Assessment of Microplastics in Fish GI Tracts and Shallow Water Sediments in Pugad Baboy Mangrove Area, Kawit, Cavite Using Fourier Transform Infrared-Attenuated Total Reflectance Spectroscopy

Plastic pollution has been an ongoing environmental problem overwhelming people worldwide. Microplastics (MPs) are defined by their small sizes (<5mm) and are continuously pressing concerns due to the threats they bring to the ecosystem. The scarcity in microplastics study limits the resources for future researchers for methods and applications to explore. This study assessed, characterized, and quantified microplastics contamination in fish gastrointestinal (GI) tracts and sediments in the Pugad Baboy Mangrove areas of Kawit, Cavite. Sediments and fish GI tract samples were treated using a modified methodology. The collected microplastic particles under investigation were separated through density separation using ZnCl2 followed by base digestion using KOH. MP particles were examined using an optical microscope and characterized through Fourier Transform Infrared– Attenuated Total Reflectance (FTIR-ATR) spectroscopy. Results showed that four polymer identities were detected in the particles – polyethylene, polypropylene, polystyrene, and polyethylene terephthalate. A total of 67 fragments were isolated from which approximately 26.9% exhibited irregular shapes, 35.8% had a rounded and pellet-like appearance, and 37.3% were filaments. A high recovery rate of at least 90% upon analysis was recorded and the implementation of the proposed modified methodology is strongly recommended based on recovery and results obtained. These findings provided valuable insights into the physical characteristics and distribution of microplastics in the studied environment.