THE ABUNDANCE OF MICROPLASTICS IN THE DIGESTIVE SYSTEM OF SILVER BARB (Barbonymus gonionotus) FROM THE WATERS OF THE KARANG MUMUS RIVER, SAMARINDA CITY, INDONESIA

Abstract

The intensive use of plastic materials worldwide has raised concerns about microplastic pollution which is ubiquitous in aquatic environments around the world and can negatively impact aquatic biota. There are, however, many unknowns about pollutant quantities and interactions with biota, especially in developing regions of the globe. The purpose of this study was to investigate the abundance and types of microplastics consumed by fish and to determine the relationship between fish size and microplastic consumption. In this study, we examined silver barb (Barbonymus gonionotus) (n=20) sampled from Karang Mumus River, Samarinda City, East Kalimantan, Indonesia. Samples were obtained from a fisherman who were fishing with passive fishing gears along the Karang Mumus River. The length and weight of the fish were measured, and then the separated organs of the digestive system were then processed for microplastic content analysis: dissolving organic matter (digestive process) using potassium hydroxide (KOH) solution, leaving only non-organic material, including microplastics, then observed under a stereo microscope. We enumerated and identified types of microplastics encountered. Microplastic particles were found in all silver barb samples. The results of this investigation found an average microplastic abundance of 22.40 (SE: 2.5) per fish. Fiber microplastic particles were the most prevalent, comprising 70% of the total, with film microplastics accounting for 26%, and fragment microplastics making up the remaining 4%. The results of a linear model showed that there was a positive relationship between total length (p-value <0.06) and wet weight (p-value <0.07) of silver barb on the abundance of microplastic particles per individual fish, but both relationships were not significant. This study provides the first evidence of microplastic consumption by fish in the Karang Mumus River, which also indicates the potential for microplastic content in the water column, sediment, and interactions to and impacts on aquatic biota. © 2024, Zibeline International Publishing Sdn. Bhd.. All rights reserved.