Abstracts of Annual Meeting of the Geochemical Society of Japan

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Aerosol samples were collected at Mangshan in the north of Beijing, China in autumn 2007 and analyzed for dicarboxylic acids (C2-C12), ketoacids and dicarbonyls (glyoxal and methylglyoxal). Oxalic (C2) acid was found as the most abundant species, comprising 38-77% of total diacids, followed by succinic (C4) and malonic (C3) acids. Concentrations of most compounds, except for C2 and some other species, were higher in daytime than nighttime, indicating that diacids are produced by photochemical oxidation of organic precursors emitted from anthropogenic sources such as fossil-fuel combustion in Beijing, and are transported to Mangshan area by the northerly wind in daytime. Phthalic acid (Ph) was detected as the 4th most abundant diacid both in daytime and nighttime samples, indicating that anthropogenic sources significantly contribute to the organic aerosols. However, lower adipic (C6)/azelaic (C9) acid ratios in nighttime than daytime suggest that biogenic source makes more contribution to the aerosols in nighttime. Higher ratios of C2/total diacids in nighttime than daytime suggest the aging of aerosols proceed more in nighttime, probably due to the aqueous phase oxidation of biogenic precursors. The concentrations of water soluble organic acids and dicarbonyls significantly decreased after rainfall, indicating that the polar organics are effectively scavenged by raindrops and the atmospheric compositions in the north of Beijing are largely controlled by the regional meteorology. This study demonstrates that water-soluble organic aerosols are secondarily produced in the vicinity of Beijing by the oxidation of both anthropogenic and biogenic precursors.

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Noble gas isotope ratio is valid tracer of material movement in the earth. There are a lot of paper about noble gas isotope ratio. In this study we investigated cubic diamonds from the Udachnaya kimberlite pipe using infrared spectroscopy and noble gas mass spectrometry. The purpose of this study is to make it clear where the center part(core) and the outer part(coat) of diamonds grew in the earth. The helium isotope ratio of the core is not different from that of coat and both are very close to that of the subcontinental lithospheric mantle. Considering the chemical composition of the carbonatitic melts trapped in the diamonds as inclusions and uniform carbon isotope ratio,we can conclude that the cubic diamonds from the Udachnaya kimberlite pipe grew at chemically and isotopically uniform environment in subcontinental lithospheric mantle beneath Siberia.

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In 2009 meeting,I concluded that the vapor in Taiga forest is formed by both the vapor from transpiration and evaporation from rainfall.This year I calculated the contribution value of transpiration to the vapor in Taiga forest.Also,NCEP/NCAR data was used to check if the value is reasonable.

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Lead had been utilized for various usages such as pigments, plumbing and addition to gasoline as antiknock agent. The emission of lead into atmosphere by human activity is estimated much higher than that from natural resources. These days, developed countries advance lead-free policy by tightening of regulations. However, since developing countries have not effectively regulated, lead emission into environment is ongoing; cross-border pollution is concerned about. In this study, we determined lead isotope ratios in grains (barley, wheat, rice) grown in various areas in Japan by the easy and rapid method that we developed. The results showed that those grains had the almost same isotope compositions that were different from those of uncontaminated Japanese soil and geology. The lead in grains was presumed to originate in Chinese coal, because lead compositions of aerosols in Japan and China have been reported to have high similarity. By expanding this presumption to overall Japanese agricultural products, Japanese people are presumed to ingest lead from Chinese coal through Japanese agricultural products.

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