A comparison of an optimised sequential extraction procedure and dilute acid leaching of elements in anoxic sediments, including the effects of oxidation on sediment metal partitioning

The effect of oxidation of anoxic sediment upon the extraction of 13 elements (Cd, Sn, Sb, Pb, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As) using the optimised Community Bureau of Reference of the European Commission (BCR) sequential extraction procedure and a dilute acid partial extraction procedure (4 h, 1 mol L⁻¹ HCl) was investigated. Elements commonly associated with the sulfidic phase, Cd, Cu, Pb, Zn and Fe exhibited the most significant changes under the BCR sequential extraction procedure. Cd, Cu, Zn, and to a lesser extent Pb, were redistributed into the weak acid extractable fraction upon oxidation of the anoxic sediment and Fe was redistributed into the reducible fraction as expected, but an increase was also observed in the residual Fe. For the HCl partial extraction, sediments with moderate acid volatile sulfide (AVS) levels (1-100 μmol g⁻¹) showed no significant difference in element partitioning following oxidation, whilst sediments containing high AVS levels (>100 μmol g⁻¹) were significantly different with elevated concentrations of Cu and Sn noted in the partial extract following oxidation of the sediment. Comparison of the labile metals released using the BCR sequential extraction procedure (ΣSteps 1-3) to labile metals extracted using the dilute HCl partial extraction showed that no method was consistently more aggressive than the other, with the HCl partial extraction extracting more Sn and Sb from the anoxic sediment than the BCR procedure, whilst the BCR procedure extracted more Cr, Co, Cu and As than the HCl extraction.     

Study of the Contents and Speciation of Heavy Metals in River sediments By Factor Analysis

Abstract

Heavy metals Zn, Cd, Pb, Cu, Ni and Co from two spanish river sediments have been determined by voltammetric techniques, along with % CaCO₃ and % organic matter, and the whole data set examined by means of Factor Analysis, finding a different behaviour of the metals in each river.

Heavy metal speciation in the sediments was carried out by using the Tessier's scheme: Zn and Pb were mainly associated to ‘reducible phases’, Cd and Cu bound to ‘organic matter and sulphides’, and Ni and Co were distributed between the above fractions. The ‘residual’ metals were used as pollution indicators from the rivers, finding a similar behaviour to other industrialized river systems.     

Ultrasound-Assisted Extraction for the Evaluation of Element Mobility in Bottom Sediment Collected at Mining and Smelting Pb–Zn Ores Area in Poland

The current BCR procedure for metal fractionation recommended by the Standard Measurement and Testing Programme requires rather time-consuming sample pretreatment. Ultrasonic energy seems to be an attractive alternative for leaching metal from solid samples into a liquid extractant phase. This study aims at optimizing ultrasonic extraction in order to replace the BCR method of leaching using acetic acid and to apply the procedure of assessing element mobility in bottom sediment rich in moderately soluble carbonate minerals. The application of ICP-MS allowed the determination of As, Cd, Cr, Cu, Pb, Ni, Tl and Zn in extracts, in a wide range of concentration without any special treatment. Finally, 40’min extraction in an ultrasonic bath was proposed for evaluation of the mobile fraction of As, Cd, Cr, Cu, Pb and Zn as an assessment of environmental risk. The recovery of the ultrasound-assisted extraction in comparison to the shake-filter method, as applied in the common BCR procedure, was slightly higher than 100% for As, Cr and Pb, reasonably high (about 70%) for Cd, Zn and Cd, but did not exceed 21% for Tl. Also, the mobility and extractability (relative mobility) of the studied elements from sediment collected over one year were compares. According to the results obtained after 40’min of ultrasound-assisted extraction it can be concluded that mobility did not change over one year for Cr, Cu, As, Cd, Ni and Tl, but noticeable differences for Zn and Pb were observed. The total content of all studied elements was almost the same in samples taken in the years 2003 and 2004, respectively.     

