Determination of chemical species of selected trace elements in fly ash

Complex analytical methods have been developed for determining the chemical composition of fly ashes. Samples were collected at coal-fired power plants and municipal waste incinerators. Morphological investigations and single particle analysis were performed by SEM/EDAX method. A survey of mineralogical phases was made by X-ray powder diffraction and infrared spectrometry. Solvent-leaching experiments were carried out for the information on the mobility of metal pollutants under real environmental conditions. Copper, Ni, Co, Cr, Pb and Cd have been studied, and of the toxic metals, Cd has been found in exchangeable forms in a great amount. Mobile species of toxic metals may have an impact on the quality of receiving waters or on organisms in soils.     

Determination of trace elements in biological fluids

Main approaches to the trace element analysis of biological fluids and problems appearing in this case are considered. The specific character of these approaches is illustrated by the examples of the analysis of real samples for various trace elements. The advantage of methods for the direct determination of trace elements in these samples is demonstrated.     

Mushrooms as biological monitors of trace elements in the environment

Mushrooms as a functional system relating to the most important environmental compartments (soil, water, air), may be used advantageously as biological monitors of the state of the environment. In particular the aerial parts of the mushroom (head and stem), because of their rapid growth rate from a few days to a few weeks, could be a useful indicator of fluctuations that may occur in the ecosystem. In this study the levels of fallout radionuclides¹³⁴Cs,¹³⁷Cs, due mostly to the Chernobyl nuclear accident, of natural radionuclide⁴⁰K and of the stable elements Se, Hg, Cr, Cs, Sc, Rb, Zn, Fe, Co, Eu, Sb, Ag, Ce, Ba, Ni present in the head and stem of mushroom samples from an area of the Italian Alps were measured. The analytical technique used was Instrumental Neutron Activation Analysis and gamma-spectrometry. The results are discussed and possible correlations with other environmental parameters are examined.     

Considerations in the preparation of biological and environmental reference materials for use in the study of the chemical speciation of trace elements

Summary The role that information on chemical speciation can play in the selection of reference materials for the analysis of biological and environmental samples is reviewed. Some considerations that might go into the preparation of materials designed for chemical speciation studies are explored. Individual steps in the preparation of lyophilized serum and urine reference materials are examined in relation to changes that could occur in the chemical speciation of trace elements.     

Determination of trace elements in biological materials by neutron activation and extraction with TOPO

Solvent extraction with TOPO from 6M hydrochloric acid is proposed as a method for the elimination of interfering activities in neutron activation analysis of biological material for trace elements. By this procedure²⁴Na,⁴²K,³²P,⁸²Br, and⁴⁷Ca are efficiently removed, and a number of trace element activities can be measured by Ge(Li) spectrometry. Chemical yields are determined by re-activation. Data for Cu, Zn, Mo, and Cd in two biological standards are presented.     

Analytical evaluation of comparative data on trace elements in biological materials

Large bodies of data on a given material from different sources appear a major advantage of intercomparison experiments and a sound basis for a straight statistical evaluation (as is the usual approach in the assignment of recommended or consensus values). On closer inspection of the results, however, it is usually found that only one or two techniques are represented in statistically significant numbers, most frequently AAS and NAA, and their distribution may not be normal. Correct results are sometimes hidden among laboratory means in the lower or upper part of the frequency distribution plots. Conventional statistics neglecting procedural details and the chemistry behind a procedure may result in incorrect assignment from the reported data, which can be affected by unidentified systematic effects. Generally, in the lowest concentration range contamination predominates as the systematic error determining the accuracy of results. Activation analysis being the least vulnerable to this type of error, it is, if applicable, in principle the most likely to give correct answers. Follow-up work was carried out in this laboratory on the IAEA reference samples of Milk Powder A-11, Muscle Tissue H-4, Fish Flesh MA-A-2 and the Soil-5, clearly demonstrating the potential of activation analysis as verification technique. By determining the same element in the destructive and nondestructive mode, and on the basis of two different isotopes, virtually independent approaches are achieved, often allowing the disclosure of different types of errors. Results are also reported for nickel by a new voltammetric technique enabling its determination at the microgram per kilogram level.     

