Low Ecotoxicological Impact of Magnesium Oxychloride Cement Composites Doped with 2D Carbon-Based Nanoadditives

Magnesium oxychloride cement (MOC) is gaining attention as a sustainable alternative to Portland cement. Its mechanical performance and water resistance may be enhanced by reinforcement with two-dimensional nanomaterials, such as graphene (G) and graphene oxide (GO). However, the ecotoxicological impact of these composites, determining their implementation, remains largely unexplored. This study evaluated the effects of G platelets with a surface area of 750 m²/g (G750) and GO, both as isolated particles and embedded within MOC, on a range of prokaryotic (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) and eukaryotic (Artemia salina, Sinapis alba, and Desmodesmus subspicatus) model organisms. G750 and GO exhibited species-specific antibacterial activity, notably inhibiting S. aureus growth and biofilm formation, while P. aeruginosa remained largely unaffected. The addition of G750 or GO did not enhance MOC's antibacterial effect, as MOC alone exhibited strong antimicrobial activity. Both G750 and GO were toxic to A. salina at concentrations of ≥0.05 g/L, with GO showing greater toxicity. Phytotoxic effects were observed in S. alba, particularly with the GO and MOC-G750 composites. Algal growth was unaffected by MOC-G750 but inhibited by MOC-GO after extended exposure. G750, GO, and MOC samples showed no genotoxic potential in vitro and in vivo; ROS production occurred without a significant change from the control. Overall, incorporating G750 and GO into MOC improved material properties without substantially increasing ecotoxicity, though species- and material-specific responses underscore the need for thorough environmental impact evaluation.