Abstract
The rare earth elements (REES) transported through rivers from the continents to the ocean play an important role in the geochemical cycle of REEs in the ocean, and help the interpretation of the REE pattern of seawaters. This work studies the REE concentrations of Changjiang water, to characterize the REE fractionations between suspended loads and dissolved phase, and to estimate the riverine input of the REEs to the East China Sea. River water samples were collected across 2500 km along the river from Changjiang inlet to upper reaches during October 13-19, 1997. Sampling was made by using a 10 L clean polyethylene bucket while the ship was slowly steaming. Immediately after collection, all river water samples were filtered through 0.1 mm hollow fibres (Milli pore). The samples used for REE determination were acidified to pH 95 %), and Cd added to the final solution was used as a monitor in the efficiency of ionization and ICP-MS detection. The blanks for the entire procedure and reagents were measured in parallel with the samples and suitably corrected. They were the highest for the LREEs being ~10 % for Ce and ~5% for La, Pr and Nd, but relatively minor ( Mg 2+ > Na + > K +. The cations in this calcic water show conservative abundances from the Changjiang inlet to the upper reaches like almost other world river, with one exception collected from Shanghai bay which probably influenced by urban draining water. Ca 2+ and Mg 2+ concentration are quite high as compared with other large rivers. The total cations (~50 mg/L) are about 1.7 times that of the global average (29 mg/ L). It suggests that the high suspended sediment and major element loads of the Changjiang reveal intense chemical weatherings over the Chinese continent.
Published Version
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