THE RELEASE OF IRON FROM DIFFERENT ASBESTOS STRUCTURES BY HYDROGEN-PEROXIDE WITH CONCOMITANT O-2 GENERATION

Treatment of aqueous suspensions of different asbestos fibers (amosite , anthophyllite, chrysotile, and crocidolite) at 0-4 degrees C and pH 7.2 with H2O2 results in the consumption of H2O2 with concomitant rele ase of iron and production of O-2. During incubations, [H2O2] decrease d in proportion to the mass of the suspended fiber, the duration of in cubation, and the initial [H2O2]. The consumption of H2O2, production of O-2 and release of iron all vary synergistically with the structure of the asbestos fiber. Release of silicon during the incubation was s mall relative to the decrement in [H2O2], reflecting a lack of dissolu tion of the fiber. The data are consistent with a redox process for th e release of surface bound iron and it is significant that iron releas e occurs in the absence of a Fe(II) or Fe(III) chelator. The implicati ons of iron release from the asbestos surface may be important in infl ammatory disorders in which both silicate bound iron and H2O2 accumula te.