Horizontal and Vertical Distribution of Heavy Elements on the Coast of the Shatt al-Arab, Basrah -Iraq

Soil pollution hampers the achievement of the Sustainable Development Goals (SDGs), which include promoting human well-being, ensuring healthy lives, and eradicating poverty. Therefore, this study aimed to determine the pollution levels of heavy elements along the coast of the Shatt al-Arab in Basrah Governorate, southern Iraq. Soil core samples were randomly collected between October 2022 and April 2023 to measure the concentrations of heavy elements—manganese (Mn), lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), iron (Fe), and nickel (Ni)—in both exchangeable and residual phases, using a flame atomic absorption spectrometer (AAS). A one-way analysis of variance (ANOVA) was performed using Minitab version 16.1. Additionally, pollution indicators including the geoaccumulation index (I-geo), contamination factor (CF), and enrichment factor (EF) were calculated. The highest concentrations of heavy elements (Ni, Fe, Zn, Cr, Cd, Pb, Mn) in the exchangeable phase were 120.59, 2158.02, 69.63, 262.16, 1.91, 714.13, and 837.83 μg/g dry weight, respectively, while the lowest concentrations were 21.25, 0.81, 7.44, 98.22, 22.45, 446.63, and 7.64μg/ g dry weight, respectively. In the residual phase, the highest concentrations were 109.01, 3005.05, 87.93, 383.5, 1.94, 339.66, and 306.38μg/ g dry weight, respectively, while the lowest were 18.52, 1511.6, 6.12, 39.13, 0.33, 4.53, and 24.8μg/ g dry weight, respectively. Pollution assessment using the calculated indices showed that the annual average of the I-geo values indicated moderate to significant pollution, particularly with Ni, Pb, and Cd. The contamination factor (CF) revealed very high contamination levels, especially for Pb, Ni, and Cd, while the enrichment factor (EF) indicated an extremely severe enrichment for the same elements. Based on the pollution indices, the order of heavy element pollution in the study area was: Pb > Ni > Cd > Cr > Mn > Zn > Fe.