Accuracy of selective extraction procedures for metal speciation in model aquatic sediments

Kheboian, C.; Bauer, Christopher F.

doi:10.1021/ac00137a010

Cited by 394 publications

(167 citation statements)

References 28 publications

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“…use of model synthetic phases, natural sediments spiked with model synthetic phases and the standard addition method. Kheboian and Bauer [15], using model synthetic phases, observed a significant readsorption of Cu, Pb and Zn when the Tessier scheme was applied. Ajayi and Vanloon [16] employed the natural sediments spiked with model synthetic phases with the aim of supplying fresh unoccupied sites for retention of any metals released during extraction.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of Metal Readsorption in the Application of a Three-Stage Sequential Extraction Scheme and Two Accelerated Versions (Ultrasonic and Single Extractions)

Pérez¹,

Valiente²,

Bendicho³

2008

TOACJ

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Accelerated methods for partitioning of Cd, Cr, Cu, Ni, Pb and Zn, such as the use of single and ultrasonic extractions are assessed in terms of readsorption and compared with the three-stage sequential extraction scheme (SES) of the Standards Measurements and Testing Programme (SM&T). The standard addition approach was employed for characterising the readsorption artefact by applying the above fractionation methods over different certified reference materials (CRMs), BCR 701, BCR 601 (lake sediments), and BCR 141R soil. Ultrasonic extractions provided higher readsorption, mainly for BCR 141R and 601 as compared to conventional SES, the role of ultrasound in the activation of adsorptive sites being significant. The single extraction approach seemed to be inadequate with samples containing large amounts of carbonates such as BCR 141 R but worked well with both lake sediments.The readsorption phenomena are mainly occurring in the most labile fraction (i.e. acid soluble) and has been observed to be matrix dependent. The extent of such phenomenon is also dependent on the extraction methodology, i.e conventional vs accelerated.

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Section: Introductionmentioning

confidence: 99%

A Comparative Study of Metal Readsorption in the Application of a Three-Stage Sequential Extraction Scheme and Two Accelerated Versions (Ultrasonic and Single Extractions)

Pérez¹,

Valiente²,

Bendicho³

2008

TOACJ

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“…5,6 Embora os métodos de extração apresentados na literatura devam ser devidamente melhorados, ainda são a única forma de se avaliar a distribuição dos metais entre as fases geoquímicas que compõem o sedimento. 7 O método de extração seqüencial de metais adotado neste trabalho de pesquisa compreendeu as seguintes etapas: 4,5 Fração trocável -a dupla camada elétrica estabelecida na superfície do sedimento é controlada principalmente pelo pH da superfície e pela força iônica do meio.…”

Section: Introductionunclassified

Extração seletiva de metais pesados em sedimentos de fundo do Rio Tietê, São Paulo

Bevilacqua

Silva²,

Lichtig³

et al. 2009

Quím. Nova

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Recebido em 24/10/07; aceito em 13/8/08; publicado na web em 20/1/09 SELECTIVE EXTRACTION OF HEAVY METALS IN BOTTOM SEDIMENTS FROM TIETÊ RIVER, SÃO PAULO. Sediment samples from Tietê river were submitted to chemical and sequential extractions of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn). It was followed a single extraction by using 0.1 mol L -1 hydrochloric acid and a sequential procedure to evaluate possible chemical associations described as exchangeable, carbonate, reducible oxides, sulfide, organic matter and residual fractions. High concentrations of heavy metals were determined at Pirapora reservoir, which is closer to the Metropolitan Area of São Paulo while for Barra Bonita reservoir, the results showed low concentrations for such elements. Acid volatile sulfides, grain size distribution and carbon contents were also determined.Keywords: heavy metals; sediment; chemical and sequential extractions. introduçãoHá pelo menos 3 décadas, os sedimentos já não têm sido considerados somente ambientes de deposição de espécies químicas, mas um compartimento aquático ativo que desempenha um papel fundamental na redistribuição dessas espécies à biota aquática. 1 Os processos naturais de formação de sedimentos vêm sendo intensamente alterados pela ação do homem. A erosão do solo causada pela construção de prédios e rodovias, bem como o lançamento direto de efluentes industriais e municipais têm propiciado um perfil significativamente diferente daqueles verificados em ambientes naturais não impactados. 2 Nesse contexto, uma atenção especial deve ser dada aos metais pesados, que não são naturalmente degradados, nem mesmo permanentemente fixados pelos sedimentos, podendo assim retornar à coluna d'água através de alterações de suas propriedades físico-químicas, tais como pH e potencial redox. 3 Sob condições operacionais definidas, os métodos analíticos de extração seqüencial têm sido aplicados com a proposta de se avaliar a distribuição dos metais nas diferentes formas que compõem o sedimento, tendo em vista o comportamento, a reatividade e o destino dessas espécies nos ambientes aquáticos. 3 Os métodos de extração seqüencial consistem em submeter uma determinada amostra de sedimento sob condições de extração em etapas cada vez mais enérgicas (tipos de reagentes, concentração, tempo e temperatura). As frações obtidas dizem respeito à proporção do metal que está associada a uma referida fase geoquímica. .Kersten e Förstner 4,5 desenvolveram um método de extração seqüencial que foi aplicado num estudo dos sedimentos do Rio Elba, altamente impactados, cujas frações foram definidas como trocáveis, metais ligados a carbonatos, metais associados aos óxidos facilmente redutíveis, metais associados aos óxidos moderadamente redutíveis e residual.Alguns problemas têm sido apontados aos métodos de extração seqüencial, tais como possíveis redistribuições do metal entre fases, seletividade dos reagentes, além da falta de concordância entre os resultados, principalmente para sedimentos anóxidos. 5,6 Embora os métodos de extração aprese...

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“…In contrast, sequential extraction procedures have been applied to soils and sediments to characterise their respective metal fractions, by selectively targeting and releasing metals bound in certain geochemical phases, such as carbonate, iron and manganese oxide/hydroxide, sulfidic, organic, and silicate [4]. Several problems have been identified with the use of sequential extraction procedures, including non-selectivity and readsorption [5][6][7][8]. Consequently, fractionation of metals is operationally defined in terms of the extraction mechanism used to release the metals rather than in terms of the discrete geochemical phases.…”

Section: Introductionmentioning

confidence: 99%

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

Larner

Seen

Townsend

2006

Analytica Chimica Acta

109

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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.

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Accuracy of selective extraction procedures for metal speciation in model aquatic sediments

Abstract: A and B are constants related to the nature of the transfer ion and interface.(5) The linear relationship between the peak current and the concentration of BCG in the two phases can be used for BCG analysis, providing a new way for organic dye analysis.LITERATURE CITED

Cited by 394 publications

References 28 publications

A Comparative Study of Metal Readsorption in the Application of a Three-Stage Sequential Extraction Scheme and Two Accelerated Versions (Ultrasonic and Single Extractions)

A Comparative Study of Metal Readsorption in the Application of a Three-Stage Sequential Extraction Scheme and Two Accelerated Versions (Ultrasonic and Single Extractions)

Extração seletiva de metais pesados em sedimentos de fundo do Rio Tietê, São Paulo

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

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