Heavy-metal content of roadside soil in Mersin, Turkey

Lead, nickel, cadmium, copper, and zinc were determined in roadside soil samples collected from different locations in Mersin metropolis. The samples were digested with a 3/1 mixture of conc. hydrochloric/ nitric acid. The metal content was determined by flame atomic absorption spectrometry. The method of analysis was evaluated using Soil-7. a certified reference material (International Atomic Energy Agency. IAEA). For each location, the numbers of vehicles driven on the road were counted. Results showed that the soil contained significant levels of metals, when compared to control values. The mean values for Pb, Ni, Cd, Cu, and Zn in street soil were 183, 120, 3.4, 55 and 20 mu g g(-1), respectively. A significant correlation was found between the number of vehicles and the metal contents in soil samples. These values suggested that motor vehicles form a major source of these metals in the soil. The concentrations of heavy metals in the samples were also compared with those reported by scientists in various countries.