Estimation Of Soil-To-Plant Transfer Factors For 238U, 232Th, 40K And 137Cs Radionuclides For Some Selected Medicinal Plants In Some Part Of Minna And Kaduna, Nigeria

Abstract

This study was carried out in some part of Minna (River basin (9.66667oN, 6.55000oE) and Mekunkele (9.5836oN, 6.5463oE)) and Kaduna (Mando (10.590030oN, 7.430019oE) and Kachia (9.8734oN, 7.9552oE)) were Moringa leave, Goat weed, Ginger, and Turmeric are mostly grown in Northern Nigeria. Eleven samples of the medicinal plants comprising of three samples each of Moringa leave, Goat weed, Ginger and two sample of Turmeric, and eleven soil samples of corresponding area where the medicinal plant are grown, were analysed for activity concentrations of natural and artificial radionuclides using HPGe gamma spectrometry. The average annual committed effective dose (AACED) due to the ingestion of radionuclides from medicinal plants were also estimated. The Annual effective dose equivalent (AEDE) for soil sample radiological assessment was estimated. The activity concentrations 238U, 232Th, and 40K were found to vary in the range of 9.512 to 58.984 Bqkg-1, 17.852 to 71.972 Bq kg-1, and 309.836 to 729.451 Bqkg-1, respectively, in the soil samples and 1.343 to 10.367 Bqkg-1, 5.215 to 13.752 Bq Kg-1, and 11.700 to 239.765 Bq kg-1, respectively, in the medicinal plants corresponding to the soil samples. The activity concentration of artificially produced radionuclide 137Cs was BDL to 0.062 Bqkg-1 in the soil and it was below detectable level (BDL) in all the plant samples. The soil to plant transfer factors (TF) varied from 0.330 to 1.089 Bq Kg-1, 0.067 to 0.762 Bq Kg-1 and 0.0740 to 0.318 Bq kg-1, respectively, for 238U, 232Th, and 40K. The AACED due to the ingestion of radionuclides from the medicinal plants varied from 0.0107 to 0.0542 mSvy-1. The AEDE estimated for soil samples vary between 0.0358 to 0.1279 mSv y-1. The reported AACED and AEDE values in this study are much below the world average value of 0.30 mSv y-1 and ICRP recommended safe limit of 1mSv y-1 for an individual respectively. This indicates that it is safe to use these plants for medicinal purposes as there is no radiological health risk attached to the plant and members of the public. This study may also contribute data on local medicinal plants to formulate regulations related to radiological healthcare.