Comparative study of optimised BCR sequential extraction scheme and acid leaching of elements in the certified reference material NIST 2711

The optimised BCR sequential extraction procedure and a 4 h 1 mol L⁻¹ HCl partial extraction have been performed on the NIST 2711 reference material for a suite of 12 elements (Cd, Sb, Pb, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As) using magnetic sector ICP-MS. A pseudo-total aqua regia digest of NIST 2711 has also been undertaken for quality assurance purposes, and comparison of the sum of the four BCR fractions, which included an aqua regia digest on the residue, with the pseudo-total aqua regia digest has been used to assess the accuracy of the BCR partitioning approach. As a result of this work, discrepancies between previous studies about BCR partitioning of elements in NIST 2711 have been discussed and an increase in confidence about the use of BCR partitioning scheme on seven elements (Cd, Pb, Al, Mn, Fe, Cu, Zn) in this standard material has been obtained. On the other hand, BCR partitioning for Sb, Cr, Co, Ni and As has been provided for the first time. Partial extraction results are also reported for the same 12 elements analysed by the optimised BCR procedure, with the partial extraction results exhibiting a strong correlation with the sum of the three labile steps of the BCR procedure.     

Evaluation of heavy metal bioavailability in soil amended with poultry manure using single and BCR sequential extractions

In the present study, three-step Community Bureau of Reference sequential extraction scheme (BCR-SES) and single extraction methods were performed to assess the mobility and availability of heavy metals (Cd, Cu, Pb, Fe and Zn) in an agricultural soil before and after amendment with poultry waste (PW).The PW samples were collected from poultry farms, situated in Hyderabad Sindh, Pakistan. The extractable heavy metals were measured by flame and electrothermal atomic absorption spectrometry. The validation of the method was carried out by analysis of a certified reference material of soil amended with sewage sludge (BCR-483). The single extractions using calcium chloride and EDTA, separately, while BCR-SESs were developed to evaluate the available heavy metals to plants and their environmental accessibility for control soil (CS), PW and soil amended with PW (SPW).The pH of the PW and SPW were found to be < 6.0, which may enhance the leaching of heavy metals to agricultural soil. The results from the partitioning study indicated that easily mobilised forms (acid exchangeable) of Cd were higher than other heavy metals. The oxidisable fractions of all heavy metals were dominant in PW and SPW as compared to found in CS samples. The EDTA- and CaCl₂-extractable heavy metals correspond to 5.0 to 10 and 0.5 to 3.0%, respectively of total contents in all three solid samples. Contamination factors revealed that the retention of Pb and Zn were higher compared with Cu, Cd and Fe in CS, PW and SPW samples.     

Comparison of Two Sequential Extraction Procedures for Trace Metal Partitioning in Sediments

Abstract

Two sequential extraction schemes (a modified Tessier procedure with five steps and a three steps protocol designed by BCR) are applied to four sediment samples with different heavy metal contents. The results obtained for Cd, Cr, Cu, Ni, Pb and Zn partitioning show that the metal distribution obtained with both procedures are significantly different. With the second procedure amounts of all the heavy metals are extracted with the oxidizing reagent (third fraction) whereas with the first one the non residual metals are distributed among the second, third and fourth fractions (acetic acid-acetate buffer (pH=5), reducing and oxidizing reagents respectively). The residual fraction obtained applying the three steps procedure is in general higher than that obtained using the five steps procedure, except for cadmium.     

Current interlaboratory precision of exchangeable soil fraction measurements

 In addition to conventional aqua regia and EDTA extracts for monitoring trace metals in soils, the technique of examining exchangeable soil fractions has been suggested to estimate soil contamination and trace metal availability to plants. In order to establish a useful method for soil monitoring, interlaboratory precision as a primary selection criterion has been investigated. In order to assess the quality of data provided by laboratories participating in the organization of the Austrian Governmental Agricultural Research Institutes (ALVA), three soil samples have been analysed in a common ring test, annually, for the last 20 years. In addition to the annual list of parameters used for soil monitoring, within ALVA two NH₄-acetate extracts were run in 1994, three NH₄-acetate and NH₄NO₃ extracts in 1995 and three LiCl extractions in 1998. The procedures were tested for analytical precision and environmental indications in up to 12 laboratories, with respect to Cd, Cr, Cu, Ni, Pb and Zn. Due to the low extraction efficiency, for determinations in the resultant solutions, graphite furnace AAS was preferably selected, except for Zn and Cu. Flame-AAS and ICP-OES were not sensitive enough for non-contaminated sites. Interlaboratory precision of the data was in the range 10–65% coeff.var., and thus within the range of data given in the appendix of DIN 19730 (NH₄NO₃), as well as in a previous BCR report. Indications from exchangeable fractions seemed to be good for Zn and Cu, whereas they were impossible for Cr. Received: 25 October 1998 / Accepted: 26 January 1999     

