Abstracts of Annual Meeting of the Geochemical Society of Japan

Cosmogenic stable nuclide, ⁴⁵Sc, concentrations in Gibeon iron meteorite were determined by radiochemical neutron activation analysis. ⁴⁵Sc concentration down to 0.0064 ppb was able to determined in this study. Blank value was estimated to be less than 0.001 ppb.⁴⁵Sc concentrations in Gibeon were found to be highly correlated with ⁴He concentrations. It was consistent with the correlation observed in iron meteorites other than Gibeon meteorite. In Gibeon meteorite two different irradiation ages were observed using rare gas isotopes. In this study 8 fragments with different irradiation ages were analyzed. Systematic difference among 8 fragments was not found for the correlation between ⁴⁵Sc and ⁴He. It was concluded that 2 different irradiation ages observed in Gibeon was not resulted from loss of rare gases from the body.

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To answer a question whether 14C concentration is higher for plants growing at high altitude areas than those growing at the sea level, we recently have collected plant samples from four sites at different altitudes: (1) plants from Lake Pumayum area at the altitude of 5,030m; (2) plant samples from the suburbs of Lhasa city at the altitude of 4,000m; (3) needle leaves from pine tree at 2,600m-high location of Mt. Fuji; and (4) needle leaves from pine trees growing in the Higashiyama Campus of Nagoya University at the altitude of 50m. 14C concentrations of the terrestrial plants will be discussed in accordance with their growing altitudes.

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IntroductionThe toxicity and persistence of booster biocides are of major concern. This study reports the occurrence of diuron (3,4-dichlorophenyl-1,1-dimethylurea) biocide in surface off shore waters, surface sediments and plankton samples. Diuron is the Halogenophenylureas form one of the main groups of herbicides used for more than 40 years in fields and antifouling is also a source of pollution in marine environment. This work shows data on the occurrence of diruon in the surface waters, sediments and planktons. To our knowledge, this is first study reporting diuron concentration in planktons in Japan, particularly in Seto Inland Sea.Sample collection, preparation and analysisDiuron in surface sea water, sediment and plankton were measured with respect to the distribution around Hiro bay, Aki Nada, Osaka bay, Harima bay, Kozima bay and Bingo nada sites were surveyed on the Seto Inland Sea in west Japan and samples were collected in the off-shore area at Autumn Cruise (October 20-24, 2008) by research vessel Toshiomaru, Hiroshima University. Seawater sample was collected by Niskin samplers and filtration was done immediately by GF/C filters (0.45 μm) in ship. Diuron compound is extracted from the samples by solid phase extraction (SPE) using C18 sep-pack cartridge column. Sample extracted were analysed by HPLC-UV detection (254 nm). Recovery rate of diuron from SPE was examined and the recovery rate was 95% for distilled water and 88% for sea water. The recovery rate of diuron from sediment was 92% and plankton recovery analysis was not done. Results and discussionConcentration of Diuron in marine samplesranged from 30 to 60 ng/L, 11.8 to 87.8 μg/kg dry wt. and 75 – 450 μg/kg dry in sea water, sediments and plankton respectively. Sampling sites were fixed according to the river discharge in each and every perfection sea lines. By this higher and lower value experiences that near to the mouth given significantly higher while comparing to offshore. The bioconcentration factor (BCF) of diuron from the concentration of diuron in sea water and in plankton, it was ranged80-15000 (average 4520), but were estimatednot to be widely different from Watanabe et al. (2004)*, who estimated on nonylphenol from Hiroshima bay. From the results of this study it can be concluded that residue levels found in the water, sediment and plankton may not likely produce acute toxicity effects to larger animals, but the accumulation of these same concentration may be detrimental to aquatic organisms.

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The concentrations of trace anion species including metalloids in natural water are much lower than those predicted by solubilities of solid phases containing these anion species. It is thought to be related to adsorption of those anions on the surface of an iron or aluminum oxides or hydroxides which are ubiquitously distributed in surface environment. The binding forms of ions on mineral surface are able to be divided into two categories. One is inner-sphere complex which adsorbs as chemical bonding directly to the metal-ion in surface. The other is outer-sphere complex which adsorbs to the surface hydroxyl electrostatically. These surface speciation are important considering the long-term behavior of toxic ion and the bioavailability of dissolved ion. In addition, the speciation influences the physical-chemical property of the mineral, such as solubility of nanosized mimeral (Fukushi and Sato, 2005) and solubility rate of mineral (Blum and Lasaga, 1988). Ferrihydrite is a low crystallinity ferric hydroxide widely distributed in soils and rivers. It is also thought to be an effective anion adsorbent substance because of its high-specific surface area and property of positively-charged surface in natural water. Sulfate (SO42-) is common anion in soils and rivers. It is reported that sulfate competes with phosphate, carbonate and organic acid, trace metal adsorption (Fukushi and Sverjensky, 2007). For this reason, adequate understanding of sulfate adsorption mechanisms is needed. The present study aim to reveal the surface speciation of sulfate at a water-ferrihydrite interface under various pH and ionic strength conditions by in-situ IR spectroscopic analysis (ATR-FTIR: Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy) and surface complexation modeling (ETLM: Extended Triple Layer Modeling).

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