Description
Statement of the Problem: Researchers have reported the transfer and accumulation of naturally occurring radioactive isotopes and progenies in different plant species and herbal remedies through direct deposition or indirectly by the root system. Although essential for the human body's physiological functions, including the synthesis of enzymes, their intake above certain permissible limits can become toxic, resulting in most types of leukemia and cancer. Considering the rich tradition and diverse range of flowering plant species in South Africa for therapeutic usage, monitoring the radionuclides content and the potential health risks based on acceptable limits is necessary.
This study evaluated the activity levels of natural radionuclides 238U, 232Th, and 40K in samples of prominent South African Medicinal plants to assess the radiological health hazards associated with their use by the local population. Methodology & Theoretical Orientation: Commonly used therapeutically plants samples (Gunnera perpensa, Crocosmia paniculata, Gymnanthemum corymbosum, and Passiflora suberosa) were acquired from herbal (muthi) shops in consultation with local traders. At the laboratory, samples were cleaned, crushed, dried, weighed, and sealed in Marinelli beakers to reach the secular radioactive equilibrium condition (the minimum period used was 60 days). Radiation spectra were acquired with a broad energy high-purity germanium crystal (Canberra HPGe) with a 30% relative efficiency. A counting time of 28800s was utilized for the prepared samples, background, and standards for detector calibration. Findings: The mean activity concentrations of the measured radionuclides (238U, 232Th, and 40K) were 47, 40, and 220 Bq/Kg for the Gunnera perpensa; 45.7, 35.7, and 230 Bq/Kg for Crocosmia paniculata; 31.3, 26, and 186.7 Bq/Kg for Gymnanthemum corymbosum with 25.7, 20.3 and 496.7 Bq/Kg for the Passiflora suberosa. The estimated annual effective dose due to ingestion and lifetime cancer risk values were lower than internationally permissible limits. Conclusion & Significance: These findings suggest no radiological health hazards. However, other contributions to dose and cancer risk exist from sustained intake or use with other plants. Recommendations are made for periodic assessment considering possible elevation in natural radioactivity levels and consumption rate.
