Assessment of Natural Radionuclide Content in Some  Commonly Consumed Vegetables and Fruits in Oil Mining  Lease (OML) 58 and 61, Oil and Gas Producing Areas in  the Niger Delta Region of Nigeria Using Gamma–Ray

Avwiri G. O.; Osarolube E.; Alao A.A.

Volume : II, Issue : II, February - 2013

Assessment of Natural Radionuclide Content in Some Commonly Consumed Vegetables and Fruits in Oil Mining Lease (OML) 58 and 61, Oil and Gas Producing Areas in the Niger Delta Region of Nigeria Using Gamma–Ray

Avwiri G. O. , Osarolube E. , Alao A. A.

Abstract :

The presence and levels of Naturally Occurring Radionuclides (NORM) in some commonly consumed vegetables and fruits in OML 58 and 61, in Niger Delta Region of Nigeria were determined in this work and the effect of resulting dose on the population assessed. Twenty (20) Vegetable samples and eleven (11) of fruits were harvested and collected from agricultural farms and gardens where they were produced. Six Zones (A, B, C, D ,E ,F) were selected considering factors such as population density, educational Institutions, farm settlements, markets and cultural background taken into account the consumption rates. Food crops samples were dried at room temperature to a constant weight powdered and sieved to pass through a 2mm mesh. All the samples were then sealed in pre-treated 1-L Marinelli beakers for at least 28 days for secular equiliium to set-in before Gamma Spectroscopy analysis. The Canberra passive gamma Spectrometer with a well caliated high purity germanium detector (HpGe) system was employed (NaI(T1)Detector,Model Bircom,Preamplifier Model 2001,Amplifier Model 2020,ADC Model 8075,HVPS Model 3105). Mean Specific Activity values obtained for 40K, 228Ra in Vegetables are 95.95� 18.85 Bqkg-1, 10.79 � 3.46 Bqkg-1, 6.83 � 2.32 Bqkg-1and in fruits, the Mean Specific Activity values for 40K, 226Ra, 228Ra, are 77.67 � 18.90 Bqkg-1, 8.12 � 3.00 Bqkg-1, 6.17 � 2.15 Bkg-1.The Mean Radium Equivalent Activity (Raeq) calculated for vegetables and fruits ranged from 27.81 Bqkg-1 to 18.60 Bqkg-1. The Mean Effective dose calculated in all surveyed samples ranged from 0.014 mSvy-1 to 0.030mSvy-1 respectively which did not show any significant health impact. The radiation hazards indices (External hazard Index (Hex), Internal hazard Index (Hin) calculated in all the surveyed samples were less than unity (ICRP) standard, therefore all food crops examined are suitable for consumption. The overall results obtained agreed with other earlier works in Nigeria and all over the world(Arogunjo et al; 2005, Olomo; 1990, G. Shanthi et al; 2009., Mlwilo et al; 2007; Jibiri et al; 2007; Badar,et al.,2003,Baeza et al.,2001 etc). In conclusion, the study confirmed the presence of series radionuclides (238U, 232Th) and non-series, 40K. in the areas surveyed but their activity levels were low when compared with the UNSCEAR standard and hence were not expected to constitute any health hazard to the inhabitants. However,it is recommended that seasonal variations in radionuclides transfer should be investigated and regular monitoring of the areas should be conducted from time to time to check any eventuality as a result of continuous consumption of these foodcrops.