Assessing the oxidative damage potential of engineered stone dust using a deoxyguanosine assay

The popularity of engineered stone (ES), alternatively known as artificial stone, as a building material for kitchen and bathroom benchtops in residential houses has expanded rapidly over the last decade. This has been associated with a global increase in occupational lung disease in workers exposed to the respirable dust produced during fabrication of ES products. In this study, we evaluated the reactivity and subsequent oxidative reduction potential of ES dusts generated by dry-cutting different ES materials using a common fabrication tool in a controlled environment and subsequently applying these freshly generated dusts to a cell-free deoxyguanosine hydroxylation assay to assess the potential for oxidative DNA damage. The objectives of this study were to (1) compare the potential for oxidative damage by (i) engineered vs. natural stones, (ii) settled vs. respirable stone dust fractions and (2) assess the effect of ageing on the reactivity of freshly-generated stone dust. Engineered stone dust was found to exhibit a higher relative reactivity than the majority of natural stones tested.  Respirable dust fractions were found to be significantly more reactive than their corresponding settled fraction (p<0.05), across all stone types and samples. However, settled dusts still displayed relatively high reactivity overall. No significant change in respirable dust reactivity was observed for three ES samples over a 21-day period; whereas a significant decrease in reactivity was observed in the natural stone studied. These results indicate that ES dusts are able to maintain their relatively high reactivity for extended time periods and settled dust fractions remain a significant hazard if resuspended within the workplace. This study has practical implications for dust control and housekeeping in industry, risk assessment and management.