Host: Japan Association of Mineralogical Sciences
Although sequential extractions of heavy metals from soils and sediments have been widely adopted as one of the promising tools for partitioning the different forms of metals in the samples, their applications towards rock samples are rather limited. For establishing this technique for rock samples, we tested the sequential extraction procedure by using powdered and non-powdered (grain size: 2-1mm, 1-0.5mm, 0.5-0.25mm, < 0.25mm) sedimentary rocks to fractionate heavy metals into water, acetic acid and nitric acid extractable fractions, because these reagents are traditionally used for the selective dissolutions for soils and sediments. While alkaline metals were more easily eluted into water from powdered samples as compared with from non-powdered samples, the amounts of eluted heavy metals from the latter were less than those of the former, possibly due to readsorption during the extraction procedure. Certain heavy metals were also dissolved more efficiently from non-powdered sample by acetic acid extraction. The above phenomena caused a considerable change in the obtained fractionation as the decrease of one phase resulted in the increase of another fraction.
