The use of fertilizer is a routine method of soil improvement, and thereby fertilizer is considered as an emerging factor affecting the transport of plastic particles in agricultural soils. Nano-CaCO3 was selected as representative of nano-fertilizer to investigate its effect on the transport and release of nano- and micro-plastics (NPs and MPs) in saturated porous media. 200 mg L-1 nano-CaCO3 on the transport of nano- (0.51 μm, PS NPs) and micro- (1.1 μm, PS MPs) polystyrene particles (5 mg L-1) in saturated quartz sand were investigated. Nano-CaCO3 facilitated both the transport and release of PS NPs and MPs under examined 0.1-10 mM NaCl and 0.1-1 mM CaCl2 solutions. In addition, it was believed that the remaining deposition of PS NPs and MPs after nano-CaCO3 copresent and release treatment was solid and stable, as evidenced by the negligible detachment of PS NPs and MPs with deionized water wash. Further investigation indicated that the competition for deposition sites on quartz sand surfaces by nano-CaCO3 copresent in solutions was the major factor dominating the enhanced transport of both PS NPs and MPs. It was verified by the transport of single nano-CaCO3, the increased transport of PS NPs and MPs in quartz sand that was subjected to pre-equilibration with nano-CaCO3 and also the SEM images of quartz sand covered with nano-CaCO3. Meanwhile, the sweeping effects induced by nano-CaCO3 were found to be responsible for the enhanced release of PS NPs and MPs during the transport process. It was further confirmed by the relatively high surface area, roughness of nano-CaCO3 and the fluorescent microscopy imaging of the detached particles in effluents of PS NPs and MPs column experiments induced by nano-CaCO3. The findings of this study give insights to assess the ecological risks of plastic particles with agrochemicals.

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