A holistic appraisal of the quality of groundwater from the Tuticorin District has been conducted using multivariate statistical and spatial analyses. The objectives of the study were to delineate the spatial and temporal variabilities in groundwater quality and to understand its suitability for human uses. A total of 100 groundwater samples were collected and analyzed for major cations and anions during pre-monsoon and post-monsoon. Water quality index rating was calculated to quantify overall water quality for human consumption. The PRM samples exhibit poor quality in greater percentage when compared with POM due to the dilution after rainfall. Correlation, factor analysis, and plot of the factor scores reflect the seawater intrusion and weathering process. The mineral stability diagrams indicated that the groundwater is in equilibrium with kaolinite and Ca-montmorillonite, whereas Gibbs plot showed that the chemical composition of groundwater in both districts is controlled by the natural weathering processes irrespective of seasons. The major water type identified in this study is the Ca2+–Mg2+–HCO3? type, which degrades into predominantly Na+–Cl?–SO42? more saline groundwater toward the coast. 相似文献
Labeo rohita fingerlings were exposed to zinc metal toxicity (5 and 10 ppm) for duration of 5 and 15 days. The histological changes were studied in brain and liver of the treated fish. The brain tissues showed enlarged pyramidal cells with extensive vacoulation while severe necrosis, haemorrhage and degeneration of hepatocytes were witnessed in the liver tissues. 相似文献
This paper reviews the progress in inherent safety. A summary of the historical developments up to the year 2000 is first presented which sets the stage for a review of the key developments during the first 11 years of the 21st century. A landscape of inherent safety is developed by mapping publications on two coordinates. The first coordinate, the risk coordinate, indicates if the focus of a paper relates to inherent hazard or to the likelihood of events. The second coordinate, the management coordinate, focuses on the ways and means to understand and assess inherent safety. Out of the 187 papers that have appeared over this 11-year period, 131 pertained to developments in inherently safer design; these have been organized on the proposed landscape. The rest introduce the basic concepts of inherent safety and address its incorporation into regulation, education and accident investigation. These along with the application of inherent safety in industry are also discussed. We conclude with a discussion on recent trends in industry and suggest directions for future research. 相似文献
Arylsulfatase activity and arylsulfatase-producing bacteria were estimated in sediment samples collected from 3 different biotopes: marine, estuarine, and mangrove. No direct relationship could be established between activity and the number of bacteria at any station. In general, clayey sediments always harboured more arylsulfatase producers than sandy sediments, irrespective of salinity variations. Of the 3 biotopes investigated, the mangrove area exhibited maximum activity. The enzyme showed two pH optima, one at 6.2, the other at 9.0. The optimum substrate concentration was 12x10-4M. Higher substrate concentrations tended to inhibit arylsulfatase activity. The recovery of added phenolphthalein was maximum only at pH 6.2; KCN, Na2So4, and KH2Po4 inhibited enzyme activity by 65.5, 46.8 and 37.5%, respectively. More than one type of arylsulfatase may be present in marine sediments; further studies on the role of arylsulfatases are required, since arylsulfatases have been reported to bear on the formation and hardening of exoskeletons in marine forms. 相似文献
A significant concern of our fuel-dependent era is the unceasing exhaustion of petroleum fuel supplies. In parallel to this, environmental issues such as the greenhouse effect, change in global climate, and increasing global temperature must be addressed on a priority basis. Biobutanol, which has fuel characteristics comparable to gasoline, has attracted global attention as a viable green fuel alternative among the many biofuel alternatives. Renewable biomass could be used for the sustainable production of biobutanol by the acetone-butanol-ethanol (ABE) pathway. Non-extinguishable resources, such as algal and lignocellulosic biomass, and starch are some of the most commonly used feedstock for fermentative production of biobutanol, and each has its particular set of advantages. Clostridium, a gram-positive endospore-forming bacterium that can produce a range of compounds, along with n-butanol is traditionally known for its biobutanol production capabilities. Clostridium fermentation produces biobased n-butanol through ABE fermentation. However, low butanol titer, a lack of suitable feedstock, and product inhibition are the primary difficulties in biobutanol synthesis. Critical issues that are essential for sustainable production of biobutanol include (i) developing high butanol titer producing strains utilizing genetic and metabolic engineering approaches, (ii) renewable biomass that could be used for biobutanol production at a larger scale, and (iii) addressing the limits of traditional batch fermentation by integrated bioprocessing technologies with effective product recovery procedures that have increased the efficiency of biobutanol synthesis. Our paper reviews the current progress in all three aspects of butanol production and presents recent data on current practices in fermentative biobutanol production technology.
The Coordinating Research Council held its 14th Vehicle Emissions Workshop in March 2004, where results of the most recent on-road vehicle emissions research were presented. We summarize ongoing work from researchers who are engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research. 相似文献
The Coordinating Research Council held its thirteenth Vehicle Emissions Workshop in April 2003, when results of the most recent on-road vehicle emissions research were presented. Ongoing work from researchers who are engaged in improving understanding of the contribution of mobile sources to ambient air quality and emission inventories is summarized here. Participants in the workshop discussed efforts to improve mobile source emission models, the role of on-board diagnostic systems in inspection and maintenance programs, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research. 相似文献
The present study investigates the thermally activated carbon derived from Nerium oleander flower which was used an adsorbent. Physicochemical properties of Nerium oleander flower carbon (NOFC) were characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared for the removal of DTB (Direct Turquoise Blue) and RR-HE7B (Reactive red–HE7B) dyes from aqueous solution. Adsorption studies were carried out with different pH, adsorbent dose, contact time, and initial concentration dye solution. Optimum conditions for maximum removal of DTB and RR-HE7B was achieved to be pH 2 for both dyes, adsorbent dose of 100 mg and equilibrium time of 35 and 60 min, respectively, for NOFC. The maximum adsorption capacity of NOFC was found to be 33.33 and 19.60 mg g?1, respectively, for the removal of dye solution. The mechanism of adsorption was studied by using different kinetic models and isotherms. The results clearly showed that the NOFC adsorption was fitted to pseudo–first-order for DTB and pseudo–second-order for RR-HE7B. Equilibrium data were well fitted with both isotherm models. According to the results, NOFC can effectively remove DTB and RR-HE7B from aqueous solutions. 相似文献
Environmental Science and Pollution Research - Soil contamination by heavy metals is one of the major abiotic stresses that cause retarded plant growth and low productivity. Among the heavy metals,... 相似文献
Environmental Science and Pollution Research - The optimal design and performance monitoring of wind farms depend on the precise assessment of spatial and temporal distribution of wind speed. The... 相似文献