ALUMINUM TOXICITY AND METAL SPECIATION - ESTABLISHED DATA AND OPEN QUESTIONS

Histopathological findings in humans and extensive toxicological inves tigation in vivo and in vitro point to an unambiguous neurotoxic poten cy of Al(III). Experimental toxicology with aqueous Al(III) is very di fficult owing to the complex and somewhat uncontrollable aqueous chemi stry of the metal centre in the neutral range. The choice of neutral, hydrolytically stable synthetic toxins makes possible both the control of metal speciation and of analytical metal concentration down to abo ut 1 mM in neutral buffered solutions. The employment of less stable c omplexes like Al-2(citrate)(2)(H2O)(6) and Al(lactate)(3) or of ordina ry salts is unavoidably complicated by the precipitation of Al(OH)(3) under the same conditions. In spite of this, the choice of a carefully designed protocol, based on ensuring well defined steps, enables one to successfully control the analytical metal concentration down to 10 mu M Al(III). The control of the metal speciation at these concentrati on levels remains an open question.