Investigation of Some Heavy Metal Contents of Soils at Different Distances and Depths in Agricultural Areas Near the Silopi Thermal Power Plant

Abstract

Silopi Thermal Power Plant is located in Şırnak province and uses asphaltite as its fuel source. Emissions from the power plant chimneys are likely to be dispersed in the region and accumulate on soils due to various factors. This could lead to an increase in the concentrations of some heavy metals (such as Cr, Ni and Cd) in soils. In this study, it was aimed to determine the plant-available (extractable) and total heavy metal contents of soils taken from areas close to the power plant where agriculture is intensively practiced. A total of 42 soil samples were collected from 7 different distance classes (D1, D2, D3, D4, D4, D5, D6 and D7) and 21 soil samples from 3 different points in each class and two different depths (0-30 cm and 30-60 cm) close to Thermal Power Plant. The concentrations of plant-available chromium (Cr), nickel (Ni), cadmium (Cd), cobalt (Co) and lead (Pb) were determined in soil samples. As a result of the research, the extractable concentrations were found to be in the ranges of Cr 0.11-0.29 mg kg-1, Ni 0.4-1.71 mg kg-1, Cd 0.02-0.1 mg kg-1, Co 0.17-0.39 mg kg-1 and Pb 0.82-2.37 mg kg-1; total Cr 22-55 mg kg- 1, Ni 56-102 mg kg-1, Cd 0.6-0.7 mg kg-1, Co 41-51 mg kg-1 and Pb 69-93 mg kg-1. Statistically (p<0.01); Ni and Pb were found to be significant for depth and distance averages, while Cd, Cr and Co were not considered significant. The concentrations of Cr and Ni concentrations decreased with distance from the power plant. Pb and Ni concentrations were higher in the 0-30 cm depth than in the 30-60 cm depth, suggesting the possibility of an external contamination of the topsoil. However, as a result, both the total and extractable concentrations of all the heavy metals examined did not exceed the permissible limit values according to the Turkish Soil Pollution Control Regulation.