X-ray micro-analysis of aluminium in pumpkinseed gills

Energy dispersive X-ray micro-analysis was applied to study the (sub-) cellular distribution of aluminium at the gill level of "acid-resistant pumpkinseeds (Lepomis gibbosus) exposed to acidified water (pH = 4.2) and an elevated level of aluminium (1.4 mg Al/l, exposure period = 21 days). Electron dense deposits, located in invaginations as well as inside the gill tissue, were shown to contain elevated levels of aluminium and phosphorus. The micro-analytical findings suggest that the pumpkinseed possesses a defence mechanism, in which the intracellular accumulation of aluminium is limited to restricted sites and to storage in macrophages.