Model-based estimation of plastic debris accumulation in Banten Bay, Indonesia, using particle tracking - Flow model hydrodynamics approach

Abstract

Coastal pollution caused by marine debris in Banten Bay is increasing and threatening the environmental and ecological sustainability of the bay's coastal area. This study aims to simulate the particle tracking of floating plastic debris within Banten Bay and to estimate the coastal debris accumulation for the period 2018 to 2028 based on numerical spatial modeling. To determine the dominant direction of plastic debris flow, we recorded floating plastic waste at four locations (Bojonegara port, Karangantu Estuary, Cibanten Estuary, and the Sunda Straits) by releasing wooden drifters. The numerical model was developed using a Particle Tracking module based on the Langevin equation. In comparison to data provided by the drifter survey, the particle tracking showed a similar distribution trace that tended to move westward during the northeast monsoon and eastward during the southwest monsoon. During the northeast monsoon, marine debris intake peaked, ranging from 2.25 kg to 5.75 kg. We estimated that over the ten years modeled plastic debris accumulation would increase by approximately 11%, to a maximum rate of 9.42 kg/day. Of particular concern, it is modeled that 41% of Banten Bay will be covered by plastic debris in 2028 if effective mitigations are not immediately applied. We recommend conducting a coastal cleanup operation every ten days so that coastal debris deposits can be well-controlled.