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1.
The strong adaptability of Broussonetia papyrifera (L.) Vent. to low phosphorus (P) conditions can be attributed to the large amount of root-exuded organic acids and the high efficiency of P extraction. However, microelement contents are influenced by low-P stress, and their effects on the photosynthetic capability of B. papyrifera remain unknown. In this study, we investigated the effects of low-P treatment on net photosynthetic rate (P N); chlorophyll a fluorescence (ChlF) characteristics; and Fe, Mn, Cu, and Zn contents of B. papyrifera and Morus alba L. seedlings. Results show that B. papyrifera exhibited better photosynthetic capability under moderate P deficiency (0.125, 0.063, and 0.031 mmol/L P treatments), whereas the photosynthetic capability of M. alba decreased under moderate and severe P deficiency (0.016 and 0 mmol/L P treatments). Under moderate P deficiency, the decrease in Cu and Zn contents in B. papyrifera was lower than that in M. alba. Under severe P deficiency, a considerable decrease of photosynthetic capability in B. papyrifera and M. alba was associated with low Cu and Zn contents. The P N of the two Moraceae species exhibited a better correlation with Cu and Zn contents than with Fe or Mn content. P deficiency could not only decrease cyclic photophorylation and photosynthetic efficiency, but could also affect the stability of thylakoid membrane structure and electron transport efficiency by influencing the contents of Cu or Zn, thereby affecting photosynthesis.  相似文献   

2.
The West Development Program, initiated in 2000 by the central government of China, has attracted huge investments in the arid and semiarid regions of northwest China. As a consequence of this development, environmental pollution and ecological degradation have been widely reported. The Silk Road economic belt proposed by China promotes further economic development in the regions, but rational planning and regular monitoring are essential to minimize any additional negative impacts of the anthropogenic activities. This article reports an investigation on the distribution, enrichment and sources of trace metals in the topsoil in and around the Ningxia Hengli Steel Wire Plant (HSWP) situated along the Silk Road economic belt. The concentrations of Cd, Pb, Cr, Cu, Zn, Ni, Mn, V and Co in the surface soils of the study area vary, respectively, in the following ranges: 0.083–18.600, 21.9–2681.0, 58.0–100.0, 14.6–169.9, 59.0–4207.3, 19.3–40.8, 411–711, 55.2–76.6 and 7.46–25.21 mg/kg. The concentrations of Cd, Pb, Cr, Cu, Zn and Co are significantly higher than their local background values. Pollution levels of these trace metals in the surface soils were assessed using contamination index (C f i ), geo-accumulation index (I geo), modified contamination degree (mC d) and pollution load index. The potential ecological risks caused by the metal pollution were assessed by means of potential ecological risk factor (E f i ) and potential ecological risk index. The Spearman correlation and cluster analysis were applied to determine the contamination sources. The HSWP zone, associated with very high potential ecological risk caused by Pb and Cd, is more seriously contaminated by trace metals than the residential zone. This study indicates that Cd, Pb, Cu, Zn and Co mainly originate from industrial pollution, whereas Cr, Mn, Ni and V result from both industrial activities and natural processes.  相似文献   

3.
The technique of diffusive gradients in thin films (DGT) was applied to obtain high-resolution vertical profiles of trace metals in sediment porewater of a eutrophic lake, Lake Chaohu. All sampling sediments were under anaerobic conditions with Eh values below 0, the redox potential profile in M4 was relatively stable, and higher Eh values in M4 than that in M1 were observed due to hydrodynamic effects. Fe, Mn and As exhibited closely corresponding profiles due to the co-release of Fe and Mn oxides and the reduction of As. Higher Fe and Mn concentrations and lower As concentrations were observed in M1 of the western half-lake than those in M4 of the eastern half-lake due to different sources and metal contamination levels in the two regions. Cu and Zn showed increasing concentrations similar to Mn and Fe at 1–2 cm depth of sediments, while DGT measured Co, Ni, Cd and Pb concentrations decreased down to 3–4 cm in the profiles. Co, Ni, Cu, Zn, Cd and Pb showed insignificant regional concentration variances in the western and eastern half-lakes. According to the R(C DGT/C centrifugation) values, the rank order of metal labilities decrease as follows: Fe (>1) > Cu, Pb, Zn (>0.9) > Co, Ni, Cd (>0.3) > Mn, As (>0.1).  相似文献   

