Assessment of radioactivity levels and radiological hazards of soil samples from vineyards in mountainous areas in the Raparin district, Iraqi Kurdistan

Understanding soil radioactivity in agricultural vineyards is essential for environmental safety and public health. However, limited data exist on radioactivity levels in vineyard soils of mountainous regions, particularly those with natural irrigation sources. This study aims to assess natural and artificial radionuclide levels in vineyard soils and evaluate potential radiological hazards. A total of forty-five soil samples were collected from vineyards across five sub-districts and analyzed using an Ortec high-purity germanium (HPGe) detector (30% relative efficiency) with GammaVision software. Sampling sites were selected based on soil characteristics, irrigation sources and environmental conditions. The activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰ K and ¹³⁷Cs ranged from (5.5 ± 0.9 to 27.3 ± 0.4) Bq Kg⁻¹ with an average value of (15.5 ± 1.0) Bq Kg⁻¹, (2.9 ± 0.9 to 18.0 ± 0.6) Bq Kg⁻¹ with an average of (9.1 ± 1.0) Bq Kg⁻¹, (58.3 ± 0.1 to 318.2 ± 4.6) Bq Kg⁻¹ with an average of (174.9 ± 1.0) Bq Kg⁻¹ and (2.0 ± 0.1 to 17.3 ± 0.9) Bq Kg⁻¹, with an average value of (8.3 ± 1.0) Bq Kg⁻¹, respectively, all below global average levels. To assess potential health risks, key radiological hazard indices were computed, including radium equivalent activity (\({Ra}_{eq}\)), gamma index (\({I}_{\gamma }\)), absorbed dose rate (\(D\)), hazard indexes (\({H}_{ex} and {H}_{in}\)), annual effective dose rate (\({\text{AEDR}}_{out} and {\text{AEDR}}_{in}\)) and excess lifetime cancer risk (\(ELCR\)). Were averaged at 41.95 ± 1.67 Bq Kg⁻¹, 0.31 ± 0.01, 19.93 ± 0.73 nGy h⁻¹, 0.11 ± 0.01 and 0.72 ± 0.01, 0.024 ± 0.01 mSv y⁻¹ and 0.189 ± 0.01 mSv y⁻¹ and 0.09 ± 0.0031 × 10^–3, respectively. The Pearson correlation analysis showed that ²²⁶Ra, ²³²Th and ⁴⁰K are strongly correlated and significantly influence radiation hazards, whereas ¹³⁷Cs exhibits weak correlations, indicating its minimal contribution to radiation risks. This study provides baseline data for vineyard soil radioactivity, contributing to environmental risk assessments in naturally irrigated agricultural areas.