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1.
Phytoremediation is a developing technology that uses plants to clean up pollutants in soils. To adopt this technology to cadmium (Cd)–contaminated soils efficiently, a Cd hyperaccumulator with fast growth rate and large biomass is required. In the present study, we selected Caryophyllales as a potential clade that might include Cd hyperaccumulators because this clade had a high mean concentration of zinc (Zn), which is in the same element group as Cd. Three species in Caryophyllales and three species in different clades were grown with Cd. Among them, Amaranthus tricolor showed high accumulating ability for Cd under both water‐culture and soil‐culture conditions, whereas Brassica juncea, a known Cd hyperaccumulator, accumulated high concentrations of Cd in shoots only under water‐culture conditions. This result suggests that A. tricolor has Cd‐solubilizing ability in rhizosphere. Because A. tricolor has large biomass and high growth rate, this species could be useful for phytoremediation of Cd‐contaminated fields.  相似文献   

2.
The increasing number of degraded soil areas caused by open cast mining activities has brought about a critical damage to the environment. The mine spoil must be ameliorated with anthropogenic interferences which consist of revegetating soils after organic matter amendment and provision of microbial diversity, to guarantee basic conditions for a sustainable soil biological activity. Five woody species, Acacia mangium Willd., Inga edulis Mart., Mimosa caesalpiniaefolia Benth, Parkia multijuga Benth., and Schinus terebinthifolia Schlecht. & Cham were cultivated under greenhouse conditions to evaluate the potential of plant establishment on cassiterite mining waste, considering the contribution of mycorrhizal fungi inoculation, organic compost, and thermophosphate amendment. The shoot height, dry weight, and nitrogen and phosphorus shoot contents were determined. Three species of nodulating legumes, A. mangium, M. caesalpiniaefolia, and S. terebinthifolia showed a great positive response to organic compost, termophosphate, and mycorrhizal inoculation, increasing the plant height and the shoot dry weight. Plants inoculated with arbuscular mycorrhizal fungi and fertilized with organic compost also increased their nitrogen and phosphorus shoot contents. The addition of organic compost and mycorrhizal fungi were essential for plant development and the reforestation of mining areas should be initiated with mycotrophic and nodulating legumes.  相似文献   

3.
Abstract

Spatial variability of soil nutrients is known to exist at distances of less than 1 m. Recently, an on‐the‐go system for application of nitrogen (N) fertilizer based on spectral measurements known as in‐season estimated yield (INSEY) improved N use efficiency (NUE) by as much as 17% in winter wheat. Six trials were conducted in 2001, 2002, and 2003 at Ardmore and Burneyville, OK, with an objective to develop an index similar to INSEY for use in predicting yield potential in bermudagrass (Cynodon dactylon L.) that can be used for adjusting fertilizer N rates. Initial results indicate that 55% of variation in predicted bermudagrass forage yield was explained by a Bermudagrass–INSEY (B‐INSEY) index and 54% of the variation in forage N uptake was explained using the normalized difference vegetative index (NDVI). The remaining challenge is to develop appropriate N fertilizer rates based on this information and apply these rates using on‐the‐go technology.  相似文献   

4.
Gaseous phosphine (PH3) in the inshore atmosphere was observed from October 2005 to August 2006 at a coastal site of the Yellow Sea in China. The concentration of PH3 ranged from 0.01 to 14.86 ng m?3 with an average of 1.14 ng m?3. The concentration showed a diurnal variation in PH3 with the peak occurring at morning and the lowest point at noon. An obvious seasonal variation of atmospheric PH3 was found, with the PH3 levels in the summer higher than those in the winter. The PH3 levels in the atmosphere were apparently affected by temperature, radiation, sources, and other meteorological factors. The data indicate that PH3 can be transported between the terrestrial and inshore atmosphere of Qingdao and the Yellow Sea or the East China Sea in both directions. The study increases evidence that PH3 participates within the global biogeochemical phosphorus cycle in P transport from land and inshore waters to the sea where commonly P is scarce and where PH3 inflow could be of important.  相似文献   

5.

Purpose

Almost 20 nuclear reactors are situated along the Rh?ne valley, representing Europe??s largest concentration of nuclear power plants. The fate of suspended sediments and natural and artificial particle-bound radionuclides in relation to extreme hydrological events was assessed at the lower course of the Rh?ne River, which provides the main source of water and sediment inputs to the northwestern Mediterranean Sea.

