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  • Author or Editor: Sabiha-Javied x
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Abstract  

Analysis of geological materials requires the use of matrix specific reference materials (RMs). Phosphate rocks (PR), the basic ingredient of phosphate fertilizers, are very important in agriculture. A project was undertaken to study the PRs of the Hazara Deposits of Pakistan. Due to the unavailability of phosphate rock reference materials (PR-RMs) with a large number of certified elements, validation of the results was problematic when carrying out elemental analysis of PR samples and their derived products. Therefore a parallel study was performed to determine the composition of three phosphate based RMs; BCR-RM-032 (Natural Moroccan Phosphorite), IAEA-434 (Phosphogypsum) and PRH (a local PR-RM from the Hazara Deposits of Pakistan). Instrumental Neutron Activation Analysis was used for this purpose and more than 30 elements including rare earth elements were determined in the three PR samples.

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Abstract  

Wheat is staple food of the people of Pakistan. Phosphate fertilizers, used to increase the yield of wheat, enhance the natural radioactivity in the agricultural fields from where radionuclides are transferred to wheat grain. A study was, therefore, carried out to investigate the uptake of radioactivity by wheat grain and to determine radiation doses received by human beings from the intake of foodstuffs made of wheat grain. Wheat was grown in a highly fertilized agricultural research farm at the Nuclear Institute of Agriculture and Biology (NIAB), Faisalabad, Pakistan. The activity concentration of 40K, 226Ra and 232Th was measured in soil, single superphosphate (SSP) fertilizer, and wheat grain using an HPGe-based gamma-ray spectrometer. Soil to wheat grain transfer factors determined for 40K, 226Ra and 232Th were 0.118 ± 0.021, 0.022 ± 0.004 and 0.036 ± 0.007, respectively, and the annual effective dose received by an adult person from the intake of wheat products was estimated to be 217 μSv.

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Abstract  

The rare earth elements (REEs) content of Kakul phosphate rock (PR) from different localities of the main Hazara deposits of Pakistan were determined using instrumental neutron activation analysis (INAA). 25 phosphorite samples were collected from different phosphorite sites and 6 samples representing different batches from the crushing plant near Kakul Mine. Concentrations of seven REEs (Ce, Eu, La, Lu, Sm, Tb and Yb) were determined in the PR samples. The highest amounts of Heavy and light rare earth elements (HREE and LREE) were quantified in the PR samples collected at the Phosphate Rock Crushing Plant while the lowest amounts of these REEs were measured in the Lambidogi Phosphorite deposit samples. Comparison with global data showed the REEs content of the studied PRs show lower range for all REEs and mostly comparable to the data reported by Israel and Syria. Calculated chondrite ratio for these elements depicts enrichment of LREEs in all phosphorite deposits.

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Abstract  

Sensitive nondestructive instrumental neutron activation analysis (INAA) technique has been applied for the determination of rare earth elements (REEs) (Ce, Eu, La, Lu, Sm, Tb and Yb) in phosphate rocks (PR) and granulated single super-phosphate (GSSP) fertilizer samples from Hazara district of Pakistan. The comparison of the PR with product fertilizers shows that most of the quantified REEs were found to be in lower contents in the fertilizers. Six fertilizer samples with different N, P and K ratio for distinctive application to plants were also characterized. The REEs in these showed irregular patterns that can be attributed to difference in their manufacturing and chemical processes. The REEs contents of local phosphate fertilizer were found to be lower in comparison to the values cited in the literature; however Ce is relatively high. For quality assurance fair agreement was found between the results obtained for reference materials IAEA SL-1 (Lake Sediment) and GSJ-JR-1 (Rhyolite).

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Abstract  

The concentration of 32 elements was determined in phosphate rock samples from the Hazara phosphate deposits of Pakistan using instrumental neutron activation analysis (INAA) technique employing different irradiation protocols. These included 23 major, minor and trace elements (Al, As, Ba, Br, Co, Cr, Cs, Fe, Ga, Hf, K, Mn, Na, Rb, Sb, Sc, Sn, Ta, Th, U, V, Zn and Zr) and 9 rare earth elements (REEs) namely Ce, Eu, Ho, La, Lu, Nd, Sm, Tb and Yb. The results have been compared with the global values of these elements. The concentrations for most of the elements studied are lower than the concentrations reported in the literature whereas the concentrations of As, Co, Fe, K, Mn, Na and Sb are comparable. Two samples namely HR-4 and HR-5 have the highest concentrations for majority of the REFs with high enrichment factors. The quality assurance of data was performed through the concurrent use of Lake Sediment (SL-1) and GSJ-JR-1 (Rhyolite) reference materials. The acquired data will serve as a reference for the follow-up studies to assess the agronomic effectiveness of the Hazara phosphate rocks.

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