4.
The accumulation efficiency of selected trace elements in the leaves of Melandrium album and Robinia pseudoacacia grown on heavy metal contaminated sites in comparison with a non-contaminated one was evaluated. The study was undertaken to calculate air pollution tolerance index and to determine the contents of selected metabolites: glutathione, non-protein thiols, ascorbic acid, chlorophyll and the activity of antioxidant enzymes: guaiacol peroxidase and superoxide dismutase. Such estimations can be useful in better understanding of plants defense strategies and potential to grow in contaminated environments. The results in the most contaminated site revealed higher contents of metals in M. album leaves, especially Zn, Cd and Pb (3.4, 6 and 2.3 times higher, respectively) in comparison with the R. pseudoacacia. Better accumulation capacity found in M. album was shown by metal accumulation index values. The plants could be used as indicators of Zn, Cd (both species) and Pb (M. album) in the soil. Glutathione content (in both species) and peroxidase activity (in M. album), general markers of heavy metals contamination, were increased in contaminated sites. In most cases in contaminated areas R. pseudoacacia had decreased ascorbic acid and chlorophyll levels. Opposite tendency was recorded in M. album leaves, where similar or higher contents of the above-mentioned metabolites were found. In our study, M. album and R. pseudoacacia proved to be sensitive species with the air pollution tolerance index lower than 11 and can be recommended as bioindicators.  相似文献   

5.
This study presents both qualitative and quantitative data regarding marine mollusk (gastropods and bivalves) shell bioerosion and encrustation based on death assemblages obtained from a recent supratidal environment in Playa Norte, Veracruz State. The objectives of this study were to assess the nature of bioerosion and encrustation processes and to investigate the role of these taphonomic features contributing to the deterioration of natural shell accumulations within a tropical siliciclastic tidal environment. The assemblage comprises 31 species: 13 gastropods and 18 bivalves. The bioerosion and encrustation degrees were low to moderate for both types. The most abundant traces were predatory gastropod structures (Oichnus paraboloides and O. simplex), whereas sponge borings (Entobia isp.), polychaete dwellings (Caulostrepsis taeniola), and echinoid raspings (Gnatichnus isp.) were less frequent. The encrusting organisms include polychaete serpulids, bryozoans, and rare foraminifers (Homotrema rubrum). Because of the low bioerosion and encrustation degrees occurring in this area, accumulation is expected to predominate over biotic destruction. As deposition conditions (richly fossiliferous carbonate sandstone beds) were similar to those prevailing in the Tuxpan Formation during the Miocene (Langhian), it is suggested that this study provides an equivalent reference to interpret mollusk fossil assemblages located in this site.  相似文献   

6.
Heavy metals’ frequent occurrence and toxicity caused considerable concerns in assessing the interactive effects of metals on exposed plants. Therefore, a hydroponic study was conducted to assess the growth response and physio-chemical changes in Brassica napus plants under single and combined stress of two environmentally alarming metals (Cd and Cu). Results showed that 15-day metal exposure to different metal concentrations (0, 50, 200 µM) significantly enhanced Cd accumulation, while lesser extent of Cu was observed in plant tissues. Nonetheless, Cu caused more pronounced oxidative damages and plant growth retardation. Both metals showed similar trend of changes in mineral composition, although Cu proved more damaging effect on K and Mn contents, and Cd on Zn contents. In combined treatments, Cd stimulated Cu uptake, notably at low concentration, while its own uptake was restricted by the presence of Cu. At either level of concentration, combined stress of these metals exacerbated plant growth inhibition and caused further oxidative damages compared to their individual stress. However, metals synergistic effects occurred only in conditions where Cu uptake was enhanced by Cd. A greater synergistic effect was observed in sensitive cultivar Zheda 622 as compared to the tolerant cultivar ZS 758. As to mineral composition, no metals synergistic effects were noted. This study highlighted the ecotoxicological significance of Cd-led Cu uptake in B. napus, which was assumed to drive metals’ synergistic toxicity, and showed that the relationship between Cd-led Cu uptake and plant growth responses could vary with respect to cultivar.  相似文献   

