Influence of the near roadsoil contamination on the germination and biochemical factors of two species in the region of Sfax (Tunisia)

Abstract

In this work we highlight the contamination of three soils in the Sfax region by heavy metals and polycyclic aromatic hydrocarbons and the impact of this contamination in the germination and biochemical factors of two selected species Lycopersicum esculentum and Cucumis sativus. The use of contamination index showed a moderate soil contamination by Zn and Pb up to 50m from gremda road, up to 10m from Manzel Chaker road and 3m from Tunis road. In contrast, no site was contaminated by Cu and Cr. The highest levels of hydrocarbon aromatique polycyclic are recorded in the vicinity of Manzel Chaker soil. On the other hand, the physico-chemical characteristic of studied soils affect the speciation of metals and hydrocarbon. We noted that the metal contamination of gremda soil and the hydrocarbon contamination of Manzel Chaker soil affected the cucumber germination less than tomato germination. The use of germination tests for the two selected species highlighted the capacity of cucumber to resist to both types of pollutants. This resistance is manifested by the slight modification of chlorophyll, proline and soluble sugars contents expressed by the cucumber in polluted soils are less than those expressed by the tomato. An increase in catalase and ascorbate peroxidase activity in tomato plants was observed in vicinity of Gremda road but for cucumber, the levels of these antioxydants enzymes are higher than those recorded in tomato leaves which leads us to the use of cucumber in the phytoremediation of polluted soils near roads in the Sfax region.