Investigation of Heavy Metal Contents of Road-Deposited Sediment in Expressways

Road-deposited sediment (RDS) is an important carrier of heavy metal contaminants. Understanding the contribution of RDS and its potential to runoff pollution is essential for pollution control. Fifty one samples were collected from five different highways of Jilin Province and heavy metal elements (i.e., Cr, Cu, Ni, Pb, and Zn) were estimated in RDS. The RDS particles from all impervious road surfaces were predominantly coarse particles (>250 μm, 50.8-67.7%). The four expressways have higher concentrations of heavy metals in RDS than background concentrations of heavy metal in soils of Jilin Province. The authors' findings imply that RDS from expressway is a potential pollution resource. For controlling runoff pollution from RDS, transportation agencies should pay much attention to expressway maintenance, and improve existing cleaning methods and cleaning frequency into account.