Comparison of original and modified BCR sequential extraction procedures for the fractionation of copper, iron, lead, manganese and zinc in soils and sediments

Abstract

This article describes a detailed comparison between the original BCR sequential extraction procedure, step 2 of which involves treatment with 0.1 mol l(-1) hydroxylammonium chloride at pH 2, and the revised BCR procedure (step 2: 0.5 mol l(-1) hydroxylammonium chloride at pH 1.5). An intermediate protocol was also evaluated in which 0.5 mol l(-1) hydroxylammonium chloride at pH 2 was used. The procedures were applied to five soil and sediment substrates: a sewage sludge-amended soil, two different industrially contaminated soils, a river sediment and an inter-tidal sediment. Extractable iron and manganese concentrations were measured to assess the effects of the procedural modifications on dissolution of the reducible matrix components. Trace elements copper, lead and zinc were also determined. Statistical analysis (two-tailed t-tests at 95% confidence interval) indicated that recovery of iron in step 2 was not markedly enhanced when the intermediate protocol was used. However, significantly greater amounts were isolated with the revised BCR scheme than with the original procedure. Copper behaved similarly to iron. Lead recoveries were increased by use of both modified protocols, with the greatest effect occurring for the revised BCR extraction. In contrast, manganese and zinc extraction did not vary markedly between procedures. The work indicates that the revised BCR sequential extraction provides better attack on the iron-based components of the reducible matrix for a wide range of soils and sediments. (C) 2002 Elsevier Science B.V. All rights reserved

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

“…We then consider that readsorbed metal is redistributed to iron and manganese oxides, what has been elsewhere assessed by means of radiochemical techniques [26]. In contrast, the readsorption phenomena was successfully avoided in F2 as a result of the initial acidic conditions and the poor buffering capacity of the matrix, which prevents the pH to rise, and in turn, readsorption [27]. Within the oxidisable fraction, the soil CRM generally displays a lower readsorption than the sediments.…”

Metal speciation in surface sediments of the Uberabinha river in Uberlândia, MG State, Brazil

“…4 Sequential extraction procedures have been widely used for determining specific chemical forms of heavy metals in a range of environmental media, including sediments and waste materials. [5][6][7][8] The number of steps in these extractions varies from three to six and the extraction procedures adopted can show different results. [9][10][11][12] However, since the extraction sequences and operating conditions involved in these procedures differ, it is difficult to compare the data obtained with these methods.…”

The distribution of sequentially extracted Cu, Pb, and Zn fractions in Podzol profiles under dwarf pine of different stages of degradation in subalpine zone of Karkonosze Mts (central Europe)

“…To quantify the contributions of particular fractions, chemical solutions of varying strength and reactivity are applied to soils in order to release metals bound to different soil components. A commonly used, relatively simple BCR method, developed by the Community Bureau of Reference (Ure et al 1993;Mossop and Davidson 2003) determines four fractions of metals (acid soluble, reducible, oxidizable, and residual). A method by Zeien andBruemmer (1989, 1991), which is more laborious, provides greater insight into the mechanisms of metal binding in soils and, therefore, has been widely applied to both nonpolluted and variously polluted soils (Karczewska 1996;Wenzel and Jockwer 1999;Kabała and Szerszeń 2002;Marschner et al 2006;Rao et al 2008;Kabala et al 2011).…”