Microplastic Abundance in Stomach and Gill Tissues of Siganus vermiculatus Landed at Fish Landing Port, Palopo City, South Sulawesi, Indonesia

Abstract

Graphical Abstract Highlight Research Microplastics were detected in the gills and stomach of S. vermiculatus. Microplastic abundance was higher in the gills than in the stomach. Fiber were the most dominant shaped of microplastic in both organs. FTIR analysis confirmed the presence of PE, PES, PP, and HDPE in a selected subset of particles.   Abstract Microplastic contamination in coastal ecosystems has become an environmental issue attracting attention due to its potential impact on humans through marine food. This study employed a cross-sectional observational design to investigate microplastic contamination in the gills and stomachs of Siganus vermiculatus landed at the Palopo Fish Landing Port. Fifteen fish samples were examined, and particles resembling microplastics were isolated from gill and stomach tissues using chemical digestion method, these were visually identified using a stereo microscope based on their morphological characteristics. The particles were characterized according to shape, color, and size. To confirm the polymer types, selected particles from 7 of the 15 fish (gills: individuals 1, 6, 8, and 10; stomachs: individuals 1, 4, 6, 12, and 13) were analyzed using Fourier Transform Infrared Spectroscopy (FTIR) with a spectral similarity level of ≥70%. Microplastic-like particles were visually identified in all 15 samples S. vermiculatus (100%), indicating exposure among the sampled fish. The dominant shape of microplastics were primarily fibers, with white particles dominant in the gills and blue particles dominant in the stomach, while the 1-5 mm size class was the most frequently observed. FTIR analysis of selected particles from 7 of the 15 fish confirmed the presence of five polymers type: polyethylene (PE), polyester (PES), polypropylene (PP), and high-density polyethylene (HDPE). These results confirm significant microplastic contamination of the edible fish S. vermiculatus from the Palopo City fish landing port. These finding provide evidence of microplastic-like particle exposure in the sampled S. vermiculatus and provide a baseline for further investigation of microplastic contamination in the study area.