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381.
The present work undertaken in the environmental context aims to study the distribution of heavy metals in plants that grow naturally around uncontrolled landfills. The study's goal was to identify plants that can be used to remediate contaminated soils. For this purpose, 14 plants species and their rhizospheric soil samples were collected and analyzed for arsenic, cadmium, cobalt, chromium, copper, lead, nickel, and zinc by inductively coupled plasma‐atomic emission spectrometry. The results showed the presence of elevated metal concentrations in soil, many exceeding the regulatory values, and that many species exhibited an ability to accumulate multiple metals in their shoots and roots without sustaining toxicity. This was confirmed by bioconcentration and translocation factors generally higher than 1.  相似文献   
382.
The objective of this study was to investigate the properties of poly(vinyl alcohol)/chitosan nanocomposite films reinforced with different concentration of amorphous LCNFs. The properties analyzed were morphological, physical, chemical, thermal, biological, and mechanical characteristics. Oil palm empty fruit bunch LCNFs obtained from multi-mechanical stages were more dominated by amorphous region than crystalline part. Varied film thickness, swelling degree, and transparency of PVA/chitosan nanocomposite films reinforced with amorphous part were produced. Aggregated LCNFs, which reinforced PVA/chitosan polymer blends, resulted in irregular, rough, and uneven external surfaces as well as protrusions. Based on XRD analysis, there were two or three imperative peaks that indicated the presence of crystalline states. The increase in LCNFs concentration above 0.5% to PVA/chitosan polymer blends led to the decrease in crystallinity index of the films. A noticeable alteration of FTIR spectra, which included wavenumber and intensity, was obviously observed along with the inclusion of amorphous LCNFs. That indicated that a good miscibility between amorphous LCNFs and PVA/chitosan polymer blend generated chemical interaction of those polymers during physical blending. Reinforcement of PVA/chitosan polymer blends with amorphous LCNFs influenced the changes of Tg (glass transition temperature), Tm (melting point temperature), and Tmax (maximum degradation temperature). Three thermal phases of PVA/chitosan/LCNFs nanocomposite films were also observed, including absorbed moisture evaporation, PVA and chitosan polymer backbone structural degradation and LCNFs pyrolysis, and by-products degradation of these polymers. The addition of LCNFs 0.5% had the highest tensile strength and the addition of LCNFs above 0.5% decreased the strength. The incorporation of OPEFB LCNFs did not show anti-microbial and anti-fungal properties of the films. The addition of amorphous LCNFs 0.5% into PVA/chitosan polymer blends resulted in regular and smooth external surfaces, enhanced tensile strength, increased crystallinity index, and enhanced thermal stability of the films.  相似文献   
383.
Chitosan, its nanoparticles and whiskers present an excellent capacity to complex chromium ions. However, this phenomenon is influenced by different parameters. In our search, we determined the appropriate range of pH to form chitosan–Cr(III), nanoparticles Cr(III) and whiskers–Cr(III) complex. We studied also the influence of chromium concentration and nature of chitosan-based materials on complexation process. Our main aim is approximate the optimal conditions to remove chromium(III) from tanning bath, recuperated from tannery wastewater of Marrakech in Morocco. However, the results of adsorption kinetic in tannery wastewater revealed that chitosan, its nanoparticles, whiskers and biocomposites are good sorbent of chromium as well, even if the adsorbed quantity is less compared to chromium solution. Although, according to ICP-OES analysis in this real effluent, nanoparticles are the best complexing ligand, after 24 h of contact nanoparticles can remove 70% of chromium from this tannery wastewater.  相似文献   
384.
The industrial production of wet phosphoric acid in Morocco led to controversial stockpiling of waste phosphogypsum by-products resulting in the release of significant amounts of toxic impurities in salt marshes. In the framework of fighting against global climate change and efforts to reduce toxic industrial wastes (phosphate industry), this work presents a new polymer composite based on phosphogypsum (PhG) and polypropylene (PP).The compounds were produced by twin-screw extrusion and injection molding. The morphological results show that good affinity between PhG and PP led to good particle dispersion/distribution in the polymer matrix. Thermal characterizations showed that PhG particles improved the thermal stability of PP with a 50 °C increase at 40 wt%. The optimum tensile modulus was also obtained at 40 wt% with a 74 % increase over neat PP. Dynamical mechanical analysis showed that PhG addition can improve the viscoelastic properties of PP for potential applications under dynamic stress. Overall, it can be concluded that PhG is potential reinforcing filler for the production of PP composites and represents a promising avenue for the valorization of this waste as a new raw material while resolving some environmental issues.  相似文献   
385.
The recent development of infrastructure all around the world has resulted in an increasing trend of online examination in universities. The paper is an approach in theory and practical aimed at analyzing the feasibility of sustainable examination in four universities and its environmental impact reducing the paper use terming it as green examination. The paper studied the integration of sustainability through the use of computers and technology in the examination of the universities viz. King Khalid University (KKU), Saudi Arabia, Integral University (IU), India, Aligarh Muslim University (AMU), India, and The Hague University (HU), The Netherlands. The study has analyzed the trend of paper requirement, paper utilized and paper wasted in all the four universities. The environmental impact resulting from reduced paper use has been also analyzed. The feasibility of e-examination, its implementation and the implications has been undertaken in the study. The study concludes that the e-examination can almost make the examinations paperless and feasible in the four universities.  相似文献   
386.
