SEQUENTIAL EXTRACTION SPECIATION OF HEAVY METALS IN SEDIMENTS BASED ON GRAIN SIZE

Surface sediments collected from the bottom of the Lower Sakarya River were analyzed for their metal levels based on their grain size. For this purpose, a three-step sequential extraction procedure was used to elucidate the amount of metals released at each stage. Some studies using a three-stage sequential extraction procedure for the determination of extractable heavy metals in sediments of various rivers in Turkey were mainly focused on sediments without mentioning grain size. However, this study directly focused on the sediments having different grain sizes. In this work, the sediment samples were collected from the bottom surface of the river for a 10-month time period and analyzed each month for their metal contents. The metals in sediments were fractionated as acid soluble, exchangeable, reducible, and oxidisable. Determination of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn metals was performed by flame atomic absorption spectrometry.