Abstract

Soil contamination by microplastics (MPs) threatens soil health and structure. This study examined how six common polymers (PE, PP, PS, PET, PU, PVC) interact with soil minerals in four textures (SCL, SiCL, CL, SL). We measured retention, porosity, and aggregate stability using SEM, FTIR, zeta-sizer, and XRD. Low-density polymers (PE, PP) improved retention in fine-textured soils, raising aggregate stability by ~20% and reaching 5–10 mg/kg. High-density polymers (PVC, PET) reduced macroporosity by up to 15% in coarser soils and were retained in clay fractions. Allophane and kaolinite strongly adsorbed low-density MPs, likely due to high surface area, whereas hematite and hornblende showed minimal retention. Our findings highlight that polymer density and mineral composition govern MPs retention and soil stability, underscoring the need for polymer-specific analyses to assess microplastic risks in soils. These results reveal critical polymer-dependent mechanisms, providing a basis for improved microplastic mitigation and future management in terrestrial environments.