Geochemical fractions and modeling adsorption of heavy metals into contaminated river sediments in Japan and Thailand determined by sequential leaching technique using ICP-MS

In order to provide information on the chemical processes in sediment fractions and their adsorption models, we investigated the contaminated sediments of the Sumida River in Tokyo, Japan and the Chao Phraya River in Bangkok, Thailand. Samples were leached through a sequential leaching technique to perform metal concentration analysis for the sediment fraction assessment and then samples were tested for the model adsorption of the highest level of sediments contaminated by heavy metals using the isotherm Langmuir and Freundlich equations. Metal (Pb, Cd, Zn, As, Cu, Ca, Fe, and Mn) concentration in the leached solutions was analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The pattern of geochemical fractions in both sediment samples showed the maxima leached levels of Cd (38.6 %), Ca (55.2%), and Mn (41.3%) in the soluble fraction; Pb (52.1%), and Zn (56.7%) in the reducible fraction; Cu (61.2%) in the oxidizable fraction; and As (47.1%) and Fe (55.9%) in the residual fraction. The total level fractions of Pb (62.6 ppm), Zn (240 ppm), As (27.2 ppm), Fe (16,636 ppm) and Mn (419 ppm) in the Chao Phraya River sediments were higher compared to those in the Sumida River, indicating the high anthropogenic effect in Bangkok. In the most contaminated sediments, the higher adsorption capacity of heavy metal concentrations was contributed by SiO_2, CaCO_3, and Al₂O₃ determined by the X-ray diffraction and organic contents. The model of adsorption of Cd fitted to the linear form of Langmuir’s equation with the correlation coefficients (r² = 0.94), b (0.467) and k (7137), whereas Pb, Cu, Cr, and Zn conformed to the model of the Freundlich equation.     

A Sequential Extraction Method Measures the Toxic Metal Content in Fly Ash from a Municipal Solid Waste Incinerator

The purpose of this research was to develop an optimized pretreatment procedure for toxic metals (Pb, Cd, Zn and Cu) content in fly ash from a municipal waste incinerator. In addition, modified sequential extraction procedures were used to characterize the chemical composition of the fly ash samples. The sequential extraction resolved the fly ash elements into the following chemical forms: soluble, exchangeable, carbonate, oxide, organic, and silicate compounds. Certified reference city waste incineration ash (BCR.176) was used as target ash samples. A H₂O₂+HNO₃+HF mixed acid digestion solution with a low temperature evaporation procedure was selected as optimal for the fly ash digestion. The digested solution was analyzed by inductively coupled plasma mass spectrometry (ICP‐MS), which effectively determined the concentrations of the toxic metal elements in BCR.176. Except for Cd, the recovery of Pb, Zn, and Cu under H₂O₂+HNO₃+HF digestion and their sequential extraction procedures were higher than 95%. The relative standard deviations (RSD) for recoveries of the four elements were within 10%. Furthermore, the sequential extraction procedure's results provided information on the potential mobility of the studied elements. Most of the Cd was bound to water‐soluble and carbonate material in the fly ash samples. Most of the Pb, Zn, and Cu was released to carbonates and bound to organic matter in the fly ash samples.     

Effect of air drying on speciation of heavy metals in flooded rice paddies

Flooded soil samples were collected in the typical area of the Yangtze Delta Region;fractions of heavy metals in flooded and air dried samples were measured with BCR sequential extraction method and atomic absorption spectrometry.In flooded soils, fractions of heavy metals increased in the order of acid soluble < oxidizable < reducible < residual.The acid soluble and reducible fractions significantly decreased but residual fraction significantly increased when the samples were air dried.The data obtained from air dried soil samples could not accurately represent the speciation of heavy metals in flooded field conditions.     

