The natural radionuclide contents in some medicinal plants commonly found around oil and gas facilities in Ughelli and nearby communities have been investigated. A class of such medicinal plants are those that are regarded as grasses and are usually taken for healing purposes. The plants investigated are lemon grass (Cymbopogan citrates), Spear grass (Imperata cylindrical) and Carpet grass (Eleusin indicageartin). The plants were assayed for their radionuclide contents by means of gamma spectrometry using a shielded and well calibrated NaI(Tl) detector coupled to a computer interfaced multichannel analyser, quantum Tm MCA 2100R. Results of the analysis showed that the radionuclides detected in the grasses around the oil and gas facilities belong to the primordial radionuclide series of 238 U and 232 Th as well as non serial 40 K. On the average, the values for lemon grass has 238 U (15.3 + 1.7 Bqkg -1 ), 232 Th (1.1 + 2.7 Bqkg -1 ) and 40 K(67.9 + 7.4 Bqkg -1 ). In spear grass, 238 U (15.8 + 2.4 Bqkg -1 ), 232 Th (1.7 + 4.3 Bqkg -1 ) and 40 K(69.3 + 9.4 Bqkg -1 ) were determined while carpet grass recorded 40 K (70.2 + 11.6 Bqkg -1 ) with 238 U(16.0 + 1.9 Bqkg -1 ) and 232 Th(1.6 + 4.2 Bqkg -1 ). The measured levels of the radioactivity in the samples translated to very low values of the annual effective dose equivalent, implying safe level of radiological health consequences. No significant difference was determined between radionuclide contents of samples of medicinal plants around oil and gas facilities and samples of the same species of medicinal plants from an undisturbed and virgin location in Nigeria where industrial activities, waste dump nor is farming practised. However, no trace of artificial radionuclide was determined in all the samples assayed in both areas, hence, measurements can be taken as representing baseline values of the radionuclides in medicinal plants in the areas.

Natural Radionuclides are elements that are found in the air, water and soil. They find their ways in to the plants through the leaves and absorption of nutrients and water from the soil through the roots. Intake of fruits is very essential for human beings as part of balance diet. The concentrations of natural radionuclides in some fruits from three major markets at Ijebu-Ode town in Nigeria were determined and annual committed effective dose to the consumers was also determined. The gamma spectrometry method was used for the analysis. The highest concentrations of 40 K, 238 U and 232 Th were from pineapple of value 102.36 ± 10.81Bqkg -1 , orange of value 12.18 ± 4.36Bqkg -1 and mango of value 8.01 ± 3.25 Bqkg -1 respectively. The average annual committed effective dose of the natural radionuclides to the consumers was calculated to be 0.11mSvyr -1 , which is below the limit of 0.3mSvyr -1 recommended globally. This indicates that the ingestion of these radionuclides through the consumption of these fruits has no radiological health hazard to the consumers.

Primordial radionuclides are transported in to the plants through the leaves and roots. Medicinal plants are widely used in Africa for prevention and treatment of diseases. Ocimum Gratissimum is medicinal plant that is so used in southwest of Nigeria due to its multifunctional traditional medicinal health uses and as spice in cooking. The research is to determine the radiological health risk of these primordial radionuclides to the  consumers of Ocimum Gratissimum in the study area. Fresh leaves of the medicinal plant were plucked from ten (10) different locations at Ewekoro where mining of limestone had been taking place in Ogun State, southwest of Nigeria, been the part of the plant that was commonly used. The concentrations of 40K, 238U and 232Th in the fresh leaves were determined using gamma spectrometry method, and average annual committed effective dose to the adult consumers was determined. No artificial radionuclide was detected. The highest annual committed effective doses of 40K, 238U and 232Th to the consumers of Ocimum Gratissimum were obtained to be 0.00133mSvy-1, 0.00147mSvy-1 and 0.00336mSvy-1 respectively. The highest excess lifetime cancer risk of 40K, 238U and 232Th to the consumers were calculated to be 0.0211 x 10-3, 0.0136 x 10-3 and 0.1434 x 10-3 respectively. The average annual committed effective dose and average excess lifetime cancer risk of the radionuclides to the consumers were calculated to be 0.0109mSvy-1 and 0.0379 x 10-3 respectively. The values were below the limits of 0.3mSvy-1 and 0.29 x 10-3 respectively,  recommended globally. The consumers of the medicinal plant do not have significant radiological health risk. Furthermore, the results obtained can serve as reference data for future studies in the study area and its environs. Keywords: Primordial Radionuclide, Medicinal plant, Dose, Cancer

ABSTRACT:The radioactivity concentrations of 40 K, 238 U and 232 Th in sediment samples of Imayan river at Odogbolu local government area, Ogun State in Nigeria were determined by gamma spectrometry using NaI (TI) detector coupled with a pre-amplifier base to a multiple channel analyzer (MCA), these were then used to determine the radiological indicators; radium equivalent activity, internal and external hazard indices, and absorbed dose rate which translated to the annual effective dose rate. 10 sediment samples were collected from the river.