Microplastic Characteristics and Abundance in Water, Sediment, and Sulcospira testudinaria in a Freshwater Aquaculture System

Abstract

Microplastic contamination has become an emerging issue in freshwater ecosystems due to its persistence and potential ecological impacts. This study aimed to investigate the characteristics, abundance, and pollution status of microplastics in the water, sediment, and the freshwater gastropod Sulcospira testudinaria along the flow of the Freshwater Aquaculture Installation (IBAT) Punten, Batu City, Indonesia. Microplastics were identified using an inverted microscope, while pollution levels were assessed using the Microplastic Contamination Factor (MCF) and Microplastic Pollution Load Index (MPLI). Film was the dominant type in water and S. testudinaria, whereas fragments predominated in sediment. Brown is the most abundant colors across all environmental compartments, indicating extensive weathering of plastic debris. Microplastic abundance was highest in sediment, confirming its role as the primary sink for microplastics in the aquatic environment. MCF analysis indicated that most sampling sites were classified as significant contamination, while sediment at Site 2 reached the very high contamination category. MPLI values of 3.48 (water), 4.34 (sediment), and 3.16 (S. testudinaria) further indicated a very high level of microplastic pollution. These findings demonstrate widespread microplastic contamination throughout the IBAT Punten freshwater system and highlight sediment and S. testudinaria as effective indicators for monitoring freshwater microplastic pollution.