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1.
Three hundred and twenty‐two samples of desalinated household water were collected from 99 sampling locations that covered 95% of Kuwaiti's residential areas. Seventy‐one brands of bottled water were collected from Kuwaiti markets. The water quality parameters that were studied included pH, electrical conductivity (EC), total dissolved solids (TDS), F?, Cl?, Br?, , , , , , , , and the major macronutrients Na+, K+, Ca2+, and Mg2+. The analysis yielded a large range of results for most of these parameters, with differences in some cases exceeding 10‐fold. With a few exceptions, the results were found to comply with US‐EPA and WHO standards. Only the water in two brands of bottled water was acidic (pH < 6.5). The TDS was found to be higher than the US‐EPA regulated value in 4 and 3% of the household samples and bottled water brands, respectively. The fluoride levels were generally higher in bottled water than in household water. However, the household water that was produced by the Doha desalination plant and some of the European brands of bottled water were the best samples studied in terms of their quantity of Ca2+, Mg2+, and Na+ compared with the DRI values for those substances. EC and TDS were positively correlated with , , Na+, K+, Ca2+, and Mg2+ for household water but only with Ca2+ and Mg2+ for bottled water.  相似文献   

2.
Studies on the hydrogeological conditions of the Mesogea basin in east Attica reveal that the aquifers developed on the post‐alpine formations at the inner part of the coastal brackish zone exhibit positive hydraulic head. These Neogene and Quaternary deposits present high salt concentrations. Selected points were sampled (total 85: 51 wells and 34 boreholes) in order to obtain hydrogeological and hydrochemical data for a better understanding of the structure, operation and dynamics of the aquifer of the area. Statistical methods, R‐mode factor analysis and scatter‐plot diagrams were used for the hydrochemical analysis and presentation of the data. The groundwater resources are relatively weak and there is significant quality degradation due to the geological structure of the greater area, as well as the bad management of the aquifer and anthropogenic activities. Groundwater is characterized by high salt concentrations. Electrical conductivity values range between 260 and 6970 µS cm?1. High salt concentrations at the coastal aquifers are due to sea intrusion, whereas they are attributed to the dissolution of minerals of the geological environment in the inland area. The groundwaters of the study area can be classified into five water types: Ca–HCO3, Mg–HCO3, Na–HCO3, Na–Cl and Mg–Cl. They are saturated in dolomite and calcite, whereas they are unsaturated in anhydrite. High ion concentrations, e.g. ] (0‐221 mg l?1), ] (0·01‐1·88 mg l?1), ] (0·01‐6·75 mg l?1), as well as high heavy metals concentrations are attributed to anthropogenic impacts. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

3.
A novel method has been put forward to retrofit the wet ammonia desulfurization process to realize the combined removal of sulfur dioxide and nitric oxide by introducing soluble cobalt(II) salt into aqueous ammonia solution. The active constituent of scrubbing NO from the flue gases is the produced by ammonia coordinating with Co2+. The regeneration of can be realized under the catalysis of activated carbon so as to sustain a high NO removal efficiency for a long time. In this paper, the adsorption–reduction behavior of on activated carbon has been researched using scanning electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. A conclusion can be drawn from the results that cobalt ions in the aqueous solution are adsorbed by activated carbon and most of them are reduced to Co2+ ions, and some of the Co2+ ions are further reduced into metallic cobalt. The results also demonstrate that the functional groups on the surface of carbon take part in this redox reaction. The C? H groups on the carbon surface are oxidized into C? OH, and then some of the hydroxyl groups are further oxidized into carbonyl or carboxyl groups.  相似文献   

