Behavior canola (Brassica Napus) following a sewage sludge treatment

Najla Lassoued (1, 2) , Essaïd Bilal (3, 4, 5) , Saloua Rejeb (2) , Issam Guénole-Bilal (6) , Naceur Khelil (2) , Mohamed Nejib Rejeb (2) , Frédéric Gallice (3, 4, 5)

1 Département du Génie rurale, eaux et fôrets
2 INRGREF - Institut National de Recherche en Génie Rural Eaux et Forêts
3 GSE-ENSMSE - Département GéoSciences et Environnement
4 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
5 EVS - Environnement, Ville, Société
6 DP - Département de Physiologie

In this study, two types of sludge were being used, while the first was with urban dominance, the second was with industrial dominance. The effects of sewage sludge had been studied in a Brassica Napus field. The mineralogical, chemical and microscopic study of the sludge showed that industrial sludge had very high levels of Cr, Pb and Cd. These metals existed mainly under the form of daubreelita Cr₂FeS₄, brezininaite Cr₃S₄, wattersite Hg₅CrO₆, crocoite PbC₂O₄, pheonicochroite Pb₂O(CrO₄) and Pb-oxalate PbC₂O₄. The results showed that sludge significantly improves the growth of the underground part of the plant (root) and the upper part (stem, leaves etc...). This improvement is more important for urban sludge. However, this beneficial effect was accompanied by a change in the composition of the plant some trace element metals. An abnormal accumulation of Cr was found in the roots, stem, leaves, and siliques when the industrial sludge was brought which reflected the richness of the latest. The dose-effect sewage sludge was very clear at the levels of Pb in the roots especially for industrial sludge which exceeded the threshold values of toxicity starting from the dose of 25t/ha of industrial sludge. Cd levels only increased with the addition of 100t/ha of industrial sludge. For Ni, Cu, Co and Zn, especially at roots level, the increase depends on mud's dose and especially on its type. On the contrary, levels of iron, and to a less extent manganese levels, had been reduced due to sludge despite their richness with these elements. That was probably due to antagonism with one or more particular elements especially Zn.

Mots clés: heavy metals; accumulation; <i>Brassica Napus</i>; urban sludge; industrial sludge

Domaines: Génie des procédés; Hydrologie; Milieux et Changements globaux

Najla Lassoued, Essaïd Bilal, Saloua Rejeb, Issam Guénole-Bilal, Naceur Khelil, et al.. Behavior canola (Brassica Napus) following a sewage sludge treatment. Carpathian Journal of Earth and Environmental Sciences, 2013, 8 (3), pp. 155-165. ⟨hal-00904278⟩