Kikawada Yoshikazu

草津白根火山地域の温泉水ならびに硫黄鉱山排水が周辺河川の水質に与える影響の見積

Sequential extraction procedure was applied to the volcanic marine sediments collected at Wakamiko Caldera in Kagoshima Bay and Teishi Knoll in Sagami Bay for interpretation of their sedimentary environments. The extraction behaviors of arsenic and antimony in the Wakamiko Caldera sample suggest that those elements, which have been introduced to seawater through volcanic hydrothermal fluids, have been held in sediments in two states;one is in the oxidative form, in which they may be scavenged by iron-manganese hydroxides, and the other is in the reductive form, like sulfides. Contrary to this, arsenic sulfides are not found in the Teishi Knoll sample, although the existence of antimony sulfides is suggested. The existence of arsenic sulfides in the Wakamiko Caldera sample may be ascribed to the relatively high concentration of hydrogen sulfide in the hydrothermal fluids ejected there. The sequential extraction procedure for volcanic marine sediments is thus a useful tool for the chemical characterization of hydrothermal fluids supplied from the seabed, where the sediment samples were collected.