4.
Shallow and bedrock groundwater from granitic aquifers were investigated for the hydrogeochemistry of major and minor constituents in an agricultural area. Nitrate concentrations were observed up to 49 mg/l as NO3‐N, with 22% of samples exceeding the drinking water standard, which could pose a significant threat because most residents rely on groundwater as their drinking water source. Principal component analysis revealed three principal components (PCs): (1) nitrate contamination, contributed by major cations, Cl?, SO and NO , (2) reduction processes positively involving Fe, Mn and B, and negatively involving dissolved oxygen and NO and (3) natural mineralization, involving HCO and F?. Cluster analysis, performed on the PC scores, resulted in seven sample groups, which were successfully identified by total depth, elevation and land use. The nitrate‐contaminated groups had mixed land uses, with locally concentrated residential areas. Uncontaminated groundwater groups were found in the natural environment, including high‐altitude spring water and bedrock groundwater with a higher degree of natural mineralization. Shallow groundwater groups in paddy fields in lowlands were affected by reducing environments, of which one group was characterized by high Fe, Mn and B, and negligible nitrate. Groundwater with intermediate nitrate and lower Cl? and SO was found primarily in hilly terrains with orchards and vegetable gardens, indicating lower contaminant loadings than lowland areas. Higher concentrations of F? and nitrate were observed in the nitrate‐contaminated water, which seemed unlikely to be explained by groundwater mixing. The strong acidity generated from nitrification may infiltrate deeper into the aquifer, induce accelerated weathering of bedrock and result in the coexistence of F? and nitrate, which may be an evidence of intense nitrate loading, leading to soil acidification. Multivariate statistical analysis successfully delineated hydrochemical characteristics of groundwater attained by natural and anthropogenic processes in an agriculturally stressed area with complex topographic land use patterns. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

5.
In the Pearl River Delta (PRD), river water quality deteriorates continually due to the population increase and ongoing industrialization and urbanization. In this study, a water quality management paradigm based on the seasonal variation is proposed. For better exploring the seasonal change of water quality, wavelet analysis was used to analyze the division of dry and wet seasons in the PRD during 1952–2009. Then water quality seasonal variation in 2008 and relevant impact factors were analyzed by multivariate statistic methods as a case to make some management measures. The results show that there are some differences of dry and wet seasons division among different years. Wet season mainly appear from April to September, which occupy the largest proportion among the 58 years (about 70%) and then followed by the wet season from May to October (about 13.8% of the total years). As to the water quality of 2008, significant differences exist between dry and wet seasons for 17 water quality parameters except TP, , Fe2+, and Zn2+. Levels of parameters pH, EC, CODMn, BOD5, , , and Cl? in dry season are much higher than those in wet season. In dry season the variations of river water quality are mainly influenced by domestic sewage, industrial effluents, and salt water intrusion. While in wet season, except the aforementioned pollution sources, drainages from cultivated land and livestock farm are also the main factors influencing water pollution. Thus, water quality management measures are proposed in dry and wet seasons, respectively. The results obtained from this study would further facilitate water quality protection and water resources management in the PRD.  相似文献   

6.
In this study, bench‐scale experiments were conducted to examine the UV/H2O2 oxidation of 17α‐ethynyestradiol (EE2) in water in a batch operation mode. The EE2 degradation exhibited pseudo‐first‐order kinetics, and the removal was ascribed to the production of hydroxyl radicals (?OH) by the UV/H2O2 system. Typically, the EE2 oxidation rate increased with increasing UV intensity and H2O2 dose, and with deceasing initial EE2 levels and solution pH. At EE20 = 650 µg/L, UV intensity = 154 µW/cm2, H2O2 = 5 mg/L, and neutral pH, the UV/H2O2 treatment was able to remove 90% of the EE2 content within 30 min. Four anions commonly present in water were found to inhibit EE2 degradation to varying degrees: > > Cl? > . Our results demonstrate that the described UV/H2O2 process is an effective method to control EE2 pollution in water.  相似文献   

7.
Pollutants affect not only the environment in which they originate since they are also transported by air currents to other locations. For this reason, air pollution is a global problem for all countries and the air and water quality need to be monitored carefully. More information on precipitation chemistry is required to determine the source of pollution as well as its effects on the ecosystems. In this study, precipitation chemistry has been analyzed for the first time by using simple bulk collectors located at four different sites in Northwest Turkey for a period of two years. About 650 sequential rainwater samples were collected and analyzed for pH, electrical conductivity, anions such as , , Cl?, and cations such as Na+, K+, Mg2+, Ca2+, and . The selected sites were under the effect of different environmental factors. Our results showed that the highest and concentrations were measured in the Northwest of the research area. Additionally, it has been found that Ca2+ ions are abundant within all rainwater samples.  相似文献   

