バクテリア活動と地球環境  [in Japanese] Remarkable microbial remediation and bioassay in global environments  [in Japanese]

近年の地球環境汚染源の主なものは(1)重油流出事故, (2)鉱山からの鉱毒の流出, (3)重金属の濃集と蓄積, (4)工場廃水と生活排水である。このうち, 1997年1月に発生した, ロシア船籍ナホトカ号による重油流出事故において汚染された環境の回復法について報告した。温海水による重油の分離と回収, 紫外線と重油分解細菌による重油の分解方法について述べた。また, 鉱山廃水による環境汚染について, 神岡鉱山廃水中のバクテリアや周囲に生息するヘビノネゴザによる重金属の濃集の実態を明らかにした。さらに, 煙媒や廃砕を加えた実験結果から, バクテリアやホテイアオイも汚染環境の浄化には, 重要な役割を果たすことが明らかにされた。

Recent results of various bioremediation researches into environmental hazards such as aerial seashore polution by heavy oil spills, and heavy metal contamination of soil by waste water from abandoned metal mines are reported. A serious heavy oil spill from the Russian tanker Nakhodka in January, 1997 covered the seashore from Mikuni, Fukui Prefecture to Noto Peninsular, Ishikawa Prefecture. Clean up of beach daubed with spilled oil is a serious and hard problem to dissolve. Our new simple method to rinse the polluted beach and gravels with warm sea water remove soils efficiently from beach materials. Hydrocarbon-degrading microbes were found in the polluted area of the near-shore environment. Microbial degradation is the conversion process which dissolves and disperses hydrocarbons into oxidized products by micro-organisms. It is a fine and lasting process, known as bioremediation, which has received wide attention, notably after the Exxon Valdez accident off Alaska. Fluorescence microscopic observations of emulsified heavy oil reveal that an ultra-violet beam is effective in dissolving the oils. Heavy metal releases from abandoned dumps of metal-mines through a waste water pool into streams or rivers causes dreadful contamination of water-soil environments. In the Kamioka metal mining area in Gifu-Toyama Prefectures, Cd, Pb, Zn and Fe were released from an abandoned dump into the Jintsu-River. During the past decades, remediational evaluations of soil recovery have not been clarified though various trials for recovery of the area have been carried out. Such plants as Athyrium yokoscens and Eichhornia crassipes have been discovered to capture and concentrate heavy metals (Cd, Zn and Pb) in the cell of conduits. Several biomat-forming micro-organisms have also been found to concentrate heavy metals. Bioremediation includes physical and chemical methods, which have been the subject of much debate and to which some research efforts are being directed in recent years. A number of biological methods and technologies may contribute toward the advancement of earth sciences and environmental geology.