Neutron activation analysis of respirable mica samples and their pathological effects in lungs of rats

Instrumental and radiochemical neutron activation analyses (INAA, RNAA) have been used to quantify the different elements present in mica samples derived from Indian mines and a factory, together with USGS standards using high-resolution gamma-ray spectrometry. Both samples revealed the presence of several toxic elements in appreciable quantities. When tested in a rat model system over a period of 360 days after intratracheal injection of mica samples of respirable size (50 mg/animal), the animals which received the factory sample containing shellac exhibited enhanced dust-induced pulmonary reaction together with characteristic abscess formation at later periods. The significance of these findings is discussed.