In this paper, a novel approach using XAFS will be introduced for the study of the problem of cytotoxicity of metal ions. A micro beam from a SR source was used to measure the time-dependent distributions and chemical states of elements in mouse macrophages that were cultured in metallic solutions of different concentration. It is revealed that the concentrations and distributions of calcium, zinc and potassium in a single cell are closely related to the uptake of the metal. Using XAFS analysis, it is shown that metal elements absorbed by the cell interact with the cell and that the chemical state of the metal is changed.