Degradation pathways and microplastic pollution of polypropylene geotextiles in soil systems

Abstract

Polypropylene (PP) geotextiles and composite materials, though valued for their durability and cost-effectiveness, contribute significantly to environmental plastic pollution. This review evaluates the degradation mechanisms and environmental fate of PP and its blends, particularly under field-relevant exposure conditions. Emphasis is placed on the formation and transport of microplastics (MPs) in soil systems, driven by mechanical stress, thermal aging, UV exposure, and biodegradation. The review examines the impacts of PP-derived MPs and additive leachates on soil biota, including microbial community shifts, enzyme activity disruption, and rhizosphere function impairment. Modeling approaches are presented to explore the feedback loops between polymer surface morphology, degradation rate, and exposure intensity. Comparative analysis of biopolymer-reinforced PP composites (e.g., PLA, jute, coir) highlights trade-offs between mechanical stability and environmental degradability. Key knowledge gaps are identified in MP transport in soils and toxicity pathways of chemical additives. This synthesis supports the development of predictive frameworks and sustainable materials engineering strategies to mitigate the long-term ecological risks associated with PP-based geotextiles.

Keywords: Biodegradable composites; Biopolymers; Geotextiles; Microplastics formation; Polypropylene degradation; Soil contamination.