Fragmentation Behavior of Microplastics from Plastic Products on Road Surface

Abstract

 Fragmentation behaviors of microplastics (MPs) have been studied in recent years. Studies have been done on the fragmentation behaviors of MPs in seabed and beaches; however, such studies have not been performed on the roadway. The main objective of this study is to evaluate the fragmentation behaviors of MPs on roadway surfaces. In order to simulate the behavior of MPs fragmentation in the roadway environment, three types of plastic bags and three types of plastic straws cut into 1 cm x 1 cm were exposed to ultraviolet light and stepped on by foot. As a result, 3,900 – 5,710 MPs particles with diameters over 20 µm were produced from a piece of plastic bags, and 3 – 1930 were produced from a piece of plastic straw. It is found that 37 – 40% of plastic bags by area ratio have disintegrated into 1.47 million – 1.62 million particles with diameters smaller than 20 µm after 1152 hours of ultraviolet light exposure and 400 times of foot stepping. The present study indicated a possibility that microplastics can be produced on the roadway.