7.
The aim of this study was to determine the influence of sewage sludge (SLU) amendment on the desorption characteristics of zinc (Zn), lead (Pb), and cadmium (Cd) in contaminated calcareous soils. Three levels of SLU (0, 1, and 3% w/w) were added to the two calcareous contaminated soils. Samples were incubated for 30 days and equilibrated with 0.005 M DTPA for 0.25 to 240 h. The addition of SLU significantly increased the amount of DTPA-extractable Zn in soils. While the amounts of Cd, Pb, dissolved organic carbon (DOC), and pH showed a significant increase only in 3% w/w of SLU, with the exception of Cd desorption in 1% w/w of SLU, kinetics of Zn, Pb, and Cd extraction increased together with an increase in the level of applied SLU. The best models for describing desorption data were explicitly power function and Elovich. The rate constants of Zn and Pb had significant correlations with DTPA-extractable Zn and Pb, DOC and pH, which affect Zn and Pb desorption. Also, the rate constants of Cd had significant correlations with CEC that can be deemed as equivalent to the fact that Cd desorption is controlled by surface adsorption, particularly in the lower sludge application amount. These results can be used for management of sewage sludge application in contaminated calcareous soils.  相似文献   

8.
Mining and milling of metal ores coupled with industries have bequeathed many countries the legacy of wide distribution of metal contaminants in sediments. The aim of this study was to assess potential sediment contamination via useful screening methods (XRF, CHNS, TGA/MS). The sediments were collected from the water reservoir Krompachy Eastern Slovakia in April 2015. Within the frame of evaluation it was found that the concentrations of the study elements (Cu, Zn, As, Pb, Cr, Ni, Cd) exceeded some of the MPC, TV and IV values. Sample c was the most polluted by metals, which evident according to it’s the highest CHNS proportion as well as the highest clay and silt proportion. In the samples studied the best correlation was confirmed between weight losses in the temperature range (400–620 °C) and the following metal concentrations: Cu (r = 0.89), Zn (r = 0.88), As (r = 0.93), Hg (r = 0.83), Pb (r = 0.87). The greatest proportions of m/z 44, m/z 18 were detected at temperatures (400–620 °C) associated with decomposition of minerals such as siderite, barite, and exothermic loss of more refractory aromatic C took also place.  相似文献   

9.
This research is focused on evaluating heavy metals (Cd, Cu, Fe, Mn, Pb, and Zn) uptake and removal by Eleocharis ovata, Cyperus manimae, Typha dominguensis, and Pteridium aquilinum in a natural wetland impacted by mining activities. We analyzed heavy metals content and distribution in native plants, soils, and water of a semipermanent natural wetland in Taxco de Alarcón, Guerrero, and we also determined the physicochemical characteristics of the water. Translocation factor (TF) and bioconcentration factor (BCF) were evaluated. Results showed that physical and chemical conditions are favorable for plants development. Correlation analysis showed a good and positive relation (0.95) between Cu and Pb in soils and plants. In the analyzed matrices: Zn (0.62–2.20 mg/L) exceeded the permissible limits in water, high concentrations of Pb and Zn (26.57–525.67 and 266.67–983.33 mg/kg, respectively) were detected in the studied soils, and Pb exceeded the normal range for E. ovata and P. aquilinum in the analyzed plants. Uptake of heavy metals in the tissues of different species was found in the following order: root > leaf. Data of TF and BCF showed that E. ovata is a tolerant plant with respect to heavy metals exposure since TF value was greater than 1. This study showed that E. ovata could be considered as a bioaccumulator of heavy metals in contaminated soils.  相似文献   

