The Elemental Composition of Fimbristylis ochotensis in Relation to Its Geothermal Habitat.

Fimbristylis ochotensis (Meinsh.) Kom. is a rare and vulnerable plant species of significant scientific and ecological importance. It is an obligate thermophyte that grows exclusively around hot springs and geothermal fields on the Kamchatka Peninsula and in northern Japan. For the first time, the elemental composition of Fimbristylis ochotensis and its associated soils was determined using neutron activation analysis, supplemented with ICP-OES and a direct mercury analyzer, on samples collected from three hot spring zones on the Kamchatka Peninsula. In total, 43 elements were quantified in soil samples and 31 elements in plant samples. Both soil and plant material collected near different hot springs exhibited significant variation in elemental composition. Mass fractions of most elements were higher in soil samples, with the exceptions of Zn, Br, Rb, Cs, and Cd. Enrichment factor values indicated moderate to extreme soil enrichment in As, Br, Cd, Sb, and W, while transfer factors greater than unity were obtained for K, Rb, Cs, Br, Zn, S, and Cd, suggesting efficient accumulation of these elements by the plant from the soil.