No abstract

One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient, nutritionally adequate, and safe food. Decades of tin mining in the Bitsichi area of the Jos Plateau, Nigeria, have left a legacy of polluted water supplies, impoverished agricultural land, and soil containing abnormally high levels of naturally occurring radioactive elements. In order to ascertain the radiological food safety of the population, different crops that constitute the major food nutritive requirements were collected directly across farmlands in the area. The activity concentrations of (226)Ra, (228)Th, and (40)K were determined in the food and soil samples using gamma-ray spectrometry. Additionally, in situ gamma dose rate measurements were performed on the farms using a pre-calibrated survey meter. The corresponding activity concentrations in the food crops ranged from below detection limit (BDL) to 684.5 Bq kg(-1) for (40)K, from BDL to 83.5 Bq kg(-1) for (226)Ra, and from BDL to 89.8 Bq kg(-1) for (228)Th. Activity concentrations of these radionuclides were found to be lower in cereals than in tubers and vegetables. As for the soil samples, activity concentrations of these radionuclides varied from BDL to 166.4 Bq kg(-1), from 10.9 to 470.6 Bq kg(-1), and from 122.7 to 2,189.5 Bq kg(-1) for (40)K, (226)Ra, and (228)Th, respectively. Average external gamma dose rates were found to vary across the farms from 0.50 +/- 0.01 to 1.47 +/- 0.04 microSv h(-1). Due to past mining activities, the soil radioactivity in the area has been modified and the concentration level of the investigated natural radionuclides in the food crops has also been enhanced. However, the values obtained suggest that the dose from intake of these radionuclides by the food crops is low and that harmful health effects are not expected.

No abstract

Farming on soils situated in high background radiation areas can result to enhanced radiation exposure scenarios and pathways to humans. To assess the likely levels of exposures, farm soil samples were collected from different farmlands in three old tin mining localities (Bitsichi, Bukuru and Ropp) in Jos Plateau Nigeria, known for high radiations. The soil samples were analyzed for the activity concentrations of 226 Ra, 232 Th and 40 K, using gamma-ray spectroscopy. The outdoor annual effective dose rates were calculated using the activity concentrations of the radionuclides and were found to vary from 0.07 mSv to 2.02 mSv across the three localities. Considering dust generation from soil tillage and inadvertent ingestion of soil particles, the likely internal radiation hazards were estimated using conservative dust and soil loading factors.

No abstract