著者

板井 啓明 兵部 唯香 田辺 信介

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集

巻号頁・発行日

vol.60, 2013

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琵琶湖の湖底表層には、マンガン濃集層が広く存在することが知られている。このマンガンは主に酸化物態で存在することから、近年の琵琶湖の貧酸素化により還元反応が進行し、湖水へ大量溶出することが懸念されている。本研究では、琵琶湖北湖盆7地点で採取したコア堆積物と間隙水の化学組成を基に、今後貧酸素化が進行した際のマンガンの形態変化および固-液分配変化を仮定し、拡散モデルを用いて底泥からの溶出フラックスの変化を推定した。その結果、貧酸素化にともなう溶出挙動変化は地点間で異なるものの、底泥からの溶出フラックスとして最大で現在の20倍程度に増加ことが推察された。

著者

坂本 峰至 板井 啓明 村田 勝敬

出版者

一般社団法人日本衛生学会

雑誌

日本衛生学雑誌 (ISSN:00215082)

巻号頁・発行日

vol.72, no.3, pp.140-148, 2017 (Released:2017-09-21)

参考文献数

34

被引用文献数

10 19

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Methylmercury, the causative agent of Minamata disease, can easily penetrate the brain, and adult-type Minamata disease patients showed neurological symptoms according to the brain regions where the neurons, mainly in the cerebrum and cerebellum, were damaged. In addition, fetuses are exposed to methylmercury via the placenta from maternal fish consumption, and high-level exposure to methylmercury causes damage to the brains of infants. Typical patients with fetal-type Minamata disease (i.e., serious poisoning caused by in utero exposure to methylmercury) were born during the period of severe methylmercury pollution in 1955–1959, although they showed no abnormality during gestation nor at delivery. However, they showed difficulties in head control, sitting, and walking, and showed disturbances in mental development, these symptoms that are similar to those of cerebral palsy, during the growth periods after birth. The impaired development of fetal-type Minamata disease patients was one of the most tragic and characteristic feature of Minamata disease. In this review, we first summarize 1) the effects of prenatal methylmercury exposure in Minamata disease. Then, we introduce the studies that were conducted mainly by Sakamoto et al. as follows: 2) a retrospective study on temporal and regional variations of methylmercury pollution in Minamata area using preserved umbilical cord methylmercury, 3) decline in male sex ratio observed in Minamata area, 4) characteristics of hand tremor and postural sway in fetal-type Minamata disease patients, 5) methylmercury transfer from mothers to infants during gestation and lactation (the role of placenta), 6) extrapolation studies using rat models on the effects of prenatal methylmercury exposure on the human brain, and 7) risks and benefits of fish consumption.