8.
This 2‐year study (2000, 2001) reports annual nutrient (phosphorus, nitrate) export from a first‐order agricultural watershed in southern Ontario based on an intensive monitoring programme. The importance of storm and melt events in annual export estimates is demonstrated and the temporal variability in nutrient loading during events is related to processes occurring within the catchment. The feasibility of predicting event‐related nutrient export from hydrometric data is explored. The importance of sampling frequency throughout events is also shown. Export of total phosphorus (TP), soluble reactive phosphorus (SRP) and nitrate ( ) for 2000 and 2001 averaged 0·35 kg ha?1 year?1, 0·09 kg ha?1 year?1, and 35 kg ha?1 year?1 (as N) respectively. Approximately 75% of annual TP export, 80% of annual SRP export and 70% of annual export occurred during 28 events per year. A small number of large‐magnitude events (>34 mm) accounted for 18–42% of annual TP export, 0–61% of annual SRP export and 13–33% of annual NO export. Our results show that temporal variability in nutrient export is largely governed by discharge in this basin, and export can be predicted from discharge. SRP and TP export can also be predicted from discharge, but only for events that are not large in magnitude. The sampling interval throughout events is important in obtaining precise estimates of nutrient export, as infrequent sampling intervals may over‐ or under‐estimate nutrient export by ± 45% per event for P. This study improves our understanding of and P export patterns and our ability to predict or model them by relating temporal variability in event nutrient export to discharge and processes occurring within the basin, and also by exploring the significance of sampling interval in the context of the importance of individual events, season and temporal variability during events. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

9.
Nano‐alumina modified by 9‐aminoacridine was used as a sorbent for separation and determination of dichromate ions from water. Statistical method, based on surface response design, has been used for the optimization of dichromate ions elution from 9‐aminoacridine nano‐alumina. The adsorbed dichromate ions were found to be eluted quantitatively with 0.8 mol L?1 KCl in 1.6 mol L?1 NaOH which optimized by response surface design. Under optimum conditions, the accuracy, precision (relative standard deviation, RSD%) and R‐square of the method were calculated as >98, <3, and >94%, respectively. Remarkable agreement between experimental and theoretical data was confirmed the predicted assumption. The method was applied to the simultaneous determination of dichromate in natural and industrial water samples. We also examined the retention of dichromate anions in the presence of Cl?, , and anions at pH 3.  相似文献   

10.
The paper presents the results of field measurements of critical conditions for bedload motion conducted in the Rio Cordon, a steep boulder‐bed stream in the Italian Alps, under conditions of high Reynolds numbers and low relative submergence poorly explored before. Two methods have been used to determine threshold of motion: the displacement of marked clasts and the flow competence approach, which uses the largest grain size diameter transported by each flood event. The high values of confirm the great relevance of non‐bedload effective shear stresses in step–pool streams given by the additional form drag associated with this morphology. Relative submergence effects on the dimensionless critical shear stress have been quantified by considering the relative submergence ratio Rh/D84, and the major effect of relative size on the mobility of each particle in steep, widely graded bed mixtures has been evaluated. Finally, the dimensionless critical unit discharge has also been adopted in the regression equations as the critical hydraulic parameter, because it may represent an easier parameter to use than the critical shear stress for steep, rough mountain rivers. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

11.
Recent studies of soil loss by the integrated action of raindrop impact and wind transport have demonstrated the significance of this mechanism. This paper presents data obtained during wind‐tunnel experiments examining the ‘Raindrop Detachment and Wind‐driven Transport’ (RD‐WDT) process to investigate average sand particle trajectory and the spatial extent at which the process operates. In the experimental design, at the same time as the horizontal wind velocities of 6·4, 10, and 12 m s–1 passed through the tunnel, rainfall was simulated falling on very well sorted dune sand. The aspect and slope of the sand bed was varied to reproduce both windward (Ww) and leeward (Lw) slopes of 4º and 9º with respect to the prevailing wind direction. The average sand particle trajectories by the RD‐WDT process ( ) were estimated by a mass‐distribution function, which was integrated over a 7‐m uniform slope segment. The results showed that depended statistically upon the wind shear velocity (u*), and the effect of the slope gradient (θ) was insignificant on . This was different from that of the windless rain process ( ), ‘Raindrop Detachment and Splash‐driven Transport’ (RD‐ST), the spatial range of which relies strongly on θ. Additionally, was approximately 2·27 ± 2·2 times greater than the average path of a typical saltating sand particle of the rainless wind ( ), ‘Wind Erosion Saltation Transport’ (WE‐ST). Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

