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251.
Environmental Chemistry Letters - Climate change is a major threat already causing system damage to urban and natural systems, and inducing global economic losses of over $500 billion. These issues...  相似文献   
252.
Environmental Chemistry Letters - Adopting waste-to-wealth strategies and circular economy models can help reduce biowaste and add value. For instance, poultry farming is an essential source of...  相似文献   
253.
The N simulation model, DRAINMOD-N II, was field-tested using a 6-yr data set from an artificially drained agricultural site located in eastern North Carolina. The test site is on a nearly flat sandy loam soil which is very poorly drained under natural conditions. Four experimental plots, planted to a corn (Zea mays)-wheat (Triticum aestivum L.)-soybean (Glycine max.) rotation and managed using conventional and controlled drainage, were used in model testing. Water table depth, subsurface drainage, and N concentration in drain flow were measured and meteorological data were recorded continuously. DRAINMOD-N II was calibrated using the data from one plot; data sets from the other three plots were used for model validation. Simulation results showed an excellent agreement between observed and predicted nitrate-nitrogen (NO(3)-N) losses in drainage water over the 6-yr period and a reasonable agreement on an annual basis. The agreement on a monthly basis was not as good. The Nash-Sutcliffe modeling efficiency (EF) for monthly predictions was 0.48 for the calibration plot and 0.19, 0.01, and -0.02 for the validation plots. The value of the EF for yearly predictions was 0.92 for the calibration plot and 0.73, 0.62, and -0.10 for the validation plots. Errors in predicting cumulative NO(3)-N losses over the 6-yr period were remarkably small; -1.3% for the calibration plot, -8.1%, -2.8%, and 4.0% for the validation plots. Results of this study showed the potential of DRAINMOD-N II for predicting N losses from drained agricultural lands. Further research is needed to test the model for different management practices and soil and climatological conditions.  相似文献   
254.

In this study, nano-sized cellulose modified with lactic acid (MW-Ce-LA) was prepared with the assistant of microwave then used for the adsorption of Cu2+ from real samples. This modified cellulose was characterized by means of FTIR, TEM, XRD, and elemental analysis. ICP-OES was used for determination of Cu2+. The effect of pH, adsorption times, temperature, sorbent dose, and initial adsorbate concentration were studied to detect the ideal adsorption condition. Langmuir model proved to be the best to fit the adsorption isotherm experiments with maximum adsorption capacity of 90.3 mg g?1 Cu2+. Calculated thermodynamic parameters (ΔG° and ΔH°) for adsorption of Cu2+ on MW-Ce-LA suggested exothermic and nonspontaneous character of the adsorption process. The reusability tests indicated regeneration of the prepared adsorbent simply using 1 mol L?1 of HCl. The examined method was used effectively to preconcentrate Cu2+ from water, blood, and food samples.

  相似文献   
255.
Environmental Science and Pollution Research - The purpose of this study was to investigate, for the first time, the effects of Bifenthrin (Bif) chronic exposure on plasmatic and aortic lipid...  相似文献   
256.
The kinetics of the reaction between carbon dioxide (CO2) and mixed solutions of methyldiethanolamine (MDEA) and piperazine (PZ) was investigated experimentally in a laminar jet apparatus. The experimental kinetic data were obtained under no interfacial turbulence and over a temperature range from 313 to 333 K, MDEA/PZ wt% concentration ratios of 27/3, 24/6 and 21/9, and CO2 loadings from 0.0095 to 0.33 mol CO2/mol amine. In addition, a new absorption-rate/kinetics model for the kinetics of the mixed of solvents was developed, which takes into account the coupling between chemical equilibrium, mass transfer, and all possible chemical reactions involved in the CO2 reaction with MDEA/PZ solvent. The partial differential equations of this model were solved by the finite element numerical method (FEM) based on COMSOL software. The obtained experimental kinetics data were used to obtain the kinetic parameters of CO2 absorption into MDEA/PZ solutions. The reaction-rate constant obtained for PZ blended with MDEA was kPZ = 2.572 × 1012 exp(?5211/T). The 2D model for the blended amines MDEA/PZ has revealed the concentration profiles of all the species in both the radial and axial directions of the laminar jet which has enabled a better understanding of the correct sequence in which the reaction steps involved in the reactive absorption of CO2 in aqueous mixed MDEA/PZ solution occur. It also revealed that PZ may be depleted by the time the solvent blend of MDEA/PZ with a loading greater than 0.015 mol/mol amine is exposed to CO2 from the top of the laminar jet absorber.  相似文献   
257.
