Evaluation of some heavy metals contaminated soils around the Shahid Salimi power plant, Neka, Mazandaran Province, Iran

One of the most important problems threatening the health of natural resources and, in turn, the food safety of societies is environmental contamination. Heavy metals are considered as the environmental pollutants. The entry of heavy metals into the soil is done through the atmospheric sources and mostly via melting plants, oil refieries and power plants. Due to the mazut consumption in some seasons, power plants are considered as a threat to the soil. This study was conducted with the aim of evaluating contamination of some heavy metals including copper, zinc, cadmium, lead, and nickel in the soils around the Shahid Salimi power plant, Neka located in Mazandaran province, north of Iran. One of the greatest threats is the possible contamination of cultivated paddy by pollutant elements. A number of 50 samples from the soil around the power plant were taken from a depth of 0–20 cm within the form of a regular grid and the concentration of the corresponding metals was measured in each of them. The mean background concentration of copper, nickel, lead, zinc, and cadmium was 36.2, 339.8, 90.8, 13.8, and 0.20 mg∙kg, respectively. The maximum mean contamination factor belongs to nickel, lead, copper, zinc, and cadmium, respectively. The frequency of the obtained contamination evaluation classes indicates that the majority of the analyzed samples have a medium level of contamination. Copper, nickel, and lead belong to the class of very high contaminants. By comparing the concentrations of the heavy metals of studied region with quality standard of Iranian soil resources, presented by the Department of Environment Protection of Iran, it was observed that the concentrations of cadmium, zinc, and copper have been signifiant at the level of 5% based on the standards determined by the agency for agricultural uses, environmental standard and groundwater level. In other words, they do not have conflct with the determined standard at any of the three levels.