Vol.3 No.4 2011

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Research paper : Investigation of the distribution of elements of the whole of Japan and their applications (N. Imai)−279−Synthesiology - English edition Vol.3 No.4 (2011) study, it was about 10 km mesh. Therefore, one sample was collected from every 10 × 10 km area. The sampling density was so coarse that the sampling points were determined carefully, and they should represent a wide area in producing a nationwide map. Actually, while we referred to and compared the geological and the soil maps, the sampling points were determined so that the points represent the geological and soil divisions of each area. Results show that the geochemical map using the stream sediments agrees well with that using the soil. However, when we can take a higher sampling density, the soil is basically collected in an exact grid.6 Sample storage and future studyQuestion (Akira Ono)In the investigation of marine sediments, it is written that the samples collected by AIST in the past were used for the chemical analysis in this study. This indicates satisfactorily the continuity, integrity, and mutual availability of research which reflect the excellent function and system of the AIST organization.Are the samples as well as those newly collected in your project in land and sea stored in Geological Museum for the use in which more detailed analysis will be needed in the future?Answer (Noboru Imai)The researchers and persons in charge of the GSJ project of collecting bottom sea sediment in the marginal sea in Japan also joined our project of the geochemical map for the collection of the marine sediment. Therefore, we were able to use a huge number of sediment samples collected in the past, and in this study by collecting the new samples in areas for which there were no samples, we were able to obtain a full set of sediments for areas throughout Japan. Therefore, we were also able to contribute much to their project of marginal sea mapping and assessment.About 3,000 stream sediments, 5,000 bottom sea sediments, and 3,000 soils collected in the geochemical map project are stored and classified to be used anytime. That inventory is extremely valuable property for which the samples whose chemical composition is known are kept to be used as a set for the whole country. The samples have been used by outside researchers to date for making a national soil database of the Institute of Police Science and for producing a national map of a strontium isotopic ratio at Nagoya University. Principally, the geological samples were kept in the Geological Museum. The samples collected through the geochemical map project are also kept in the Geological Museum, as you have pointed out.Fig. b Scatter plotThe average concentrations of zinc andphosphorus for all samples agree well withthe concentration of 39th sampleP205 (%)Zn (ppm)0.10.080.060.040.02005010015020025039average

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