Basic Reseach for Using as a New Environmental Indicator

地衣被认为是环境中积累某种污染物的物质。为了证实这一点，我们调查了在日本各地收集的地衣的元素浓度和放射性水平。我们用仪器中子活化分析测定了日本地衣的元素浓度。采用<137>HPGe探测器，用γ射线能谱仪测定了样品中~（13）Cs的含量，选择了日本较容易获得的石蕊、裸缘梅、棒肋梅和黄缘梅。我们在日本的40个地方收集了样本。在本研究中检测到Na、Mg、Cl、K、Ca、Ti、V、Cr、Mn、Fe、Co、Cu、As、Br和I等7种营养元素，这些元素的含量在不同生境中的分布范围相对较窄，而在不同生境中的分布范围相对较宽。例如，在Parmelia中Al和V的浓度强烈地依赖于它们的基质、树皮或岩石。除石蕊（Cladonia carassensis subsp.）日本石蕊和火山石蕊生活在fumerole周围。铜屋顶神社下的棒肋藓（Rimelia clavulifera）的Cu含量明显高于其他地方的棒肋藓（Rimelia clavulifera）。我们认为地衣是化学元素的指示物。我们在日本最北方的北海道采集的样品中观察到了87 Bq/kg的最高值。这一结果与日本的^<137>Cs沉降水平随海拔升高而增加的假设相一致。

Lichens have been considered to accumulate some kind of pollutants in the environment. To confirm this, we investigate the elemental concentration and radioactivity level of lichens collected in various places in Japan. We determined elemental concentrations of Japanese lichens using instrumental neutron activation analysis. The ^<137>Cs concentration of samples were measured by γ-ray spectromoetry using HPGe detector.Species of Cladonia rangiferina, Parmotrema tinctrum, Rimelia clavulifera and Flavoparmelia caperata are selected, which were relatively easily available in Japan. We collected samples in 40 places in Japan. Na, Mg, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, As, Br and I were detected in Thalli in the present study.Generally, the concentration of each element distributes within relatively narrow range irrespect of their habitat, which some elements spread over a relatively wide inflecting their habitat. For example, concentration of Al and V in Parmelia strongly depends on their substrate, bark or rock. Arsenic was not detected in almost of all samples except Cladonia carassensis subsp. Japonica and Cladonia vulcani living around fumerole. Rimelia clavulifera living under the edge of copper roof shrine showed particularly higher concentration of Cu than that living in the other places.In this study we obtained typical concentrations of chemical element in Japanese lichen and some exceptional levels inflecting their habitat. We expect that lichen is an indicator of chemical elements.We observed the highest value of 87Bq/kg in the sample collected in Hokkaido, the most northern part of Japan. The result is consisitent with the hipothesis that the ^<137>Cs fallout level increased as higher the altitude in Japan.