Determination of trace elements in biological material by neutron activation analysis

Eighteen trace elements in biological material [grass /Imperata cylindrica/, mimosa plant /Mimosa pudica/, rice] by neutron activation method were determined. In the comparative analysis, we found the content of the same elements was different in the each material, although they were collected at the same place and the same sampling method was applied.     

Bioavailability of essential trace elements in the presence of phytate, fiber and calcium

Summary Bioavailability and/or homeostasis of some essential trace elements such as zinc, iron, etc., in the presence of phytate, fiber and calcium are subject to alteration. These factors were measured in this study for Iranian diets in a frame of a Coordinated Research Project (CRP). However, the most prominent dietary factor in this regard is phytate. The phytate effect on zinc homeostasis is a chemical phenomenon dependent physiologically on pH in the gastrointestinal tract at or near the sites of absorption. Calcium is a synergistic coprecipitating factor in the complexation of zinc by phytate. Fiber has also a tendency to absorb insoluble compounds in gastrointestinal tract including zinc, iron and many other trace elements. One of the most known clinical observations regarding zinc deficiency was found in the rural area of the Fars province of Iran in the late 1950s at Shiraz University. However, the molar ratio of [phytate] : [zinc] and [calcium] [phytate] : [zinc] in Iranian Diets in a recent study are 7-17 and 150-800, respectively. The critical ratios of [phytate] : [zinc] of 10 or less will provide adequate zinc to sustain homeostasis.     

Radiochemical determination of some trace elements in biological materials using short-lived isotopes

A radiochemical procedure for the consecutive separation of vanadium and molybdenum, copper, manganese, rubidium and potassium is proposed for the analysis of biological materials. Vanadium and molybdenum are extracted together with 0.1% BPHA solution in toluene, copper followed by manganese are extracted as diethyldithio-carbamate complexes with chloroform and rubidium and potassium are precipitated as tetraphenylborates.     

Determination of trace elements in biological standard kale by neutron activation analysis

Fifteen elements at trace levels have been determined by neutron activation analysis in the biological standard kale distributed byBowen. La, Br, As, Se, Sc, Ag, Zn, Co, Cr, Sb, Eu, Fe, and Zr have been determined by a nondestructive technique using a high-resolution Ge(Li) detector. Two more elements, Au and Hg, have been determined after radiochemical separation. The nondestructive procedure is shown to yield data in generally good agreement with those obtained by destructive techniques. Potential sources of error in the nondestructive technique are discussed.     

Speciation of trace elements in biological materials: trends and problems.

In the determination of trace elements in biological materials, speciation is of particular importance as the essential effects or toxicity of an element and its metabolic behaviour depend to a large extent on the chemical forms in which it is present in the organism. Speciation is relatively easy if a property of a particular compound can be measured directly in the sample without interference from the other components of the material, e.g., the enzymic activities of the metallo-enzymes. Another possibility for speciation is immunoassay, which likewise allows direct determination of a particular trace element. At present, however, with most trace elements both fractionation methods and analytical procedures have to be combined and speciation has to be carried out by determining the elemental content in the separated fractions. The methods and apparatus used in taking, storing and preparing the samples can, therefore, not be selected solely according to the requirements of trace element determination, but it is also essential to ensure that the biological structures of the components to be separated remain intact. In this work the need for speciation in the investigation of the toxic and essential effects of trace elements is shown with the help of some examples, and the problems that can occur in the various steps of sampling, storage and sample preparation are discussed.     

Mineral elements and essential trace elements in blood of seals of the North Sea measured by total-reflection X-ray fluorescence analysis

Mineral and essential trace elements are involved in numerous physiological processes in mammals. Often, diseases are associated with an imbalance of the electrolyte homeostasis. In this study, the concentrations of mineral elements (P, S, K, Ca) and essential trace elements (Fe, Cu, Zn, Se, Rb, Sr) in whole blood of harbor seals (Phoca vitulina) were determined using total-reflection X-ray fluorescence spectrometry (TXRF). Samples from 81 free-ranging harbor seals from the North Sea and two captive seals were collected during 2003–2005.Reference ranges and element correlations for health status determination were derived for P, S, K, Ca, Fe, Cu, and Zn level in whole blood. Grouping the seals by age, gender and sample location the concentration levels of the elements were compared.The blood from two captive seals with signs of diseases and four free-ranging seals showed reduced element levels of P, S, and Ca and differences in element correlation of electrolytes were ascertained.Thus, simultaneous measurements of several elements in only 500 μL volumes of whole blood provide the possibility to obtain information on both, the electrolyte balance and the hydration status of the seals. The method could therefore serve as an additional biomonitoring tool for the health assessment.     