Materials and methods

We sampled water at a high frequency over the period 2001?C2008 and measured suspended particulate matter (SPM) loads and particle-bound natural and artificial radionuclide concentrations at the SORA observatory station in Arles, France. We monitored various hydrological events (either natural or anthropogenic origin) and characterize their influence on concentrations and fluxes.

Results and discussion

The relationship between SPM concentration and the very wide range of water discharges did not differ significantly from previous periods, indicating no significant shift in the average sediment delivery over the last 20?years. Unexpected hydrological events of anthropogenic origin, in particular those associated with flushing of reservoirs that are generally not captured by sampling strategies, were recorded and were shown to transfer significant additional sediment and associated contaminants towards the marine environment. Concentrations of anthropogenic radionuclides associated with sediment (i.e., 137Cs, 60Co, 54Mn, 110mAg, and Pu isotopes) varied over two to three orders of magnitude during periods of low and moderate flow due to variations in the liquid release from nuclear facilities. Except for Pu isotopes, the concentrations of the various particle-bound radionuclides generally showed a decreasing trend with increasing discharge, revealing the geochemical or anthropogenic background values, and providing a useful flood fingerprint for this large fluvial system before its entry into the marine environment.

Conclusions

Our approach produced key data on the level and fate of suspended solids and radionuclide concentrations during flood events occurring in a large river system that could be contaminated by chronic or accidental radioactive releases. These results are of fundamental importance for further interpretations of sediment dynamics at the river mouth.  相似文献   

6.
Eurasian Soil Science - Data on concentrations and distribution of tritium in soils of the “Atomic” Lake excavation explosion area of Semipalatinsk Nuclear Test Site (Kazakhstan, East...  相似文献   

7.
A battery of eight biomarkers was used on the freshwater bivalve Dreissena polymorpha in order to evaluate potential sub-lethal effects of the nonsteroidal anti-inflammatory drug diclofenac (DCF; 2-[(2,6-dichlorophenyl)amino]phenylacetic acid). By an in vivo approach, mussels were exposed for 96 h to increasing concentrations (0.3, 1, and 2 nM) of DCF perfectly comparable with current surface water levels. We determined the single cell gel electrophoresis assay, the apoptotic frequency (DNA Diffusion assay), the micronucleus test (MN test), and the lysosomal membrane stability (Neutral Red Retention Assay) in mussel hemocytes. Moreover, the activity of catalase, superoxide dismutase, glutathione peroxidase, and the phase II detoxifying enzyme glutathione S-transferase was measured in the cytosolic fraction extracted from a pool of entire bivalves to reveal possible alterations of the oxidative status of exposed specimens. The biomarker battery pointed out a negligible cyto- and genotoxicity on zebra mussel hemocytes since only a slight decrease of lysosomal membrane stability from baseline levels was measured at the end of exposures at the highest concentration (2 nM). In addition, environmental concentrations of DCF seem to have a negligible effect on the activities of antioxidant and detoxifying enzymes.  相似文献   

8.
Erosion and transport of soil has worldwide implications for agriculture, landscape stability, climate, natural hazards, and clean, renewable resources of water and air. Assured access to clean water and a healthy and safe environment requires an ethic of conservation and protection. The minimum scale in which these principles apply successfully is basin wide. These are the fundamental concerns of the Sino-US Centers for Soil and Water Conservation and Environmental Protection.  相似文献   

9.
This study examines the synoptic conditions controlling NO x pollution in the metropolitan area of Tel Aviv, using a semi-objective synoptic classification for the eastern Mediterranean. A day in which NO x concentration exceeded the Israeli standard in ≥1 of the seven monitoring stations was defined an “exceeding day” and in ≥5 as an “extensive exceeding day”. For 1998–2004, 19% and 3% of the days were found exceeding and extensive exceeding days, respectively, over 85% of them in the winter months, November–March. The inter-annual variation in the occurrence of the synoptic types was found to explain 72% of the variations in the number of exceeding days. A significant negative trend in the occurrence of types with high pollution potential explained the decrease of 10% per year in the number of exceeding days during 1998–2004. The Red Sea Trough, though being cyclonic system, contributed 51% of the exceeding days, while highs, though being more frequent, contributed only 35%. The “pollution potential” of a synoptic type was defined as the percentage of exceeding days belonging to this type. The majority of synoptic types with the highest pollution potential were cyclonic, most being the Red Sea Trough with western axis, with 82% potential. Our findings indicate that the identity of the synoptic system as cyclonic or anticyclonic is not the key factor for the pollution potential in the study region, but rather, the ambient atmospheric conditions they induce, i.e., high temperatures, static stability, and weak easterly offshore flow. Local processes are the direct cause of the pollution and that the role of the synoptic conditions is to enable, or even to reinforce, the supportive meso-scale processes. This study is a first step in downscaling synoptic features to local NO x pollution potential, constituting a basis for alarming against pollution events, based on the predicted synoptic conditions.  相似文献   

