Effect of near-road soil contamination on Solanum lycopersicum L., Cicer arietinum L. and Cucumis sativus L

The present research assessed soil contamination along the roadside in the central littoral region of Tunisia. Road Gremda (toward the northwest), road Manzel Chaker (toward the southwest) and road Tunis (toward the north) were chosen for this study. Fourteen stations located on different road sides were sampled. Soil samples were analyzed for Pb, Zn, Cu, Cr and Fe. The range of the metals was as follows: Pb 1.23–88 µg/g, Zn 1.23–295.2 µg/g, Cu 3.8–11.04 µg/g, Fe 1972.7–3647.9 µg/g and Cr 10.8–32.2 µg/g. Iron is an abundant element in the Earth’s crust, and it was considered in this work as a reference for naturally occurring metals and was used in the determination of geoaccumulation index. Soil metallic contamination affected the percentage and kinetic of germination of tomato and chickpea, whereas these parameters did not affect cucumber. Contamination of soil by the polycyclic aromatic hydrocarbons reaching 1550 mg/kg affected only the rate of germination of tomato and chickpea. Cucumber showed a resistance to both of metals and polycyclic hydrocarbons which can attest the resistance of this species. The hydrocarbon content recorded in the soil affected shoot elongation of tomato, while the metal contamination affected the root elongation of this species. In contrast, cucumber showed resistance to both types of pollutants. This species has shown an accumulation of Pb, Zn and Cr, especially when germinated on Gremda soil.