has met the requirements of minimum investment. It also takes into account the requirements of the development of incineration technology. Regarding environmental pollution in terms of groundwater pollution and atmospheric pollution, this plan is a feasible one by meeting various requirements with low environmental impact among the three plans discussed in this study. 相似文献994.
Hauke Reuter Ulrike Middelhoff Frieder Graef Richard Verhoeven Thomas Batz Martin Weis Gunther Schmidt Winfried Schröder Broder Breckling 《Environmental science and pollution research international》2010,17(8):1479-1490
Background, aim and scope
European legislation stipulates that genetically modified organisms (GMO) have to be monitored to identify potential adverse environmental effects. A wealth of different types of monitoring data from various sources including existing environmental monitoring programmes is expected to accumulate. This requires an information system to efficiently structure, process and evaluate the monitoring data. 相似文献995.
In this study, we analyze the evolution of Canada's mining industry from 1929 to 2006, focussing on the determinants of the number of firms in the industry and why this number changed over that period. Most empirical studies of industry evolution have focused on manufacturing industries that share similar structural characteristics. Perhaps because of this, extant models of industry evolution tend to ignore industry-specific and national-specific factors that can cause atypical trajectories, that is, heterogeneous industry evolution. Initial inspection of the Canadian mining industry shows that it is atypical in that it exhibits “negative skew” over time in the number of firms rather than the typical “positive skew.” We review two dominant theoretical approaches to industry evolution: the density-dependence theory and variants of industrial organization economics. We also consider possible sources of industry evolution heterogeneity, focussing particularly on “regulatory punctuation”. Using Canadian mining data, we find that the traditional models do not fully explain the changes in population size in Canada's mining industry. As a result, we introduce a number of hybrid models. The results from these hybrid models suggest that Canadian-specific regulatory punctuations, particularly the introduction of significant new taxes, environmental legislation, and incentives have shaped the trajectory of mining firm participation. 相似文献
996.
In this second part of the work, two other long-term technologies for power generation from coal are investigated. The Zecomag plant has the same syngas production system of the Zecomix plant, described in the first part of this paper, but hydrogen-rich syngas is here burned with air in an open-cycle gas turbine. The aim is a simplification of the power island, more similar to a combined cycle; however, CO2 capture falls from 100% to about 90% and NOx emissions are present.An advanced oxy-fuel IGCC is the second plant investigated in this paper, presenting the same zero-emission potential of Zecomix. Syngas is produced in a high pressure, dry feed, oxygen blown gasifier and cleaned in a hot-gas-clean-up system. Clean syngas is then burned with oxygen and expanded in a turbine, using compressed recirculated CO2 to moderate firing temperature and to cool turbine blades.The loss of net efficiency, with respect to Zecomix, is very limited (1–2 points) with both configurations. In order to better evaluate the performances obtained, a comparison with reference state-of-the art IGCCs and a long-term IGCC without CO2 capture is also presented. 相似文献
997.
The In Salah Gas Joint Venture CO2 storage project has been in operation in Algeria since 2004 and is currently the world's largest onshore CO2 storage project. CO2 is injected into the saline aquifer of a gas reservoir several kilometres away from the gas producers. Current focus in the project is on implementing a comprehensive monitoring strategy and modelling the injection behaviour in order to ensure and verify safe long-term storage. A key part of this effort is the understanding of the processes involved in CO2 migration within relatively low-permeability sandstones and shales influenced by fractures and faults. We summarise our current understanding of the fault and fracture pattern at this site and show preliminary forecasts of the system performance using discrete fracture models and fluid flow simulations. Despite evidence of fractures at the reservoir/aquifer level, the thick mudstone caprock sequence is expected to provide an effective flow and mechanical seal for the storage system; however, quantification of the effects of fracture flow is essential to the site verification. 相似文献
998.