258.
Climatic drivers of potential hazards in Mediterranean coasts   总被引:1,自引:1,他引:0  
This paper studies climatic drivers (air and water temperature, precipitation rates, river discharge, sea level and storm patterns) in four Mediterranean regions: the Catalan-Valencia Coast (Spain), the Oran (Algeria) and Gabès (Tunisia) Gulfs and the western Nile Delta (Egypt). The paper also considers the potential hazards that these drivers can induce. It first analyses climatic trends in the drivers, taking into account the available time series of recorded and simulated meteo-oceanographic data from different sources. Next, it presents the general framework to assess biogeophysical hazards (flooding, erosion, droughts and water quality), followed by a simple and yet robust evaluation of those hazards for the four studied coastal sites. Assuming climate change projections under different scenarios and considering the observed trends in drivers, the resulting erosion rates due to sea-level rise and wave storm effects have been estimated. The Nile and Ebro Deltas, together with the Oran Gulf, are more vulnerable than the Gulfs of Valencia and Gabès. Regarding water quality in terms of (a) precipitation and dissolved oxygen in the water column and (b) sea surface temperature, the results show that the most vulnerable zones for the projected conditions (a) are the Gulfs of Oran, Valencia and Gabès, while the Nile Delta is the region where the decrease in water quality will be less pronounced. For the projected conditions (b), the most vulnerable zone is the Ebro Delta, while the impact in the other three cases will be smaller and of comparable magnitude. Finally, the overall future impact of these hazards (associated to climatic change) in the four sites is discussed in comparative terms, deriving some conclusions.  相似文献   
259.
This paper proposes a hydrological modeling framework to define achievable performance standards (APSs) for pesticides that could be attained after implementation of recommended management actions, agricultural practices, and available technologies (i.e., beneficial management practices [BMPs]). An integrated hydrological modeling system, Gestion Intégrée des Bassins versants à l'aide d'un Système Informatisé, was used to quantify APSs for six Canadian watersheds for eight pesticides: atrazine, carbofuran, dicamba, glyphosate, MCPB, MCPA, metolachlor, and 2,4-D. Outputs from simulation runs to predict pesticide concentration under current conditions and in response to implementation of two types of beneficial management practices (reduced pesticide application rate and 1- to 10-m-wide edge-of-field and/or riparian buffer strips, implemented singly or in combination) showed that APS values for scenarios with BMPs were less than those for current conditions. Moreover, APS values at the outlet of watersheds were usually less than ecological thresholds of good condition, when available. Upstream river reaches were at greater risk of having concentrations above a given ecological thresholds because of limited stream flows and overland loads of pesticides. Our integrated approach of "hydrological modeling-APS estimation-ecotoxicological significance" provides the most effective interpretation possible, for management and education purposes, of the potential biological impact of predicted pesticide concentrations in rivers.  相似文献   
260.
The aim of this study was to develop an analytical method for the determination of residues of organophosphorus and carbamate pesticides which are widely used in Tunisia. This method involves a liquid-liquid extraction procedure followed by liquid chromatography tandem mass spectrometry (LC/MS/MS) for the identification and quantification of compounds. Ionization of molecules was performed by the electrospray mode. Multiple reactions monitoring (MRM) was the acquisition mode used for the monitoring of two MS/MS transitions for each compound. The average recoveries obtained, at three different fortification levels, ranged between 65% and 106% for most of the pesticides studied, except for methamidophos (lower than 25%).The linearity of the method was in the range of 5 to 50 μ g/L with a correlation coefficient from 0.995 to 0.999, depending on the analyte. The estimated limit of detection and limit of quantification were 2 μ g/L and 5 μ g/L, respectively. The precision of the analytical procedure was satisfactory and the coefficients of variation, evaluated at three concentration levels were lower than 15% for most pesticides studied. The application of the method was investigated in a population of agricultural workers chronically exposed to various pesticides some of which, such as carbofuran, carbendazim, methomyl and pirimicarb, were detected in some serum samples.  相似文献   
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