ショウワキチ ニ オケル エーロゾル ノ カガク セイブン

南極昭和基地, 環境科学棟の北東30mでミリポアフィルター(径47mm, 孔径0.45μm)上にエーロゾル試料をエアポンプで10～30m^3の大気を吸引し採取した。これらのエーロゾル試料について, フレームレス原子吸光法によりAl, Fe, Mn, Zn, Cuの微量元素を測定した。これら各元素濃度のAl濃度に対する比を, MIYAKE (Elements of Geochemistry, Maruzen, 290p, 1965)の平均地殻組成のデータを基に, 地殻の各元素濃度のAl濃度比で割って濃縮係数(E_)を求め, ZOLLER et al. (Science, 183,199,1974), DUCE et al. (Science, 187,59,1975)の南極点, 北大西洋上での測定値と比較した。Fe, Mn, Zn, Cuの濃縮係数は南半球の昭和基地, 南極点, 北半球の北大西洋上で同オーダの興味ある結果を得た。濃縮係数が10以下のFe, Mnについては, エーロゾル中のこれら元素の起源は地殻物質であると考えられる。しかし, 濃縮係数が10^2～10^3のZn, Cuについては地殻物質起源では説明困難である。1つの可能な起源として, 化石燃料の燃焼によるものではないかと考えられる。Atmospheric aerosol samples were collected at Syowa Station, Antarctica, on a 47mm millipore filter with 0.45μm pore size, using an air-pump. Air sampling volumes ranged from 10m^3 to 30m^3,which were collected about 30m windward of the Laboratory of Environmental Science at Syowa Station. After that, all samples were stored for the analysis in laboratory. The trace elements such as Al, Fe, Mn, Zn and Cu in these samples were determined by the atomic absorption spectrophotometric method with a graphite furnace atomizer. Enrichment factor, E_, is calculated for the trace elements in atmospheric aerosol samples. Enrichment factor is defined as the element/Al ratio in atmospheric aerosol samples divided by the element/Al ratio in crustal rocks based on the table of MIYAKE (Elements of Geochemistry, Maruzen, 290p, 1965). For the trace elements such as Mn, Fe, Zn and Cu, enrichment factors at Syowa Station are the same order of magnitude as the value at the South Pole in the southern hemisphere and over the North Atlantic Ocean in the northern hemisphere reported by ZOLLER et al. (Science, 183,199,1974) and DUCE et al. (Science, 187,59,1975). From the results, enrichment factors suggest that Fe and Mn are likely to be associated with a source largely derived from crustal rocks. But, Zn and Cu have such high values for enrichment factors that a normal crustal weathering source for these elements must be ruled out. Oxides of these elements have a high volatility, as measured by the elemental boiling point. During the dispersion process, a certain fraction of the original source material escapes into atmosphere as particles. If, however, this dispersion process occurs at elevated temperatures, these volatile elements of the original source material may be emitted as gases or vapor. If this volatilization is anywhere near upon quantitatively, a significant enrichment will have occurred. And then, one possible source for these elements in the atmosphere may be either volcanic activity or the combustion of fossil fuel. The results suggest that the high enrichment factors may be due to anthropogenic rather than natural sources

Chemical composition of atmospheric aerosol collected at Syowa Station

Atmospheric aerosol samples were collected at Syowa Station, Antarctica, on a 47mm millipore filter with 0.45μm pore size, using an air-pump. Air sampling volumes ranged from 10m^3 to 30m^3,which were collected about 30m windward of the Laboratory of Environmental Science at Syowa Station. After that, all samples were stored for the analysis in laboratory. The trace elements such as Al, Fe, Mn, Zn and Cu in these samples were determined by the atomic absorption spectrophotometric method with a graphite furnace atomizer. Enrichment factor, E_, is calculated for the trace elements in atmospheric aerosol samples. Enrichment factor is defined as the element/Al ratio in atmospheric aerosol samples divided by the element/Al ratio in crustal rocks based on the table of MIYAKE (Elements of Geochemistry, Maruzen, 290p, 1965). For the trace elements such as Mn, Fe, Zn and Cu, enrichment factors at Syowa Station are the same order of magnitude as the value at the South Pole in the southern hemisphere and over the North Atlantic Ocean in the northern hemisphere reported by ZOLLER et al. (Science, 183,199,1974) and DUCE et al. (Science, 187,59,1975). From the results, enrichment factors suggest that Fe and Mn are likely to be associated with a source largely derived from crustal rocks. But, Zn and Cu have such high values for enrichment factors that a normal crustal weathering source for these elements must be ruled out. Oxides of these elements have a high volatility, as measured by the elemental boiling point. During the dispersion process, a certain fraction of the original source material escapes into atmosphere as particles. If, however, this dispersion process occurs at elevated temperatures, these volatile elements of the original source material may be emitted as gases or vapor. If this volatilization is anywhere near upon quantitatively, a significant enrichment will have occurred. And then, one possible source for these elements in the atmosphere may be either volcanic activity or the combustion of fossil fuel. The results suggest that the high enrichment factors may be due to anthropogenic rather than natural sources

Trace element concentration of pond and lake waters near Syowa Station, Antarctica

