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.     

Leaching Behaviour and Solid Phase Fractionation of Selected Metals as Affected by Thermal Treatment of a Polluted Sediment

Abstract

A contaminated dredged sediment was subjected to a thermal treatment at temperatures ranging from 120 to 450°C. The leaching behaviour of selected metals (Cd, Cu, Pb, Zn, Fe, Mn) was studied using NH₄OAc-EDTA extraction. In addition, solid phase fractionation was carried out by means of a sequential extraction procedure.

The NH₄OAc-EDTA extraction showed a sharp increase in metal leachability from sediments treated at intermediate temperatures (120–350°C). The metal fractionation of the solid phases at the different temperatures did not reveal relevant shifts except for Cu. The decrease of the oxidizable Cu fraction was highly correlated (P < 0.001) with the disappearance of organic matter at higher treatment temperatures. It is suggested that binding energy changes within the fractions rather than shifts between chemical forms account for the observed leaching behaviour.     

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.     

Certification of the contents of some heavy metals (Cd, Co, Cu, Mn, Hg, Ni, Pb and Zn) in three types of sewage sludge

Summary The element contents of Cd, Co, Cu, Mn, Hg, Ni, Pb and Zn of three different types of sewage sludge were certified. The preparation, the homogeneity and the stability are reported. The certified contents as well as values for Cr and Se and for the aqua regia soluble contents of Cd, Cr, Co, Cu, Mn, Ni, Pb and Zn are given.

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Zertifizierung von Schwermetallspuren (Cd, Co, Cu, Mn, Hg, Ni, Pb und Zn) in drei Klärschlammproben

Zusammenfassung In drei verschiedenen Klärschlammproben wurden die Elementgehalte an Cd, Co, Cu, Mn, Hg, Ni, Pb und Zn zertifiziert. Es wird berichtet über die Herstellung, Homogenität und Stabilität. Die zertifizierten Gehalte sowie der Gehalt von Cr, Se und der Gehalt an königswasserlöslichem Cd, Cr, Co, Cu, Mn, Ni, Pb und Zn werden angegeben.

     

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.     

Certification of the contents of some heavy metals (Cd, Cu, Hg, Ni, Pb and Zn) in three types of soils

Summary The element contents of Cd, Cu, Hg, Ni, Pb and Zn of three types of soil were certified. The preparation, homogeneity and stability are reported. The certified contents as well as values for Co, Cr, Mn and Se and for the aqua regia soluble contents Cd, Cr, Cu, Mn, Ni, Pb and Zn are given.

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Zertifizierung von Schwermetallspuren (Cd, Cu, Hg, Ni, Pb und Zn) in drei Bodenproben

Zusammenfassung In drei verschiedenen Bodenproben wurden die Elementgehalte an Cd, Cu, Hg, Ni, Pb und Zn zertifiziert. Es wird berichtet über die Bereitung, Homogenität und Stabilität. Die zertifizierten Gehalte sowie der Gehalt an Cr, Co, Mn und Se und der Gehalt an königswasserlöslichem Cd, Cr, Cu, Mn, Ni, Pb und Zn werden angegeben.

     

Determination of Trace Metals in Antarctic Sediments from Terra Nova Bay - Ross Sea

Abstract

Trace metals (Cu, Pb, Zn, Cd, Cr, Ni, Co, Mn) and iron concentration were determined in several sediments collected in the Antarctica (Terra Nova Bay—Ross Sea). Samples were analyzed by inductively coupled plasma (ICP-AES) after selective and total extraction. The results are in good agreement with the data previously collected in the same area.     

Solvent extraction of metals using LIX26 extractant

Solvent extraction of some selected metals from an aqueous buffered solution by LIX26 extractant has been studied. The pH_1/2 values (at which 50% of metal ion is extracted) for extracting different metals by 1 v/v% LIX26 extractant in methyl isobutyl ketone have been obtained. The order of extraction of metals by LIX26 extractant as a function of pH_1/2 value is Pd(II)<Cu(II)<Sb(III)<Fe(II)<Co(II)<Zn(II)<Ni(II) <Pb(II)<Mn(II)<Cd(II).     

Polyethyleneimine Methylenephosphonic Acid for the Solid-Phase Sorption of Lead(II)

Abstract

In the first part of this work, polyethyleneimine methylenephosphonic acid (PEIMPA) was used as an effective sorbent for solid-phase extraction of Pb(II) ions from an aqueous solution. Conditions for effective sorption are optimized with respect to different experimental parameters in a batch process. The results showed that the amount of extraction decreases with solution pH in the range between 3.5 and 5.8. The sorption capacity is 609 mg·g^?1. The second part of the study focuses on the recovery of Pb(II) from a synthesized binary solution of Pb(II)–Zn(II) and from real Zn(II)-electrolyzed wastewaters. The presence of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), and Zn(II) in large concentrations has a significantly negative effect on extraction properties.     

