@misc{oai:repo.qst.go.jp:00069410,
 author = {Takata, Hyoe and Aono, Tatsuo and Tagami, Keiko and Uchida, Shigeo and 高田 兵衛 and 青野 辰雄 and 田上 恵子 and 内田 滋夫},
 month = {Jul},
 note = {Introduction and Methods
Direct determination using ICP-MS for rare earth elements (REEs) in seawater, which are presumably present at less than the detection limit, is a difficult analytical task in the presence of seawater matrix. A simple and rapid method to separate and concentrate REEs in seawater was developed using a new chelating resin, NOBIAS chelate-PA1, which is a polyamino-polycarboxylic acid type resin. The resin was then used in an investigation of the geochemical behaviors of REEs in Japanese estuaries which are reported here. 
\nResults and Discussion
The REEs were recovered at more than 90% for a pH ranging between 5 and 6 in spiked seawater samples which were diluted in a salinity value ranged from 0 to 34. Total procedural blanks for REEs for the present study were lower than 0.1 ppt. It was concluded that the chelating resin can be applied for the preconcentration of REEs in estuarine water samples. 
The determined REE concentrations in the natural water samples indicated geochemical properties in the Japanese estuaries. These concentrations increased rapidly at low salinity (~1). Such a trend has been observed in some rivers [1, 2]. The increase in REEs concentrations was attributed to the salt-induced desorption from resuspended particles in river waters [3]. The concentrations of the REEs were constant at high salinity (>20) near the mouth of the rivers, indicating the removal of REEs during mixing in the estuary at a salinity value less than 20, as has been reported in other estuaries [2]. The REE concentrations slightly decreased with distance from the mouth of the rivers. 
This work has been partially supported by the Agency for Natural Resources and Energy, the Ministry of Economy, Trade and Industry (METI), Japan.
\n [1] Nozaki et al (2000) GCA 64, 3975-3982. [2] Nozaki et al. GCA 64, 3983-3994. [3] Elderfield et al. (1990) GCA 54, 971-991., The 18th annual V.M. Goldschmidt Conference},
 title = {Distributions of rare earth elements in Japanese estuaries},
 year = {2008}
}