The pond and lake water samples which were collected from near Syowa Station by the JARE-22,-23 and -24 activities were analyzed for the trace elements. The correlatios of chemical compositions between snow samples and the waters of Lakes Nurume, Suribati, Hunazoko and O-ike indicate that trace elements in these lake waters might have been derived mostly from snow

Origin of salt in Antarctic saline lake waters through trace element analysis

The origin of trace elements in Antarctic saline lake waters is still not clear. Waters of five Antarctic saline lake and ponds in the Wright Valley and the Taylor Valley, and one coastal glacier ice were analyzed by the neutron activation method. Three possible origins, connate sea water, rock weathering and tropospheric aerosol particle, were investigated. The correlations of chemical constituents between the South Pole aerosol particle and the lake and pond waters indicate that trace elements in the Antarctic saline lake and pond waters might have been derived mostly from aerosol particles

Monitoring of pond waters near Syowa Station (II)

The water samples collected in 1981 and 1982 were analyzed from the geochemical and environmental viewpoints. The water samples were collected from the following five lakes which have been selected as monitoring stations since 1978 : Mizukumi Stream (East Ongul Island), Lake O-ike (West Ongul Island), Lake Nurume (Langhovde), Lake Hunazoko (Skarvsnes) and Lake Skallen Oike (Skallen). Comparing the data obtained in this work with available previous data, the authors point out the results as follows. 1) Five lakes selected in 1978 were found suitable as monitoring stations. 2) Chemical compositions and dissolved salts in Lake Nurume and Lake Hunazoko have not changed markedly in the last fifteen years. 3) The amount of dissolved salts in three lakes, Mizukumi Stream, Lakes O-ike and Skallen Oike, has changed considerably

15N abundance in the Dry Valley area, south Victoria Land, Antarctica: Eco-physiological implications of microorganisms

Stable nitrogen isotope ratio in nitrogen-bearing substances from the Dry Valley area, south Victoria Land, was reported. The lowest δ^N value of around -50‰ was found for the epibenthic algae collected from nitrate-rich saline ponds in the Labyrinth. In Lake Vanda, nitrate in its maximum layer (57-59m) was significantly rich in ^N (10.3-13.4‰) as compared with the sedimentary organic nitrogen (-4.6‰). The variation of δ^N seemed to probably result from nitrogen isotope fractionation associated with nitrate assimilation by algae. In the east lobe of Lake Bonney, the δ^N value in nitrate increased with depth from 4.9 to 31.2‰. Dissolved N_2 gas in the west lobe exhibited the highest δ^N value (1.5-2.5‰) among those observed in anoxic layers of various aquatic systems. The latter results from denitrification of nitrate with high δ^N value at temperatures lower than 0℃

Geochemical Study of the Formation Process for the Saline Lakes in the Dry Valleys, South Victoria Land, Antarctica

A simple model is proposed for the present chemical composition of the saline lakes in the Dry Valleys. A diluted water of sea salt whose compositional ratio was that of sea water was concentrated by evaporation to the present chlorinity. During the concentration process, a part of Na^+ and K^+ replaced Ca^ and Mg^ of the sediment or weathering rock, and some part of CaSO_4 deposited from the solution. All the reaction proceeded under an ionic massbalance. This simple idea can beautifully explain the origin of the chemical compositions of Lakes Vanda and Bonney. The salt concentration profiles in these saline lakes can be explained by the molecular diffusion (or ionic diffusion) of dissolved chemical substances from the bottom layer to the surface layer. The vertical transport of salt from the bottom layer is given by a conventional Fickian equation, with a diffusion coefficient (D); [numerical formula] where C is the salt concentration, z is the vertical distance coordinate increasing upward from z=0 at the bottom to z=h at the top of the saline layer, and t is time. For eq. (1), the initial and boundary conditions are [numerical formula] [numerical formula] [numerical formula] The solution of (1), obtained by the Laplace transformation with the boundary conditions (2)-(4) is [numerical formula] whereφ_1 is a function of time (t), height (z), and diffusion coefficient (D), its complete form being [numerical formula] The value of t of these saline lakes in the Dry Valleys is estimated by trial and error computation using eq. (5) and (5a). The age of stratification estimated for the salt diffusion from the bottom layers ranges from 1,000 to 1,250 years

Interpretation of Salt Deposition in Wright Valley, Antarctica: Chemical Analysis of DVDP 14 Core

Powder X-ray diffraction analysis, water and perchloric acid extraction and chemical analysis of extracts were carried out on DVDP 14 core to discuss the past environment in the Wright Valley. From the results of X-ray analysis, quartz and feldspar-group were found as primary minerals, with calcite and halite as secondary minerals. In the results of chemical analysis, the composition of the water soluble part was neary equal to that of ground water and the composition of the perchloric acid soluble part was neary equal to that of DVDP 13 core and soil of the Wright Valley. In general, the sodium content was higher in the upper part, while the calcium ion content increaesd with depth, and sulfate ion was negligibly small through the core. The vertical distribution of the water and perchloric acid soluble matter showed several peaks. This suggests some epochs in sedimentation in the area, such as drying up of or filling up with water