Fractionation of potentially toxic elements in urban soils from five European cities by means of a harmonised sequential extraction procedure

The revised (four-step) BCR sequential extraction procedure has been applied to fractionate the chromium, copper, iron, manganese, nickel, lead and zinc contents in urban soil samples from public-access areas in five European cities. A preliminary inter-laboratory comparison was conducted and showed that data obtained by different laboratories participating in the study were sufficiently harmonious for comparisons to be made between cities and land types (e.g. parks, roadside, riverbanks, etc.). Analyte recoveries by sequential extraction, with respect to direct aqua regia digestion, were generally acceptable (100 ± 15%). Iron, nickel and, at most sites, chromium were found mainly in association with the residual phase of the soil matrix. Copper was present in the reducible, oxidisable and residual fractions, whilst zinc was found in all four sequential extracts. Manganese was strongly associated with reducible material as, in some cities, was lead. This is of concern because high lead concentrations were present in some soils (>500 mg kg⁻¹) and the potential exists for remobilisation under reducing conditions. As would be expected, extractable metal contents were generally highest in older, more heavily industrialised cities. Copper, lead and zinc showed marked (and often correlated) variations in concentrations between sites within the same city whereas manganese and, especially, iron, did not. No overall relationships were, however, found between analyte concentrations and land use, nor between analyte partitioning and land use.     

Assessment of trace metals contamination in estuarine sediments using a sequential extraction technique and principal component analysis

Fractionation of the metals Cd, Cr, Cu, Ni, Pb and Zn in sediments was performed for samples collected from eight locations in the Poxim river estuary of Sergipe State, northeast Brazil, using the 3-stage sequential extraction procedure proposed by the European Community Bureau of Reference (BCR). The extraction method was found to be satisfactory for analysis of certified reference material BCR-701, with recovery values ranging from 85% (Cu) to 117% (Cr). The detection limits obtained were 0.001 to 0.305 µg g^− 1. Zn exhibited greatest mobility and bioavailability, indicative of anthropogenic sources, while Cr was mainly found in the residual fraction and could be used as an indicator for the contribution from natural sources. Cd, Cu, Ni and Pb were associated with the oxidizable fraction, and Pb, Cr and Ni with the reducible fraction. Principal component analysis (PCA) clearly separated the metals into three groups: I (Zn); II (Pb); III (Cd, Cu, Cr and Ni). These groupings were mainly due to different distributions of the metals in the various fractions, in sediments from the different locations. Risk assessment code (RAC) analysis indicated that although the metals presented a moderate overall risk to the aquatic environment, nickel showed a low risk (RAC < 10%) at three sites, while zinc presented a high risk (RAC > 30%) at four other sites.     

Determination of heavy metals (Pb, Cd, Cu, Zn, Cr) in sedimentary reference materials with IDMS: total concentration and aqua regia soluble portion

Summary The total concentration and the aqua regia soluble portion of traces of Pb, Cd, Cu, Zn, and Cr are determined with isotope dilution mass spectrometry (IDMS) in three different types of sediments using a thermal quadrupole instrument (THQ). The results are compared with those obtained by other methods during a certification project to establish these sediments (BCR 277, BCR 280, BCR 320) as standard reference materials. The IDMS (THQ) results are in good agreement with the preliminary certification values and the results of two other laboratories, which applied IDMS using magnetic sector field mass spectrometers. Significant differences between the different analytical methods were found for the total Pb concentration, which could be explained by adsorption and coprecipitation effects during the chemical pretreatment of samples. Using aqua regia instead of HF/HNO₃ for the decomposition of sediments, only 65%–95% of the total Pb and 60%–90% of the total Cr could be dissolved. On the other hand, only a small or negligible portion of Zn, Cd, and Cu could not be dissolved by aqua regia. The IDMS values for the aqua regia soluble Cr portion are significantly higher compared to the results of other methods. This can be explained by adsorption effects.

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Bestimmung von Schwermetallen (Pb, Cd, Cu, Zn, Cr) in sedimentären Standard-Referenzmaterialien mit massenspektrometrischer Isotopenverdünnungsanalyse: Totalgehalt sowie in Königswasser löslicher Anteil

     

Certification of trace element contents (As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn) in a fly ash obtained from the combustion of pulverised coal

Summary The element contents of As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb und Zn of a fly ash from pulverised coal are certified. The procedures and their results for the homogenisation, the contamination and homogeneity checks and the analytical campaign are reported. The certified mass fractions and indicative values for Cr, Ni, Th, V and water soluble sulphate are given. The work was carried out within the framework of the activities of the Community Bureau of Reference (BCR) of the Commission of the European Communities.

