Determination of Activity Concentration of 40K and Gross Beta activity in Soil from Kavadarci and its Environs

Abstract

A survey was carried out to determine the activity concentration and distribution of 40K and gross beta activity in the soil from the city of Kavadarci, Republic of Macedonia, and its environs. A total of 45 surface soil samples were collected from evenly distributed sampling sites over an area of 360 km2. The activity concentrations of 40K were measured using a high purity germanium (HPGe) gamma-ray detector, while the gross beta activity measurements were made using a low background gas-flow proportional counter. The obtained values for the activity concentrations of 40K were found to be in the range of 286±6 and 801±12 Bq/kg with an average value of 545±118 Bq/kg. The gross beta activities varied between 438±21 and 1052±36 Bq/kg, with an average value of 681±146 Bq/kg. These values allowed the determination of the elemental concentrations of potassium as well as the air absorbed gamma dose rate, which were found to range from 0.92±0.02 to 2.56±0.04% and from 11.9±0.1 to 33.4±0.5 nGy/h, respectively. The mean values of these parameters were 1.74±0.37% and 22.8±4.9 nGy/h. All obtained values fall within the worldwide range as reported in the literature. A strong correlation between the content of potassium in the soils and their geological origin was observed.