10.
Several coagulants/flocculants have been studied in order to remove the color and turbidity of raw water, employing natural ones demonstrated advantages in relation to chemicals. Moringa oleifera Lam is a natural polymer that has been gaining prominence in water treatment. It acts as a clarifying agent, providing a cationic protein that destabilizes the particles contained in a liquid medium. The main objective of the present work is to study the efficiency in terms of removing color and turbidity of raw water in order to obtain drinking water. For this purpose, different coagulant solutions were obtained utilizing three solutions of KCl in different concentrations (0.01, 0.1, and 1 M) and pure water combined with M. oleifera Lam seed. Each coagulant solution obtained was studied with concentrations ranging from 50 to 600 ppm of Moringa in solution. The pH was varied (4.0, 6.0, and 8.0) with 25% and 50% sodium hydroxide solution (NaOH) and hydrochloric acid (HCl), respectively. The tests were conducted with the “Jar Test Device” and the efficiency of the process was evaluated regarding the reduction of color and turbidity. The best results were found employing the coagulant solutions extracted with 1 M salt solution, pH 8.0, and different concentrations of coagulant solution. It is important to explain that the best results were in various concentration ranges, as the concentration of protein in solution becomes higher, the greater is its power as a coagulant. The lowest content of protein was found in the solution extracted with water, which consequently had the lowest values of color and turbidity removal.  相似文献   

11.
The separation of agroclimatic areas for optimal crop growing within is suggested within the framework of the natural–agricultural zoning of Russia developed under the supervision of I. Karmanov. Overall, 64 agroclimatic areas have been separated in Russia. They are specified by the particular soil and agroclimatic conditions and by the particular crops recommended for cultivation. The biological potential of these crops should correspond to the soil potential of the given area. A combined scheme of the natural–agricultural zoning of Russia and the separated agroclimatic areas is presented. It is argued that the information contained in this scheme can be used for developing landscape-adaptive farming systems, land cadaster, and land valuation; it is also helpful for terrain and remote sensing monitoring of soil fertility on arable lands and for soilecological monitoring.  相似文献   

12.
Yu Zhang  Li  Chen  Wang  Maolin 《Eurasian Soil Science》2020,53(7):892-901
Eurasian Soil Science - Grain for Green Program (GFGP) by establishing revegetation on degraded cropland has been considered effective to capture soil carbon (C) in terrestrial ecosystems. However,...  相似文献   

13.
14.
CHEN TONG-BIN 《土壤圈》1993,3(4):377-382
Soil test for availability of nutrients and heavy metals is extensively served as a means for the evaluations of soil fertility, and environmental effects and phytotoxicity of pollutants in soils, and for the fertilizer recommendation in agricultural and environmental sciences. Therefore, great attention has been paid to the measurement of elemental availability in soil test.  相似文献   

15.

Purpose

Environment-friendly management of sites used for disposal of locally generated sedimentary material involves designation of an optimal dumping site location which will render the dredged material re-usable for beneficial purposes. The objective of this research was to determine whether wind, waves, and currents can induce transport of sediment from offshore dumping sites located at intermediate depths in the southern Baltic.

Materials and methods

The problem was addressed by exploring potential sediment transport from two sites located in the Gulf of Gdańsk at depths of about 20 m. A total of 29 combinations of hydrodynamic variables, representing the most extreme possible situations in the area, including eight theoretical uniform wind fields over the entire Baltic Sea from the W, NW, N, NE, E, SE, S, and SW sectors, the wind speed of 30 m s?1, as well as 21 historical extreme storms, retrieved from the HIPOCAS project database, were used.

