Uranium and Trace Metals Contamination in Topsoil from Different Zones Around Industrial City, Al Jubail, Saudi Arabia

The concentrations of uranium and 9 trace metals were analyzed in 116 topsoil samples collected from 6 zones around the most important and oldest industrial city in Al Jubail, eastern Saudi Arabia. The concentrations of U, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, and Zn were measured using gamma ray spectrometry and plasma atomic emission spectrometer. The obtained data showed that the mean values of uranium in all zones were below or similar to the world average and the background value of soil. In contrast, the results revealed that the selected metals were higher than the background values in most zones, where the highest mean value of Pb was 2270 times higher than the background value in the eastern border of the industrial city (Zone 5), and the lowest mean value of Pb was 980 times higher than the background value in the western border of the industrial city (Zone 1). Moreover, the concentrations of uranium and metals were compared with local and global mean values. The geoaccumulation index (Igeo) and pollution load index (PLI) were calculated to assess the pollution levels of trace metals in topsoil. The Igeo values indicated uncontaminated to moderately contaminated for all metals except Pb, which was extremely contaminated in all zones. The PLI value was much higher than 1 for all zones. Accordingly, the topsoil around the industrial city is contaminated with metals.