10.
In the present study, bulk contents of Ni, Zn, Cu, Pb and Mn in urban area of Tehran city are determined. Subsequently, the chemical bonds of metals with various soil fractions are brought out. Chemical partitioning studies revealed that various percentile of Ni, Zn, Cu, Pb and Mn is found in anthropogenic portion of soils. Zinc, Ni, Cu, Pb and Mn fall within “low pollution” class in accordance with index of pollution (I POLL). The trend of anthropogenic share of studied metals in soils of Tehran is Zn (55 %) > Cu (31 %) > Ni and Pb (30 %) > Mn (12 %). The overall potential of studied plants in metal removal from soil is Salvia > Viola > Portulaca. It should be pointed out that roots have higher potential in metal removal from soil when compared with leaf and stem. Lithogenic portion of metals remains intact before and after pot analysis. Thus, phytoremediation is highly dependent on the chemical bonds of metals. Present study showed that metal contents of loosely bonded ions, sulfide bonds and organometallic bonds are reduced after 90 days of plant cultivation. The overall removal trend of studied metals is Zn (16 %) > Cu (14 %) > Ni (11 %) > Pb (7 %) > Mn (6 %). The obtained results show that the anthropogenic portion of metals is reduced after the phytoremediation practice. For instance, the initial anthropogenic portion of Zn (55 %) is changed to 39 % showing an overall reduction of about 16 %. The anthropogenic portions of Cu, Ni, Pb and Mn are also reduced by 14, 11, 7 and 6 %, respectively.  相似文献   

11.
The aim of this research was to identify plant species with potential to accumulate and stabilize arsenic (As), lead (Pb) and cadmium (Cd) in mine tailings reforested and naturally recolonized locations in a semiarid region of Zacatecas, Mexico. Plant shoots from 44 species and their rhizospheric soils were analyzed for As, Pb and Cd concentration using atomic absorption spectroscopy. Most represented plant families were Asteraceae, Poaceae, Fabaceae and Cactaceae. The highest concentrations in shoots were As, followed by Pb and Cd. Among herbaceous species, Bouteloua gracilis showed the highest bioconcentration factor (BCF) of As, while Plantago lanceolata showed the highest bioconcentration factor of Pb. The shrub species with highest concentration of As in the rhizospheric soil were Opuntia robusta, Melilotus alba, Baccharis neglecta and Arundo donax (near BCF to 1.0). Similar results were observed in trees Casuarina equisetifolia, Prosopis laevigata, Fraxinus uhdei and Eucalyptus globulus. In addition, Tillandsia recurvata showed a suitable indicator of atmospheric deposition to As. In general, the results suggest that these species can be effective for tailings reforestation with the possibility to enclose potentially toxic elements. Specially, C. equisetifolia which is abundant, having the potential for future applications in other contaminated sites with different types of mine tailings or abandoned mines from arid and semiarid zones.  相似文献   

12.
The use of agricultural wastes as biosorbents is gaining importance in bioremediation of heavy metal-polluted water and soils, due to their effectiveness and low cost. This work assesses the Cd, Pb and Cu adsorption capacity of the raw materials used in the production of substrates for mushroom production (Agaricus bisporus and Pleurotus ostreatus) and the spent mushroom composted (SMC), based on the functional groups of their organic carbon. The raw materials studied included agricultural wastes (wheat straw, wheat and rice poultry litter, grape pomace) and inorganic substances (gypsum and calcareous sand). Organic carbon from wastes and their composting products were characterized by CP-MAS 13C NMR. Langmuir adsorption isotherms of metals were plotted for each raw material, composting step, spent A. bisporus and P. ostreatus substrates and the final SMC. The maximum adsorption capacities of SMC were 40.43, 15.16 and 36.2 mg g?1 for Cd, Pb and Cu, respectively. The composting process modified the adsorption properties of raw materials because of the enhanced adsorption of Cd and Cu and decreased adsorption capacity of Pb. CP-MAS 13C NMR and potentiometric titration were used to identify the functional groups of the organic carbon responsible for the metal adsorption. The content of cellulose was correlated with Pb adsorption (p < 0.001), alkyl and carboxyl carbon with Cd adsorption (p < 0.001), and N-alkyl (p < 0.001) and carboxyl (p < 0.010) groups with Cu adsorption. These results are valuable to develop new biosorbents based on agricultural wastes and demonstrate the high potential of SMC to adsorb heavy metals from polluted environments.  相似文献   

