O-126 OCCUPATIONAL EXPOSURE DURING GRAPHENE NANOFLAKES PRODUCTION PROCESS: AN INTEGRATED APPROACH TO MONITOR EARLY CYTO-GENOTOXIC EFFECTS BY SENSITIVE AND NONINVASIVE BIOMARKERS AND WORKPLACE CONTAMINATION

Introduction Standardized exposure monitoring procedures and suitable biomarkers and biological matrices are needed to evaluate the potential health risk of occupational exposure to graphene-based nanomaterials. Methods We enrolled 5 workers of a graphene start up (mean age 39±13) and 5 controls (mean age 38±12). Harmonized OECD methodology was used to measure workplace and personal worker exposure. We used Buccal Micronucleus Cytome (BMCyt) assay (buccal cells) for local cyto-genotoxic effects and fpg-comet test (lymphocytes) and oxidized DNA bases 8-oxoGua, 8-oxoGuo and 8-oxodGuo measurements (urine) for systemic genotoxic/oxidative effects. Results Particle number concentration during the graphene-based powders handling differs significantly from the background (Wilcoxon test p<0.05). Furthermore morphological analyses on airborne sampled materials showed rare particles attributable in size and shape to the produced graphene-based nanomaterials. BMCyt assay showed in exposed workers nuclear buds (indicative of genic amplification) and slight MN frequency induction and a subject MN positive (exceeding a fixed cut-off value for MN frequency 1.5‰). Fpg-comet assay showed induction of direct and oxidative DNA damage in exposed vs controls. A slight increase of urinary oxidized DNA bases in exposed workers was also found. Discussion The study confirms BMCyt and fpg-comet assays as the most sensitive biomarkers of early, still reparable, genotoxic and oxidative effects that, related to exposure measurements, represent useful non-invasive tools for the biomonitoring of workers involved in graphene production. Conclusions The integrated approach including workplace exposure characterization and biomonitoring of early health effects is useful for risk assessment and could be also used for long-term studies of workers exposed to nanomaterials.