The mechanisms of lung disease induced by inhalation of mineral dusts are only partly understood. Chemical oxidative stress has been strongly implicated in lung fibrosis and cancer. For example, it is thought that deposited asbestos fibres may lead to the formation of DNA-damaging oxygen radicals directly, or indirectly, by inducing an inflammatory reaction. If this oxidative stress mechanism is generally important, it is possible that a variety of minerals, not just asbestos, may be capable of catalysing the formation of free radicals and thereby cause lung damage. This project addressed the issue of the surface catalytic formation of DNA-damaging radicals with regard to a range of locally extracted minerals. Using a laboratory assay, based on the hydroxylation of deoxyguanosine, it was found that all of the local mineral samples displayed a low reactivity, and nearly all displayed less reactivity than the asbestos reference minerals. Various experimental conditions were used, including different pHs, concentrations and buffer systems.
Funding
South Australian Mining and Quarrying Occupational Health and Safety Committee