Purpose: Nanoplastics (NPs) have garnered increased attention recently due to their potential to cause harmful effects in living things. We still don't fully understand the combination chronic toxicity of ZnO-NPs and PSNPs in aquatic ecosystems, which makes it more difficult to evaluate and reduce potential environmental risks related to the co-occurrence of these newly emerging pollutants in natural water bodies. Understanding the impact of both individual and combined exposure to ZnO-NPs and PSNPs on the reproductive endpoints of zebra fish (Danio rerio) was the goal of this study. Herein lies the uniqueness and significance of the present investigation. Method:Adult zebra fish were exposed to individual and combined concentrations of PSNPs and ZnO-NPs for a duration of 28 days in the present study. The concentrations were 50 and 100 µg/L PSNPs, 10 and 20 mg/L ZnO-NPs, 100 µg/L PSNPs + 10 mg/L ZnO-NPs, and 100 µg/L PSNPs + 20 mg/L ZnO-NPs. Results: While individual exposures and combinations both greatly reduced GSI and relative fecundity(15%–32%) in comparison to the control, combinational treatments typically produced comparable levels in the same endpoints. Significant decrease of late and mature oocyte (LMO) were observed in the treatments of 100 µg/L PSNPs + 20 mg/L ZnO-NPs. Significant presence of Degenerate oocytes (DO) were visible in 100 µg/L PSNPs+ 10 mg/L ZnO-NPs and 100 µg/L PSNPs + 20 mg/L ZnO-NPs treatments. This change indicated adverse effect of dual exposure of PSNPs and ZnONPs in these treatments. Conclusions: It appears that PSNPs limited the effect of ZnO-NPs (i.e., antagonism) because the individual exposures decreased both GSI and relative fecundity. An additional crucial discovery revealed that while PSNPs alone did not significantly alter egg fertility or hatching rate, both individual and combined exposure to ZnO-NPs (ZnO-NPs©20 and PSNPs/100+ZnO-NPs©20) reduced these reproductive characteristics.
