Pascale Bourgeade

Performance assessment of Etueffont (France) lagooning treatment system: Report from a 16-year survey

This study examined the lagooning treatment system of the Etueffont landfill (France) over a period of 16 years. Outflow concentrations in total suspended solids, biological oxygen demand (BOD5) and trace metal elements largely met outflow standards and were on average of 5, 8 and 6 times lower than those observed at inflow, respectively. In 2000, however, high levels of BOD5 were observed in both the influent and effluent, exceeding the authorized outflow limits. At that time the lagooning ponds were subjected temporarily to organic pollution, coinciding with the arrival of the first leachates from a new cell. Though the chemical oxygen demand (COD) and total organic carbon in the influent exceeded authorized limits, overall values conformed to official standards with outflow exhibiting mean concentrations four times lower than those observed at inflow. The first period took place just after the arrival from the new cell of young leachates containing a very high level of COD (>10,000 mg L-1), causing an organic overload that led to a temporary dysfunctioning of the treatment installation lasting approximately two years. Additionally, the COD in the leachates fell below the strictest limits (125 mg L-1) at the end of monitoring (2005-2009). The initial nitrogen load brought in by the influent decreased progressively over time, evidence of continuous degradation. At the end of monitoring, regardless of the arriving inflow load, the discharge presented stable concentrations of approximately 30 mg L-1, appearing to indicate that the limits for nitrogen elimination. Total phosphorus elimination was optimal as the concentrations at outflow were minimal throughout most of monitoring, even though the phosphorus load at inflow was from two to thirty-five times greater. Thus, the findings show that landfill leachates in the methanogenic phase can be treated efficiently by lagooning without risk to the surrounding environment.

Influence of different sludge compositions on understorey vegetation in an amended Pinus pinatser forest plantation

The present study reports on the influence of sludge application on understory abundance and species richness in an eight year-old maritime pine forest. Four types of sludge (liquid, dewatered, limed and composted sludge) were applied at a rate equivalent to 3 tons dry weight per ha-1 per year-1. Understorey vegetation was monitored before treatment and for three successive years following initial sludge application. Species richness, the biodiversity index and naturally occurring plant community cover in maritime pine forests were measured. Results showed a significant increase in species richness two years following initial sludge application. In fact, compared to the unamended plot, eighteen additional species (Aira caryophyllea, Cerastium glomeratum, Conyza canadensis, Danthonia decumbens, Geranium robertianum, Gnaphalium sylvaticum, Hypericum humifusum, Hypericum perforatum ssp. perforatum, Jasione montana, Lonicera periclymenum ssp. periclymenum, Ornithopus compressus, Phytolacca americana, Rhamnus frangula, Teesdalia nudicaulis, Veronica arvensis, Vicia sativa angustifolia and Vulpia myuros) appeared after sludge application. Most of these species were observed with the solid limed or composted sludge treatments. The new species then declined the following year, highlighting the temporary effect of sludge treatment on species diversity. However, the cover by these eighteen new species was low and did not exceed 1%, except for Hypericum perforatum and Jasione montana for the limed sludge treatment and Vulpia myuros for the liquid sludge treatment. Additionally, sludge significantly reduces bare soil percentage, which ranged from 5 to 18% compared to the control (38%). According to sludge type, treatment also led to a significant change in species dominance of the understorey plant communities. Indeed, the cover of Molinia caerulea decreased in spite of an increase in Agrostis capillaris and/or Holcus lanatus following application of solid limed, liquid or composted sludge.

Potential vulnerability of oak forests to climate change-induced flooding: effects of mild oxygen deficiency on Quercus robur and Quercus petraea seedling physiology

Flooding is characterized by saturation of soil pores with water, leading to hypoxic conditions which affect plant root development and metabolism. We investigated the oxygen deficiency tolerance observed in Quercus robur and Quercus petraea and seek to understand whether it can be explained by enhanced efficiency in oxygen use in the roots, as estimated through radial oxygen loss visualization in relation to growth measurements and root apex respiration. The study showed that root growth, under oxygen deficiency conditions, was significantly reduced only in Q. robur seedlings. Root respiration was maintained in Q. robur, whereas it was decreased in Q. petraea. Both species set up a barrier against radial oxygen loss, though measurement of apex oxygen leakage showed greater oxygen efficiency in Q. robur seedlings. This strategy might allow Q. robur to maintain its respiration and thus to survive longer under oxygen deficiency conditions by facilitating the seedling establishment in transient flooded soils.

Protein markers of the movement of twining bean shoots

xqpanosoma cruzi is the causative agent of the american trypanosomiasis or Chagas’disease, transmited to human by reduviid bugs. More than 20 millions of human beings are infected by this flagellated protozoa. T. cruzi division is initiated by duplication of basal bodies, then of flagellum followed by duplication of the kinetoplast Nuclear division occures subsequently to the kinetoplaste division As the cytoskdeton is directly involved in the parasite division and in the differentiation of parasite forms (epimastigote, trypomastigote, amastigote), we have studied the effects of antimicrotubular drug&inducing depolymerization (colchicine, Nocodazole, vinblastine and vincristine) and polymerization of microtubules (Taxol, Taxotere or rhazinilam) on the development of T cruzi. epimastigotes. Taxotere inhibits the most efficiently the parasite growth (1C~0=100 nM). Taxol preselits an ICjo of 400 nM, vinblastine and vincristtine ICX, of about 5 pM, rhazinilam of 100 KM, colchicine and Nocodazole I&O > 0,5 mM. Beyond different ICra, these drugs produce a diversity of atypic forms In presence of vinblastine, vincristine, Taxotere or Taxol, a duplicatiop -6f basal bodies, flagellum, kinetoplast and of nucleus is observed, but there is no cytokinesis the aberrant forms can exhibit up to 4 nuclei and s kinetoplasts However, morphological differences are observed belween vincristine treated parasites and Taxotere treated parasites. On the other hand, in presence of colchicine, Nocodazole and rhazinilam, no duplication.is observed These results indicate that the antimicrotubular drugs act on different subpopulations of microtubules involved in the Trvpanosoma cruzi division BEMAVIOR AND COMPOSITION OF Tt4E MICROTU6lJlAR CYTOS&&.ETQN JN A PRlllltrTRJE Gf?OUP OF PF16’

Sensing and signalling during plant flooding.

‘%STS: THE TRtCkC)NIOiGAbS: DELGADO Pildi, VlScOGLtOSt Eric and BRUGEROLLE Guy Laboratoire de B@logie des ProWes, URA CNRS 1944, Auw3us des Landais, 6317? Aub&e Cedex8 France