Correlation between radioactivity levels and heavy metal content in the soils of the North Kosovska Mitrovica environment

Abstract

This paper reports the results of radioactivity concentrations and heavy metal content in soil samples collected from non-agricultural areas in the municipality and vicinity of North Kosovska Mitrovica, formerly the most important mining area in Europe. The estimated average activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs are 40.6 ± 19, 48 ± 25.4, 743.2 ± 200.5 and 81 ± 119 Bq kg⁻¹, respectively. The estimated average absorbed dose rate in the air and the annual effective dose are 78.7 nGy h⁻¹ and 96.6 μSv, respectively. The radium equivalent activity and external hazard index were also calculated. High contents of Pb, Zn, Cu, Cd, As and Ni were found in the analyzed soil samples, thus indicating pollution of the environment. Most metals have a wide range of values spanning 2 to 3 orders of magnitude, which is particularly evident for Pb and Zn. Correlations between the activity concentrations of the radionuclides, the heavy metal content in soil and the basic soil properties were determined by means of the Pearson linear coefficient. Strong positive correlations between the naturally occurring radionuclides, and also among Pb, Zn, Cu and Cd were found.