2001 Fiscal Year Final Research Report Summary
Development and application of Bark pocket-method for historical monitoreing.
| Project/Area Number |
09480119
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | National Institute for Environmental Studies |
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Principal Investigator |
SATEKE Kenichi National Institute for Environmental Studies・Global Environment Group, Head., 地球環境研究グループ, 総合研究官 (50101051)
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| Co-Investigator(Kenkyū-buntansha) |
FURUTA Naoki Chuo University Faculty of Sscience and Engineering, professor, 理工学部, 教授 (90101055)
TANAKA Atsushi National insutitute for Environmental Studies・Environmental Chemistry Division Senior researcher., 化学環境部, 主任研究員 (80171734)
ITO Hiroyasu National insutitute for Environmental Studies・Environmental Chemistry Division Senior researcher., 化学環境部, 主任研究員 (50223178)
NAKAI Izumi Science University of Tokyo・Faaculty of Science, professor, 理学部, 教授 (90155648)
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| Project Period (FY) |
1997 – 2000
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| Keywords | pollution / time capsule / monitoring / bark pockets / lead |
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| Research Abstract |
We discovered a new time capsule for historical monitoring of environmental pollution. This is the bark pockets found in trees. A bark pocket is bark encapsuled within the tree trunk. There are four types of bark pocket formation. The common feature of these four types of bark pocket is that the bark is initially located on the outermost part of the tree. Air pollutants are deposited on the surface of the outer bark, and they then become encapsulated in the tree with the outer bark, and consequently preserved between the annual rings. The annual rings of trees allow accurate dating of bark pockets. Among various kinds of pollutant, the first element we analyzed was lead. Analysis of the amount of lead contained in the bark pockets of cedar trees in the Edo era and the amount of lead in the outer bark of modem cedar trees shows that there are differences between them. In the case of the cedar trees from Nikko, comparison with the Edo era shows that present-day contamination is about 1000 times higher. Another example is the analytical results for lead and mercury collected from the Muroh Temple, Nara Prefecture. If we consider both the level of lead and mercury contamination from the contents of lead and mercury in the bark pockets of the cedar trees, 140 years previously as 1, the level of lead and mercury contamination 70 years previously was 1, then the present level of lead contamination is 40 and that of mercury is 3. The historical monitoring of environmental pollution using bark pockets as pollution time capsules is new. In addition to studying the history of pollution, we have started to create a Time Capsule Forest . This Forest may help to investigate the pollution throughout the past, present and future.
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