A study of different analytical extraction methods for nondetrital heavy metals in aquatic sediments

Agemian, Haig; Chau, Alfred S Y

doi:10.1007/bf02097751

Cited by 85 publications

(28 citation statements)

References 11 publications

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“…Because of the observed severity of attack of the 0.5 N HCl solution on clay lattices (Ray et al, 1957;Bradshaw et al, 1974), this method :t.s (Chester and Hughes, 1967) and lack of specificity of attack (Agemian and Chau, 1977). Consequently, the only individual weak method studied was the pH 5 buffer solution of Froelich et al (1977), referred to here generally as Method 1.…”

Section: Individual Methodsmentioning

confidence: 99%

Transport of angular momentum in damped nuclear reactions

Randrup

1982

Nuclear Physics A

152

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EXECUTIVE SUMMARYThe operation of an OTEC plant will result in the m~x~ng of large volumes of seawater from different depths within the ocean. Associated with this seawater will be suspended particulate material.This solid material is capable of both adsorbing and releasing transition metals. Because suspended particulate material is intimately involved in marine food webs and transition metals such as copper can have toxic effects, it is important to develop a sound methodology for characterizing and quantifying transition metals which will be associated with solid material passing through an OTEC plant.The characterization of soild-phase associated transition metals in the marine environment has largely been directed at marine sediments. Studies of sediment-associated transition metals have generally indicated that it is not possible to uniquely identify the solid phases or chemical speciation of a given metal. There are many reasons for this difficulty, but the probable major analytical problems arise from the fact that many of the transition metals of interest are present only in trace concentrations as adsorbed species on amorphous oxides or as coprecipitates. These difficulties have led to an approach in which transition metals are classified according to how easily they are solubilized when exposed to different types of chemical attack, as defined in chemical extraction schemes.There are at present a large number of different transition metal extraction schemes in use. Only rarely have these different techniques been carefully compared on a variety of solids from the marine environment. Consequently, it is often not possible to make a sound assessment of the results obtained by investigators who have used different extraction methods to characterize solid-phase associated transition metals or to select the most appropriate methodology for making measurements on a given type of solid material.In this study, several of the most widely accepted techniques were compared for many of the most commonly measured transition metals. The use of a variety of marine sediments, rather than trapped suspended particulate matter, was necessitated by both the relatively large amount of material needed for an examination of all the methods and the lack of any OTEC program collected particulate material.In order to determine the true extraction efficiency of the methods studied, all solid concentrations have been normalized to total metal concentration values as obtained by neutron activation analysis and/or x-ray fluorescence measurements.On weak, four intermediate strength and two strong metal extraction methods were studied individually.The weak method had the lowest extraction efficiency, but dissolved all solid carbonate phases. A potential problem with the weak method is that it does not retain extracted metals quantitatively in solution, but allows them to be adsorbed on remaining solids. The simplest of the four methods (0.5 N HCl) caused the release of lower amounts of most metals studied when compared to the other ...

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Section: Individual Methodsmentioning

confidence: 99%

Transport of angular momentum in damped nuclear reactions

Randrup

1982

Nuclear Physics A

152

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“…Although there are numerous methods for partial extractions, they generally fall into three groups: (i) dilute solutions of strong mineral acids, (ii) weak acids and (iii) solutions of complexing or reducing agents [11,12].…”

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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“…This procedure usually provided a rapid way of establishing a potential contrast between anomalous and background levels of elements in environmental monitoring (4,5).…”

Section: Introductionmentioning

confidence: 99%