13.
With the increasing industrialization, heavy metals concentration in soils has greatly increased. Phytoremediation is a low-cost, non-intrusive and aesthetically harmonious technology that uses plants to remediate contaminated sites by heavy metals. The aim of the study was to determine Cd, Pb and Zn concentration in the biomass of plant species growing on a multi-metal-contaminated site of lead smelter processing, to assess the workability of using these plants for phytoremediation purposes and highlight possible damage in morphological leaf changes. Two plant species, i.e., Ipomoea asarifolia and Urochloa decumbens and the associated soil samples were collected and analyzed Cd, Pb and Zn concentrations and then calculating the bioconcentration factor and translocation factor parameters for each element. Leaves and roots samples were observed by light microscopy. Metal concentrations varied greatly and majorly depend on site sampled, plant species and tissue. Cd, Pb and Zn in tissue ranged from 0 to 102.48, 0 to 381.04 and 12.84 to 295.02 mg Kg?1. However, none of the plant showed potential for hyperaccumulation. Both plants showed bioaccumulation factor more than one, where it was 7.66 and 6.82 for Pb and Zn in U. decumbens, respectively. Translocation factor was calculated below one for both plants and all metals. Morphological studies revealed development of adaptive features that strengthen the U. decumbens to grow in contaminated soil. Our study suggests that I. asarifolia and U. decumbens have potential for phytostabilization at multi-metal-contaminated site.  相似文献   

14.
Petrographic thin section analysis of the samples collected from the type section of Neil West Coast Formation, situated in the west coast of Neil Island yielded moderately preserved coralline red algae, benthic and planktic foraminifers, coral fragments, echinoid spines and gastropod shells. The coralline red algae are represented by both non-geniculate and geniculate forms. The non-geniculate forms belong to melobesids, lithophylloids and mastophoroides. The geniculate forms are represented by species of Amphiroa, Corallina, and Jania. However, the diversity and abundance of coralline algal forms are less in comparison to the benthic foraminifers those are represented by Amphistegina, Neorotalia, Ammonia, Elphidium, Operculina, Assilina, Amphisorus and texularids. Planktic foraminifers like Globigerinoides and other biogenic components viz., gastropod shells, echinoid spines and coral fragments are also common. A foraminiferal-algal grainstone facies has been recognized as observed in the field as well as in thin section analysis. The overall assemblage of the biogenic components and facies analysis indicate intertidal to near shore environment of deposition with high energy condition and increased hydrodynamic activity.  相似文献   

15.
The total concentrations of Cd, As, Pb, Cr, Ni, Co, Zn, Cu, Ag, Hg, and Mo were determined in the atmospheric dust of the city of Yerevan by atomic absorption spectrometry (AAnalyst PE 800). Heavy metal pollution levels were evaluated by calculating geo-accumulation (I geo ) and summary pollution (Zc) indices. Potential human health risk was assessed using the United States Environmental Protection agency’s human health risk assessment model. The results show that mean contents of all elements tested except Ni and Cr were substantially higher than local geochemical background values. According to the I geo , Yerevan territory is strongly-to-extremely polluted by As, Ag, Hg, Mo, and Cd. The Zc assessment indicated that very high pollution was detected in 36 % of samples, high in 32 %, average in 12 %, and low in 20 %. The health risk assessment revealed a non-carcinogenic risk (HI >1) for children at 13 samplings sites and for adults at one sampling site. For children the risk was due to elevated levels of Mo, Cd, Co, and As, while for adults, only Mo. Carcinogenic risk (>1:1,000,000) of As and Cr via ingestion pathway was observed in 25 and 14 samples, respectively. This study, therefore, is the base for further detailed investigations to organize problematic site remediation and risk reduction measures.  相似文献   

