Hubungan Mikroplastik di Sedimen dengan Ukuran Butir Sedimen Pulau Panjang, Banten

Abstract

Mikroplastik merupakan partikel plastik berukuran =5 mm yang distribusinya di dasar perairan dipengaruhi oleh ukuran butir sedimen. Ukuran butir sedimen dapat mengindikasikan kondisi energi suatu perairan. Pulau Panjang yang terletak di Teluk Banten berpotensi mengakumulasi mikroplastik dari Teluk Banten dan aktivitas antropogenik lokal. Penelitian ini bertujuan mengkaji kondisi hidrodinamika perairan Pulau Panjang dan mengidentifikasi keterkaitan komposisi ukuran butir sedimen dengan kelimpahan mikroplastik di sedimen perairan tersebut. Sampel sedimen diambil dari area lamun, batas vegetasi lamun, dan area non-lamun di tiga stasiun untuk analisis kandungan mikroplastik dan komposisi ukuran sedimen. Kondisi hidrodinamika diperoleh melalui pemodelan menggunakan perangkat lunak Openflows Flood. Perbedaan kelimpahan mikroplastik antar area dan stasiun dianalisis menggunakan uji Kruskal-Wallis, lalu korelasi dan asosiasi mikroplastik dengan ukuran butir sedimen dianalisis menggunakan koefisien Spearman dan principal component analysis (PCA). Hasil pemodelan hidrodinamika menunjukkan arus berkecepatan lebih tinggi di utara pulau, dan lebih rendah di barat daya dan selatan pulau. Kelimpahan mikroplastik di sedimen berkisar antara 240–1.880 partikel/kg, dengan fraksi sedimen dominan berupa pasir halus dan pasir medium. Tidak ditemukan perbedaan signifikan kelimpahan mikroplastik antar stasiun dan antar keberadaan lamun. Kelimpahan mikroplastik berkorelasi positif dengan fraksi sedimen halus (rs = 0,58 dan 0,45) yang mengindikasikan bahwa peningkatan butiran sedimen halus cenderung diikuti dengan peningkatan kelimpahan mikroplastik. Analisis PCA menunjukkan adanya asosiasi kelimpahan mikroplastik dan sedimen di area lamun, namun tidak dengan fraksi sedimen tertentu, yang mengindikasikan distribusi mikroplastik di sedimen Pulau Panjang cenderung dipengaruhi oleh keberadaan vegetasi lamun.

Microplastics, defined as plastic particles =5 mm, are influenced in their distribution on the seafloor by sediment grain size, which also reflects the hydrodynamic energy of aquatic environments. Panjang Island, located in Banten Bay, has the potential to accumulate microplastics from bay-wide transport and local anthropogenic sources. This study aims to assess the hydrodynamic conditions around Panjang Island and examine the relationship between sediment grain size composition and microplastic abundance in sediments. Sediment samples were collected from seagrass, seagrass edges, and non-seagrass areas at 3 stations. Microplastic content and sediment grain size composition were analyzed in the laboratory, while hydrodynamic conditions were simulated using OpenFlows Flood software. Spatial differences in microplastic abundance were evaluated using Kruskal–Wallis test while correlations and associations between microplastic and sediment grain size were assessed using Spearman’s coefficient and principal component analysis (PCA). Hydrodynamic modeling results showed stronger current in the northern part of the island, with weaker flows observed in the southwestern and southern regions. Microplastic abundance ranged from 240 to 1.880 par/kg, with fine and medium sand being the dominant sediment fractions. No significant differences in microplastic abundance were found accross stations or areas. Microplastic abundance showed a positive correlation with finer sediments (rs = 0,58 and 0,45), suggesting that microplastic accumulation increases with the proportion of fine sand. PCA indicated an association between microplastic abundance and sediments from seagrass areas, although not directly with sediment. These findings indicate that seagrass presence may influence microplastic distribution in Pulau Panjang beyond sediment characteristics.