Microplastic pollution has emerged as a critical environmental challenge, with freshwater systems serving as major conduits and sinks for plastic debris from terrestrial and municipal sources. To investigate distribution, concentration, and ecological impact of microplastics (<5 mm) across three peri-urban river catchments, with emphasis on macroinvertebrate community structure and ecosystem services.

Water and sediment samples were collected across 18 sampling stations over 12 months. Microplastic characterisation used stereomicroscopy and ATR-FTIR spectroscopy. Shannon-Wiener H' and EPT richness were computed.

Mean microplastic concentration reached 847 ± 213 particles/L (water) and 3,240 ± 680 particles/kg (sediment). Sites with higher contamination showed significantly lower EPT richness (r = −0.81, p < 0.001). Fiber-type plastics dominated (62%).