Geochemical study of groundwater from a structurally deformed granitic terrain near Hyderabad (India) was carried out to understand
and evaluate the hydrogeochemical processes and quality of groundwater. Several trace elements (Fe, Mn, Be, Al, V, Cr, Co,
Ni, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, Pb, U) along with major ions and minor elements were precisely estimated in shallow and
drilled wells to know the suitability of water for drinking and irrigation purposes. Analytical data shows that pH and major
ion chemistry in dug wells and bore wells do not vary significantly, while some trace elements (Fe, Mn, Al, Be, Co, Pb, U
and Zn) vary in dug wells and bore wells, which can be attributed to differential mineral weathering and dissolution/precipitation
reactions along fractures/joints. Although the water is not potable, it was found to be suitable for irrigation with little
danger in the development of harmful level of exchangeable sodium. It is inferred that the chemical composition of the groundwater
in this region is likely to have its origin from silicate weathering reactions and dissolution/precipitation processes supported
by rainfall and groundwater flow. 相似文献
Since analysis of both soil and plants are useful to assess contamination of a geographic area, concentrations of five representative metals: copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), and iron (Fe) in soil and associated plants were measured by atomic absorption spectroscopy. Samples were collected from four different Egyptian regions (El-mehala El-kobra, Kafr El-Sheikh, Kafr El-zayat, and Al-fayoum) during spring and summer 2010. Concentrations of the selected metals in agricultural soils were significantly different among locations and seasons. Concentrations of Cd and Fe in soils at the four locations exceeded the maximum allowable concentrations for Cd (8 mg/kg, dry mass (dm)) and Fe (1000 mg/kg, dm). Accumulation was different for clover and cotton. Clover blossoms grown in soil from Kafr El-zayat contained the greatest concentrations of Cu, Zn, Pb, and Fe. Cotton flowers from El-mehala El-kobra accumulated the highest levels of Cd. Concentrations of Cd and Pb in both clover and cotton flowers from the four locations exceeded maximum allowable concentrations (3 mg/kg, dm) for both Cd and Pb. Using such agricultural soils for cultivation of edible crops for consumption may result in chronic hazards to human health. 相似文献
The study, which measured the concentrations of Hg, Pb, Cd, Zn and As in various fish tissues (muscle, gill and liver) of
10 fish species (Abramis brama danubii, Alburnus alburnus alburnus, Barbus meridionalis petenyi, Carassius auratius gibelio, Cyprinus carpio, Lepomis gibossus, Leuciscius cephalus cephalus, Perca fluviatilis fluviatilis, Rutilus rutilus, Scardinus erythrophtlalmus erythrophtlalmus) collected in the Šalek lakes, is the first survey regarding metal concentrations in fish species with samples originating
from Slovene lakes, while only a limited number of such studies have been carried out in southeastern Europe. Since these
lakes are situated in the close vicinity of the largest Slovene thermal power plant, the study provides an insight into the
potential impact of increased levels of metals in the environment as well as an estimate of the contamination of fish tissues
with metals. Furthermore, it was possible to compare the results obtained with those from other studies regarding metal levels
in freshwater fish species. The mean metal concentrations of different tissues irrespective of species varied in the following
ranges: Zn 4.31–199 mg/kg ww, Pb 0.01–0.48 mg/kg ww, As 0.02–0.44 mg/kg ww, Hg <0.01–0.31 mg/kg ww, Cd < 0.01–0.19 mg/kg ww.
In general, higher contents of Hg were found in muscles and livers than in gills and higher contents of As in gills and livers
than in muscles, respectively. The accumulation of Pb and Zn was most pronounced in gills. The result obtained regarding metal
concentrations in fish revealed that the ecosystems of the Šalek lakes are not polluted with Hg and Pb, slightly loaded with
As and Cd and moderately polluted with Zn. In addition, the potential human health risk due to fish consumption was assessed.
This showed that the estimated weekly intakes for all metals were far below provisional permissible tolerable weekly intakes
determined by WHO/FAO. The consumption of fish from the Šalek lakes, therefore, does not pose a risk to human health. 相似文献
Polyethylene laminated disposable paper cups are commonly used as a container for hot drinks, yet there is limited knowledge on the transfer of contaminants from the cup to the drink. Here we poured 95?C hot water in 14 cups, to simulate the preparation of hot beverage for daily use. We studied the water composition after 15 min by inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography. Results show the presence of metals such as vanadium, chromium, copper, cobalt and arsenic at concentration ranging from 0.04 to 1.80 µg/L. Nitrate, nitrite, chloride, bromate, fluoride and sulfate ions were also detected at concentration from 0.003 to 49.21 mg/L. All concentrations are below the WHO maximum permissible limits in drinking water. However, the levels of vanadium at 1.24 µg/L and fluoride ions at 1.03 mg/L are likely to induce a health risk by bioaccumulation after long-term water ingestion. Therefore paper cups composition should be modified to avoid the release of contaminants in hot drinks.
