MICROPLASTICS CONTAMINATION IN FRESHWATER SYSTEMS OF PAKISTAN: ECOLOGICAL RISKS AND POLICY IMPLICATIONS

Abstract

Microplastic (MP) contamination poses escalating threats to Pakistan's freshwater ecosystems, vital for irrigation, fisheries and drinking water. This study quantifies MPs across 25 sites in Swat River, Ravi River, Rawal Lake, Thal Canal and Indus distributaries, analyzing water, sediments and fish biota. The results indicate a high level of contamination, as indicated by the average measure for water of 42.3 MPs/L with peaks in urban areas reaching 192 MPs/L, an average for sediment of 182 MPs/kg dry weight compared to 450 MPs/kg for the Ravi surface, and an average for fish of 1.4 MPs/individual, composed mainly of PE/PP fragments that are less than 1 mm in size (62%). The amount of MPs present in urban sites were 3.2 times greater than in rural sites (p < 0.001) and there was a post monsoon increase of 62% due to surface runoff from wastewater and inadequate waste management. Sediments were functioning as sinks for MPs (PLI > 1.5 and in a degraded state), and species at risk from bioaccumulation of MPs include the Indus dolphin.. PCA identified urban discharge as primary driver (67% variance). Results exceed regional benchmarks, urging Pak EPA policy enhancements: tertiary wastewater treatment, polymer bans, and monitoring standards (<50 MPs/L). Low cost methods enable scalable assessments amid Pakistan's urbanization crisis.