12.
Y. Zhao  S. Peth  X. Y. Wang  H. Lin  R. Horn 《水文研究》2010,24(18):2507-2519
Temporal stability of soil moisture spatial patterns has important implications for optimal soil and water management and effective field monitoring. The aim of this study was to investigate the temporal stability of soil moisture spatial patterns over four plots of 105 m × 135 m in grid size with different grazing intensities in a semi‐arid steppe in China. We also examined whether a time‐stable location can be identified from causative factors (i.e. soil, vegetation, and topography). At each plot, surface soil moisture (0–6 cm) was measured about biweekly from 2004 to 2006 using 100 points in each grid. Possible controls of soil moisture, including soil texture, organic carbon, bulk density, vegetation coverage, and topographic indices, were determined at the same grid points. The results showed that the spatial patterns of soil moisture were considerably stable over the 3‐y monitoring period. Soil moisture under wet conditions (averaged volumetric moisture contents > 20%) was more stable than that under dry ( ) or moist ( ) conditions. The best representative point for the whole field identified in each plot was accurate in representing the field mean moisture over time (R2 ≥ 0·97; p < 0·0001). The degree of temporal persistence varied with grazing intensity, which was partly related to grazing‐induced differences in soil and vegetation properties. The correlation analysis showed that soil properties, and to a lesser extent vegetation and topographic properties, were important in controlling the temporal stability of soil moisture spatial patterns in this relatively flat grassland. Response surface regression analysis was used to quantitatively identify representative monitoring locations a priori from available soil‐plant parameters. This allows appropriate selection of monitoring locations and enhances efficiency in managing soil and water resources in semi‐arid environments. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

13.
Permafrost and fire are important regulators of hydrochemistry and landscape structure in the discontinuous permafrost region of interior Alaska. We examined the influence of permafrost and a prescribed burn on concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and other solutes ( , Ca2+, K+, Mg2+, Na+) in streams of an experimentally burned watershed and two reference watersheds with varying extents of permafrost in the Caribou–Poker Creeks Research Watershed in interior Alaska. The low‐permafrost watershed has limited permafrost (3%), the high‐permafrost watershed has extensive permafrost (53%), and the burn watershed has intermediate permafrost coverage (18%). A three end‐member mixing model revealed fundamental hydrologic and chemical differences between watersheds due to the presence of permafrost. Stormflow in the low‐permafrost watershed was dominated by precipitation and overland flow, whereas the high‐permafrost watershed was dominated by flow through the active layer. In all watersheds, organic and groundwater flow paths controlled stream chemistry: DOC and DON increased with discharge (organic source) and base cations and (from weathering processes) decreased. Thawing of the active layer increased soil water storage in the high‐permafrost watershed from July to September, and attenuated the hydrologic response and solute flux to the stream. The FROSTFIRE prescribed burn, initiated on 8 July 1999, elevated nitrate concentrations for a short period after the first post‐fire storm on 25 July, but there was no increase after a second storm in September. During the July storm, nitrate export lagged behind the storm discharge peak, indicating a flushing of soluble nitrate that likely originated from burned soils. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

14.
HCHO is ubiquitous and important chemical constitutes in the troposphere. The concentrations of the HCHO (aq) in the rainwater were measured in the Guiyang city, southeastern of China from May 2006 to April 2007 and 153 discrete samples were collected. Rainwater (N = 151) HCHO (aq) concentrations ranged from lower than method detection limit (MDL) to 40.2 µmol/L with a volume weighted mean value of 7.4 ± 8.8 µmol/L. The strong correlations between HCHO (aq) and HCOO? (r = 0.69, n = 137), HCHO (aq) and nss‐ (r = 0.74, n = 137), HCHO (aq) and (r = 0.67, n = 137), HCHO (aq) and (r = 0.74, n = 133) suggest the significant influence of the anthropogenic input for the HCHO (aq) levels. The concentration levels of rainwater HCHO (aq) was inversely proportional to the amount of rainfall, indicating the below‐cloud process is the most important mechanism for rainwater HCHO (aq) scavenging processes. More than 70% of the HCHO (aq) wet deposition took place during the early stage of the rainfall. According to the air mass back‐trajectory analysis, the rainwater with industrial back‐trajectories coming from the north had the highest levels of HCHO (aq) while the rainwater with the green‐covered or marine back‐trajectories from the southeast had the lowest concentrations, and this indicate the HCHO (aq) originated from urban or industrial regions served as an important source of the rainwater. The annual HCHO (aq) wet deposition flux was calculated as 6.96 mmol/m2 per year and the total deposition flux was estimated as 24.35 mmol/m2 per year, 71.4% of which was dominated by dry deposition.  相似文献   

