Spatial and seasonal variation of lead concentration in surface soils of Al-Zubair City, Southern Iraq

The present study examines the spatial and seasonal variation of lead (Pb) concentration in the surface soils of Al-Zubair City, Basra Governorate, Iraq. The importance of the study is related to the rapid urban expansion of Al-Zubair, the growth of industrial activity, increasing traffic density, and the reduction of agricultural and natural land. Under such conditions, surface soils become the main sink for pollutants originating from industry, transport, generators, construction activities, and agriculture. The study was based on 80 soil samples collected from four land-use categories: industrial areas, main roads, residential areas, and agricultural lands. Sampling was carried out during four periods between September 2023 and July 2024 at a depth of 0-15 cm. Lead concentration was measured using atomic absorption spectrometry. The results showed that Pb concentration ranged from 19.2 to 171.5 mg/kg. The highest contamination was recorded in industrial areas, where the average concentration reached 78.35 mg/kg. Lower values were observed near main roads and agricultural lands, whereas the lowest concentrations were found in residential areas. In addition, a clear seasonal pattern was identified. The highest average concentration was recorded in December 2023, while the lowest value occurred in July 2024. Statistical analysis using the Kruskal-Wallis test confirmed significant differences both between land-use categories and between sampling periods at p<0.05. Therefore, anthropogenic activity appears to be the main factor controlling lead accumulation in the soils of Al-Zubair City. The obtained findings provide a basis for environmental monitoring and for measures aimed at reducing heavy-metal contamination.