Radionuclides and trace elements in centipede species Scolopendra cingulata from Serbia

The adults of centipede Scolopendra cingulata from Serbia have been analyzed for ²¹⁴Bi, ¹³⁷Cs, ²²⁸Ac, ⁴⁰K, ²¹²Pb and ²¹⁴Pb activity. The top 5 cm of soil from the same locations (Novi Pazar, Izbice and P?inja) is also measured—to estimate upper limit of the soil–S. cingulata radionuclide transfer factors (i.e., S. cingulata/soil concentration ratios), as well as the total dose rate—external and internal exposure. Cesium-137 activity was found to be below (or equal to) minimum detectable activity in all 16 specimens. The highest measured ²¹⁴Bi activity was 0.1 Bq g^?1, while ²²⁸Ac—0.086 Bq g^?1, ⁴⁰K—0.12 Bq g^?1, ²¹²Pb—0.012 Bq g^?1 and ²¹⁴Pb—0.029 Bq g^?1. Bismut-214 transfer factors are found to range from <0.34 to 6, as ²²⁸Ac—from <0.4 to 3, whilst the total dose rate is found to be less than 18 μGy h^?1. The As, Se, Cd, Co, Cr, Cu, Mn, Ni, Pb, but also Zn and Fe concentrations—in three individuals, were also determined. All the elements showed concentrations in the P?inja S. cingulata significantly lower than in S. cingulata from Novi Pazar and Izbice.     

Interaction of arsenic and selenium on the metabolism of these elements in hamsters

The interaction of arsenic and selenium compounds on the metabolism of these elements in golden hamsters was studied. Golden hamsters were divided into three groups and administered sodium selenite (Na₂SeO₃), sodium arsenite (NaAsO₂) and Na₂SeO₃ with NaAsO₂, respectively, by a single Subcutaneous injection of 25 m?mol kg^?1 body weight as As or Se (arsenic and selenium were calculated as weight of elemental arsenic and selenium). Selenium and arsenic metabolites were determined by high-performance liquid chromatography–graphite furnace atomic absorption spectrometry (HPLC–GFA AA) and gas chromatography (GC). The results show (1): About 10% by weight of the given dose of selenium was excreted in expiration air as dimethylselenide (Me₂Se) during 12 h after administration of Na₂SeO₃. Excretion of dimethylselenide with the respiratory air was inhibited by administration of Na₂SeO₃ simultaneously with NaAsO₂. (2) Giving Na₂SeO₃ plus NaAsO₂ had no appreciable effect on the excretion of the trimethylselenonium ion (Me₃Se⁺) into the urine and the feces. (3) Giving Na₂SeO₃ plus NaAsO₂ increaed the excretion into the feces of an insoluble unknown-structure selenium compound, the proportion of which was 10.9% by weight of the given dose of selenium. (4) Giving NaAsO₂ plus Na₂SeO₃ decreased the excretion of dimethylarsinic acid (Me₂AsOOH) and inorganic arsenic into the urine during 120 h after the administration of the reagents, the decreased amount being 5.3% (dimethylarsinic acid) and 7.7% (inorganic arsenic) of the given dose of arsenic, respectively. (5) Giving NaAsO₂ plus Na₂SeO₃ increased the excretion into feces of insoluble unknown-structure arsenic compound and inorganic arsenic, the increased amounts being 10.6% and 7.0% of the given dose of arsenic, respectively. (6) Giving NaAsO₂ plus Na₂SeO₃ decreased the excretion into feces of extractable unknown-structure arsenic compound, and the decreased amount was 4.9% of the given dose of arsenic. (7) It made little difference to the excretion of monomethylarsonic acid [MeAsO(OH)₂] into urine and feces and of dimethylarsinic acid (Me₂AsOOH) into feces whether NaAsO₂ was administered alone or with Na₂SeO₃.     

