Cyclic and pseudocyclic instrumental neutron activation analysis (INAA) has been used to determine the Se content of 40 Libyan food items. The selected samples include different varieties of local and imported foods such as wheat and barley products (bran and flours), rice, bread, almond, peanuts, vegetables as bean and peas, tea, coffee, sugar, and commonly used spices such as red and black paper, curry, cumin, mixture of spices, thyme, coriander, and fenugreek. Both conventional and anticoincidence gamma-ray spectrometry techniques have been employed. Pseudocyclic INAA in conjunction with anticoincidence counting has been found to provide the most reliable results. The precision of the method has been significantly improved by recycling the samples up to three times. The accuracy has been evaluated by analyzing a number of certified reference materials of varied Se levels. The detection limit has been found to vary between 26 and 90 ppb Se depending on the sample composition. The range of daily dietary intake has been calculated as 13-44 microg of Se per day.

Epithermal instrumental neutron activation analysis (EINAA) has been used to determine the iodine content of many individual food materials that constitute the typical Libyan diet. The selected samples include different varieties of local and imported foods such as wheat and barley products, rice, bread, legumes such as chick peas and lentil, table salt, and commonly used spices, including thyme and fenugreek. Both conventional and anticoincidence gamma-ray spectrometry techniques have been employed. Epithermal INAA in conjunction with anticoincidence counting has been found to provide the most reliable results. For quality control purposes, a number of NIST biological reference materials were analyzed. The range of daily dietary intake has been calculated as 100-180 microg of iodine per day, which is within the recommended range. Bread was identified as a significant source of iodine in the Libyan diet, as it contributed 99 microg/d.

Elemental analysis of soils from two different arable regions in Libya was carried out to measure the level of many trace elements. Instrumental neutron activation analysis was used for the determination of 10 elements, viz., (Ba, Ce, Co, Cr, Cs, Fe, Sc, Se, Th, and Zn), using their long-lived radionuclides. The accuracy of the measurements has been evaluated by analyzing two IAEA soil reference materials: IAEA Soil-7 and IAEA leak sediment SL-1; precision has been estimated by triplicate analysis of the sample and that of the reference material. Irradiations were carried out at the Tajura Research Center reactor, at 5-MW power level. It is clear that in the Libyan soil selenium concentration is somewhat lower than in other countries. The results show that trace metal concentrations in Libyan clay surface soil are higher than the sandy soil.