Comparison of three sequential extraction protocols for the fractionation of potentially toxic metals in coastal sediments
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Olayinka, K. O.
Oyeyiola, O. A.
Alo, B. I.
In the determination of the best sequen- tial extraction procedures (SEP) for the speciation of metals in sediment samples from the Lagos lagoon system, three sequential extraction proce- dures were compared for the fractionation of Cd, Cr, Cu, Pb, and Zn. The SEP compared included a modified Tessier’s procedure carried out in five steps, while the two other procedures were the three-step original Community Bureau of Refer- ence (BCR) and the modified BCR techniques (four steps). Quantification of the metal concen- tration was achieved with a flame atomic absorp- tion spectrophotometer. The results obtained by the three methods were compared, and the modified BCR and Tessier SEP were found to extract more Cu, Cr, Pb, and Zn in the reducible phase and therefore a decrease in the oxidizable phase than the original BCR SEP. The most mo- bile elements were found to be Cd, Pb, and Zn. These are of environmental concern, as these po- tentially toxic metals could be easily released into the aquatic environment with consequent ingestion by aquatic organisms, thereby entering the food chain. The mass balance (percent recovery) was found to be between 85% and 115% in most cases. Prior to the comparison, the analytical per- formance of the laboratory was tested using a secondary reference material, GLAURM, using the three-step modified BCR procedure. The results showed high reliability of the analytical performance of the laboratory for all the metals considered.
Research Subject Categories::NATURAL SCIENCES::Chemistry::Analytical chemistry::Separation methods , Speciation , Potentially toxic metals , Sediments , Lagos lagoon , Sequential extraction
Oyeyiola, A. O., Olayinka, K. O., & Alo, B. I. (2011). Comparison of three sequential extraction protocols for the fractionation of potentially toxic metals in coastal sediments. Environmental Monitoring and Assessment, 172(1-4), 319-327.