Analisis Pengaruh Aktivitas Domestik dan Pratik Open Dumping terhadap Persebaran Mikroplastik di Sungai Gisik, Kecamatan Sedati

Ramadhani, Yudan (2026) Analisis Pengaruh Aktivitas Domestik dan Pratik Open Dumping terhadap Persebaran Mikroplastik di Sungai Gisik, Kecamatan Sedati. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Sungai Gisik di Kecamatan Sedati mengalami tekanan ekologis akibat limpasan dari pemukiman padat dan praktik open dumping di bantaran sungai, yang menjadikannya sumber signifikan pencemaran mikroplastik. Penelitian ini bertujuan untuk menganalisis pola sebaran dan karakteristik fisik mikroplastik pada matriks air permukaan dan sedimen, menentukan indeks beban pencemaran (Pollutant Load Index/PLI) dari aktivitas antropogenik tersebut, serta mengevaluasi pengaruh fluktuasi pasang surut terhadap dinamika transportasi polutan dari hulu hingga muara.
Pengambilan sampel dilakukan pada tiga stasiun pengamatan, yaitu Titik 1 (hulu), Titik 2 (area open dumping), dan Titik 3 (area muara/pelabuhan), menggunakan pendekatan composite sampling pada saat pasang dan surut. Preparasi sampel menggunakan metode Wet Peroxide Oxidation (WPO) tersuspensi Fe(II) pada suhu 75°C untuk menghilangkan gangguan material organik. Identifikasi partikel dilakukan secara visual menggunakan mikroskop stereo untuk mengklasifikasikan kelimpahan, bentuk, warna, serta ukuran, lalu divalidasi komposisi polimernya menggunakan instrumen Fourier Transform Infrared Spectroscopy (FTIR) dengan basis data Open Specy.
Hasil penelitian menunjukkan kelimpahan mikroplastik air permukaan berada pada rentang 12–21 partikel/L tanpa perbedaan statistik yang nyata antara pasang dan surut akibat pengadukan hidrodinamis yang kontinu. Sebaliknya, matriks sedimen menunjukkan gradien akumulasi yang meningkat ke arah hilir, memuncak di Titik 3 (2.983 partikel/kg) yang bertindak sebagai sink point akibat energi transportasi yang rendah dan hambatan fisik perahu. Analisis PLI menunjukkan kawasan hilir menerima beban pencemaran tertinggi. Dominasi bentuk fragmen (55–60%) dan film (15–22%) berukuran sangat halus (<100 µm; 73–79%), didukung temuan FTIR berupa polimer PET di area open dumping dan Polyamide 6 di muara, membuktikan sampah sekunder dari bantaran sungai dan domestik adalah kontributor utama. Secara hidrolis, dinamika pasang surut memengaruhi transportasi polutan secara mekanis melalui karakteristik asimetri dominan surut (ebb-dominant). Arus dan debit puncak di Titik 3 saat surut (11,72 m³/detik) jauh melampaui kondisi pasang, membuktikan bahwa fase surut berfungsi sebagai mekanisme penggelontoran (flushing) utama, sementara efek backflow saat pasang memicu retensi dan pengendapan sedimen pada skala estuari yang lebih kecil.
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The Gisik River in Sedati District faces severe ecological pressure from dense residential runoff and open dumping practices along its banks, making it a significant source of microplastic pollution. This study aims to analyze the distribution patterns and physical characteristics of microplastics in surface water and sediment matrices, determine the Pollutant Load Index (PLI) contributed by these anthropogenic activities, and evaluate the influence of tidal fluctuations on the transport dynamics of pollutants from the upstream to the estuary.
Sampling was conducted at three observation stations: Titik 1 (upstream), Titik 2 (open dumping area), and Titik 3 (estuary/port area), utilizing a composite sampling approach during high and low tides. Sample preparation applied the Wet Peroxide Oxidation (WPO) method with Fe(II) suspension at 75°C to eliminate organic interference. Particle identification was performed visually using a stereo microscope to classify abundance, shape, color, and size, followed by polymer composition validation using Fourier Transform Infrared Spectroscopy (FTIR) against the Open Specy database.
The results showed that surface water microplastic abundance ranged from 12–21 particles/L with no significant statistical difference between tides due to continuous hydrodynamic mixing. In contrast, the sediment matrix displayed an increasing accumulation gradient downstream, peaking at Titik 3 (2,983 particles/kg), which acts as a final sink point due to low transport energy and physical obstruction by docked boats. PLI analysis revealed that the downstream area receives the highest pollution load. The dominance of fragments (55–60%) and films (15–22%) sized <100 µm (73–79%), supported by FTIR findings of PET polymers at the open dumping area and Polyamide 6 at the estuary, confirms that secondary plastics from the riverbanks and domestic waste are the main contributors. Hydraulically, tidal dynamics mechanically control pollutant transport through an ebb-dominant asymmetry. The peak current and discharge at Titik 3 during low tide (11.72 m³/s) far exceeded those during high tide, proving that the low tide phase serves as the primary flushing mechanism, while the backflow effect during high tide triggers retention and sedimentation in this smaller-scale estuary.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	fourier transform infrared spectroscopy (FTIR), mikroplastik, open dumping, pasang surut, pollutant load index (PLI), sungai gisik, wet peroxide oxidation (WPO),fourier transform infrared spectroscopy (FTIR), microplastics, tidal dynamics, pollutant load index (PLI), gisik river, wet peroxide oxidation (WPO)
Subjects:	T Technology > TD Environmental technology. Sanitary engineering > TD194.6 Environmental impact analysis T Technology > TD Environmental technology. Sanitary engineering > TD427.P62 Microplastics--Environmental aspects.
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Environmental Engineering > 25201-(S1) Undergraduate Thesis
Depositing User:	Yudan Ramadhani
Date Deposited:	24 Jul 2026 02:30
Last Modified:	24 Jul 2026 02:30
URI:	http://repository.its.ac.id/id/eprint/136947

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