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421.
Gianotti V  Gosetti F  Polati S  Gennaro MC 《Chemosphere》2007,67(10):1993-1999
HPLC-DAD, HPLC-MS/MS, GC-MS and spectrophotometric methods are employed to investigate the degradation process of sodium 1-amino-5-naphthalene sulfonate (1A5NS) aqueous solutions, when exposed to sunlight and UV-lamp (254 nm) irradiations. Experimental results show that both sunlight and 254 nm UV-lamp irradiations destroy the chemical and give rise to major degradation products, characterised by the same m/z ratios. Degradation times are lower for sunlight irradiation, for which a t(1/2) value of 137.4 min has been evaluated, in comparison with the value of t(1/2) of 26.8 min, observed for UV-lamp irradiation. The degradation pathway and the structures of the degradation products are proposed.  相似文献   
422.
Lobes of the lichen Pseudevernia furfuracea (L.) Zopf and shoots of the moss Hypnum cupressiforme Hedw. were subjected to different treatments (water washing, oven drying, HNO3 washing, NH4-oxalate extraction) to assess the influence of vitality on accumulation efficiency, during a 6-week exposure in bags in two Italian cities, Trieste and Naples. No trend emerged between treatments, in terms of accumulation ability, for major and trace elements. Only water-washed lichens showed an increased C and N content after exposure in both cities. Element concentrations generally reached higher values in mosses than in lichens, especially for Al, Fe, and Zn (both cities), and for Cu, Mg and Na (Naples). Surface development strongly influenced accumulation capacity of the biomonitors. Quartzose and cation exchange filters revealed, on a weight basis, a poor performance. In urban environments, surface interception of atmospheric particulate seems to play a major role in accumulation, irrespective of organism vitality.  相似文献   
423.
Recent advances in both information and sensor technologies have enabled the development of Real Time Remote Monitoring (RTRM) capabilities for environmental management. An online and real time remote monitoring system for air pollution has been designed and installed at a traffic police station at Punjagutta in Hyderabad, India. The system is optimized using electrochemical sensors and a real time particulate matter analyzer. The system also monitors meteorological parameters such as temperature, humidity, rainfall, barometric pressure, wind speed and wind direction. The system periodically monitors both pollution and meteorological parameters at pre- programmed intervals of hr during peak periods and 1 hr during non peak periods of the day and continuously uploads to a predestinated web site (www.appcb.org/home.htm) using File Transfer Protocol. The web site renders a quick, simple and graphical display of air pollution levels and meteorological parameters and their significance to humans. The present paper highlights design considerations of a pollution monitoring system, system hardware and software requirements and practical limitations and future directions for real time remote monitoring of air pollution.  相似文献   
424.
During the second half of the 20th century, the Ganga River ecosystem has been continuously altered by several ongoing anthropogenic processes, accommodating multi-dimensional pressure due to increase of nearly four-fold human population. For solution of any environmental issues of the river, the Earth System Science approach is required to have maximum socio-economic benefits to millions of people living in Indian and Bangladesh. A bibliography containing more than 250 references on environmental studies of the Ganga River was prepared to preserve its ecosystem by providing the baseline support in this regard.  相似文献   
425.
Numerical models are often used to evaluate the potential impact of human alternation of natural water bodies and to help the design of the alternation to mitigate its impacts. In the past decade, three-dimensional hydrodynamic and reactive transport modeling has matured from a research subject to a practical analysis technology. This paper presents a practical study in which a three-dimensional hydrodynamic and water quality model [hydrodynamic eutrophication model (HEM-3D)] was applied to determine the optimal location for treated wastewater discharged from marine outfall system in the Keelung harbor and the adjacent coastal sea. First, model validation was conducted with respect to surface elevation, current, and water quality variables measured in the Keelung harbor station and its coastal sea. The overall performance of the model was in qualitative agreement with the available field data. The model was then used to evaluate several scenarios of the locations from marine outfall system. Based on model simulation results, a location at the northeast of Ho-Ping Island was recommended for adoption because the environmental impact is smaller than any other alternative.
Wen-Cheng LiuEmail:
  相似文献   
426.
