Natural and Artificial Radioactivity, Heavy Metals and Physicochemical Properties of Loess Soils in the “Korzeniowy Dół” Gully (Kazimierz Landscape Park, Poland)

The “Korzeniowy Dół” gully, located on the Nałęczów Plateau within Kazimierz Landscape Park (SE Poland), is a distinctive loess landform surrounded by agricultural land, where surface runoff may contribute to the accumulation of fertiliser-derived radionuclides and heavy metals. This study presents the first integrated assessment of natural and artificial radioactivity, heavy-metal concentrations, and selected physicochemical properties of soils from this site. Eight surface soil samples (0–10 cm) were analysed using high-resolution HPGe gamma-ray spectrometry, X-ray fluorescence (XRF), and standard soil-science methods. Relationships among the measured parameters were investigated using correlation analysis, hierarchical cluster analysis (HCA), and principal component analysis (PCA). The mean activity concentrations of ⁶Ra, Th, and ⁴⁰K were 24.6, 23.5, and 370 Bqkg⁻, respectively, all below the corresponding UNSCEAR world averages. The mean activity concentration of ⁷Cs was 1.07 Bqkg⁻, indicating low-level residual fallout. Radiological hazard indices were also low, with a mean external hazard index (Hₑₓ) of 0.23, an absorbed gamma dose rate of 41.0 nGyh⁻, and an outdoor annual effective dose of 0.050 mSvy⁻. Heavy-metal concentrations were generally within the range reported for Polish loess soils. Correlation and multivariate analyses indicated that the distribution of natural radionuclides and several trace elements was predominantly controlled by lithogenic factors, particularly the clay fraction and the carbonate-rich soil matrix. Overall, the results indicate a low external radiological hazard and provide baseline data for future environmental monitoring of loess landscapes in the Lublin Upland.