Ecological risk assessment and ingestion of microplastics in edible finfish and shellfish species collected from tropical mangrove forest, Southeastern India

Abstract

In the Pichavaram mangroves in Southeast India, this study examines the seasonal trends and consumption of microplastic (MPs) by several fish and shellfish species. Four different seasons viz. summer, pre-monsoon, monsoon, and post-monsoon were used to gather the fish and shellfish samples from Pichavaram Mangrove Forest. The results of the present investigation revealed that MP abundance was higher during the monsoon (45 %), suggesting seasonal runoff and increased plastic pollution during heavy rains as key contributors. We observed microplastics in Liza tade (mullet), with 13.33 MPs/individuals in the summer, 0.77 MPs/individuals in the pre-monsoon, 6.3 MPs/individuals in the monsoon, and 2.67 MPs/individuals in the post-monsoon. A significant proportion (32 %) of MPs were smaller than 1 mm. The fibres were predominated with blue (40 %) and red (13 %). The polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) were the primary polymers, according to μ-Raman spectroscopy. The fish species Liza tade and Etroplus suratensis showed the highest levels of contamination, while the shellfish species Portunus sanguinolentus and Scylla serrata did the same. Comparative global analyses reveal that mangrove ecosystems across different regions exhibit the presence of similar polymer types, but microplastic sources vary greatly from place to place. This work highlights the pervasive nature of MPs, their complex seasonal behavior, and their ecological implications, advocating for targeted mitigation strategies to address MP pollution and its potential risks to marine life and ecosystems.