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1.
Abstract

A new spectrophotometric method is described for the determination of thallium in soil by extraction of Tl(III) with a toluene solution of N,N′-diphenylbenzamidine after acidification with 0.2–4.0 M HCl, and reaction of the extract with Crystal violet in the presence of 0.01–0.8 M HCl. The value of molar absorptivity of Tl(III)-X-CV complex (where X = Cl or Br; CV = Crystal violet) in toluene is 7.00 × 104 1 mole?1 cm?1 at the absorption maximum of 610 nm. The detection limit of the method is 20 ng ml?1. The present method is free from interference of almost metal ions commonly associated with Tl. The method has been applied for analysis of the metal to soils.  相似文献   
2.
The effect of contamination of a cyanide, phosphate-buffered gold-plating bath with iron, cobalt, or nickel on the codeposition of these metals with gold, was investigated using 59Fe, 58Co and 63Ni. It was shown that cobalt and nickel were practically not codeposited in gold if present in the solution in amounts up to 1000 or 2000 mg/dm3 respectively. Iron deposited in high amounts (up to 18%) depending on its concentration and the cathode current density. The diminishing in current efficiency of the plating process is proposed as an early signal of the contamination of gold deposit with iron.  相似文献   
3.
Es werden Varianten der Probenchemie für 15N-Bilanzexperimente in der Düngungsforschung vorgestellt, die den Erfordernissen des Isonitromat-5200 und des NOI-5 angepaßt sind. Die skizzierten Methoden umfassen die destillative Präparation markierter N-Mengen (0,1–1 mg) aus Bodenextrakten, verbunden mil einem Zvsatz unmatkierter N-Mengen bei der Titration sowie eine für den Routinebetrieb geeignete N-Bestimmung in nicht angereicherten Pflanzenaufschlüssen mit dem Isonitromat-5200 als 15N-Verdünnungsanalyse. Weiterhin werden einfache apparative Varianten zur Bestimmung von sog. Gasförmigen Düngersticksloffverlusten durch Denitrifizierung in gasdichten Kammern dargestellt.

Durch 15N-Analyse von Luftproben über 15N-angereicherten natürlichen Bodenmonolithen mit dem NOI-5 können unmittelbar die vom Dünger freigesetzten N2 und N2O-Mengen bestimmt werden. Bei Spezialversuchen in stickstofffreier Neon(He)-Atmosphäre können gebildete N2-, NO- und N2O-Spuren (um 1 Vol. %)nach gaschromatographischer Trennung (auf Perapak-Q) individuell am NOI-5 gemessen werden. Unter Verwendung von CO2-Trägergas werden die N-Komponenten in einem Azotometer isoliert und mit Hilfe eines Dosierhahnes, dessen Volumen den geforderten Gasdruck garantiert, in Entladungsrohre überführt.  相似文献   
4.
The application of polarized X-rays in energy dispersive X-ray fluorescence analysis (EDXRF) is prooved to be one method for improvement the sensitivity of trace analysis at rock- and soil-samples. The use of a high power X-ray tube in connection with an amorphous Barkla-scattering target for polarization makes possible the increase of peak-to-background ratios in a wide energy range (5 keV < E < 40 keV) in comparison to direct excitation. The influence of the polarization on the peak-to-background ratios at trace analysis at geological samples will be shown.  相似文献   
5.
Für die Ermittlung der Transferkoeffizienten im System Boden–Pflanze wurden in drei Stellen der Tschechoslovakei Boden- und Pflanzenproben entnommen. Die niedrigsten Transferkoeffizienten für Getreide und für mehrjährige Futterpflanzen wurden in der Ostslovakei festgestellt. Die Werte der Transferkoeffizienten waren durch den Bodentyp, den Gesamt-Sorptionskapazität und dem Grad der Sorptionssättigung beeinfluβt.