Leachate recirculation or liquid injection in municipal solid waste landfills offers economic and environmental benefits. The key objective of this study was to carry out numerical evaluation of key design variables for leachate recirculation system consisting of vertical wells. In order to achieve the objective, numerical modeling was carried out using the finite-element model HYDRUS-2D. The following design parameters were evaluated by simulating liquid pressure head on the liner and the wetted width of the waste under steady-state flow conditions: (1) hydraulic conductivities of the waste and vertical well backfill; (2) liquid injection rate and dosing frequency; (3) well diameter, screen height and screen depth; and (4) hydraulic conductivity of the leachate collection system, slope of the leachate collection system and spacing of the leachate collection pipes. The key findings of this study are as follows. The well diameter, hydraulic conductivity of the well drainage pack, and screen height and screen depth of the well have very little effect on the wetted width for a given liquid flux. The wetted width and the injection pressure for a given liquid flux decrease with the increase in the hydraulic conductivity of the waste. The pressure head on the liner increases with the decrease in the vertical distance between the bottom of the well screen and the top of leachate collection system. The liquid injection flux increases with the decrease in hydraulic conductivity of the leachate collection system. Unlike sand (k approximately 10(-4)m/s), pea gravel (k approximately 0.01 m/s) resulted in less than 0.3m pressure head on the liner for all simulations carried out in this study.  相似文献   
427.
The purpose of this study is to determine the impact of leachate recirculation on the degradation of municipal solid wastes (bioreactor concept). The study was carried out using columns containing approximately 50 kg of waste, in order to follow waste degradation over a limited time. Three types of waste were studied: fresh waste of standard composition, fresh waste of fermentable composition and some 8-yr-old waste extracted from a site in France. Measurement of the global parameters, such as chemical oxygen demand (COD), volatile acidity, alkalinity, leachate conductivity, methane potential of the wastes and biogas production monitoring (volume of CO2 and CH4 produced), were carried out. The quantity of oxydizable matter and biogas production was increased by the leachate recirculation, and the duration of the first degradation phases was reduced in all cases. Chloride, ammonium and organic pollution accumulation was observed according to the duration of recirculation. After 400 days of degradation, waste stabilization seemed to be reached for all of the recirculated columns (COD<300 mg/L O2, and methane potential reached).  相似文献   
428.
Background, Aim and Scope Numerous herbicides and xenobiotic organic pollutants are detoxified in plants to glutathione conjugates. Following this enzyme catalyzed reaction, xenobiotic GS-conjugates are thought to be compartmentalized in the vacuole of plant cells. In the present study, evidence is presented for long range transport of these conjugates in plants, rather than storage in the vacuole. To our knowledge this is the first report about the unidirectional long range transport of xenobiotic conjugates in plants and the exudation of a glutathione conjugate from the root tips. This could mean that plants possess an excretion system for unwanted compounds which give them similar advantages as animals. Materials and Methods: Barley plants (Hordeum vulgare L. cv. Cherie) were grown in Petri dishes soaked with tap water in the greenhouse. - Fluorescence Microscopy. Monobromo- and Monochlorobimane, two model xenobiotics that are conjugated rapidly in plant cells with glutathione, hereby forming fluorescent metabolites, were used as markers for our experiments. Their transport in the root could be followed sensitively with very good temporal and spatial resolution. Roots of barley seedlings were cut under water and the end at which xenobiotics were applied was fixed in an aperture with a thin latex foil and transferred into a drop of water on a cover slide. The cover slide was fixed in a measuring chamber on the stage of an inverse fluorescence microscope (Zeiss Axiovert 100). - Spectrometric enzyme assay. Glutathione S-transferase (GST) activity was determined in the protein extracts following established methods. Aliquots of the enzyme extract were incubated with 1-chloro-2,4-dinitrobenzene (CDNB), or monochlorobimane. Controls lacking enzyme or GSH were measured. - Pitman chamber experiments. Ten days old barley plants or detached roots were inserted into