Impact of heavy metals in sewage sludge on soil and plants (colza and wheat)

National audienceWe are testing the impact of heavy metals in sludge from urban and industrial wastewater treatment plants. We try to understand their influence on plant growth and their bioaccumulation. We chose two plants: the wheat and rapeseed to their specific characteristics; wheat is a herbaceous low accumulator of heavy metals, however rape (colza) is a plant of the family Brassica napus, is an excellent bio-accumulator of heavy metals. The mean levels found in the soil are organized in the following order: Fe >> Mn> Zn> Pb> Cu> Ni> Co> Cd. The contents of heavy metals in the sludge is made very high and exceed European values allowed for that type of use but remain in the standard NT106 Tunisia. The effects of the contribution of sludge are manifested by a significant increase in the weight gains of the whole plant, these results in a variation of the ratio between the aerial part and roots of the plant; this ratio tends to increase with dose of mud brought in soil increase. The roots of both plants show high levels of Zn even on the ground untreated control. The contents of Ni, Pb and Zn compared to Cu and Co are higher in the roots of rape than wheat

Transfert heavy metal sewage sludge as fertilizer from soil to ray grass

International audienceThe 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

Behavior canola (<i>Brassica Napus</i>) following a sewage sludge treatment

International audienceIn 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

Transfer heavy metal from soil treated to colza

International audienceThe impact of heavy metals were tested in sludge from urban and industrial wastewater treatment plants, trying to understand their influence on colza growth and their bioaccumulation. We chose the colza to their specific characteristics. The colza is a plant of the family Brassica Napus, is an excellent bio-accumulator of heavy metals. The mean levels found in the soil are organized in the following order: Fe >> Mn> Zn> Pb> Cu> Ni> Co> Cd. The contents of heavy metals in the sludge are very high and exceed European values allowed for that type of use. The effects of the contribution of sludge are manifested by a significant increase in the heavy metals of the colza, these results in a variation of the ratio between the aerial part and roots of the plant; this ratio tends to increase with the dose of mud brought in soil. The roots of plants show high levels of Zn even on the ground of untreated soil. The contents of Ni, Pb and Zn, compared to Cu and Co, are higher in the roots of colza

Effects of temperature and treated urban wastewater on seed germination and seedling growth in different populations of Moringa oleifera (Lam.)

Drought is an environmental concern in North Africa. Hence, countries in this region promote treated wastewater reuse in agricultural irrigation as sustainable practice in reducing the increasing stress on water resources. Here, we evaluated the treated urban wastewater (TUW) impact on seed germination and seedling growth of four Moringa oleifera (MO) populations in different temperature conditions. Seeds were brought from Morneg and Kairouan in Tunisia and from India and Egypt. Germination tests were performed using different TUW concentrations at 25 and 35°C for 9 days under darkness and distilled water for control. Parameters such as germination percentage (GP), mean germination time (MGT), shoot length (SL) and TUW half-maximal effective concentration (EC50) were measured. GP, MGT, and SL varied significantly with incubation temperature and seed source. Only SL did not show any significant variations in all TUW concentrations. Increased temperature had a positive influence on GP and SL; on the contrary, a negative impact on MGT was observed in Kairouan, Egyptian and Indian seeds. EC50 evaluation showed that TUW was less harmful on Indian Moringa seeds. Seeds incubated at 25°C were structured into two groups: the first containing Morneg, Indian and Egyptian seeds; and the second one with Kairouan seeds. At 35°C, Egyptian seeds left the first group and joined the second indicating that their germination didn’t occur rapidly for temperature increase. Considering Tunisian climate conditions, results showed that Moringa oleifera is able to acclimatize to temperatures of this country

Apoptose du colza induite par de fortes doses de boues industrielles issues de station d'épuration

National audienceCette étude préliminaire consiste à évaluer sur le colza les effets de l'épandage des boues industrielles chargées en métaux lourds surtout en plomb et chrome. Nous nous sommes intéressés aux fortes doses d'épandage 100tnia pour mieux observer les phénomènes de transformations induites sur le colza par l'absorption des métaux lourds. Nous avons utilisé la technique ultra structurale pour l'observation en microscope électronique à transmission

L'effet des boues d'épuration (liquides et sèches) sur l'absorption des métaux lourds par le ray grass (<i>Lolium Perenne</i>)

National audienceL'épandage des boues résiduaires liquides et sèches a entraîné une augmentation de la production de la biomasse du Ray Grass. Cette augmentation est fonction des doses croissantes appliquées. Cet effet positif des boues sur les rendements a été constaté sur d'autres cultures. En effet, de nombreux auteurs ont signalé une augmentation significative des rendements de différentes cultures tels que le sorgho, le maïs, le piment, la pomme de terre. Nos essais ont également montré un meilleur rendement avec la boue sèche qu'avec la boue liquide l'année de l'épandage. Ceci pourrait également être le résultat d'une part d'une perte probable des nitrates apportés dans les boues liquides et d'autre part de la richesse de la boue apportée en matière sèche. En effet, la teneur de la boue en matière sèche est très variable soit environ 5% et 67% de matière sèche respectivement dans la boue liquide et la boue sèche. Pour ce qui est de l'accumulation des métaux lourds dans la plante, nos résultats ont montré que les teneurs en Cd, Pb, Zn, et Cu de la partie aérienne de la plante ne varient pas avec l'apport de 5 et 10 t/ha de boue sèche ou liquide. Ces résultats sont en accord avec ceux qui ont étudié l'évolution des teneurs en plomb des tissus du ray-grass, soumis à trois types de traitement (témoin sans apport, fertilisation minérale et amendement en boues). Ils ont montré qu'il n'existe aucune différence significative entre les quantités moyennes de plomb des différentes récoltes de ray-grass, issus des différents traitements d'une même série de culture, effectuées à une même date. Ils ont constaté le même effet pour le Zn

Transfert sol-plantes des métaux lourds des boues d'épuration urbaines et industrielles

National audienceLe principal objectif de cette étude consiste à évaluer sur le blé et le colza l'effet de deux types de boues résiduaires (boues urbaines / boues industrielles) chargées en métaux lourds surtout en plomb et chrome. Ces boues sont apportées à différentes doses (5,25, 50 et 100 t/ha). Nous nous intéressons donc à la croissance et l'absorption des métaux lourds par les plantes (le blé dur et le colza) et à suivre le devenir de ces derniers dans le sol afin de prévenir des phénomènes de pollution et de toxicité

Colza cell autophagy induced of high dose of industrial sewage sludge

International audienceThis preliminary study is to evaluate the effects on colza of land application of industrial sludge containing heavy metals especially lead and chromium. We are interested in high doses spreading 100t/ha to better observe the phenomena of induced transformations on colza by the absorption of heavy metals. We used the technique for ultrastructural observation in a transmission electron microscope. The colza cells show a compaction and marginalization of nuclear chromatin, nuclear membrane and cytoplasmic convolution and condensation of cytoplasm. The kernel then fragments, each fragment are surrounded by a jacket. Some cytoplasmic and nuclear elements are released and are phagocytized by neighboring cells. We observed vacuolation of the cytoplasm and the formation of autophagic vesicles