Results and discussion

The bottom velocities resulting from waves and currents at the dumping sites considered were computed using wave models (WAM, SWAN) and the M3D hydrodynamic model (based on the POM model). To estimate the velocities critical for bedload transport, formulae developed by Soulsby (1997) and Sawamoto and Yamashita (Proc Coastal Sediments 87:415–423, 1987) were used. The volumetric bedload transport was computed based on Meyer-Peter and Müller (1948). The model simulations demonstrated that, for the storm conditions analyzed, the current velocity in the area of the two dumping sites would be so low that it would practically not affect the magnitude of the bottom sediment transport. Thus, the resultant volume of bedload transported would be equal to that generated by the wave action. For the heaviest historical storm, the maximum transport is about 3?×?10?5 m2 s?1.

Conclusions

Under conditions of theoretical storms, the bottom orbital velocities would be higher and the resultant sediment transport would reach almost 7?×?10?5 m2 s?1 for northerly winds. However, this value is still very low compared with the volume of sediment being dumped. The findings of this study may prove useful in designation of future dumping sites.
  相似文献   

16.
17.
A method is described for the rapid and simple assay of soil β-glucosidase activity. It involves colorimetric estimation of ρ-nitrophenol released by β-glucosidase activity when soil is incubated in McIlvaine buffer (pH 4.8) with ρnitrophenyl βd-glucoside and toluene at 30°C for 1 hr. The method has been applied to three different soils. The range of β-glucosidase activity in cultivated soils was from 10.1 to 15.2 mµ mole per min per gram of dried soil. Km value for ρ-nitrophenyl β-d-glucoside was 3.3 × 10-4 M. Optimum pH was 4.8.  相似文献   

18.
Abstract

An electrolytic method for the copperization of cadmium as a reducing agent for nitrate‐nitrogen (NO3 ‐N) determination is described. The conditions, medium, and time of copperization as well as the length of the cadmium reducing column has been studied in detail. This column was placed in a flow injection analyzer for the online determination of NO3 ‐N in soil extracts. The results obtained show that 1% copper sulfate (CuSO4), 30 min and 55 mm are the optimal medium, time, and column length, respectively. With this reducing column, the method is linear between 0 and 12 ppm NO3 ‐N with a precision of 0.29% and a sampling frequency of 80 determinations per hour. The proposed method has been applied to the determination of NO3 ‐N in soil extracts and the results agree with those obtained by the reference method (r = 0.9998). The optimized electrolytic procedure for the copperization of cadmium permits more than 3000 determinations without any significant loss of sensitivity.  相似文献   

19.
20.
Soil greenhouse gas (GHG) emissions are complex, and their study requires considerable sampling of field spatial and temporal differences. Manual and simple automated gas‐collection techniques used at multiple sites during specific time intervals are labor intensive. The objective of this work was to construct a device that can independently collect GHG samples with the accuracy and precision of manually drawn samples. An automated collector of terrestrial systems (ACTS) is a 24‐h, 7‐d/week programmable sampler used in the field for real‐time gathering and containment of soil GHG emissions. The sampler opens and closes an exterior soil gas chamber, mixes gases in the chamber by turning fans on/off, and utilizes programmable circuits to purge the system and draw a sample from the chamber with a pneumatic‐driven syringe. Each sample was stored in an evacuated vial held in a 30‐vial capacity carousel. Vial content was analyzed for carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) at the U.S. Department of Agriculture (USDA)–Agricultural Research Services (ARS) Agroecosystem Management Research Unit (AMRU). A Tracor MT‐220 gas chromatograph (GC) configured with a thermal conductivity detector (TCD) was used for CO2 analysis, and an automated gas‐sampling system (AGSS) attached to a Varian 3700 GC configured with flame ionization detection (FID) and electron capture detection (ECD) was used for CH4 and N2O analysis. Field and laboratory mean values and coefficients of variation (standards and field concentrations of CO2, CH4, and N2O ranging from ambient to 71 kg ha?1 d?1 had coefficients of variation ranging from 1.2 to 4.2%) were similar between ACTS and manually drawn samples. Results showed strong correlation (R2 = 0.81 to 1.00) between sampling methods. The sampler design provides a realistic and inexpensive approach for collecting emission samples while reducing human error associated with adverse sampling conditions and fatigue. The ACTS has potential for use in monitoring and comparing management practices in terrestrial systems to determine their contribution to GHG emissions.  相似文献   

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