抄録
The elements existing as "water soluble form" and "ion exchangeable and surface complexed forms" were extracted from weathered slates with different weathering level by water and diluted HNO3 (ca 3%), respectively. The sample (Spl) is almost non-weathered black slate sample. On the contrary, the sample (Sp3) is intensely weathered and oxidized fragile sample. The weathering level of the sample (Sp2) is intermediate between Spl and 3. The purpose of this study is to investigate the effects of weathering level on the states in rocks and dissolution behavior of each element.
The amounts of elements extracted by water and diluted HNO3 from slates with different weathered level are different, indicating that elemental states in slate change due to the chemical weathering.
Further, the solutions extracted by water were successively filtered through 0.45 mm, 0.20 mm and 100 kDa. The almost of all elements extracted from fresh black slate (Spl) exist in solution as truly dissolved species. On the other hand, truly dissolved species do not almost exist in solution extracted from weathered slate (Sp2 and 3), and almost of all elements are completely removed by the ultrafiltration except some of alkali and alkali earth elements (Li, Sr and Cs) and oxyanions (As and Sb). They are adsorbates on Al and Fe-bearing colloidal particles or their components.
