Activity concentrations of 226Ra, 228Th, and 40K in different food crops from a high background radiation area in Bitsichi, Jos Plateau, Nigeria

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.

Assessment of external and internal doses due to farming in high background radiation areas in old tin mining localities in Jos-plateau, Nigeria

“…The net area under the corresponding peaks in the energy spectrum was computed by subtracting counts due to Compton scattering of higher peaks and other background sources from the total area of the peaks. From the net area, the activity concentrations in the samples were obtained using the equation (Jibiri and Bankole, 2006;Jibiri et al, 2007aJibiri et al, , 2007b:…”

“…Majority of these reports attributed these high levels primarily on the influence of tin and its mining activities in the area while the influence of the geological formation of the area was also identified as a factor (Farai and Jibiri, 2000;Jibiri et al, 2007aJibiri et al, , 2007bJibiri and Agomuo, 2007;Ademola, 2008). Presently, no attempt has been made to consider singularly farm soils in relation to radioactivity levels, the effects it portents to the farmers during farming activities based on the fact that the areas under investigation are known for high radiations.…”

“…According to Jibiri et al (2007aJibiri et al ( , 2007b, Jibiri and Agomuo (2007), Alexander and Kidd (2000) and Pasquini and Alexander (2005), heavy applications of different brands of chemical fertilizers and refuse ash were used by local farmers to improve the soil fertility and reclamation initiatives. Mittra et al (2003) reports that one of the possible ways of enhancing productivity of acidic soil is the use of fly ash in appropriate combination with organic matter and chemical fertilizer which would act as soil amendment and source of nutrient supply system.…”

Radioecological impacts of tin mining

“…Attempts have been made in the past to assess the human health impacts of tin mining in the Jos Plateau, Nigeria (e.g., Ibeanu 2003;Funtua and Elegba 2005;Ademola and Farai 2006;Jibiri and Agomuo 2007;Jibiri et al 2007aJibiri et al , b, 2009Ademola 2008;Ajayi 2008;Arogunjo et al 2009;Olise et al 2010Olise et al , 2014, but few studies have considered non-human biota (but see Møller and Mousseau, 2013). Recently, international standards have also been set to protect non-human biota from the effects of exposure to ionizing radiation (ICRP 2003;UNSCEAR 2008;ICRP 2009;IAEA 2011).…”

Estimation of Annual Effective Dose Due to Ingestion of Natural Radionuclides in Cattle in Tin Mining Areas of Jos Plateau, Nigeria: Are Large Mammals Really Affected?

“…The author's failure to compare her results with earlier studies that were conducted in the study area is also a major limitation. For instance, [8], [7] and [9] have presented data on the activity concentrations of natural radionuclides in food samples from the same area.…”