Temporal dynamics and geomorphological influences on plastic waste accumulation

Abstract

Background: Plastic waste is a significant global environmental issue and constitutes the dominant type of marine debris. Its durability, lightness, and stability make plastic widely used in daily life, but its degradation process takes an extremely long time. Teluk Laikang, located in Mangarabombang Subdistrict, Puntondo Hamlet, Takalar Regency, serves as both a coastal tourism destination and a site for seaweed cultivation. This study aims to quantify the amount, weight, and composition of stranded plastic waste at Teluk Laikang Beach over a specific observation period and to analyze the accumulation rates influenced by the geomorphology and oceanographic conditions of the area. Methods: The study utilized a shoreline survey method with an accumulation survey type. This method involves regular monitoring of the same stretch of coastline, which was initially cleaned, to record changes in the amount, weight, and composition of plastic waste over time. Direct field measurements were carried out to assess current speed and direction, wave height, and beach slope. Findings: The study identified a total of 709 plastic waste items weighing 3,584 grams in Teluk Laikang. Statistical analysis using repeated measures ANOVA revealed significant differences in plastic accumulation rates based on lunar phases. Pairwise comparisons showed that the highest accumulation rates occurred during the full moon phase, with an average of 0.00063 items/m²/week and 0.00841 grams/m²/week. Conversely, the lowest rates were recorded during the first-quarter moon phase, with an average of 0.00023 items/m²/week and 0.00082 grams/m²/week. The most dominant type of plastic waste during the observation period was drink bottles smaller than 2 liters (PL02). Novelty/Originality of this Article: This study provides a detailed analysis of plastic waste accumulation in a semi-enclosed coastal area influenced by geomorphological and oceanographic factors. By focusing on the temporal variation of waste deposition, the research highlights the critical role of natural cycles in plastic waste distribution