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Zertifizierung von Spurengehalten (As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb und Zn) in einer Flugasche aus Pulverkohle

Zusammenfassung In einer Flugasche aus Pulverkohle wurden die Elementgehalte an As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb und Zn zertifiziert. Über die Homogenisierung, die Kontrolle der Kontaminierung und Homogenität und die analytischen Ringversuche wird berichtet. Die zertifizierten Gehalte sowie der Gehalt von Cr, Ni, Th, V und wasserlöslichem Sulfat werden gegeben. Die Arbeit wurde ausgeführt im Rahmen des Programms des Referenzbüros der Kommission der Europäischen Gemeinschaften (BCR).

     

Determination of Al, Cu, Fe, Mn, Pb and Zn in certified reference materials using the optimized BCR sequential extraction procedure

Sequential extraction procedures are widely used to characterize the fractionation of metal species in solid media. With the variety of different sequential procedures used in environmental and geochemical exploration studies, it is difficult to compare results between studies. Thus, harmonization and standardization are required to provide greater inter-study comparability for fraction-specific metals. In this study, the optimized BCR three-step sequential extraction procedure is applied to five certified reference materials (SRM 2710, SRM 2711, CRM 483, CRM 601 and CW 7). Four fractions are reported, acid extractable, reducible, oxidizable, and residual for Al, Cu, Fe, Mn, Pb and Zn. The objectives of this study were to characterize experimental precision and/or accuracy and to establish baseline data of fraction-specific element concentrations for future studies applying the optimized BCR three-step extraction procedure. The optimized procedure was found to be precise (typically <5%) for all metals in all fractions. Accuracy was acceptable (typically ±15% relative to published indicative values for Cu, Pb and Zn for CRM 483 and CRM 601) for all individual fractions. Detailed fraction-specific concentration data are presented, based on five replicates, for the first time using the optimized procedure for Al, Fe and Mn in CRM 483 and CRM 601, and for Al, Cu, Fe, Mn, Pb and Zn in SRM 2710, SRM 2711 and CW 7.     

Preparation of morin modified nanometer SiO<Subscript>2</Subscript> as a sorbent for solid-phase extraction of trace heavy metals from biological and natural water samples

Morin was successful as a chemical modifier to improve the reactivity of the nanometer SiO₂ surface in terms of selective binding and extraction of heavy metal ions. This new functionalized nanometer SiO₂ (nanometer SiO₂-morin) was used as an effective sorbent for the solid-phase extraction (SPE) of Cd(II), Cu(II), Ni(II), Pb(II), Zn(II) in solutions prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of trace levels of metal ions were optimized with respect to different experimental parameters using static and dynamic procedures in detail. The pH 4.0 was chosen as the optimum pH value for the separation of metal ions on the newly sorbent. Complete elution of the adsorbed metal ions from the nanometer SiO₂-morin was carried out using 2.0 mL of 0.5 mol L⁻¹ of HCl. Common coexisting ions did not interfere with the separation and determination at pH 4.0. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 22.36, 36.8, 40.37, 33.21 and 25.99 mg metal/g SiO₂-morin for Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II), respectively. The time for 95% sorption for Cu(II) and Ni(II) and 70% sorption for Cd(II), Pb(II) and Zn(II) was less than 2 min. The relative standard deviation (RSD) of the method under optimum conditions was lower than 5.0% (n = 11). The procedure was validated by analyzing the certified reference river sediment material (GBW 08301, China), the results obtained were in good agreement with standard values. The nanometer SiO₂-morin was successfully employed in the separation and preconcentration of trace Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) from the biological and natural water samples yielding 75-folds concentration factor.     

Investigation of heavy metals mobility in shrimp aquaculture sludge—Comparison of two sequential extraction procedures

Influence of heavy metals was investigated by conducting various tests on the samples collected from aquaculture shrimp in Selangor, Malaysia. The concentration of heavy metals in the sludge and potential of mobility based on its association forms was studied. Two sequential extraction methods (five stages Tessier method and three steps BCR method) were used to determine the binding forms of the metals.From the analysis, Ca, Fe and Mn were found to be highest concentrated metals compared to Zn, Cu, Cr, Cd and Pb in aquaculture shrimp sludge. From the sequential extraction, Cd, Mn and Pb were mostly found in exchangeable/carbonate form, showed its susceptibility to be leached easily. Also Cu and Zn were extracted predominantly in oxidizable form. All metal concentrations (except Cd, Zn and Cu) were extracted to be higher in residual fraction in this method. The results of BCR method are totally similar to the five stages Tessier method. By comparing the percent of recovery, the BCR method was better than Tessier method. Nevertheless for both methods the percent of their recoveries were acceptable. For Pseudototal metal digestion, although the concentration of Cd is less than other heavy metals, it is very harmful as a fertilizer because Cd is one of the heavy metals that might be in the leaf or fruit of plants. Also for investigation of Ca in the sludge, this element was measured and high amounts of that show sludge is useful for growing of plant. The results of direct digestion of heavy metals show that with the control of Cd in this sludge we can use this sludge as fertilizer in soils for agriculture but it is better if it is used for fruitless plants.     

Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry by Means of a Lead Mediator

Anodic stripping voltammetry (ASV) is an analysis technique that permits the selective and quantitative analysis of metal ion species in solution. It is most commonly applied in neutral to acidic electrolyte largely due to inherent metal ion solubility. Bismuth (Bi) is a common film used for ASV due to its good sensitivity, overall stability and insensitivity to O₂. ASV, utilizing a Bi film, along with cadmium (Cd) and lead (Pb) as the plating mediators, has recently been adapted to determine zinc (Zn) concentrations in highly alkaline environments (30 % NaOH or 35 % M KOH). Successful analysis of Zn in alkaline relies on the ability of the hydroxide to form soluble metal anion species, such as Bi(OH)₄⁻ and Zn(OH)₄²⁻. Here, we look to extend this technique to detect and quantify copper (Cu) ions in these highly basic electrolytes. However, in general, the use of ASV to detect and quantify Cu ion concentrations is notoriously difficult as the Cu stripping peak potential overlays with that of Bi from the common Bi film electrode. Here, an ASV method for determining Cu concentration in alkaline solutions is developed utilizing Pb as a deposition mediator. As such, it was found that when analyzing Cu solutions in the presence of Pb, the stripping voltammetry curves present separate and defined Cu stripping peaks. Different analyzes were made to find the best stripping voltammetry performance conditions. As such, an accumulation time of 5 minutes, an accumulation potential of≤−1.45 V vs. Hg/HgO, and a concentration of 35 wt% KOH were determined to be the conditions that presented the best ASV results. Utilizing these conditions, calibration curves in the presence of 5.0 ppm Pb showed the best linear stripping signal correlation with an r‐squared value of 0.991 and a limit of detection (LOD) of 0.67 ppm. These results give way to evaluating Cu concentrations using ASV in aqueous alkaline solutions.     

Utilization of optimized BCR three-step sequential and dilute HCl single extraction procedures for soil-plant metal transfer predictions in contaminated lands

The prediction of soil metal phytoavailability using the chemical extractions is a conventional approach routinely used in soil testing. The adequacy of such soil tests for this purpose is commonly assessed through a comparison of extraction results with metal contents in relevant plants. In this work, the fractions of selected risk metals (Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Zn) that can be taken up by various plants were obtained by optimized BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and by single 0.5 mol L(-1) HCl extraction. These procedures were validated using five soil and sediment reference materials (SRM 2710, SRM 2711, CRM 483, CRM 701, SRM RTH 912) and applied to significantly different acidified soils for the fractionation of studied metals. The new indicative values of Al, Cd, Cu, Fe, Mn, P, Pb and Zn fractional concentrations for these reference materials were obtained by the dilute HCl single extraction. The influence of various soil genesis, content of essential elements (Ca, Mg, K, P) and different anthropogenic sources of acidification on extraction yields of individual risk metal fractions was investigated. The concentrations of studied elements were determined by atomic spectrometry methods (flame, graphite furnace and hydride generation atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry). It can be concluded that the data of extraction yields from first BCR SEP acid extractable step and soil-plant transfer coefficients can be applied to the prediction of qualitative mobility of selected risk metals in different soil systems.     

Application of sequential extraction and the ICP-AES method for study of the partitioning of metals in fly ashes

In this work, the original BCR extraction scheme was modified and applied to study the partitioning of metals in fly ashes. In the first step, the water-soluble fraction was investigated here. The next metal fractions were acid-soluble, reducible, and oxidisable. Two kinds of coal fly ash certified reference materials were analysed. Metal concentrations in the extracts were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). The efficiency of the extraction process for each step was examined. The partitioning of metals between the individual fractions was investigated and is discussed.