Roadsoil Contamination by Polycyclic Aromatic Hydrocarbon: Level and Impact on Germination of Lycopersicum Esculentum and Cucumis Sativus

The distribution and accumulation of polycyclic aromatic hydrocarbons (PAH) in soil and their impact on three selected species—Lycopersicum esculentum, Cicer arietinum, and Cucumis sativus—have been investigated in areas with high traffic pollution such as the city of Sfax, in the south of Tunisia. PAH were identified in 147 soil samples (0–10 cm). The variation between the physicochemical characteristics of three soils influenced the spatial distribution of PAH. Soil acidity at sites near the Manzel Chaker road can therefore increase the availability of hydrocarbons. Similarly, increasing of organic matter content in these sites can decrease the biodegradation of PAH. The soils near Manzel Chaker road had the highest content followed by those of Tunis road soil. Chrysene, fluoranthene, benzo(a)anthracene, and indeno(1.2.3.cd)pyrene were the most abundant compounds with a content of 49 µg/g, 51 µg/g, 3.8 µg/g, and 45 µg/g respectively. The calculation of the number of germinated seeds by referring to the number of seed germinated, also the root biomass and the shoot elongation of tomato, showed the sensitivity of this species to contamination of Gremda and Manzel Chaker soils. The use of PCA indicated the absence of the impact of fluorene, fluoranthene, naphthalene, and chrysene on the germination of tomato and cucumber and their impact on the aerial part of tomato, but no significant effect on the germination and growth of cucumber was detected. This later has shown resistance to pollution by PAH which can be linked to morphological and genetic aspects.