Occurrence of lead and zinc in soils and plants at the margins of a highway with heavy traffic

Abstract

The occurrences of lead (Pb) and zinc (Zn) were determined in soil and grasses collected at three points on stretch of 143 km of the Presidente Dutra highway between the states of São Paulo and Rio de Janeiro. The soil and plant samples were collected by sampling transections perpendicular to the highway at distances of 0, 10, 20, 35 and 50 m from the highway edge. Concentrations of Pb and Zn were higher in samples closest to the highway edge, decreasing with increasing distance from the road. There were positive correlation coefficients between the metal concentration in the soil and the metal concentration in the plant. Concentrations of Pb found in soil samples were below the reference value established for the soil quality in the state of São Paulo, while for Zn, up to 10 m away from the highway edge, the concentration was higher than the reference value.