Distribution and stoichiometry of Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb in the East China Sea

The dissolved (d) and total dissolvable (td) trace metals were determined in seawater samples collected from the East China Sea (ECS). Labile particulate (lp) species was calculated as td minus d, and the sectional and vertical distributions of d and lp trace metals were evaluated. The surface concentrations of dAl, dCo, dNi, dCu, and dPb were higher in the continental shelf region than in the Kuroshio region. lpAl and lpFe were the dominant species below a depth of 400 m, and a strong positive correlation was observed between them in the Kuroshio region. The enrichment factor (EF) against crustal abundance was calculated for the purpose of estimating the origin of dMs in the ECS. The EF(dFe) was close to unity. These results suggest that both lpFe and dFe are dominated by crustal sources. The other elements had high EF, indicating significant contributions from other sources. EF(dPb) was close to the enrichment factor in aerosol, suggesting atmospheric input from anthropogenic sources. The dM/P ratios were calculated to investigate the validity of the extended Redfield ratio in the ECS. The Mn/P, Co/P, Cu/P, Zn/P, and Cd/P ratios in shallow water (< 200 m) were within the same order of magnitude as those in phytoplankton. In contrast, the Al/P and Fe/P ratios were, respectively, 27 and 213 times higher in phytoplankton compared to those in shallow water. These results suggest that dFe is a potential limiting factor for biological production, although it is not exhausted in surface water

Study on the characterization of the water-soluble fluorescent substances in rainwater and airborne particulate matter by using three-dimensional excitation emission spectrometry

Three-dimensional excitation emission spectrometry was applied to the characterization for the water-soluble fluorescent substances (WSFS) in rainwater and airborne particulate matter. The contour plots of EEM spectra of WSFS in rainwater showed one sharp peak at an excitation wavelength 300-305nm/emission wavelength 405-415nm. The fluorescence intensity of WSFS in rainwater decreased with rainfall amount. The peak position of the WSFS in airborne particulate matter was in good agreement with the peak position of WSFS in rainwater. The fluorescent intensity of the water-soluble component was affected by the extraction operating conditions. The fluorescent substances in the water-soluble components of airborne particulate matter were defined as the filtrate obtained using a 0.45μm membrane filter after immersion in ultrasonic wave irradiation for 20 minutes. The spectrum patterns of rainwater and WSFS in airborne particulate matter were almost coincided with WSFS in the NIES standard reference material.本文データはCiNiiから複製したものである

The accumulation rate and benthic fluxes for selenium in the marginal seas

This paper describes the concentrations of selenite, selenate and organic selenide in pore water, and selenium in sediment cores in the marginal seas. The selenium accumulation rates for the Sulu Sea and the South China Sea were 1.16 and 0.21 mg cm^yr^. The upward diffusive fluxes of dissolved selenium were estimated by using Fick’s first law. The calculated fluxes od dissolved selenium as selenate in the Sulu and South China Seas were estimated to be 0.17 and 0.88 μg cm^yr^, respectively.本文データは一部CiNiiから複製したものである

Geochemical studies on the dissolved rare earth elements in the Yodo River system

[Abstract]　There are few reports on the research on the rare earth element in natural water. The difficulties for the determination of REEs in natural water are due to the low concentration in natural water. However, remarkable development of commercial chelate resin column (HITACHI NOBIAS PA-1) enabled simultaneously concentrated separation of rare earth elements in natural water sample. In this study, the geochemical studies on the rare earth elements in the river around the Lake Biwa and Yodo River system by ICP-MS with the chelate resin column separation method