16.
Analysis of coral reef species enables characterization of the coral reefs and the degree to which human activities influence the reef composition. Geochemical characteristics, X-ray diffraction, and natural radionuclides analyses of four common coral reef species representing the branching and massive forms were conducted at the three areas under threat (Quseir Harbor, Safaga Harbor, and El-Esh area) along the Red Sea coast. Branching recorded higher carbonates and lower organic matter than the massive forms. Stylophora pistillata at Safaga Harbor and El-Esh area and Acropora humilis at Qusier Harbor recorded the highest carbonate percentages (96.88, 96.24, and 96.89%, respectively) meanwhile Platygyra daedalea at Safaga Harbor recorded the highest organic matter contents (5.07 and 4.91%). The highest Ca contents were observed in S. pistillata and Porites solida (65.87 and 64.87%), the highest Mg was in Acropora humilis and P. daedalea (1.06 and 0.88%) at Qusier Harbor, whilst the highest Sr was in S. pistillata and P. daedalea at Safaga Harbor. Then highest value of 226Ra recorded in A. humilis and P. solida (71 ± 3.5 Bq/kg and 63 ± 3.1 Bq/k) and 232Th in S. pistillata at El-Esh area may attribute to petroleum exploration activities. A. humilis and P. daedalea at Safaga Harbor recorded significant high 40K values (505 ± 30 and 472 ± 13 Bq/kg, respectively) relative to the other localities. The low Ca and High Sr as well as the highest averages of 232Th and 40K at Safaga Harbor indicated that the coral reef communities were highly affected by the terrestrial inputs from phosphate shipments.  相似文献   

17.
The rift system of the Dnieper–Donets trough (DDT) is the largest magmatic area in the East European Platform. Basalts of the Voronezh Crystalline Massif (VCM) are spatially constrained to the eastern shoulder of DDT and occur far away (at a distance of 150–200 km) from the rift axis. The rocks are hosted in the Paleoproterozoic Vorontsovskii terrane and are grouped in a few fields within an area of 200 × 100 km. Basalts at most of the fields were erupted at the boundary between mid- and late Frasnian time in the Late Devonian and can be studied exclusively in core material recovered by boreholes. Newly obtained mineralogical, geochemical, and isotopic-geochemical data show that the Devonian volcanic rocks in VCM are tholeiites (Bas) and basaltic andesites/andesites (ABas). The geological section was examined most exhaustively in the Novokhopersk area (Borehole 175). The bottom of the vertical section is made up of basaltic andesites and andesites (ABas) (thickness 34 m), which rest on an eroded surface of late Frasnian sandstones. The rocks are overlain by a thin (8 m thick) tholeiite sheet (Bas2), which gives way to ABas (13 m) upsection. The top portion of the vertical section is composed of tholeiites with petrography and geochemical evidence of crustal contamination (Bas1) (apparent thickness 5 m). Geochemical parameters of Bas (mg# 42–52 at SiO2 47–51 wt %) are typical of continental tholeiites. The rocks have (87Sr/86Sr)0 = 0.7043–0.7048 and εNd(372) = 2.1–3.5. ABas (mg# 28–31 at SiO2 52–60 wt %) are enriched in Y (48 ppm), and possess Nb/Nb* = 0.7–0.8 and high Zn/Cu = 1.9–2.3. The rocks have (87Sr/86Sr)0 = 0.7034–0.7048 and Nd–εNd(372) = 0.1. Some portions of Bas melts assimilated the upper crustal material, which was similar to Paleoproterozoic granites, and ABas are contaminated in the lower crust with derivatives of Early Cambrian alkaline mafic melts. Petrographic data and simulations of fractional crystallization show that olivine and high-Mg clinopyroxene were the first to crystallize from the melt. After this, clinopyroxene and plagioclase simultaneously crystallized at temperatures from 1070 to 1020°C in Bas and at 1040–900°C at f O2 below QFM + 1 in ABas. The source of ABas was likely a network of hornblendite or amphibole pyroxenite veins in peridotite in the lithospheric mantle or amphibolized peridotite cumulate in an underplating zone; and Bas were derived from spinel peridotites of an asthenospheric diapir. The setting of the basalts relative to the DDT axis and the asymmetric zoning of magmatism in DDT (with kimberlites and other deep rocks constrained to the western shoulder and tholeiites occurring in the axial part of the rift and its eastern shoulder) can be explained by the model of an asymmetric rift structure with a translithospheric detachment gently dipping beneath VCM.  相似文献   