The purpose of this study was to determine concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in Nile tilapia (Oreochromis niloticus) and Bouri fish (Mugil cephalus) from Lake Qarun, a protected area of Egypt, and evaluate the relative ecological risk of these compounds. Different tissues of the fish species were analyzed for 26 chlorinated pesticides and 29 PCB congeners. Total concentrations (µg/kg wet weight, ww) of OCPs ranged between 1487 and 6217 (mean: 3260) and of PCBs between 9.0 and 61 (mean: 34). The trend of detected organochlorine pollutants was: endrin aldehyde > dieldrin > hexachlorobenzene > PCBs > endrin > 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethanes (DDTs). Heptachlor epoxide; oxy-, cis-, and trans-chlordane; trans-nonachlor; β-hexachlorocyclohexane; δ-hexachlorocyclohexane; and endosulfan I and endosulfan sulfate levels were below the detection limit. The ratios of (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylenes [DDEs] + 1,1-dichloro-2,2-bis(p-chlorophenyl)ethanes [DDDs])/ΣDDTs in fish tissues indicated no recent DDT exposure. Concentrations of DDTs and PCBs were generally comparable or higher than those found in studies of similar species worldwide. The concentrations of hexachlorobenzene, dieldrin, and endrin aldehyde in fish muscles exceeded the maximum residue level recommended by various organizations.  相似文献   
387.
The effects of sub-lethal concentrations of bisphenol A on some biochemical parameters in Biomphalaria alexandrina snail's hemolymph and tissues as well as on histological changes of the hermaphrodite gland were evaluated. Adult snails were exposed to sub-lethal concentrations for four weeks and samples of snails were investigated after two and four weeks. Total protein and albumin levels in hemolymph, as well as lipid peroxidation and glutathione contents of snails’ tissues, were measured. After two weeks of exposure, total protein content and albumin levels decreased in all groups. Elevation of lipid peroxidation levels was correlated with decreasing glutathione content in the treated snails. Histological examination of the hermaphrodite gland revealed deformations in eggs and affected sperm production.  相似文献   
388.
Geostatistical variogram and inversion techniques combined with modern visualization tools have made it possible to re-model one-dimensional electrical resistivity data into two-dimensional (2D) models of the near subsurface. The resultant models are capable of extending the original interpretation of the data to depict alluvium layers as individual lithological units within the 2D space. By tuning the variogram parameters used in this approach, it is then possible to visualize individual lithofacies and geomorphological features for these lithologic units. The study re-examines an electrical resistivity dataset collected as part of a groundwater study in an area of the Bannu basin in Pakistan. Additional lithological logs from boreholes throughout the area have been combined with the existing resistivity data for calibration. Tectonic activity during the Himalayan orogeny uplifted and generated significant faulting in the rocks resulting in the formation of a depression which subsequently has been filled with clay-silt and dirty sand facies typical of lacustrine and flood plain environments. Streams arising from adjacent mountains have reworked these facies which have been eroded and replaced by gravel-sand facies along channels. It is concluded that the sediments have been deposited as prograding fan shaped bodies, flood plain, and lacustrine deposits. Clay-silt facies mark the locations of paleo depressions or lake environments, which have changed position over time due to local tectonic activity and sedimentation. The Lakki plain alluvial system has thus formed as a result of local tectonic activity with fluvial erosion and deposition characterized by coarse sediments with high electrical resistivities near the mountain ranges and fine sediments with medium to low electrical resistivities towards the basin center.  相似文献   
389.
Produced water is water trapped in underground formations that is brought to the surface along with oil or gas production. Oilfield impacted soil is the most common environmental problem associated with oil production. The produced water associated with oil-production contaminates the soil and causes the outright death of plants, and the subsequent erosion of topsoil. Also, impacted soil serves to contaminate surface waters and shallow aquifers. This paper is intended to provide an approach for full characterization of contaminated soil by produced water, by means of analysis of both the produced water and the impacted soil using several recommended analytical techniques and then identify and assay the main constituents that cause contamination of the soil. Gialo-59 oilfield (29N, 21E), Libya, has been chosen as the case study of this work. The field has a long history of petroleum production since 1959, where about 300,000 bbl of produced water be discharged into open pit. Test samples of contaminated soil were collected from one of the disposal pits. Samples of produced water were collected from different points throughout the oil production process, and the analyses were carried out at the labs of Libyan Petroleum Institute, Tripoli, Libya. The results are compared with the local environmental limiting constituents in order to prepare for a plan of soil remediation. The results showed that the main constituents (pollutants) that impact the soil are salts and hydrocarbon compounds. Accordingly; an action of soil remediation has been proposed to remove the salts and degradation of hydrocarbons.  相似文献   
390.
This paper deals with the characteristics and composition of municipal solid waste (MSW) generated in Sangamner city. The composition of solid waste was studied by segregating it into different component, i.e., kitchen waste, paper, earth and fine material, slaughter house waste, leaves, metals, etc. These components were categorised into organic waste and inorganic waste. It was observed that Sangamner city produces around 61% organic waste, and the rest is inorganic waste. The characteristics of organic solid waste, i.e., pH, electrical conductivity, moisture content, organic carbon, nitrogen, phosphorus and potassium were evaluated. The analysis of organic content of MSW indicates that it is good source of nutrients for the agriculture sector whereas inorganic material can be used for landfill.  相似文献   
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