Documentation of environmental particulate exposures in humans using SEM and EDXA.

There is increasing awareness of health hazards from environmental and occupational exposures to particulates. Scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) can document these exposures by analysis of small portions of cells, tissues and environmental samples. Previous work is briefly reviewed and special attention is given to discussion, with examples, of the various types of particulates which may be found in tissues (exogenous, endogenous, inhaled, injected, ingested, inorganic, organic), the different tissues in which they may be found (lung, heart, liver, skin, brain, kidney, lymph nodes, etc.), methods of tissue sampling (e.g. pulmonary lavage, transbronchial biopsy, open biopsy, percutaneous biopsy, autopsy), specimen preparation (fixation, embedding, sectioning, choice of substrate), SEM and EDXA data collection (backscattered electron imaging, etc.) data interpretation (artefacts, limitations of SEM and EDXA) and other new techniques (ion microprobe, laser Raman microprobe).