Microplastic contamination in Nerita albicilla: Implications for marine ecosystem health along Karachi coast

Microplastics (MPs) have become a significant environmental concern globally, with their pervasive presence in various ecosystems posing threats to marine life and human health. This study investigates the MPs contamination in a gastropod species Nerita albicilla found commonly along the Karachi coast. A total of 60 individuals of N. albicilla, 5 specimens from each site monthly were handpicked from the intertidal area of Hawksbay and Buleiji rocky shore from November 2022- April 2023. The shells were noted for morphometrics and visceral tissues were digested in 10% KOH solution in a ratio of 3:1. Each digested suspension was filtered using 0.45 mu m organic filter paper and observed with the help of a compound microscope. A total of 64 MPs (1.4 +/- 0.2443.6 +/- 0.678 item ind.(-1)) were recorded from 30 N. albicilla specimens collected from Hawksbay and 59 MPs (1.4 +/- 0.4- 3 +/- 0.632 item ind.(-1)) from Buleji. The most dominant MPs types were microfibers, which made up to 84% and 88 % of total MPs at Hawksaby and Buleji, respectively whereas the most of MPs ranged in size range of 0-25 mu m indicating anthropogenic pollution sources such as textiles, fishing gears, and synthetic materials commonly found in marine environments. The study underscores the ecological significance of gastropods in monitoring marine pollution and highlights the urgent need for mitigation measures to safeguard coastal ecosystems.