special incubation chambers, either complete with tips or decapitated, as well as 10 days old barley plants without root tips. Compartment A was filled with a transport medium and GSH conjugate or L-cysteine conjugate. Compartments B and C contained sugar free media. Samples were taken from the root tip containing compartment C and the amount of conjugate transported was determined spectro-photometrically. Results: The transport in roots is unidirectional towards the root tips and leads to exsudation of the conjugates at rates between 20 and 200 nmol min-1. The microscopic studies have been complemented by transport studies in small root chambers and spectroscopic quantification of dinitrobenzene-conjugates. The latter experiments confirm the microscopic studies. Furthermore it was shown that glutathione conjugates are transported at higher rates than cysteine conjugates, despite of their higher molecular weights. This observation points to the existence of glutathione specific carriers and a specific role of glutathione in the root. Discussion: It can be assumed that long distance transport of glutathione conjugates within the plant proceeds like GSH or amino acid transport in both, phloem and xylem. The high velocity of this translocation of the GS-X is indicative of an active transport. For free glutathione, a rapid transport-system is essential because an accumulation of GSH in the root tip inhibits further uptake of sulfur. Taking into account that all described MRP transporters and also the GSH plasmalemma ATPases have side activities for glutathione derivatives and conjugates, co-transport of these xenobiotic metabolites seems credible. - On the other hand, when GS-B was applied to the root tips from the outside, no significant uptake was observed. Thus it can be concluded that only those conjugates can be transported in the xylem which are formed inside the root apex. Having left the root once, there seems to be no return into the root vessels, probably because of a lack of inward directed transporters. Conclusions: Plants seem to possess the capability to store glutathione conjugates in the vacuole, but under certain conditions, these metabolites might also undergo long range transport, predominantly into the plant root. The transport seems dependent on specific carriers and is unidirectional, this means that xenobiotic conjugates from the rhizosphere are not taken up again. The exudation of xenobiotic metabolites offers an opportunity to avoid the accumulation of such compounds in the plant. Recommendations and Perspectives: The role of glutathione and glutathione related metabolites in the rhizosphere has not been studied in any detail, and only scattered data are available on interactions between the plant root and rhizosphere bacteria that encounter such conjugates. The final fate of these compounds in the root zone has also not been addressed so far. It will be interesting to study effects of the exuded metabolites on the biology of rhizosphere bacteria and fungi.  相似文献   
429.
Goal, Scope and Background One of the advantages of long-term mesocosm experiments as compared to short-term standard toxicity tests in the laboratory is the potential for detecting secondary effects due to the interaction of species and recovery with biomass of macrophytes being an important endpoint. However, generating biomass data by harvesting is often laborious, time-consuming, costly and restricted to the end of the experiment. Moreover, valuable information may get lost, in particular in single application studies, since maximal primary effects and secondary effects or recovery occur per se at different times. Potamogeton natans was used as an example in order to test whether number and area of floating leaves can be reliably measured and be used as intermediate and final endpoints in mesocosm effect studies. Methods Digital photos, which were taken of the water surface in the course of an indoor pond mesocosm study on herbicide effects, were subjected to image analysis. The results were compared to wet weight and ash-free dry weight of Potamogeton at the end of the herbicide study. Results and Discussion Both number and area of floating leaves indicated the same herbicide effects as wet weight and ash-free dry weight of Potamogeton. Error introduced by the different work steps is small and can be further minimised by a number of method improvements. Recommendations and Perspectives In indoor mesocosm studies, errors due to the perspective adjustment may be circumvented by taking the photos perpendicular to the water surface. Correction for lens aberration, identical light conditions and the use of fluorescence images are considered promising. Field applications are proposed.  相似文献   
430.
