Spatial Distribution of Microplastics and Mesoplastics in Sediments across Hsinchu, Taiwan

Microplastics are becoming a major environmental concern, as they are ubiquitous, but their harm is not fully understood. Since research on microplastics in sediments in urban areas is scarce, this study aimed to uncover where microplastics may be the most abundant. City center, city border, and outer city sites were examined. One city center site was chosen (Gongshiyi Park), three city border sites were chosen (Touqian River North Bank, Touqian River South Bank, and Shixing Air Quality Purification Zone), and one outer city site was chosen (Shibajian Mountain). In each site, 25 samples were collected from an area of 10x10 cm and a depth of 2 cm, and plastic particles were filtered out using a 1mm sieve. The highest abundance of microplastics was at the city border (413.3 microplastics/m2), followed by the outer city (200 microplastics/m2), and lastly, the city center (100 microplastics/m2). Similarly, mesoplastics were collected and counted from the same samples, displaying a different trend with the highest abundance at the city border (273.3 mesoplastics/m2), followed by the city center (80 mesoplastics/m2), and lastly, the outer city (40 mesoplastics/m2). Contrary to previous research which showed a decrease in microplastic abundance from rural to urban areas, the findings of this study suggest that external anthropogenic variables, such as effective maintenance regimes, may have altered microplastic dispersal. Future studies should include a larger sample size, span over a longer period of time, and include a more complete land use analysis.