[A-GE28] Energy-Environment-Water Nexus and Sustainable Development

[AGE28-04] Rare earth elements analysis of fern around historical mining area in Hyogo Prefecture, Japan

*Ainun Mardiyah¹、Motohiro Tsuboi¹ (1.Kwansei Gakuin University)

キーワード：Rare earth element (REE), Athyrium yokoscense, Sediment, Mine

The industrial demands in the world increased the usage of rare earth elements (REEs) and for that reason research into the environmental biogeochemical soil-plant system behavior of REEs has grown to be the primary issue. Recent studies have shown that various fern species can accumulate the amount of REEs in the soil and may be utilized as an indicator plants. Athyrium yokoscense or commonly called hebino negoza in Japan is one of the pteridophytes which is used as an indicator of metal-contaminated soils in Japan. Mining and mineral processing increases the potential of the mine minerals to oxidize and change their chemical form. This study provides a detailed chemical analysis of rare earth elements to provide information for further studies. The REE content in sediment and pteridophyte under different mining areas was measured by inductively coupled plasma-mass spectrometry. The concentration of REEs contained in A. yokoscense was analyzed and then compared to sediment to determine the ability of the plant to absorb and accumulate rare earth elements in the mine area. Sediment and plant samples were collected from three mining areas; Ikuno mine, Akenobe mine, and Tada mine. A. yokoscense plant with 20-30 cm height collected and digested with hydrogen peroxide (H₂O₂) and nitric acid (HNO₃), with a ratio of 2:5. Sediment sample is taken and dissolved by alkali fusion method using lithium tetraborate and then processed using the conventional column method for analyzing the rare earth elements. Concentrations of La, Ce, Pr, Nd, Sm, Eu Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y in plant and sediment samples were measured. The present study determined that the concentration of REEs varies in every location, light REEs tend to be more abundant in sediments than heavy REEs. The amount that can be transferred to ferns also varies, A.yokoscense in the ex-mining area accumulates more LREEs than HREE, specifically in the A. yokoscense leaves.