Determination of trace metals in Nile River and ground water by differential pulse stripping voltammetry

The determination of trace metals in river water and ground water by DPSV is seriously disturbed by the presence of organic complexes. The influence of these substances can be eliminated by acidification of the samples with acids. Cd, Pb and Cu were determined at pH 1.1 (HNO₃ medium) and Zn, Cd, Pb and Cu at pH 2 (HCl medium), in both the Nile river and ground water. Zn was determined at pH 3.5 in HCl and pH 4.5 in HNO₃, after neutralizing the samples with NH₃/NH₄Cl buffer. Manganese could then be determined, after further addition of ammoniacal buffer solution up to pH 7.5 and 8.5. Ni and Co were determined in the adsorptive mode after formation of dimethylglyoximates at pH 9.2. The effect of pH on the stripping peaks of manganese was studied. Good agreement was observed between DPSV and AAS results for Zn, Cd, Pb, Cu and Mn, but the concentrations of Ni and Co were below the detection limits for AAS. Good agreement was obtained between DPSV results in HCl and HNO₃ for Ni and Co. The results indicate that decomposition of organic complexes by acidification with HNO₃ is better than in the case with HCl for Zn, Pb, Cu, Ni and Co, but HCl is better than HNO₃ for Cd and Mn.     

Experimental Designs in the Optimization of a Microwave Acid Digestion Procedure for the Determination of Metals in Paper and Board Samples by Atomic Absorption Spectrometry

Abstract

A Plackett-Burman design was carried out in order to find the significant experimental parameters affecting Cd, Co, Cr, Cu, Mn, Pb, and Zn extraction by microwave energy in paper samples. Eight variables were studied and optimized by means of a factorial design. The design showed that HCl and HNO₃ concentrations were the significant parameters in the microwave extraction procedure. The trace elements were determined by FAAS and ETAAS under optimum conditions. The levels of metals present in commercial samples, representing different types of paper and board and manufacturers are lower than those provided by the legislation.     

Evaluation of Ammonium Oxalate for Fractionating Metallic Trace Elements in Soils by Sequential Extraction

Abstract

Ammonium oxalate is largely used to extract the trace elements bound to Mn-oxides, amorphous compounds and crystalline Fe-oxides. The objective of this work was to evaluate the selectivity and the efficiency of ammonium oxalate for extracting Cd, Cu, Ni, Pb and Zn by sequential extraction of soils. For this purpose, three schemes were selected and applied to three different soil samples of the Swiss Jura. Each extraction scheme consisted of six steps, where different reagents were used to extract Cd, Cu, Ni, Pb and Zn bound to the Mn and Fe compounds. The results showed that metallic trace elements extraction with ammonium oxalate are very dependant on the metal studied. The reason could be the capability of oxalate to form stable complexes with the metals considered which sometimes are only slightly soluble.     

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.     

Automated titration of sub-microgram amounts of metal ions in aqueous solutions

Summary Using the same simple ion selective electrode of the copper sulphide-type, about 0.2–10 nMole of Cu(II), Zn(II), Cd(II) and Pb(II) ions can be chelometrically titrated. The sample to be analyzed disturbs an equilibrium situation in a solution containing about 2–5 · 10^–6 M of Cu²⁺-ions. In the titration of Zn, Cd and Pb the solution in equilibrium contains moreover about 0.05 mole/l of the copper-EDTA complex. The initial equilibrium signal is reset with EDTA. The standard deviation is about 0.5–2 ng (5 detn.). A titration takes about 1–4 min.

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Automatische Titration von Sub-Mikrogramm-Mengen von Metallionen in wäriger LösungI. Chelatometrische Titration von Cu(II), Zn(II), Cd(II) und Pb(II) mit einer einfachen ionenselektiven Elektrode

Zusammenfassung Mit einer ionenselektiven Elektrode vom CuS-Typ sind etwa 0,2–10 nMol Cu(II), Zn(II), Cd(II) and Pb(II) komplexometrisch zu bestimmen. Die Probe zerstört eine Gleichgewichtssituation in einer Lösung, die etwa 2–5 · 10^–6 M Cu²⁺ enthält. Bei der Titration von Zn, Cd, und Pb enthält die Lösung zusätzlich noch 0,05 Mol/l des Kupferkomplexonkomplexes. Nach Zufügung der Probe wird die Anfangslage mit ÄDTA wieder hergestellt. Die Standardabweichung (5 Bestimmungen) beträgt etwa 0,5–2 ng, die Titrationsdauer 1–4 min.

     

Distribution of Heavy Metals in Water and Soil Solutions Based on Colloid-Size Fractionation

The distribution of heavy metals Cr, Ni, Zn, Cu, Cd, and Pb among the truly dissolved (molecular weight cutoff <1 kD), colloidal (1 kD-0.20 µm and 0.20-0.45 µm) and particulate (>0.45 µm) fractions was investigated in the soil solution and surface water. In 15 soil solutions heavy metals were mainly present in the truly dissolved fraction (<1 kD) with occasional exceptions. And a good correlation was also found between the concentrations of metals in the truly dissolved fractions and the cation exchange capacity of soils. As for the surface water samples, the distribution pattern was more complicated one depending on metal properties and sampling sites.     