15.
Geochemical characterization and numerical modelling of surface water and ground water, combined with hydrological observations, provide quantitative estimates of meteoric diagenesis in Pleistocene carbonates of the northern Bahamas. Meteoric waters equilibrate with aragonite, but water‐ rather than mineral‐controlled reactions dominate. Dissolutional lowering of the undifferentiated bedrock surface is an order of magnitude slower than that within soil‐filled topographic hollows, generating small‐scale relief at a rate of 65–140 mm ka?1 and a distinctive pocketed topography. Oxidation of organic matter within the subsoil and vadose zones generates an average P of 4·0 × 10?3 atm, which drives dissolution during vadose percolation and/or at the water table. However, these dissolution processes together account for <60% of the average rock‐derived calcium in groundwaters pumped from the freshwater lens. The additional calcium may derive from oxidation of organic carbon within the lens, accounting for the high P of the lens waters. Mixing between meteoric waters of differing chemistry is diagenetically insignificant, but evapotranspiration from the shallow water table is an important drive for subsurface cementation. Porosity generation in the shallow vadose zone averages 1·6–3·2% ka?1. Phreatic meteoric diagenesis is focused near the water table, where dissolution generates porosity at 1·4–2·8% ka?1. Maximum dissolution rates, however, are similar to those of evaporation‐driven precipitation, which occludes porosity of 4·0 ± 0·6% ka?1. This drives porosity inversion, from primary interparticle to secondary mouldic, vug and channel porosity. In the deeper freshwater lens, oxidation of residual organic carbon and reoxidation of reduced sulphur species from deeper anaerobic oxidation of organic carbon may generate porosity up to 0·06% ka?1. Meteoric diagenesis relies critically on hydrological routing and vadose thickness (controlled by sea level), as well as the geochemical processes active. A thin vadose zone permits direct evaporation from the water table and drives precipitation of meteoric phreatic cements even where mineral stabilization is complete. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

16.
Low cost adsorbents were prepared from dried plants for the removal of heavy metals, nitrate, and phosphate ions from industrial wastewaters. The efficiency of these adsorbents was investigated using batch adsorption technique at room temperature. The dried plant particles were characterized by N2 at 77 K adsorption, scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, and phytochemical screening. The adsorption experiments showed that the microparticles of the dried plants presented a good adsorption of heavy metals, phosphate, and nitrate ions from real wastewaters. This adsorption increased with increasing contact time. The equilibrium time was found to be 30 min for heavy metals and nitrate ions and 240 min for phosphate ions. After the adsorption process, the Pb(II) concentrations, as well as those of Cd(II), Cu(II), and Zn(II) were below the European drinking water norms concentrations. The percentage removal of heavy metals, nitrates, and phosphates from industrial wastewaters by dried plants was ～94% for Cd2+, ～92% for Cu2+, ～99% for Pb2+, ～97% for Zn2+, ～100% for ${\rm NO}_{{\rm 3}}^{{-} } $ and ～77% for ${\rm PO}_{{\rm 4}}^{3{-} } $ ions. It is proved that dried plants can be one alternative source for low cost absorbents to remove heavy metals, nitrate, and phosphate ions from municipal and industrial wastewaters.  相似文献   

17.
Ten algae species were analyzed by comparing their growth in specific hypersaline industrial wastewater. It was a by‐product of fertilizer production which was released by K + S Aktiengesellschaft, Germany. Due to processing, brine water contains a high amount of salts ( 200 g L?1). A successful algal biotechnology mainly depends on choosing and screening the adequate algae for a specific application along with the design of optimal culture conditions with comparable photo bioreactor technologies. Therefore, a high throughput screening technology was developed. In comparison to glass flasks or flat panel reactors this system was eligible for screening applications because of disposable characteristics and the equability of each culture tube. Dunaliella salina, Tetraselmis tetrathele, and Nannochloropsis salina grew in the presence of hypersaline wastewater where T. tetrathele grew best to a wastewater concentration of 75% by salt shock experiments. D. salina tolerates a wastewater level up to 80% by gradual increase. Intracellular ion contents of lyophilized algae samples were measured. They feature special transporter to either exclude ions, i.e., sodium from the cell, or to include ions like potassium and magnesium in order to secure functionality of sensitive enzymes. Under saline stress conditions these transport systems as well as metabolic pathways leading to the production of compatible osmolytes could be induced. Stress tolerance mechanisms developed in initially unstressed culture either by stepwise adaptation or by shock exposure to harsh salt condition. For this reason a feasible mass production in industrial hypersaline wastewater was possible.  相似文献   