18.
Eastern Black Sea Region of Turkey is a sub-ecoregion of the Caucasus Ecoregion, and its Plecoptera fauna is similar to fauna of Caucasus with unique endemic species of the region. The Caucasus Ecoregion is one of the “WWF Global 200 Ecoregions,” and it is also included in the list of top 25 hotspots in the World. Running water ecosystems of Eastern Black Sea sub-ecoregion are the most sensitive to land use change and global climate change. High-altitude aquatic ecosystems are more strongly threatened by global climate change in the region. Plecoptera constitute the most important part of the biodiversity of running waters in the region. Among the benthic macroinvertebrate taxa, Plecoptera is the best indicator of ecological conditions of running waters. The influence of environmental variables on the distribution of twenty Plecoptera species in running water ecosystems (headwaters, crenon, epirhithron, metarhithron) was assessed using canonical correspondence analysis. Sampling was carried out in 2009 and 2011. Eleven end groups were generated from the TWINSPAN analysis. Isoperla rhododendri, Isoperla grammatica, Protonemura bifida, Protonemura eumontana and Perla caucasica were closely related to pH, dissolved oxygen and riparian vegetation. Brachyptera transcaucasica transcaucasica, Nemoura martynovia, Nemoura taurica and Protonemura eumontana were related to Mg and Cu. The results show that the Plecoptera assemblage composition was affected by DO, pH, EC, temperature, nitrite, Ca, Mg, Fe, Cu, Zn, Al, riparian vegetation, altitude and stream width.  相似文献   

19.
The morphological and structural characteristics of graphite from the deep Chernorudka-Barakchin Fault Zone, Western Baikal region, are described. A complex of mineralogical investigations shows that graphite varieties of the Baikal region are characterized by a perfect structure. The most crystallographically regular samples are composed only of sp 2-carbon, whereas the virtually amorphous varieties are formed by sp 2-and sp 3-carbons as well. The characteristic features of the graphite varieties distinguish them from carbonaceous matter of metamorphic rocks. High concentrations of Co, Ni, Cr, Cu, Ti, Zn, Sc, V, S, Nb, Zr, Sr, Ba, Y, Nd, and La were detected while analyzing the microcomponent composition of the graphitized rocks. The majority of these elements are contained in microinclusions hosted in graphite. The elevated noble metal contents were established in graphitized metasomatic rocks, granitoids, and particularly, in graphite concentrates extracted from these rocks. Sulfides, native metals, and intermetallic compounds were detected in microinclusions. It is suggested that the inflow of reduced high-carbonaceous fluids was responsible for the transfer of chemical elements.  相似文献   

20.
In this study, data on several metals (Cd, Pb, Zn and Cu) in soil and isopod Porcellio laevis taken at 21 sites from the most important industrial areas in Tunisia (Bizerte, Nabeul, Zaghouan, Sfax and Gabes) were presented. Heavy metal concentrations in both soil samples and isopods were determined using atomic absorption spectrometry. Soil contamination was estimated using the contamination factor (CF). On the other hand, the bioaccumulation factor (BAF) was determined to estimate metal accumulation in isopods. The CF values show that the level of contamination varies between sampled soils, which may be due to the source of pollution at each site. The BAF values allow defining the order of accumulation in P. laevis which was classified for the majority of the sampled sites as a macro-concentrator of Cu and Zn and a deconcentrator of Cd with some exceptions. A principal component analysis (PCA) was conducted between soil properties (pH, OM and CaCO3) and metal concentrations in soils. Through PCA, we obtained four groups in which soils were distinguished by their physicochemical properties and their metal concentrations. Moreover, linear multiple regressions with a downward stepwise procedure were conducted to test the relationships between the physicochemical parameters and metal concentrations in both soils and isopods. Thus, positive correlations (0.78 < R 2 < 0.99) were obtained for Pb considering dataset from the groups 1, 2 and for Zn with data of groups 2 and 3. Finally, results showed that P. laevis could be used as a bio-indicator for monitoring and reducing the impact of pollution in terrestrial ecosystems.  相似文献   

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