Distribution of lead, cadmium, copper and zinc in roadside soil of Sari-Ghaemshahr road, Iran

Abstract

This study was conducted to investigate the concentration of lead, cadmium, copper and zinc in different site of the Sari-Ghaemshahr road in Iran. The soil samples were collected along the sampling section at the distances of 4, 8, 16, 32, 64 and 100 m from the road edge of both sides of the road, while sampling depths were 0 to 5 and 5 to 15 cm from the surface. The concentrations of Cu, Zn, Pb and Cd were measured by flame atomic absorption and the data obtained was statistically analyzed using SPSS 16 software. Results showed that all the three heavy metals except Cd were significantly different (p<0.01) in the distance of 4 m. Pb concentration obtained in 4 m was 2.95 mg kg-1, this value decreased to 1.76 mg kg-1 at 64 m and then again increased at 100 m from the road. The amounts of Cd in all distances were not significantly different. At first, the distance of Cu concentration was 1.91 mg kg-1 but later dropped to 1.48 mg kg-1 at a distance of 16 m, then increased to 2.02 mg kg-1 at 32 m distance from the road, then decreased again to 1.25 mg kg-1 at 100 m. Zn concentration at the nearest distance of the road was 3.66 mg kg-1, then decreased to 0.81 mg kg-1 at 64 m distance from the road and later increased at 100 m distance from the road. Similar findings were obtained for Pb, Cu and Zn concentration in south side of the road. The highest value in nearest distances could be because of emissions from vehicle exhausts. In addition Pb, Cu and Zn concentrations in two sides of the road at the same distance were not found to be close to each other. Key words: Cadmium, copper, lead and zinc concentration, vehicular emission.