Rapid screening of ecological risks from marine plastic pellet pollution: A case study following a shipwreck

Shipwreck incidents such as the M/V X-Press Pearl (Srilanka), and MSC ELSA 3 (Kerala) have released large quantities of plastic pellets, causing widespread coastal microplastic contamination. These events highlight ship-related spills as major sources of persistent marine microplastic pollution. The immediate ecological risk assessment during the critical golden hours after the shipwreck is vital for taking critical pollution mitigation measures. By quantifying plastic pellet abundance and identifying polymer composition across 11 coastal locations, the research applies the Polymer Hazard Index (PHI), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI) to transition from descriptive density metrics to a tiered risk assessment. The risk assessment identifies Varkala (PHI = 980.2; PLI = 11.8; PERI = 1354.2), Kovalam (PHI = 858.8; PLI = 12.5; PERI = 1331.6), and Perumathura (PHI = 910.6; PLI = 10.1; PERI = 920.6) as critical hotspots, reaching Hazard Category IV and "Extreme Danger" status due to the massive scale of the spill. While most other sites, such as Puthenthopp (PHI = 650, PLI = 1, PERI = 6.5), exhibit lower pollution load intensity and low ecological risk. The dominance of high PHI categories across the coast reflects significant potential for chemical toxicity from polymer additives and also may identified as persistent secondary sources for micro- and nanoplastics due to weathering. The study demonstrates that integrating PHI, PLI, and PERI provides a reliable preliminary framework for evaluating marine pollution during a shipwreck, where specific nurdle-risk tools are often lacking. The results emphasize that targeted cleanup, long-term monitoring, and integrated chemical-biological risk frameworks are essential to mitigate chronic toxicity, bioaccumulation, and sustained ecological impacts in tropical coastal systems.