〔報告〕津波被災紙資料洗浄水の分析―塩化物イオン濃度と細菌数―  [in Japanese] Measurement of Water Washed Paper Documents Damaged by Tsunami: Chloride Content and Bacteria Count  [in Japanese]

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Abstract

The number of paper documents damaged by tsunami that accompanied the Great East Japan Earthquake in 2011 is enormous. Because documents were damaged by not only seawater but also sewage including dirt and sand, conservators cannot treat the documents with conventional methods. Stabilization treatment, which places importance on sterilization and desalination of the documents, has been performed in Iwate Prefectural Museum for six years. However, some problems have occurred, such as odor from the treated paper documents.It is inferred that the problem of odor from the documents is caused by microbes. Therefore, water temperature and dissolved oxygen content of water in tubs which were used to treat tsunami-damaged documents were measured in order to verify whether bacteria exist in the water or not. In addition, bacteria count and chloride content in the water used in washing the paper documents were measured.In conclusion, the present study has demonstrated that:1)when the tsunami-damaged documents are sunk in hot water (approximately from 40℃ to 45℃), optimum temperature for growth of bacteria (from 30℃ to 37℃) is kept for about eight hours, and 2) when the tsunami-damaged documents are sunk in water, it leads to growth of bacteria in the water. Meanwhile, chloride ions included in tsunami-damaged documents can be removed by sinking the documents in water for a short time. Thus, if removing chloride ion from the documents is only needed, the documents do not need to be sunk in water for a long time. However, further surveys of the treatment method are required in order to verify the optimum treatment time to remove other deteriorating factors from the paper documents damaged by tsunami.

Journal

  • 保存科学 = Science for conservation

    保存科学 = Science for conservation (57), 169-179, 2018-03-23

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