Iron ore mines leachate potential for oxyradical production

The ecotoxicological effects of mining effluents is coming under much great er scrutiny. It appears necessary to explore possible health effects in ass ociation with iron ore mining effluents, The present results clearly demons trate that iron-ore leachate is not an inert media but has the potential to induce lipid peroxidation. Peroxidation was assessed by measuring oxygen c onsumption in the presence of a reducing agent such as ascorbate or NADPH a nd a chelator such as EDTA, Labrador iron ore is an insoluble complex cryst alline material containing a mixture of metals (Fe, Al, Ti, Mn, Mg,...,) in contrast to the iron sources used for normal lipid peroxidation studies. T he metal of highest percentage is iron (59.58%), a metal known to induce ox yradical production. Iron ore powder initiated ascorbic acid-dependent lipi d peroxidation (nonenzymatic) in liposomes, lipids extracted from rat and s almon liver microsomes, and intact salmon liver microsomes, It also reveale d an inhibitory effect of NADPH-dependent microsomes lipid peroxidation as well as on NADPH cytochrome c reductase activity. However, nonenzymatic per oxidation in rat liver microsomes was not significantly inhibited. Cytochro me P450 IA1- and IIB1-dependent enzymatic activities as well as P450 levels were not affected. The inhibition could be due to one of the other compone nts of iron ore leachate (Mn, Al, ....). These effects of iron-ore leachate indicate that a potential toxicity could be associated with its release in to lakes, Further studies are necessary to explore in vivo effects on aquat ic animals. (C) 2000 Academic Press.