On the basis of Annals of Nature of the Prioksko-Terrasnyi Biosphere Reserve, its colonization by invasive mammal species and the current state of their populations have been analyzed. In the mammal fauna of the reserve, 13 out of 60 species can be classified as invasive. They differ in the degree of impact on the biota. The house mouse, Norway and black rats, and European bison have virtually no effect on natural ecosystems; the effect of the muskrat, raccoon dog, American mink, red and axis deer is insignificant; and that of stray dogs and Tartarian roe deer is considerable. The European beaver and wild boar play an environment-forming role. The impact of beaver activities is strong but local, whereas activities of wild boars put into question the very possibility of conservation and analysis of representative biosphere areas and biological diversity in the reserve. 相似文献
Journal of Polymers and the Environment - Modification of cellulose with silver nanoparticles produces various nanocomposites with significantly developed properties. This work aims to prepare a... 相似文献
The photo-Fenton reaction effect on the biodegradability improvement of 100 mg/L solution of 2,4-dichlorophenol (DCP) has been investigated. Biochemical oxygen demand (BOD) at 5 and 21 days, BODn/ chemical oxygen demand (COD) and BODn/total organic carbon (TOC) ratios, average oxidation state, and inhibition on activated sludge were monitored. For 50 mg/L hydrogen peroxide and 10 mg/L iron(II) initial concentrations and 40 minutes of reaction time in the photo-Fenton process, the biodegradability of the pretreated solution, measured as BOD5/COD ratio, was improved from 0 for the original DCP solution up to 0.18 (BOD21/COD = 0.24). At that point, all DCP was eliminated from the solution. To study the effect of the pretreatment step, the biological oxidation of pretreated solutions was tested in two semicontinuous stirred tank reactors, one operated with activated sludge and one with biomass acclimated to phenol. Results showed that more than 80% TOC removal could be obtained by codigestion of the pretreated solution with municipal wastewater. Total organic carbon removals of approximately 60% were also obtained when the sole carbon source for the aerobic reactors was the pretreated solution. The hydraulic retention times used in the bioreactors were of the same order of magnitude as those used at domestic wastewater treatment plants (i.e., between 12 and 24 hours). Kinetic studies based on pseudo-first-order kinetics have also been carried out. Constants were found to be in range 0.67 to 1.7 L x g total volatiles suspended solids(-1) x h(-1). 相似文献
Surface sediment samples were collected from five stations along the Jordanian coast of the Gulf of Aqaba, Red Sea, during October and November over 2 years, 2000 and 2001. The monthly sedimentation rate also was estimated for the same stations. Collected sediments were analyzed for color, odor, redox potential, grain size, organic carbon, organic nitrogen, calcium carbonate, and total phosphorus. The Hotels area at the northernmost tip of the Gulf of Aqaba, characterized by sandy beaches and sea grass bottom habitat, exhibited the lowest values for redox potential and was associated with a black color. The Phosphate Port area exhibited the highest sedimentation rate, finest grain size, highest organic carbon content, and highest total phosphorus concentration. This is a deposition habitat that receives phosphate particles lost during shipment. The Marine Science Station and the Tourist Camp, typical coral reef habitats, had the highest calcium carbonate and organic nitrogen concentrations. This is directly attributed to the nature of the bottom habitat. Calcium carbonate deposits result from the erosion of hard corals, and organic nitrogen accumulates due to the rapid consumption and recycling of plankton in the coral reef framework. Comparison of the current records with old records from the 1970s and early 1980s indicates significant improvement in the environmental quality at the Phosphate Port. Tracking the coastal management practices over time shows that these improvements in the environmental quality can be attributed both to the zero discharge policy Jordan has followed since 1986 and to improvements in the phosphate handling system by the Ports Corporation. 相似文献
In this article, energy and exergy analyses are conducted for two integrated systems which can be used in HVAC applications. These two systems are analyzed for the cases of single generation, cogeneration and trigeneration, and their performances are evaluated through energy and exergy efficiencies. The parametric studies are performed to investigate the effects of using cogeneration and extended to trigeneration on the system performance. To perform the comparisons between the systems for multiple options, the same amounts of outputs (in terms of electricity, heating, cooling) are produced for all systems. The energy analyses of systems 1 and 2 show a great benefit for moving from single generation to trigeneration, with the trigeneration efficiencies of 83.5% and 87.2%, respectively, and single generation efficiencies of 47% for both systems. However, the exergy analyses show that trigeneration may not always become more efficient than single generation, particularly for system 1, due to the fact that the trigeneration exergy efficiency is 38.7% and the corresponding single generation efficiency is 44.3%. For system 2, the trigeneration exergy efficiency is 52.7% while the single generation efficiency becomes 44.3%. Depending on the type of cogeneration or cogeneration design, the system can be more efficient. 相似文献