Studi Keberadaan Mikroplastik pada Insang dan Saluran Pencernaan Ikan Mas (Cyprinus carpio) di Perairan Danau Toba (Studi Kasus: Desa Haranggaol, Kecamatan Haranggaol Horison, Kabupaten Simalungun)

Abstract

Microplastics are emerging pollutants that are now widely found in aquatic environments and organisms. This study aims to analyze the presence, characteristics, and factors influencing the abundance of microplastics in the gills and digestive tracts of common carp (Cyprinus carpio) in Lake Toba. The research was conducted at two different locations floating net cage areas and open-water tourism areas under two rainfall conditions, namely high and low rainfall. The observed parameters included the shape, color, size, and polymer type of microplastics, microplastic abundance, the relationship between fish morphometric parameters (weight, length, and width), as well as the effects of location and rainfall conditions. The results showed that microplastics were found in all fish samples, with fibers and fragments being the dominant shapes, and blue, black, and transparent as the most common colors. The polymer type identified through Raman spectroscopy analysis was Polyethylene Terephthalate (PET). The average abundance of microplastics reached 5.5 particles per gram, with the highest concentration found in the gill organs. Regression analysis indicated that fish weight and length had a significant effect on the number of microplastics (p < 0.05), while width had no significant effect. The Mann–Whitney test revealed no significant difference in microplastic abundance between fish from the floating net cage area and the tourism area (p = 0.462), nor between high and low rainfall conditions (p = 0.753). This study indicates that microplastic pollution in Lake Toba has spread throughout the aquatic environment and is influenced by a combination of anthropogenic factors and environmental dynamics, while monthly fluctuations in rainfall have not yet shown a significant impact on the level of microplastic abundance in fish.