Isolation, Quantification, and Characterization of Microplastics in the Gastrointestinal Tract of Sardinella Tawilis Herre of Taal Lake, Batangas, Philippines

Abstract

Taal Lake, the third largest lake in the Philippines, is a freshwater ecosystem of significant importance for the country's fisheries sector and diverse fish species. However, the lake faces significant environmental challenges, particularly pollution caused by persistent plastics that degrade into microplastics (MPs). This pollution poses a potential threat to Sardinella tawilis, an endemic species of the lake and the only freshwater sardine in the world, as they are susceptible in ingesting MPs. The objective of this study is to assess the presence of MPs in the gastrointestinal tract of Sardinella tawilis and characterize them based on size, shape, and color. Fish samples were collected from three sites (Mataasnakahoy, San Nicolas, and Santa Teresita) and subjected to digestion, filtration, and stereomicroscopic visualization. Statistical tests were applied for data analysis. All 30 samples tested positive for MPs, with the highest abundance found in Sardinella tawilis samples from Santa Teresita. The ingestion of MPs by Sardinella tawilis did not show a preference for specific MP length but exhibited a higher preference within a narrower width range. The most prevalent MP shapes were fibers. Black and blue were the most abundant colors detected. These findings suggest potential sources of MPs in Taal Lake, including anthropogenic activities such as agriculture, leisure, and fishing practices, as well as consumer products like synthetic textiles, tires, and cosmetics. The findings of this study raise significant concerns about the potential impact on human health in the area due to the high prevalence and consumption of Sardinella tawilis. This increases the likelihood of MPs being bioavailable to humans and highlights the potential consequences of their exposure.