การศึกษาความเป็นไปได้ของการหลุดรอดของไมโครพลาสติกจากกระบวนการสร้างและใช้งานถนนแอสฟัลต์ผสมพลาสติก

Abstract

The Construction of roads using plastic waste as a component is an alternative method for plastic waste management. However, this method raises concerns due to the potential release of microplastics into the environment. Therefore, a laboratory simulation of asphalt concrete mixed plastic road in construction and operation was conducted to examine the release of microplastics in both air and water pathway. Four types of plastic were used in this study, categorized as follows: PE (68%), PP (20.33%), PET (7.72%), and PS (3.95%), based on a material flow analysis of recycled plastic waste found in landfills in Thailand, 2021. Water samples were collected during the simulated road operation, while air samples were collected during both the construction and simulated road operation. The collected samples were analyzed using a stereomicroscope, SEM-EDX, and FTIR. In addition, PM2.5 data were collected to analyze the release of dust particles during each road construction and operation process. The analytical results revealed no particles resembling microplastics in either the air or water samples. This absence of microplastics is likely due to the mixing process being conducted within a small-scale closed system, which allowed for precise control of the conditions. This controlled environment facilitated the complete melting of the plastics, thus minimizing the possibility for microplastic release. The highest concentration of PM2.5 particles was detected in the 0.3 µm range, the use of PM2.5 dust masks is suggested to protect against particle inhalation. Furthermore, sample pre-treatment, such as density separation and organic matter removal, remains necessary even when the study is performed in a closed system.