Elements Associated with the Cadmium Phase in a Harbor Sediment as Determined with the Electron Beam Microprobe

Lee, F. Y.; Kittrick, J. A.

Elements Associated with the Cadmium Phase in a Harbor Sediment as Determined with the Electron Beam Microprobe

1984

Lee, F. Y. | Kittrick, J. A.

A heavy metal-contaminated harbor sediment was examined with the electron beam microprobe in order to obtain specific information with regard to the elements associated with the Cd phase(s). Approximately 4.4 × 10⁴ particles were scanned in order to locate 18 that produced > 100 counts/s Cd Kα X-radiation. Of these Cd-rich particles, 72% were < 10 µm in diameter. For these particles, Cd was most frequently associated with S (in ca. 89% of the particles, presumably as S²⁻), rather than with the carbonate indicated by a chemical extraction method on the whole soil. Zinc was also significantly associated with Cd (in ca. 72% of the particles). Cadmium appeared to be precipitated with the associated elements rather than being adsorbed on the surfaces of the selected 18 particles. The formation of Cd sulfides in the sediment can be predicted from thermodynamic calculations, combined with a few reasonable assumptions.

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