Meso- and microplastics accumulation and ecological risks in Philippine urban and rural sandy beaches

Abstract

Understanding the fate of mesoplastics is crucial for inferring microplastic pollution levels, as their degradation over time contributes significantly to microplastic accumulation. However, Philippine beaches, which gained international recognition for their beautiful landscape and crystal-blue waters, are poorly studied. We assessed meso- (5-25 mm) and large-microplastic (1-5 mm) accumulation in urban and rural Philippine beaches and their ecological risks. A total of 513 meso- and 180 large-microplastics (LMP) were identified across 30 sites, with mean concentrations of 45.5 +/- 24.3 items/m(2) and 16.1 +/- 0.190 items/m(2), respectively. The plastic particles were confirmed using ATR-FTIR analysis. Expectedly, meso- and LMP abundances were significantly higher (p < 0.05) in urban than rural beaches, indicating anthropogenic pollution drivers. Dominant mesoplastics were primarily white in color (34.8 %), film-shaped (38 %), and measured 5-10 mm in size (35.1 %), with polypropylene (37.8 %) as the most prevalent polymer. Similarly, LMP were mainly white in color (68 %), foam-shaped (66.3 %), and measured 4.0-4.9 mm (34.8 %), with polystyrene (66.3 %) as the dominant polymer, showing industrial, domestic, and recreational impacts. Additionally, a strong relationship between meso- and LMP abundance suggests similar contamination sources and potential plastic fragmentation. Their proportional distribution in fine and coarse sands further indicates similar accumulation patterns. Overall, urban beaches are pollution hotspots, emphasizing the need for targeted interventions to mitigate plastic pollution impacts on Philippine beaches and the marine environment.