DISTRIBUTION OF TIRE AND ROAD WEAR PARTICLES(TRWP)-RELATED POTENTIALLY TOXIC ELEMENTS (PTEs) WITH PARTICLE SIZE IN THE PORT OF BUSAN: A POTENTIAL CONTRIBUTOR OF PORT SEDIMENT POLLUTION

Abstract

The Port of Busan is one of the busiest seaports in the world and in a metropolitan city that supports a vigorous economic activity of about three million residents. It has been reported that marine sediments around the Port of Busan, as well as major ports around the world, are contaminated with various pollutants, including potentially toxic elements (PTEs). Transporting inbound and outbound goods from and to the port via vehicles is known to be a significant source of pollution along with the incoming and outgoing ships at the onshore and offshore areas, respectively. This study aimed to identify sources of PTEs of road-deposited sediment (RDS) in the port. RDS mainly results from the deposition of tire and road wear particles (TRWP), which are mechanical abrasion of brakes and tire erosion of road surfaces by passing traffic. These vehicle-generated particulate pollutants are deposited mainly on the road surface and interact with other solid materials. In recent years, the pollutants with TRWP have been an emerging environmental concern because of their toxicity and contamination of coastal sediment. Notable findings of this study are 1) The traffic volume and vehicle type influenced the grain size of RDS, while it was negatively correlated with the accumulation of PTEs; 2) Geoaccumulation index (Igeo) of Zn, Cd, Cu, Pb, Sb, and Cr showed that the RDS were severely contaminated with PTEs-related TRWP; 3) RDS, which is <250 µm, was affected by the same anthropogenic activity traffic source, statistically (p<0.05); 4) PCA results showed that Heavy-duty vehicle (HDV) activity in the port area may have affected the most abundant PTEs, such as Zn, in RDS in this area. The fine particles of RDS on the road surface are potential coastal sediment because they can be readily washed off into the nearby water sphere by stormwater and settled down. Therefore, the results of this study suggested that it is necessary to mitigate TRWP, mainly induced by HDV, to control the sediment PTE quality in the port.