18.
Pharmaceutical compounds, widely produced and used all around the world, are partly responsible for the widespread water pollution in the environment. Carbamazepine (CBZ) is an antiepileptic drug that persists in the environment for many years. In the present study, we used the TiO2/UV, nanoparticulate zero‐valent iron (NZVI), and NZVI/H2O2 treatment processes to compare efficiency of CBZ removal from water. Influence of NZVI loading, H2O2 concentration, TiO2 loading, UV lamp power, and the matrix (distilled water and groundwater) on CBZ removal efficiency was evaluated using full factorial design. Results indicated that the NZVI/H2O2 process oxidized CBZ within 5 min. On the other hand, the NZVI process alone did not reduce CBZ concentration after 120 min of process time. The NZVI/H2O2 process was equally effective in CBZ removal from both distilled water and groundwater whereas the TiO2/UV process was less effective due to the presence of ions in groundwater. CBZ removal efficiency of the TiO2/UV process declined 30% when the matrix was changed from distilled water to groundwater. Negative divalent ions, i.e., and , were the main cause of reduction of CBZ removal efficiency from groundwater. It is likely that these two ions adsorb onto, and consequently prevent the superoxide anion and hydroxyl radical OH? from being generated on, the surface of the TiO2.  相似文献   

19.
This study examined ${\rm NH}_{{\rm 4}}^{{\rm + }} $ , ${\rm PO}_{{\rm 4}}^{{\rm 3}- } $ recovery and the concentration of residual ions from anaerobic effluent of the potato processing industry through magnesium ammonium phosphate (MAP) precipitation using a Box–Behnken design. The regression model was statistically significant in terms of ${\rm NH}_{{\rm 4}}^{{\rm + }} $ and ${\rm PO}_{{\rm 4}}^{{\rm 3}- } $ removal efficiency and residual ion concentrations. Optimum ${\rm NH}_{{\rm 4}}^{{\rm + }} $ and ${\rm PO}_{{\rm 4}}^{{\rm 3}- } $ removal was obtained at pH 9.50 and at Mg2+/${\rm NH}_{{\rm 4}}^{{\rm + }} $ /${\rm PO}_{{\rm 4}}^{{\rm 3}- } $ molar ratio of 1.8:1:1.8. Under these conditions, Mg, Ca, K, Fe, and Cl concentrations required for plant growth significantly decreased with MAP precipitation, which was supported by EDX analysis of dry MAP precipitate. The fertilizer effect of MAP on the growth of corn and tomato plants was compared with chemical fertilizers through pot trials. Nutrient element uptake levels of plants were examined in different fertilizer sources. While Mg, Fe, Cu, Mn, and Zn nutrient element uptake levels were sufficient in MAP pots, Ca uptake exceeded sufficient level. Average levels of N, P, K, Mg, Cu, and Mn of corn plant were higher in MAP than other pots. The average N, P, and Mg levels of tomato plant in MAP pots were higher than other pots. N/K ratio, which is important in tomato plants, was better optimized in MAP pots. Only Ni, Cr, and Pb heavy metals were found in plants.  相似文献   

20.
We examined spatial and temporal variations in precipitation measured during summer season between 1976 and 2007 for 28 stations located in mountain areas across Japan using the amount of precipitation (Pr), the mean depth of precipitation events (η), and the inverse of the mean interval times (λ). We obtained positive correlations between the period mean Pr (Pr ) and the period mean η ( ) and between Pr and the period mean λ ( ) for the 28 stations. Pr was more strongly related to than to , indicating the spatial variations in Pr that are primarily related to the variations in . In addition, Pr was more strongly related to η than to λ for most stations on the basis of data for 1976–2007, indicating that the year‐to‐year variations in Pr are primarily related to η. We also examined temporal trends in Pr, η and λ for 1976–2007 and found no systematic trends for 23 of the 28 stations, suggesting long‐term trends that are not common in mountain areas of Japan. The relationships between Pr and and between Pr and η presented in this study enable us to generate a temporal precipitation distribution pattern based on only Pr and Pr data, respectively. Furthermore, probabilistic stochastic hydrological models require precipitation characteristics as input; thus, this study contributes to the determination of hydrological cycles and their possible future changes in Japanese mountain areas and therefore to water resource management. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

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