Soil and plant samples were sampled for the determination of soil to plant transfer coefficients in three various Czechoslovak sites. The lowesl transfer factors for cereals and fodder were determined in the site of Eastern Slovakia. Values of transfer factors depend on soil type, cation exchange capacity and base saturation of soils.  相似文献   
6.
Determinations of soil moisture witli the aid of neutron moisture meters require calibrations under real conditions. Some efficient methods for calibrating such moisture gauges are described and working examples are presented.  相似文献   
7.
目的:连续多年监测彭州敖平镇川芎药材栽培土壤中重金属镉的含量,分析其对川芎药材中镉含量的影响。方法根据前期研究结果选取敖平镇部分川芎种植地固定采集样品。按照国家标准方法,采取0~20 cm连续根系土柱和川芎药材。采用火焰法对抽样土壤及川芎药材中镉的含量进行检测分析。结果采样区域内土壤中镉含量均符合国家二级土壤环境质量标准;部分土壤中镉的含量呈明显增长趋势。结论川芎种植土壤中镉含量与环境有较高关联,水泥厂粉尘等污染源是土壤中镉含量增加的重要来源。  相似文献   
8.
An analytical method was developed for the simultaneous extraction and determination of 18 fluoroquinolones (FQs), tetracyclines (TCs) and sulfonamides (SAs) antibiotics from soils using solid phase extraction and liquid chromatography-tandem mass spectrometry. The soils were extracted by different solvents with the help of mechanical shaking and ultrasonic treatment at 59?kHz, followed by a strong anion exchange (SAX) cartridge to clean up soil samples and a hydrophilic lipophilic balance (HLB) cartridge as enrichment. The method was evaluated by testing the following variables: extraction solvents, the type of SPE cartridges, solvent volumes, initial spiking levels and soil types (silty clay loam and clay loam soils). The soil extraction method was validated using these two types of soils, representing two typical agricultural soils in northern China. For 2?g soil, the extraction steps with the mixture of potassium phosphate buffer and acetonitrile (ACN) (1/1, v/v, pH 3.2) provided satisfactory recoveries. In the clay loam soil, the recoveries of all the compounds were from 56% to 89% at the spiking level of 50?µg?kg?1 soil, and from 69% to 97% at the spiking level of 200?µg?kg?1 soil, respectively. Recoveries in silty clay loam soil were similar to that in clay loam. The method was successfully employed using soil samples collected from a farmland and afforestion area irrigated with sewage in northern China. The result indicates that trace antibiotics in sewage may accumulate in soil irrigated by river water containing sewage.  相似文献   
9.
Abstract

The effect of soil composition on the adsorption and desorption of the herbicide thiazafluron [1.3-dimethyl-1-(5-trifluoromethyl-1,2,3-thiadiazol-2-yl) urea] by 20 soil samples of 13 selected soil profiles of southern Spain has been studied. The adsorption curves conformed the Freundlich equation and the values of the constants, Kf and nf, ranged from 0.13 to 4.64 and from 0.14 to 1.30, respectively. The simple and multiple regression analysis between Kf and soil properties revealed soil clay content, illite content and CEC as fundamental factors determining thiazafluron adsorption by soils. Unlike other substituted ureas, non significant correlation was found with soil organic matter. Desorption of thiazafluron was hysteretic in all cases, showing and values much lower than those for adsorption. Desorption kinetic indicated that this hysteresis is essentially due to irreversible adsorption, although some degradation seems also to occur. The Freundlich desorption Kfd values were closely related to the same factors as Kf: clay and illite contents and also montmorillonite content, suggesting that most of the hysteresis was due to thiazafluron irreversibly bound to soil clay mineral components.  相似文献   
10.
Abstract

Silage effluents, generated during silaging of various crops, are produced in high amounts in cattle breeding farms. Due to their acidity and high content of dissolved organic matter, they are causing disposal problems. On the other hand, their ability to mobilise soil bound trace elements (i.e. heavy metals) might be useful for the decontamination of polluted soils.

With an aim to perform metal leaching studies, silage effluents from various ensiled crops (maize, rape, grass, clover, sugar-beet leaves) were collected from Bavarian farms and analysed for their main inorganic and organic constituents. Important TOC sources (TOC concentrations from 13.9 to 53.6 gl?1) are short chain aliphatic acids (concentrations between 235 and 638 mM·D1?1; predominant compound: lactic acid), amino acids (ranging from 22.8 to 151 mM·D1?1) and polypeptides (concentrations from 3.8 to 20.0 g·D1?1).

The release of heavy metals from two adsorbents (bentonite and peat) and from a polluted soil under the influence of silage effluents was studied in batch tests. The leaching efficiencies for the soil bound metals increase following the order: sugar-beet leaves < clover < maize < rape < grass. The extraction rates obtained with grass silage juice are: Cd 74.7%, Zn 55.7%, Cu 53.5%, Ni 38.9%, Cr 12.7% and Pb 8.9%. After neutralisation the leaching rates dropped, with the exception of copper.  相似文献   
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