Abstract
Vehicle emissions have been known to cause trace metal contamination in soils. The extent of such contaminations in soils, and of the effects of traffic density and distance from highways on the concentration of trace metals in roadside agricultural soils is largely unknown. This study examined the total concentrations of common trace metals (Cd, Co, Cr, Cu, Ni, Pb, V, and Zn) in roadside agricultural soils from Thailand with diverse traffic densities (approximately 30–200 million vehicles/kilometer/year), roadside distances (0, 10, 20, 50, and 100 m from the road edge), and crops (rice, maize, and sugarcane). Cadmium, Cu, Pb, and Zn concentrations significantly decreased with increasing distance away from the roads (p < 0.05). However, the concentrations of these metals were not correlated with traffic density, probably due to extensive road maintenance and expansion. The contamination factor demonstrated that the road edge soils were moderately- to highly-polluted with Cd, Cu, Pb, and Zn. The safest distance to minimize metal pollution for agricultural production is proposed to be greater than 10 m away from the road edge.
Highlights
Traffic is a primary source of trace metal pollution in roadside soils, and plays a pivotal role in the biogeochemical cycling of trace metals, and in turn substantially affects human health [1,2,3]
Trace metal contamination can be found in road dust and roadside soils
The trace metal concentrations were analyzed using a one-way analysis of variance (ANOVA), and the mean values were compared among sampling distances for each highway using Duncan’s Multiple Range Test (DMRT) at p < 0.05
Summary
Traffic is a primary source of trace metal pollution in roadside soils, and plays a pivotal role in the biogeochemical cycling of trace metals, and in turn substantially affects human health [1,2,3]. Trace metal contamination can be found in road dust and roadside soils. Traffic density and road age impact trace metal concentrations in soils. Res. Public Health 2019, 16, 714 from the surface to the base of the Ap horizon, except for the road edge sample (0 m distance) that was taken from 0–10 cm. The road edge samples were considered as representative of the trace metal concentrations released from motor vehicles. The sieved soil samples were used for particle size distribution using the pipette method and general chemical analysis, except for the determination of organic carbon and total metal concentrations, where the sieved soil was finely ground to
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
