Reduction of non-point source contaminants associated with road-deposited sediments by sweeping

Abstract

Road-deposited sediments (RDS) on an expressway, residual RDS collected after sweeping, and RDS removed by means of sweeping were analyzed to evaluate the degree to which sweeping removed various non-point source contaminants. The total RDS load was 393.1 ± 80.3 kg/km and the RDS, residual RDS, and swept RDS were all highly polluted with organics, nutrients, and metals. Among the metals studied, Cu, Zn, Pb, Ni, Ca, and Fe were significantly enriched, and most of the contaminants were associated with particles within the size range from 63 μm to 2 mm. Sweeping reduced RDS and its associated contaminants by 33.3-49.1% on average. We also measured the biological oxygen demand (BOD) of RDS in the present work, representing to our knowledge the first time that this has been done; we found that RDS contains a significant amount of biodegradable organics and that the reduction of BOD by sweeping was higher than that of other contaminants. Significant correlations were found between the contaminants measured, indicating that the organics and the metals originated from both exhaust and non-exhaust particles. Meanwhile, the concentrations of Cu and Ni were higher in 63 μm-2 mm particles than in smaller particles, suggesting that some metals in RDS likely exist intrinsically in particles, rather than only as adsorbates on particle surfaces. Overall, the results in this study showed that sweeping to collect RDS can be a good alternative for reduction of contaminants in runoff.

Pollution Caused by Potentially Toxic Elements Present in Road Dust from Industrial Areas in Korea

“…The median total load of RD at the nine industrial complexes considered in this study was 822 g/m 2 , ranging from 334 to 1669 g/m 2 . The total load of RD in the industrial areas was 2.1-6.5 and 15-16.4 times higher than that in the heavy traffic (126-393 g/m 2 ) and urban (50 g/m 2 in commercial areas; 54 g/m 2 in residential areas) areas of Korea, respectively [10,41].…”

“…Trace metals present in soils are difficult to migrate owing to their long residual time and strong concealment [4]. Pollution caused by PTEs present in RD has become an interesting topic of research because RD is an important carrier of PTEs and can contribute as a non-point source to runoff pollution in urban areas [6,10].…”

Experimental Study on Purification Effect of Biochemical Pool Model for Treatment of Pavement Runoff by Aquatic Plants

“…Road-deposited sediments (RDS) often contain elevated concentrations of inorganic and organic pollutants such as heavy metals, metalloids, and polycyclic aromatic hydrocarbons [37]. Road sediments (RDS) from a highway were collected and analyzed and found to be highly contaminated with organic matter, nutrients, and metals [38,39].…”

“…The sediment formed on the road surface is the main source of road runoff pollution. Affected by wind and rain, about 90% of it is distributed within the range of 0-50 cm from curb [38,[40][41][42]. All the samples collected in this paper are regarded as the pavement sediment within the range of 0-50 cm of the curb, which can be used as the typical representative of the main source of pavement runoff pollution.…”