A mechanistic model for the metabolism of corrosion products and of biological trace elements in metallosis tissue based on results obtained by activation analysis

Instrumental neutron activation analyses have been carried out on tissues adjacent and distant from metal implants. From the time-dependence of the concentrations of the corrosion products some conclusions have been drawr on the routes of metal transport from the implant. Additionally, the behaviour of haematoma iron has been shown as well as the dependence of the zinc concentrations on different biochemical processes, during implantation and then at the following stages of the development of the metallosis tissue. This work was supported by the Bundesministerium für Forschung und Technologie, the Deutsche Forschungsgemeinschaft, and the Fonds der Chemischen Industrie.     

Determination of trace elements in biological materials by instrumental epithermal neutron activation analysis

The use of reactor epithermal neutrons in instrumental activation analysis is described for the determination of trace elements via long-lived isotopes. A boron carbide filter is used. Results of analyses of human erythrocytes, plasma, urine and some biological reference materials are given to demonstrate the applicability of the method to biological samples. Bromine, iron, cesium, rubidium, selenium and zinc and cobalt are determined. The method provides accuracy and reliability similar to conventional thermal neutron activation but is faster. Limits of detection attainable with the two techniques are compared.     

Determination of trace elements in biological materials using tetramethylammonium hydroxide for sample preparation

A method to prepare milk powder, bovine liver and bovine muscle samples for analysis by electrothermal atomic absorption spectrometry (ETAAS) is proposed. Samples are mixed with a small amount of tetramethylammonium hydroxide (TMAH) and a stable and homogeneous slurry is produced in ca. 2 h with heating at 60–70 °C. After such sample preparation and dilution with water, trace elements are determined in certified reference materials. Pyrolysis and atomisation temperatures are optimised for each element, and several modifiers are investigated. External calibration is used for every analyte. Limits of detection (LODs), precision and accuracy are reported for Cd, Pb, Ni, Cr, Cu and Ag and compared with those obtained after conventional acid digestion. The main advantages of the proposed method are the simplicity of sample preparation and the longer lifetime of the graphite tube.     

Neutron activation analysis of biologically essential trace elements in environmental specimens using pyrrolidinedithiocarbamate extraction

A new radiochemical group separation method using APDC reagent in the extraction procedure has been developed. The method has been applied to the radiochemical separation for activated biological samples and also to the preconcentration technique for sea water samples. The transition elements are extracted into chloroform phase from the pH 3.0 aqueous phase and only manganese is subsequently extracted from the pH 7.0 aqueous phase. The validity of the method is demonstrated by analyzing the NBS standard reference materials. In the specimens preconcentrated from the sea water samples adjusted pH to 5.5, vanadium, manganese, copper and zinc can be determined.     

Soil-to-plant transfer of 137Cs and other essential and trace elements in cabbage plants

The concentrations of ¹³⁷Cs and other essential and trace elements were determined in soils and in cabbage heads collected from 8 agricultural fields in Aomori Prefecture, Japan and the soil-to-plant transfer factors were determined. The 95% confidence intervals of the elements, excluding ¹³⁷Cs, La and Ce, were within 2 orders of magnitude. The transfer factor of ¹³⁷Cs was approximately 4 times higher than that of Cs, and they were well correlated. In addition, the distributions of elemental concentrations in different leaf positions of a cabbage plant were also determined and were divided into three groups according to their different distribution patterns in the leaf positions. These patterns were as follows: (1) the concentrations of the elements in older (outer) leaves were higher than in younger (inner) ones (Ca, Sr, etc.), (2) the concentrations of the element had a relatively constant value independent of their leaf position (K, Rb, etc.), and (3) the concentrations of the elements were higher in both the older and younger leaves compared to the leaves in the middle portion (Zn). The percentage distribution of the dry weight contents in the edible leaves of cabbage plants was 41% at harvest time, however each element had different distribution patterns.