X-ray analyses of uranium and in Pakistan

In this paper results of analyses of uranium and thorium in soil are discussed. Samples used in these studies were soil samples from the Bagarian are in Mansehra district, NWFP, Pakistan. Such radioactive elements are usually found in our lithosphere which is an important part of our environment and if unchecked may contaminate our hydrosphere and ultimately biosphere. Estimation of such radioactive elements in soil samples is thus considered important for evaluation of environmental pollution due to such sources. The analysis was designed and accomplished using the X-ray fluorescence technique. Results obtained predicted excessive mutual interferences of thorium and uranium. Efforts were made to determine the extent of these interferences required for establishment of an accurate analytical methodology. Chemical phases present in the samples were confirmed by the X-ray diffraction method to be UO/sub 2/(97.17 -+ 0.05%), ThO/sub 2/(1.26-+0.02%) and ThSiO/sub 4/(1.50-+0.02%) as the major phases. Also present in the samples were Al, Ba, Be, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Na, Ni, P, Pb, S, Sn, Ta, V and Y in the range of 50 to 100 ppm determined by using XRF. Fluorescence yield of thorium was noted to be 38 times higher than that expected theoretically and has been explained on the basis of energy transfer from major to minor component of the sample. (author)