Temporal Variation of Microplastic Abundances and Characteristics in Surface Water of Banger River of Pekalongan City, Indonesia

Abstract

The presence of microplastic pollution in coastal areas has garnered attention due to its detrimental impact on aquatic ecosystems and human health. In this study, our objective was to identify and characterize microplastics in the Banger River area of Pekalongan City, which is known for its numerous industrial activities, particularly batik small-medium industries. The extraction process involved filtration, drying, wet peroxide oxidation, density separation using NaI, and identification of microplastic particles. The shape, color, and size of the particles were characterized using a stereo microscope, while Fourier Transform Infra-Red Spectrometer and the hot needle method were employed for chemical structure analysis. Given that rivers serve as primary conduits for waste transport from land to sea, we conducted sampling at different times of the day. Our findings revealed an average of 0.61 ± 0.47 particles/m 3 in the morning, 0.59 ± 0.67 particles/m 3 in the afternoon, and 0.10 ± 0.02 particles/m 3 in the evening. Among the microplastic polymers analyzed, we successfully identified polypropylene as one of the two predominant types. To establish a baseline for mitigating the release of plastic waste and microplastic residues into the environment, long-term monitoring is essential to evaluate the flow of plastic waste and microplastics from Indonesian rivers to the oceans.