METAL FRACTIONATION USING THE BCR SEQUENTIAL EXTRACTION PROCEDURE WITH REGARD TO CARPARK DUST SAMPLES FROM SAKARYA, TURKEY

Abstract

In practice, the BCR procedure has three extraction steps; the aim of the fourth step is comparison. That is, it acts as an internal check on the procedure. Specifically, the residue from step 3 was digested with aqua regia, and the total amount of metal extracted (i.e., the sum of step 1 + step 2 + step 3 + residue) was compared with that obtained by the aqua regia reaction with separate 1-g sample of the sediment. The availability of Cr, Cu, Fe, Mn, Pb and Zn with regard to car park dust samples collected from campus area of Sakarya University, Sakarya, Turkey between May and September 2009 were investigated using this four-step BCR sequential extraction procedure. Six elements from five stations (S1-S5) were analyzed using flame AAS to obtain the metal distribution patterns in this area. In order to evaluate the reproducibility and accuracy of the method, a certified reference material (BCR-701) was subjected to the BCR protocol. The outcome of the BCR sequential extraction stages (the first three fractions) was: Mn (87%) > Cu (75%) > Zn (73%) > Pb (52%) > Cr (45%) > Fe (41%). The results confirm that the sampling area was mainly influenced by the presence of traffic and natural sources. For example Cu, Pb and Zn were found. These are metals potentially toxic human beings and originate from traffic. The results show a good agreement with the reported values in the literature between the obtained and the certified values with regard to for the metals analyzed. The results indicated low risk conditions in the selected stations (S1-S5).