Assessing the Ecological and Health Risks of Some Heavy Metals in Roadside Soil of Ahvaz

Heavy metals in the surface soils of cities from various sources (traffic, industrial emissions, erosion from buildings, etc.) can accumulate through inhalation, ingestion and dermal contact in the human body and imperil health. The purpose of this study was to assess the ecological and human health risks caused by some heavy metals in roadside soil at the intersections of Ahvaz (Modares, Kharchar, Zargan, Behbahani, Golestan, Abadan, Khorramshahr, Susangerd and Andimeshk). In this study, the concentration of heavy metals in roadside surface soils in intersections of Ahvaz in the summer of 2016 was investigated. The sampling at each intersection was carried out at specified intervals of 1, 10 and 30 meters on the sides of the main road (6 samples from each intersection) from the surface soil (depth 0 to 20 cm); the total number of samples was 54. The samples were transferred to the laboratory and dried at 60 ° C in an oven. After digestion of the samples with an acid mixture, concentrations of heavy metals Zn, Pb, Ni, Cu, Cr, Cd and As were measured by inductive coupled plasma-mass spectrometry (ICP-MS). The contamination level was estimated based on potential ecological and human health risks of heavy metals. The average concentrations of Zn, Pb, Ni, Cu, Cr, Cd and As were 116.61 ± 49.42, 284.02 ± 166.91, 25.53 ± 4.47, 220.63 ± 87.75, 137.21 ± 84.80, 3.44 ± 3.23 and 8.65 ± 3.8 mg/kg, respectively. Isotope ratios indicated that emissions from automobiles/traffic and industrial emissions were the most important sources of lead in the samples studied. The average value of potential ecological risk (RI) in Andimeshk, Golestan and Susangerd intersections was low; that in Modarres, Behbahani and Zergan intersections was medium; and that in Chaharsir, Abadan and Khorramshahr intersections was high. Cr poses the highest risk of cancer in both children and adults, although the risk of carcinogenesis in children is higher than in adults. The results show that the source of contamination with the metals studied is anthropogenic, including road traffic and industrial activities, in the area investigated.