Determination of Uranium and Thorium in Soil and Plant Parts around Abandoned Lead-Zinc-Copper Mining Area

This study reports distribution of uranium ( U) and thorium (Th) in soil samples and the roots and shoots of some plants grown around an abandoned lead (Pb)-zinc (Zn)-copper (Cu)mining area. The plants Euphorbia macroclada, Verbascum cheiranthifolium Boiss, and Astragalus gummifer were examined. The determinations of U and Th were carried out by inductively coupled plasma-mass spectrometry (ICP-MS). Uranium and Th levels of the studied soil samples were found to be in the range of 1.1-70.3 mg kg(-1) and 2.1-62.1 mg kg(-1), respectively. Some results obtained from this study were higher than the mean U and Th concentrations of soils reported around the world. Uranium and thorium concentrations in studied plant roots were in the range of 0.04-16 and 0.08-14.57mg kg(-1), whereas in plant shoots they were 0.02-2.76 and 0.07-12.3 mg kg(-1), respectively. It was concluded that the shoots of Astragalus and roots of Euphorbia and Verbascum can be used as both a biomonitor for environmental pollution and biogeochemical indicator because of their higher U and Th concentrations.