Study of the relationship between concentrations of radionuclides in the soil environment

In order to study the relationships between terrestrial radionuclides ⁴⁰K, ²³²Th, ²²⁶Ra and ²²²Rn, and to test different approaches of determining the ²²²Rn exhalation rate from the soil, the Mochovce area proved to be especially suitable since it is radiologically well documented. The correlations between ⁴⁰K, ²³²Th, ²²⁶Ra were high for the entire area of interest. After dividing the area into four quadrants, a high correlation was found in three quadrants; the remaining quadrant exhibited a markedly low correlation between the radionuclides due to the complexity of the geological subsoil and the soil cover. The correlations between ²²²Rn and ²²⁶Ra for the whole area as well as for the individual quadrants were unexpectedly low; moreover, in one of the quadrants, the relationship between ²²²Rn and ²²⁶Ra was observed to be decreasing. This rather surprising outcome may be caused by spatially varying soil parameters (such as porosity, emanation coefficient and water content) affecting the concentration of ²²²Rn in the soil air. (authors)