First comprehensive investigation of microplastics occurrence and risks in uninhabited beach environments of Suheli Par, Lakshadweep

The distribution and accumulation of microplastics (MPs) in coastal environments are driven by a complex interplay of natural processes and human activities, shaping their spatial variability across different habitats. This study presents the first detailed assessment of microplastic pollution on the beaches of Suheli Par, a remote coral island in the Lakshadweep archipelago, based on sediment sampling conducted in April–May 2024 across 16 stations covering three tidal zones at each station in two geomorphic units, namely Cheriyakara and Valiyakara. The spatial distribution of microplastic abundance in Suheli Par revealed significant variations between Cheriyakara and Valiyakara, with Cheriyakara exhibiting a notably higher microplastic load due to periodic anthropogenic activities. Microplastic accumulation was highest in the vegetation zone across both regions, highlighting its role as a retention hotspot. The average microplastic concentration in Suheli was 932 ± 534.5 particles/kg, with Cheriyakara contributing 70.2% of the total load compared to Valiyakara’s 29.7%. In Cheriyakara, microplastic concentrations followed the trend: vegetation zone > high tide zone > low tide zone, with 75.88, 57.75, and 30.13 particles/kg, respectively. A similar pattern was observed in Valiyakara, albeit with lower values. Vegetation zones act as microplastic sinks due to debris entrapment, while high tidal energy in low tide areas limits accumulation. Statistical analysis confirmed significant differences in microplastic distribution between the two regions (p = 0.002) and among different zones (p < 0.001). The dominant microplastic shapes observed were fibres, followed by fragments and films. Polymer characterization revealed polyethylene (PE) and polypropylene (PP) as the most prevalent types, reflecting the emergence of synthetic materials in fishing and packaging activities on the island. The results indicated that microplastic deposition is strongly influenced by tidal dynamics, sediment characteristics, and human impact. These findings suggest potential ecological consequences, including the ingestion of microplastics by benthic fauna and trophic transfer that may disrupt the food web in coral island ecosystems and underscore the need for targeted mitigation strategies, particularly in anthropogenically influenced zones, to address microplastic pollution in these fragile coral ecosystems. Future research should explore the compositional characteristics, degradation behaviour, transport pathways, and long-term ecological impacts of MPs in coral reef ecosystems to safeguard these valuable ecosystems from further pollution.