Assessment of Heavy Metals in Road Dust from a Strategically Important Motorway in Equatorial Climate

The current concentrations of heavy metals and their potential pollution levels were comprehensively assessed in road dust from a humid climate area, along the freeway National Route 40 in Colombia, and potential sources were identified. The mean concentrations of Pb, Ni, Cr, Cu, and Zn were 17 ± 5.6, 9.9 ± 2.4, 13.6 ± 6.3, 12.2 ± 8.3, and 57.1 ± 13.6 mg kg−1, respectively, and the maximum values were 34.3, 16.2, 28.0, 42.6, and 89.9 mg kg−1. The heavy metals were ranked in the order of relative abundance as follows: Zn > Pb > Cr >Cu >Ni. The average PLI was 1.1, indicating no or slight pollution; the CF values were also very low. Only a few sites were polluted by Pb, and only some were moderately polluted. All samples had negative Igeo values for all elements, indicating no contamination. Therefore, although the area is affected by anthropogenic sources, such as agroindustrial activities, vehicle traffic hydrocarbon emissions, and food transport, there are no obvious signs of contamination. These findings can help to shape local strategies targeted at reducing emissions and minimizing health and environmental concerns in humid tropical locations.