BCR sequential extraction

Ho M.D., Evans G.J. Operational speciation of cadmium, copper, lead and zinc in the NIST standard reference materials 2710 and 2711 (Montana soil) by the BCR sequential extraction procedure and flame atomic absorption spectrometry. Anal Commun 1997 34 353-364. 

Adapted from Nemati K, Baker NKA, Abas MRB, Sobhanzadeh E, Low KH. Comparison of unmodified and modified BCR sequential extraction schemes for the fractionation of heavy metals in shrimp aquaculture sludge from Selangor, Malaysia. Environ. Mont. Assess. 2011 176 313-320. 

Whalley C, Grant A. Assessment of the phase selectivity of the European Community Bureau of Reference (BCR) sequential extraction procedure for metals in sediment. Anal. Chim. Acta 1994 291 287-295. 

Fernandez E, Jimenez R, Lallena AM, Aguilar J. Evaluation of the BCR sequential extraction procedure applied for two unpolluted Spanish soils. Environ. Pollut. 2004 131 355-364. 

Davidson CM, Duncan AL, Littlejohn D, Garden LM. A critical evaluation of the three-stage BCR sequential extraction procedure to assess the potential mobility and toxicity of heavy metals in industrially-contaminated land. Anal. Chim. Acta 1998 363 45-55. 

Mossop KF, Davidson CM. Comparison of original and modified BCR sequential extraction procedures for the fractionation of copper, iron, lead, manganese and zinc in soils and sediments. Anal. Chim. Acta 2003 478 111-118. 

Some work on sediments is reported here in the belief that it may also be useful in the analysis of soil samples. Thus Asikainen and Nikolaides [33] have carried out a sequential extraction study of chromium from contaminated aquifer sediments and found that 65% of the chromium was extractable. Of this amount 25% was exchangeable, 11% was bound to organic matter and 30% was bound to iron and manganese oxide surfaces. Thomas et al. [34] also investigated the use of BCR sequential extraction procedures for river sediments, and found the method to work well. Real et al. [35] improved sequential extraction by optimising microwave heating. 

A modified BCR sequential extraction was recommended based on this work, and its performance compared with the original BCR procedure via an interlaboratory trial (Rauret et al, 1999). Improved reproducibility was obtained. A new sediment reference material CRM 701 has been certified for metals extractable by the modified BCR procedure (Pueyo et al., 2001). The modified extraction protocol is given in the Appendix. It is important to emphasise that extractions should be performed exacdy as described if results comparable with other users are to be obtained. 

Perez-Cid et al. (1996) compared Tessier and BCR sequential extractions for the speciation of Cu, Cr, Pb, Ni and Zn in sludge from an urban wastewater treatment plant and found similar performance for the two procedures. Zufiaurre et al. (1998) later demonstrated, using the Tessier method and PCA, that, since most metals in a sludge were bound to oxidisable and residual fractions, bioavailability was likely to be very low. 

Appendix Modified three stage BCR sequential extraction procedure... 

Figure 9.5 Copper and nickel distribution among BCR sequentially extracted fractions in Sudbury soils around the Copper Cliff smelter. (HOAc = acetic acid-extractable red = reducible oxi = oxidisable res = residual) (from Adamo ft a ., 1996).

Bacon, J. R., Hewitt, I. J., and Cooper, P. (2005). Reproducibility of the BCR sequential extraction procedure in a long-term study of the association of heavy metals with soil components in an upland catchment in Scotland. Sci. Total Environ. 337, 191—205. 

Davidson, C. M., Hursthouse, A. S., Tognarelli, D. M., Ure, A. M., and Urquhart, G. J. (2004). Should acid ammonium oxalate replace hydroxylammonium chloride in step 2 of the revised BCR sequential extraction protocol for soil and sediment Anal. Chim. Acta 508, 193—199. 

Rauret, G., Ldpez-Sanchez, J. F., Sahuquillo, A., Barahona, E., Lachica, M., Ure, A., Davidson, C. M., Gomez, A., Luck. D., Bacon, J., Yli-Halla, M., Muntau H., and Quevauviller, Ph. (2000). Application of a modified BCR sequential extraction (three-step) procedure for the determination of extractable trace metal contents in a sewage sludge amended soil reference material (CRM 483), complemented by a three-year stability study of acetic acid and EDTA extractable metal content. J. Environ. Monit. 2, 228-233. 

E. Dabek-Zlotorzynska, M. Kelly, H. Chen and C.L. Chakrabarti, Application of capillary electrophoresis combined with a modified BCR sequential extraction for estimating of distribution of selected trace metals in PM2.5 fractions of urban air particulate matter, Chemosphere, 58,1365-1376, 2005. 

Howe, S. E., Davidson, C. M., and McCartney, M. (1999). Operational speciation of uranium in inter-tidal sediments from the vicinity of a phosphoric acid plant by means of the BCR sequential extraction procedure and ICP-MS./.At. Specirom. 14(2), 163. 

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