Vertical Variation of Lead Content in Sediment Collected from Man‐made Tamagawa Dam Lake in Akita Prefecture, Japan
Vertical Variation of Lead Content in Sediment Collected from Man‐made Tamagawa Dam Lake in Akita Prefecture, Japan
复制标题
日本秋田县人工玉川水库沉积物中铅含量的垂直变化
DOI：
10.1111/rge.12164
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Y. Ogawa
中科院分区：
文献类型：
--
作者：
Quyen M. Pham;D. Ishiyama;Hinako Sato;Y. Ogawa
从位于秋田县东北部的玉川坝湖采集了从1990年到2012年累积了22年的交替层状湖泊沉积物。由于玉川温泉地区的主要温泉--小吹温泉的高酸性热水（pH = 1.2）流入，湖水被酸化（pH = 4.1）。利用XRF、EPMA和LA-ICP-MS等分析手段，研究了沉积物中Si、Al、Fe、Ti和Pb元素的垂向变化特征，以阐明湖泊沉积物的沉积过程。沉积物组成层主要分为三种类型：深褐色、黄褐色和红色层。Si、Al、Fe和Ti的含量对应于样品中各层颜色的变化。根据多摩川坝湖沉积物中Si、Al和Fe的含量，将这些元素的来源分为深棕色和黄棕色层中的碎屑来源（Si、Al和Ti）和红色层中的化学沉淀来源（Fe）。碎屑成分来自于玉川坝湖流域的火山岩。铅含量的变化与土层颜色的变化不符合雅阁。多摩川坝湖沉积物中铅的含量在45 ~ 522 ppm之间。沉积物中Pb含量的垂直变化与1990 - 2012年小吹温泉热水中Pb含量的时间变化相对应。在小吹温泉活跃期，多摩川温泉的热液活动对Pb的垂直分布有很大影响，导致样品底部5-8 cm处的层内Pb含量较高。在该范围内还发现了富含T-Fe 2 O3的红色层。因此，推测T-Fe 2 O3和Pb来自小吹温泉，沉淀在玉川坝湖。然而，在深棕色、黄棕色和红色层的T-Fe 2 O3和Pb含量之间没有发现相关性。Pb含量高的地层中SiO_2和Al_2O_3含量也较高。这些结果表明，有几种可能性的沉积过程中铅。Pb和T-Fe 2 O3在玉川坝湖的沉积提供了一个很好的例子，说明元素通过远离元素来源的化学沉淀而积累。
Alternation layered lake sediment that had accumulated over a period of 22 years, from 1990 to 2012, was collected from the Tamagawa Dam Lake, which is located in the northeastern part of Akita Prefecture. The lake water is acidified (pH = 4.1) by the inflow of high‐acidic thermal water (pH = 1.2) from the Obuki Hot Spring, the main hot spring in the Tamagawa Hot Spring area. The vertical variations in Si, Al, Fe, Ti, and Pb contents of the sediment were determined by XRF, EPMA, and LA‐ICP‐MS in order to clarify the sedimentation processes of the lake sediment. The layers consisting of the sediment could be mostly classified into three types: dark brown, yellowish brown, and reddish layers. The contents of Si, Al, Fe, and Ti corresponded to the variation in color of each layer in the sample. Based on the Si, Al, and Fe contents in the sediment of Tamagawa Dam Lake, the sources of these elements were classified as detrital origin in dark brown and yellowish brown layers (Si, Al, and Ti) and chemical precipitate origin in reddish layers (Fe). Detrital components were derived from volcanic rocks in the watershed of Tamagawa Dam Lake. The variation of Pb content did not accord with the color of layers. The content of Pb in the sediment of Tamagawa Dam Lake ranges from 45 to 522 ppm. The vertical variation of Pb content in sediment corresponded to the temporal variation of Pb content in thermal water from the Obuki Hot Spring from 1990 to 2012. A large influence of hydrothermal activity of the Tamagawa Hot Spring on the vertical distribution of Pb was found during the active period of the Obuki Hot Spring, resulting in high Pb content within layers at 5–8 cm from the bottom of the sample. T‐Fe2O3‐rich reddish layers were also found in this range. Therefore, it is assumed that T‐Fe2O3 and Pb originated from Obuki Hot Spring and precipitated in Tamagawa Dam Lake. However, no correlation was found between T‐Fe2O3 and Pb contents for any of the dark brown, yellowish brown, and reddish layers. Some layers with high Pb content were also found to have high SiO2 and Al2O3 contents. These findings indicate that there are several possibilities for the sedimentation process of Pb. The sedimentation of Pb as well as that of T‐Fe2O3 in Tamagawa Dam Lake provides a good example of the accumulation of elements by chemical precipitation away from the source of elements.