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).

     

Chemically modified silica gel with aminothioamidoanthraquinone for solid phase extraction and preconcentration of Pb(II), Cu(II), Ni(II), Co(II) and Cd(II)

Silica gel chemically bonded with aminothioamidoanthraquinone was synthesized and characterized. The metal sorption properties of modified silica were studied towards Pb(II), Cu(II), Ni(II), Co(II) and Cd(II). The determination of metal ions was carried out on FAAS. For batch method, the optimum pH ranges for Pb(II), Cu(II) and Cd(II) extraction were ≥3 but for Ni(II) and Co(II) extraction were ≥4. The contact times to reach the equilibrium were less than 10 min. The adsorption isotherm fitted the Langmuir's model showed the maximum sorption capacities of 0.56, 0.30, 0.15, 0.12 and 0.067 mmol/g for Pb(II), Cu(II), Ni(II), Co(II) and Cd(II), respectively. In the flow system, a column packed modified silica at 20 mg for Pb(II) and Cu(II), 50 mg for Cd(II), 60 mg for Co(II), Ni(II) was studied at a flow rate of 4 and 2.5 mL/min for Ni(II). The sorbed metals were quantitatively eluted by 1% HNO₃. No interference from Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻ and SO₄²⁻ at 10, 100 and 1000 mg/L was observed. The application of this modified silica gel to preconcentration of pond water, tap water and drinking water gave high accuracy and precision (%R.S.D. ≤ 9). The method detection limits were 22.5, 1.0, 2.9, 0.95, 1.1 μg/L for Pb(II), Cu(II), Ni(II), Co(II) and Cd(II), respectively.     

Determination of Trace Elements in Arsenic and Antimony Minerals by Atomic Absorption Spectrometry and k0-Instrumental Neutron Activation Analysis After Removal of As and Sb

The content of trace elements in arsenic and antimony minerals from the Allchar mine, Macedonia, was determined by electrothermal atomic absorption spectrometry (ETAAS) and k₀-instrumental neutron activation analysis (k₀-INAA) after removal of arsenic and antimony. Their direct determination by ETAAS or k₀-INAA in arsenic (realgar and orpiment) and antimony (stibnite) minerals is limited by strong matrix interferences from As and Sb. Successful elimination of both elements was realized by the extraction of their iodide complexes into toluene. It was found that the optimal conditions were triple extraction of arsenic into toluene from 6mol·L^–1 HCl with addition of KI. Triple extraction of antimony was most successful in the system 4.5mol·L^–1 H₂SO₄ and KI into toluene. In both cases, trace elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were then detected in the aqueous phase by ETAAS. The proposed procedures with ETAAS were checked by the method of standard additions and Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn determined in realgar, orpiment and stibnite. Using k₀-INAA the trace elements Ba, Ce, Co, Cr, Cs, Fe, Hg, Sc, Tb, Th, U and Zn in realgar and orpiment were determined before and after As and Sb removal from the same aliquot of sample. The removal of both elements with KI into toluene was higher than 99.8% and no losses of trace elements were observed.     

Distribution of Minor and Trace Metals in Carezza Lake (ANTARCTICA) Ecosystem

Abstract

This paper reports the distribution of a series of metals in natural samples collected at Carezza Lake in Antarctica, during the Italian Expedition in the austral summer 1989/90. The considered elements are: water, sediments and soil sampled from the surroundings of the lake and algae. The determination of the total concentration of the following metals was performed: Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Zn. In addition, for sediment and soil samples, a speciation study was performed for some metals, namely Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, using the Tessier procedure.     

Preconcentration and Fractionation of Cd, Co, Cu, Ni, Pb and Zn in Natural Water Samples Prior to Analysis by Inductively Coupled Plasma Atomic Emission Spectrometry

The strong cation exchanger Dowex 50W-x4 was used for the enrichment of traces of Cd, Co, Cu, Fe, Ni, Pb and Zn in mineral and mine waters as an alternative to the commonly applied procedures based on the application of chelating resins. The resin used was found suitable for complete retention of these metals both from the solutions of very low pH as well as those close to neutral, thus eliminating the need to buffer the samples. An analytical scheme based on filtration and solid phase extraction with Dowex 50W-x4 was proposed for partitioning Cd, Co, Cu, Fe, Ni and Pb in the examined waters. The fraction of metals associated with the suspended particles was determined after filtration through a 0.45 µm pore size filter and decomposition of the deposited matter. For the evaluation of fractions of the labile metal species and the total dissolved metals, the untreated filtrates and the solutions resulting from their digestion, respectively, were passed through Dowex 50W-x4 cation exchange columns. The retrieval of the metals was completed using a 4.0 mol L⁻¹ solution of HCl. The described metal preconcentration and fractionation protocol offered the enrichment factor of 25 with detection limits equal to 22, 30, 92, 41, 70, 36 and 340 ng L⁻¹, respectively for Cd, Co, Cu, Fe, Ni and Pb. Reasonably good precision and accuracy were attained.