Bioremediation process on Brazil shoreline   总被引:1,自引:0,他引:1  
GOAL, SCOPE AND BACKGROUND: Bioremediation technique can be considered a promising alternative to clean oil spills using microbial processes to reduce the concentration and/or the toxicity of pollutants. To understand the importance of this work we must know that there is only little research performed to date using bioremediation techniques to clean oil spills in tropical countries. So, the main objective of this work is to analyze the behavior of a laboratory's bioremediation test using nutrients on coastal sediments. METHODS: The bioremediation process is followed through geochemical analysis during the tests. This organic material is analyzed by medium pressure liquid chromatography (MPLC), gas chromatography/flame ionization detection (GC/FID) and gas chromatography/ mass spectrometry. By microbial counting, the number of total bacteria and degrading bacteria is determined during the experiments, in order to confirm the effectiveness of the bioremediation process. The seawater obtained throughout the bioremediation process is analyzed for nutrients grade (phosphate and ammonium ions) and also for its toxicity (Microtox tests) due the presence of hydrocarbons and fertilizer. RESULTS: The results from the geochemical analyses of the oil show a relative decrease in the saturated hydrocarbon fraction that is compensated by a relative enrichment on polar compounds. It's confirmed by the fingerprint evaluation where it is possible to see a complete reduction of the normal alkanes followed by isoprenoids. Seawater analysis done by toxicity and nutrients analysis, such as microbial counting (total and degrading bacteria), confirm the fertilizer effectiveness during the bioremediation process. DISCUSSION: Results from simulating test using NPK, a low-price plant fertilizer, suggest that it's able to stimulate the degradation process. Results from medium pressure liquid chromatography (MPLC), done at two different depths (surface and subsurface), show different behavior during the biodegradation process where the later is seen to be more susceptible to microbial attack. Data from bioremediation unit shows a bigger reduction of the saturated fraction, followed by some smaller reduction of aromatic fractions, compensated by a relative increase from polar compounds (NSO). n-C17/pristane, n-C18/ fitane and pristane/fitane rates show constant values for the unity control, different from bioremediation samples which have a significant reduction, especially on subsurface areas, where a strong fall in the rates, seen to be reduced to zero over twenty days, had occurred during the first ten days. However, sample surfaces are reduced to zero in thirty days of experiments, proving that biodegradation is better on subsurfaces. Gaseous chromatography/mass spectrometry (CG/MS) analysis shows constant values to cyclic biomarker rates and aromatic compounds, suggesting that the biodegradation process is not strong enough to reduce these composites. Microbial analysis shows a reduction on heterotrophic (total bacteria) number from control unit, probably because the bacteria uses the spill oil like carbon source and energy. However, the number increases on bioremediation unit, because it uses NPK like a biostimulator. The hydrocarbonoclastic number isn't enough on the first moment, but it's detected after 30 days and quantified in all units, showing big values especially in bioremediation. Toxicity tests confirm that NPK fertilizer does not intoxicate the shoreline during the application of the bioremediation technique. Some nutrient concentration shows high values of ammonium and phosphate per bioremediation unit, reducing by the end of the experiment. CONCLUSIONS: Results reached the goal, finding a proper nutrient (NPK fertilizer) to stimulate the biodegradation process, growing bacteria responsible for reducing impact-contaminated coast ambient by oil spills. Chemical analysis of oil shows a reduction in the saturated fraction with a relative enrichment in polar composites (NSO) and the aromatic fraction from oil remaining constant. Subsurface samples show more biodegradation than surface samples, probably because the first one has higher humidity. Linear alcanes are more biodegraded than isoprenoids, confirming the biodegradation susceptibility order. Saturated cyclic biomarkers and aromatic compounds show constant behavior maybe because the nutrients or time was not enough for microorganismic attack. Fertilizer does not demonstrate any toxic effects in local biota so that it does not compromise the technique applicability and the environment is not saturated by nutrients during the simulation, especially since the coastal environment is an open system affected daily by tides. Therefore, bioremediation tests can be classified as moderate, reaching level 5 in the classification scale by Peters & Moldowan (1993). RECOMMENDATIONS AND PERSPECTIVES: The use of marine environment by the petroleum industry on exploration, production and transportation operation, transform this oil to become the most important pollutant in the oceans. Bioremediation is an important technique used to clean spilled oil impacting on shorelines, accelerating the biodegradation process by using fertilizer growing the microorganisms responsible for decontaminating the environment. We recommend confirming the efficiency of NPK nutrient used on bioremediation simulating experiments on beaches, while monitoring the chemical changes long-term. NPK fertilizer can be used to stimulate the biodegradation process on shoreline impacted by spilled oil.  相似文献   
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