title: Dissolution of functional materials and rare earth oxides into pseudo alveolar fluid.
abstract: The dissolution rates of rare earth oxides and two types of rare earth containing functional materials into water, saline solution, and Gamble's fluid were measured in order to evaluate the biological effects of rare earth-containing functional materials. The tested materials were yttrium, lanthanum, cerium and neodymium oxides, and neodymium-boron-iron magnet alloy (NdBFe) and lanthanum-mish-metal-nickel-cobalt (LmNiCo) hydrogen-containing alloy. The dissolution rates of the rare earth oxides were very low, resulting in concentrations of rare earth elements in the test solutions of the order of ppb. In the most extreme case, Gamble's fluid dissolved 1,400 times more of the rare earth oxides than pure water. Fairly high concentration of neodymium were found in the dissolving fluids, which means that trace neodymium present as an impurity in each rare earth oxide dissolved preferentially. For yttrium oxide, the ratio of neodymium to yttrium that dissolved in the saline solution was greater than 78,000 to 1, taking into account the amount of each that was originally present in the yttrium oxide.
authors.affiliation: National Institute of Industrial Health, Nagao, Kawasaki, Japan.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Takaya
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shinohara
authors.forename: Fumio
authors.initials: F
authors.lastname: Serita
authors.forename: Mariko
authors.initials: M
authors.lastname: Ono-Ogasawara
authors.forename: Noriko
authors.initials: N
authors.lastname: Otaki
authors.forename: Tadao
authors.initials: T
authors.lastname: Toya
authors.forename: Ayako
authors.initials: A
authors.lastname: Takata
authors.forename: Katsumi
authors.initials: K
authors.lastname: Yoshida
authors.forename: Norihiko
authors.initials: N
authors.lastname: Kohyama
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D006207:Half-Life; D006801:Humans; D007811:Lanthanum / Q000032:analysis; D008674:Metals, Rare Earth / Q000032:analysis* / Q000633:toxicity; D009354:Neodymium / Q000032:analysis; D010087:Oxides / Q000032:analysis* / Q000633:toxicity; D012462:Saline Solution, Hypertonic / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D015019:Yttrium / Q000032:analysis
chemical_list: D008674:Metals, Rare Earth; D010087:Oxides; D012462:Saline Solution, Hypertonic; D012997:Solvents; D014867:Water; D009354:Neodymium; C119467:lanthanum carbonate; D015019:Yttrium; D007811:Lanthanum; C091417:yttria