Najla LASSOUED, Mohamed Naceur KHELIL, Saloua REJEB, Essaid BILAL, Mohamed CHAOUACHI, Mohamed Néjib REJEB, Issam GUENOLÉ–BILAL (TUNISIA, FRANCE)
Abstract. The land application of sewage sludge reveals a significant increase in dray matter production of Ray Grass (Lolium perenne L.). In equivalent dose of liquid sludge, we registered a lower production of dry material. Besides, neither the dose nor type of sludge seems to have an effect on heavy metals contents in the air part plant. On the other hand, contribution of sludge under dry or liquid forms increases significantly heavy metals contents in roots with regard to witness without sludge. The comparison between the beginning and end of culture, revealed a decrease heavy metals contents in soil in particular at horizon 0–40 cm deep. Besides, this decrease Cd, Zn, Pb and Cu contents in soil is not linking to transfer from soil to air part of plant, but rather is the accumulation in roots, which play the role of a barrier.
Key words: heavy metals, transfer, soil, Ray Grass, sewage sludge