Ingestion of microplastics in commercially important species along Thoothukudi coast, south east India

Microplastics pollute the marine environment and pose a greater risk to marine organisms. The microplastics were observed in the guts of the 12 species, which varied from 0.00 to 1.80 ± 1.19 particles /individual. Most of the microplastics were fibre shaped, 0.5-1 mm sized, blue-coloured, and polyethylene polymers. The abundance of the microplastics was higher for benthic species (0.66 ± 0.13 particles/ individual) than the pelagic species (0.53 ± 0.11 particles/individual), with no significant difference (p > 0.05). According to their feeding habits and trophic level, significantly the microplastics were abundant in the herbivores (1.23 ± 0.61 particles/individual) and quaternary consumers (0.76 ± 0.16 particles/individual), respectively. The present study suggests that microplastic ingestion in commercially important species was influenced by their feeding habits irrespective of their habitat and length and weight. In addition to this, biomagnification of the microplastics (Trophic Magnification Factor, TMF = 1.02) was also observed in the commercially important species with increasing trophic level. This further indicates that the trophic level can serve as the pathway for the transfer of microplastics from lower trophic level organisms to higher trophic level organisms. The present study concludes that the occurrence of biomagnification of microplastics and the pollutants absorbed by them might harm the commercially important species from the Thoothukudi region.