Heavy Metal Concentrations in Industrial, Agricultural, and Highway Soils in Northern Iran

Abstract

In this article, heavy metal concentrations of lead (Pb), cadmium (Cd), and zinc (Zn) in industrial, agricultural, and highway soils in the north of Iran (Amol-Babol) have been investigated. The soil samples were collected randomly from the identified areas and after transfer to the laboratory, they were dried in an oven and then ground by mill and passed through a 2 mm polyethylene sieve. A mixture of HNO3 and HCL was used to extract the metals existing in samples. The measurement of Zn, Cd, and Pb was done by Perkin-Elmer Atomic Absorption Spectrometer (AAS), model 603, after filtration by number 42 Whatman paper. Mean concentrations of the metals were calculated in mg/kg in industrial, agricultural, and highway soils, respectively as follows: Pb 213±132, 19.70±9.5, 84±38; Cd 4.90±3.80, 1.9±1.2, 0.95±0.40; and Zn 214±111.50, 112±47, and 107±39.50. The highest concentration of these metals was observed in industrial area soils. According to the obtained results, the mean concentration of Pb and Cd in the industrial areas of Amol and Babol was more than the permissible limit of Iran's environment conservation organization and Zn concentration in all of the studied regions was less than the permissible limit (400 mg/kg). A significant statistical difference has also been observed between the mean concentration of Pb, Cd, and Zn in the industrial, agricultural, and highway soils and their background concentration.