Caribbean islands, including Puerto Rico, are biodiversity hotspots threatened by microplastics (<5 mm). Little is known about the extent of microplastic pollution in coastal sandy beaches of Puerto Rico. Sand from six northern beaches was collected in the high tide line to determine microplastic abundance (0.3–4.75 mm). Península La Esperanza, the most polluted beach, exhibited higher average abundance (17 items/kg dw) and diversity. High urbanization, industrial/port activities, and riverine input are likely sources of plastic debris on this beach. The other beaches showed lower and similar average abundance (3 to 7 items/kg dw) despite having distinct potential point and non-point sources. Overall, fibers (40%), fragments (28%) and foams (27%) predominated (n = 102 particles). Results showed comparable levels to other world beaches, some classified as highly contaminated, but only when transforming units to items/m². Preliminary ATR-FTIR analysis identified mainly polyethylene. It is imperative to have plastics source reduction through waste management.

加勒比海岛屿，包括波多黎各，是受到微塑料（<5毫米）威胁的生物多样性热点。关于波多黎各沿海沙滩中微塑性污染的程度知之甚少。在涨潮线上收集了六个北部海滩的沙子，以确定其微塑性丰度（0.3–4.75 mm）。PenínsulaLa Esperanza是污染最严重的海滩，其平均丰度较高（17项/ kg dw）和多样性。高度的城市化，工业/港口活动和河流投入可能是该海滩上塑料碎片的来源。尽管有不同的潜在点源和非点源，但其他海滩的平均丰度却较低且相近（3至7个项目/千克干重）。总体而言，纤维（40％），碎片（28％）和泡沫（27％）占主导地位（n = 102个粒子）。结果显示，该水平可与其他世界海滩媲美，²。初步的ATR-FTIR分析主要鉴定出聚乙烯。必须通过废物管理减少塑料源。