Rachana Bhatt K. C. Patel Ujjval Trivedi 《Journal of Polymers and the Environment》2010,18(2):141-147
An extracellular poly(3-hydroxybutyrate) (PHB) depolymerase produced by a thermotolerant fungal soil isolate, Aspergillus fumigatus 202, was purified and characterized. Maximum PHB depolymerase production was obtained at the end of 48 h with initial medium
pH 7.0 and 45 °C in Bushnell Haas Minerals medium containing PHB as sole source of carbon. The PHB depolymerase was purified
using size exclusion chromatography to a fold purification of 20.62 and 61.62% yield. SDS-PAGE and isoelectric focusing revealed
the molecular weight and pI of the purified enzyme as 63,744 Da and 4.2, respectively. N-terminal amino acid sequence of purified
enzyme was HAXDAYLVK. This non-glycosylated enzyme was most active at pH 9.0 and 45 °C. Purified enzyme was inactivated by
N-bromosuccinimide and dithiothreitol suggesting the involvement of tryptophan residues and disulfide bonds at its active
site. Nonionic detergents like Tween 20, Tween 80 and Triton X-100 inhibited the enzyme activity. Ions like Ca+2 and Mg+2 (5 mM) increased the enzyme activity 1.5 times. Fe+2 effectively inhibited the enzyme activity to 88% whereas Hg+2 completely inhibited the enzyme. 相似文献
999.
P. Noorunnisa Khanam H. P. S. Abdul Khalil M. Jawaid G. Ramachandra Reddy C. Surya Narayana S. Venkata Naidu 《Journal of Polymers and the Environment》2010,18(4):727-733
The variation of mechanical properties such as tensile and flexural properties of randomly oriented unsaturated polyester
based sisal/carbon fibre reinforced hybrid composites with different fibre weight ratios have been studied. The chemical resistance
test of these hybrid composites to various solvents, acids and alkalies were studied. The effect of NaOH treatment of sisal
fibres on the tensile, flexural and chemical resistance properties of these sisal/carbon hybrid composites has also been studied.
The hybrid composites showed an increase in tensile and flexural properties with increase in the carbon fibre loading. The
tensile properties and flexural properties of these hybrid composites have been found to be higher than that of the matrix.
Significant improvement in tensile properties and flexural properties of the sisal/carbon hybrid composites has been observed
by alkali treatment. The chemical resistance test results showed that these untreated and alkali treated hybrid composites
are résistance to all chemicals except carbon tetra chloride. Hand lay-up technique was used for making the composites and
tests are carried out by using ASTM methods. 相似文献
1000.
This paper investigates and compares the performances of polylactic acid (PLA)/kenaf (PLA-K) and PLA/rice husk (PLA-RH) composites
in terms of biodegradability, mechanical and thermal properties. Composites with natural fiber weight content of 20% with
fiber sizes of less than 100 μm were produced for testing and characterization. A twin-screw extrusion was used to compound
PLA and natural fibers, and extruded composites were injection molded to test samples. Flexural and Izod impact test, TGA,
soil burial test and SEM were used to investigate properties. All results were compared to a pure PLA matrix sample. The flexural
modulus of the PLA increased with the addition of natural fibers, while the flexural strength decreased. The highest impact
strength (34 J m−1), flexural modulus (4.5 GPa) and flexural strength (90 MPa) were obtained for the composite made of PLA/kenaf (PLA-K), which
means kenaf natural fibers are potential to be used as an alternative filler to enhance mechanical properties. On the other
hand PLA-RH composite exhibits lower mechanical properties. The impact strength of PLA has decreased when filled with natural
fibers; this decrease is more pronounced in the PLA-RH composite. In terms of thermal stability it has been found that the
addition of natural fibers decreased the thermal stability of virgin PLA and the decrement was more prominent in the PLA-RH
composite. Biodegradability of the composites slightly increased and reached 1.2 and 0.8% for PLA-K and PLA-RH respectively
for a period of 90 days. SEM micrographs showed poor interfacial between the polymer matrix and natural fibers. 相似文献