Vertical distribution and sediment accumulation of microplastics in coastal aquaculture ponds of Kalanganyar Sidoarjo, East Java, Indonesia

This study evaluated the distribution and accumulation of microplastics (MPs) in the water column and sediment of aquaculture ponds in Kalanganyar Sidoarjo, East Java, Indonesia. Water and sediment samples were collected from several locations: the Gisik river (K1), the inlet channel (K2), the milkfish nursery pond (K3), and the milkfish grow-out pond (K4). Water samples were taken from three layers of the water column: surface (water surface), middle (half depth), and bottom (just above the sediment surface). Sediment samples were collected using a Van Veen grab sampler. The samples were then analyzed using the Wet Peroxide Oxidation (WPO) method combined with density separation. The results showed that MP abundance was highest in the water column at K4 (33.0 ± 1.41 particles/L), whereas the highest sediment MP concentration was recorded at K1 (304.35 ± 40.99 particles/kg). Plastic materials used in aquaculture operations were identified as a potential source of MPs contamination. Therefore, these findings highlight the need for improved waste management practices in aquaculture areas to mitigate MP pollution and protect coastal ecosystems.