Environmental Forensic Analysis and Risk Assessment of the Shoreline Microplastics Debris on the Limbe-Idenau Coastline, Cameroon

The incidence and unpleasant quality of plastic pollution, regularly witnessed on beach shores, has prompted researchers around the world to theses on the scale of the problem. The morphological features of waste plastics are important in understanding the nature of pollution, identifying sources, estimating dangers, and developing remediation strategies. The goal of this research is to detect, quantify, and forensically characterize the distribution of each MP/polymer composition and its associated risk on the Limbe shoreline in Cameroon. Over an 8-month period, duplicates of 4 m2 quadrants were collected at five purposive beaches. Plastic samples were thoroughly washed and sorted using a 2 mm sieve. Only particles 2 (0.69 g/m2) and 6 particles/month (2.0 g/m2), accounting for 75% of beach contamination in LDB 2, LDB 1, and IDN. May and June had 39% abundance, making them the most contaminated months. The buildup of MPs on beaches varied greatly spatially and temporally. ANOVA and Spearman’s rank correlation reveals linear correlations among the size categories. From the polymer MPs analysis, the dominant colour, shape, MPs type, size ranged, and weigh class in particle/number recorded white coloured, 50 (22.25 g) with PP (25), PE (15) and PS (5); irregularly shaped, 98 (30.5 g) with PP (39), PE (33), and PS (11); fragmented type, 80 (25.25 g) with PP (30), PE (28) and PS (15); 1.5 - 1.99 mm sized ranged, 102 (51.77 g) with PP (47), PE (41), and PS (7) and 0.01 g weighs, 98 (56.57 g) with PP (49), PE (29) and PS (13) with 65.5% of the MP’s being of old weathered plastic particles (OWPP). According to the environmental risk model, CF, PLI, PHI, and PERI pose the greatest danger of contamination to both marine life and beach tourists due to their category III polluting capacity. Similarly, the PET polymer material poses a Level III risk in both seasons. Forensic research revealed that the majority of beach MPs are heavily influenced by beach structure/water behaviour, while the risk provides critical insight into management, pollution monitoring efforts, and sustainable methods for MPs throughout the Limbe coastline as it serves as baseline monitoring materials and other methods could use for deeper investigations.