Activation of UICC crocidolite: the effect of conversion of some ferric ions to ferrous ions.

Asbestos fibers catalyze the generation of oxygen-centered radicals in the presence of oxygen or hydrogen peroxide. The amount of iron in asbestos fibers, its oxidation state, and its availability to specific chelating agents determine their ability to catalyze the aforementioned reactions. In the present study, the activation of UICC crocidolite was achieved by converting some of the ferric ions into ferrous ions. The activation process did not interfere with the size distribution, surface area, or crystal structure of these fibers. Although oxygen-centered radicals generated and lipid peroxidation produced by asbestos fibers are reported to play an important role in their toxicity, factors such as size, surface area, and durability are considered to be crucial determinants of fiber toxicity and carcinogenicity. The employment of the activated crocidolite in animal experiments to help further elucidate the importance of oxygen free radicals and lipid peroxidation in fiber-induced diseases is therefore proposed.