A baseline study of meso and microplastic predominance in pristine beach sediment of the Indian tropical island ecosystem

The global presence and prevalence of microplastic have moved microplastic from an emerging pollutant to a persistent contaminant. Microplastic prevails in almost all spheres of the environment viz. terrestrial, marine and atmosphere the globe abundantly. The prevalence and toxic effects on marine organisms have been studied around the world but the studies are limited to the coastal regime of the Andaman and Nicobar Islands (ANI). This study aims to record microplastic prevalence on the tourist beaches of Port Blair, ANI. Three coastal stations namely Cove beach, Quarry beach and Wandoor beach were examined in detail in this regard. Microplastics in the form of lines, fragments, pellets, foams and fibres were found at the sampled sites. Wandoor beach recorded the highest microplastic particles ranging from 105-475 particles kg-1 of sediment with the mean value of 249.82 ± 105.78 particles kg-1. Quarry beach near the municipal waste dumpsite showed the lowest of 72.5-222.5 particles kg-1 with a mean value of 135.625 ± 62.83 particles kg-1. The polymeric forms found were High-density polyethylene (HDPE), polystyrene (PS), polypropylene (PP) and polyethylene terephthalate (PET). This study revealed microplastic input from municipal dump waste near the beach. Fourier Transform Infrared spectroscopy (FTIR) revealed the presence of a new type of polymer namely plasta zinc in the beach sediment, which possibly could be a nanoplastic. Its presence reveals the biological enzymatic degradation of microplastic occurring in the marine environment. Further investigations are required to determine the factors influencing the prevalence of microplastic, its toxic effects on marine habitat and microplastic degradation mechanisms in the marine habitat.