Improvement of the BCR three step sequential extraction procedure prior to the certification of new sediment and soil reference materials

Abstract

The Standards, Measurements and Testing Programme (formerly BCR) of the European Commission proposed a three-step sequential extraction procedure for sediment analysis, following extensive expert consultations and two interlaboratory studies. This scheme was recently used to certify the extractable trace element contents of a sediment reference material (CRM 601). Although this procedure offers a means to ensure the comparability of data in this field, some difficulties concerning the interlaboratory reproducibility still remain, and a new project is currently being conducted to determine the causes of poor reproducibility in the extraction scheme. The final objective of the project is the certification of new sediment and soil reference materials for their extractable contents of Cd, Cr, Cu, Ni, Pb and Zn. This paper presents the results of a small-scale interlaboratory study, which aimed to test a revised version of the extraction schemes by comparing the original and the modified protocols using the CRM 601 sample. This work offers an improvement to the BCR sequential extraction procedure through intercomparison exercises. This improved procedure will allow the obtaining of CRMs to validate analytical data in the analysis of soils and sediments, and it will also facilitate comparability of data in the European Union.

Understanding the relationship between heavy metals in road-deposited sediments and washoff particles in urban stormwater using simulated rainfall

“…The BCR protocol developed by the Standard Measurement and Testing Program of the European Community [27,28] and the optimized BCR sequential extraction procedure developed by Sutherland and Tack (2002) [29] were used to fractionate the metals into the following target phases: acid-extractable (water soluble, exchangeable and bound to carbonate), reducible (bound to amorphous Fe-and Mn-oxides), oxidizable (bound to organic matter), and residual (bound to minerals). This procedure included four steps: (1) acid-extractable: extraction of 1.00 g RDS sample by adding 40 mL 0.11 M acetic acid; (2) reducible: addition of 40 mL 0.5 M NH 2 OH • HCl (pH ≈ 1.5); (3) oxidizable: addition of 10 mL H 2 O 2 (pH 2-3) to the sample followed by incubation for 1 h at room temperature, and then at 85 ± 2 • C for 1 h, after which 10 mL of H 2 O 2 are added and the sample is incubated at 85 ± 2 • C for 1 h and 50 mL 1 M NH 4 OAc (pH 2) are added; (4) residual: addition of 3 mL distilled H 2 O, 7.5 mL 6 M HCl, and 2.5 mL 14 M HNO 3 followed by overnight incubation at 20 • C, then boiling under reflux for 2 h, cooling and filtration.…”

Lateral and longitudinal patterns of water physico-chemistry and trace metal distribution and partitioning in a large river floodplain

“…The first step of the sequential extraction method recommended by the European Community Bureau of Reference was used to extract the exchangeable and carbonate bound fractions. 10 mL of 0.11 M acetic acid (Suprapur, Merck, Darmstadt, Germany) were added to filters and sediment subsamples (~300 mg dry weight) in closed 50 mL centrifuge tubes and agitated overnight at room temperature (Rauret et al, 2000;Rauret et al, 1999).…”

Factors influencing the heavy metal bioaccessibility in soils were site dependent from different geographical locations

“…In order to harmonize the various sequential extraction procedures used for HM phase analysis, a BCR three-step sequential extraction scheme was proposed by the European Community Bureau of Reference in 1992 (the Standards Measurement and Testing Program) (BCR). Subsequently, this scheme was improved as a result of further collaborative studies (Rauret et al 1999). In this study, a revised version of the BCR sequential extraction procedure was used to test the HM phases (Baig et al 2009;Rauret et al 1999;Van Herreweghe et al 2003).…”

“…Subsequently, this scheme was improved as a result of further collaborative studies (Rauret et al 1999). In this study, a revised version of the BCR sequential extraction procedure was used to test the HM phases (Baig et al 2009;Rauret et al 1999;Van Herreweghe et al 2003). In brief, the forms of HMs were classified into exchangeable (water and acid-soluble, F1), easily reduced (Fe/Mn oxyhydroxides, F2), oxidizable (organic matter and sulfides, F3), and residual fraction (F4).…”

“…Additional studies documenting the bioaccessibility of HMs (Bio-HMs), defined as the fraction that is soluble in the gastrointestinal environment and potentially available for absorption, is the major part that may render health risks (Luo et al 2012b;Sauve et al 2000). On the basis of BCR sequential extraction (Rauret et al 1999;Van Herreweghe et al 2003), the forms of HMs are classified into exchangeable (water and acid-soluble, F1), easily reduced (iron/manganese oxyhydroxides, F2), oxidizable (organic matter and sulfides, F3), and residual fraction (F4). The occurrence and relative distribution of an element among these various phases, and the physical relation between the phases in the soils, will control an element's dissolution properties and, hence, its bioavailiability.…”