A Comprehensive Ecotoxicity Study of Molybdenum Disulfide Nanosheets versus Bulk form in Soil Organisms.

The increasing use of molybdenum disulfide (MoS) nanoparticles (NPs) raises concerns regarding their accumulation in soil ecosystems, with limited studies on their impact on soil organisms. Study aim: To unravel the effects of MoS nanosheets (two-dimensional (2D) MoS NPs) and bulk MoS (156, 313, 625, 1250, 2500 mg/kg) on and . The organisms' survival and avoidance behavior remained unaffected by both forms, while reproduction and DNA integrity were impacted. For , the individual endpoint reproduction was more sensitive, increasing at lower concentrations of bulk MoS and decreasing at higher ones and at 625 mg/kg of 2D MoS NPs. For , the molecular endpoint DNA integrity was more impacted: 2500 mg/kg of bulk MoS induced DNA damage after 2 days, with all concentrations inducing damage by day 7. 2D MoS NPs induced DNA damage at 156 and 2500 mg/kg after 2 days, and at 1250 and 2500 mg/kg after 7 days. Despite affecting the same endpoints, bulk MoS induced more effects than 2D MoS NPs. Indeed, 2D MoS NPs only inhibited reproduction at 625 mg/kg and induced fewer () or no effects () on DNA integrity. This study highlights the different responses of terrestrial organisms to 2D MoS NPs versus bulk MoS, reinforcing the importance of risk assessment when considering both forms.