[Changes in chrysotile in vivo].

In an animal experimentation rats received a single intratracheal injection of 2 mg chrysotile per animal. Quantitative energy dispersive x-ray microanalysis (EDXA) and selected area electron diffraction (SAED) patterns of the chrysotile fibres, obtained from lung tissue, were performed with the aid of a transmission-electronmicroscope (TEM). During a period of four months the chemical and physical instability of asbestos fibres were investigated. The results of microanalysis were compared with standard chrysotile A, UICC as a reference material. The magnesium-leakage of chrysotile fibres and in the diameter range below 0.1 micrometer was found to be time-depending and increased during the period of the experiment. Opposite to the contents of Ca, the Fe-concentration was not significantly higher. After two months already, a greater number of depleted chrysotile fibres could be analysed. If leakage of magnesium exceeded 80 percentage, the typical single crystal electron diffraction patterns of the chrysotile could not be obtained furthermore. EDXA and SAED are inevitable techniques of identify fibres, which been altered during the period of deposition in animal lungs. There was no evidence to suggest the formation of asbestos bodies during the period of experimentation.