Ultrastructural aluminium detection in amphibian tissues by electron spectroscopic imaging and electron energy-loss spectroscopy

Aluminium causes a variety of toxic effects in living organisms but very little is known about its uptake, pathways and locations of deposition. We have applied electron spectroscopic imaging (ESI) and electron energy-loss spectroscopy (EELS) to locate aluminium at the ultrastructural level in amphibian larvae from acidic ponds. It is found diffusely bound or precipitated in cell organelles. The spatial resolution of aluminium detection is high. The elemental composition of small areas can be demonstrated by EELS. Three different fixation procedures give similar results. The two- and three-window methods at the K- and L-edges are compared.