Le politique et l’écriture de dé-raison : les Manuscrits de Pauline Archange de Marie-Claire Blais et La maison aux esprits d’Isabel Allende

L'autobiographie fictive Les manuscrits de Pauline Archange (1968-1970) de Marie-Claire Blais et la chronique familiale La maison aux esprits (traduction française de La casa de los espíritus , 1982) d'Isabel Allende se situent, malgré leur facture différente, à un point de rupture de l'ordre socio-politique du pays d'origine de leurs auteures respectives. Dans cet article, nous cherchons à distinguer et à mettre en rapport diverses stratégies narratives et discursives adoptées par ces deux femmes écrivains pour inscrire, tout en s'en distançant, le contexte social et politique tel qu'il est ordonné par la famille, l'État, l'Éducation et la Religion, les instances qui, par le discours de la raison, concourent à façonner l'individu social.Marie-Claire Blais fictitious autobiography Les manuscrits de Pauline Archange (1968-1970) and Isabel Allende's family chronicle La maison aux esprits (french translation of La casa de los espíritus, 1982) although fundamentally different occur at a breaking point of the social and political order of the writers' country of origin. This article seeks to differentiate and to establish relationships between the narrative and discursive strategies adopted by these women writers in order to inscribe, while at the same time distancing themselves from the social and political reality ordained by family, Education, State and Religion, those authorities which, through the discourse of reason, work together in the making of the social individual

Doping and temperature-dependent optical properties of oxygen-reduced BaTiO3-d

We report on optical properties of reduced BaTiO3-d at different doping levels including insulating and metallic samples. In all the samples, including metallic one, we observe structural phase transitions from the changes in the infrared-active phonon modes. Metallic ground state is confirmed by the Drude-type lowfrequency optical reflectance. Similar to SrTiO3-d we find that the midinfrared-absorption band in BaTiO3-d appears and grows with an increase in the oxygen-vacancy concentration. Upon decrease in temperature from 300 K, the midinfrared band shifts slightly to higher frequency and evolves into two bands: the existing band and a new and smaller band at lower frequency. The appearance of the new and smaller band seems to be correlated with the structural phase transitionsComment: 8 pages, 7 figure

Mobilité des métaux et risque de contamination des eaux lors de la valorisation sylvicole des boues de station d'épuration municipales au Québec : une revue

La présence de métaux dans les boues municipales demeure l'obstacle majeure à leur valorisation comme fertilisant agricole ou forestier. L'utilisation des boues en milieu forestier diminue certes les risques de contamination de la chaîne alimentaire humaine. Cependant, nos connaissances sur le comportement à long terme des métaux ajoutés aux sols forestiers sont encore très limitées. Le risque de lessivage des métaux vers les écosystèmes aquatiques situés en aval des zones traitées doit être évalué. Cet article propose une comparaison des risques de contamination de l'eau selon que l'application des boues s'effectue en forêt ou en milieu agricole. Les concentrations de métaux dans les boues municipales, leurs formes et leur mobilité dans les sols amendés sont passées en revue. Et finalement, les normes québécoises qui ont été établies pour protéger le milieu récepteur contre les métaux présents dans les boues sont comparées à celles recommandées par l'U.S. EPA.The presence of metals in municipal sewage sludge is still a major obstacle to their land application. Forest land application of sludge reduces the possibility of metals entering the human food chain. Present knowledge of their long-term behavior in forest soil is however limited. The risk of metals leaching to the aquatic ecosystem situated downstream from treated zone must be evaluated. This paper present a comparison of the risks of water contamination when sludges are applied to forests instead of cropland. The levels of metals in municipal sludge, their form and their mobility in sludge-treated soil are reviewed. Finally, the regulations of the Province of Quebec that have been established to protect forest land are compared to the recommendations of the U.S. Environmental Protection Agency. Although sludge applications to forest land reduce the risk of human foodchain contamination, properties of forest soils (low pH, low cation exchange capacity (CEC), presence of large continuous pores) could represent an increased hazard of metals leaching to aquatic ecosystems. Metal concentrations in sludge vary considerably depending on the source of the sludge. Metals found in sludge are predominantly associated with the solid phase, while soluble and exchangeable forms generally represent less than 10% of the total metals.Short term studies have revealed that metals tend to accumulate in the upper layers of soil, but few studies have evaluated long-term metal mobility or bioavailability. Many factors can contribute to an increase mobility (pH, oxidation-reduction potential, organic matter decomposition). The risk of aquatic ecosystem contamination by aluminum leached from sludge-treated soils hasn't yet been evaluated. It seems, however, that the risk exists if the soil become more acidic after sludge decomposition. Limits on the amount of metals allowed in sludge have been fixed by many countries. Nevertheless, given the wide variation in the standards used to regulate the allowable content of metal in sludge or sludge-treated soils, disagreement presently exist among regulatory agencies. For example, the maximum cadmium limit allowed in sludge destined to be used as forest fertilizer in Quebec is 15 mg kg-1, whereas it is 85 mg kg-1 in the United States. Different philosophical views on environmental protection (zero tolerance or tolerance of a certain level of metals in soil), as well as the organism chosen when standards are set, are responsible for this inconsistency. Before sewage sludge application to forests becomes a common practice, the associated risks of metals leaching to the aquatic ecosystem must be evaluated. Long-term studies should be undertaken in order to establish safe standards for applying sludge in a forest environment. Such additional efforts will enable good quality sludge to be considered as a usable and valuable resource in forestry

Étude de l'enlèvement du Cd, Cu, Mn et Zn par solubilisation biologique dans les sédiments lacustres fortement contaminés

Des essais en erlenmeyers de 0,5 L ont été faits afin d'évaluer les possibilités d'application d'un procédé de solubilisation biologique aux sédiments. Ce procédé utilise la capacité des thiobacilles de lixivier les métaux en milieu acide. Au cours des essais, l'influence, sur la solubilisation des métaux, de la quantité de substrat (FeSO4 × 7H2O), du pourcentage d'inoculum et de la teneur en solides totaux a été suivie. La concentration de substrat n'a pas d'effet sur l'enlèvement du Cd, du Zn, du Mn et du Cu. Les taux d'enlèvement moyens pour le Cd, Zn et Mn, sont, après 46 heures, de 70 à 90 %, 90 à 100 % et 64 à 72 % pour des concentrations de substrat variant de 0 à 30 % FeSO4 × 7H2O (poids sec/poids sec). A 29 et 46 heures, des coefficients de détermination (r2) de 0,46 et 0,59 entre le pH et la concentration de FeSO4 × 7H2O, et de 0,92 et 0,55 entre le POR et la concentration de FeSO4 × 7H2O ont été trouvés. A plus forte teneur en FeSO4 × 7H2O, le POR est moins élevé, surtout au début des essais. La présence des ions ferreux en plus grande quantité expliquerait les plus faibles valeurs du potentiel-rédox. A 20 % d'inoculum, la solubilisation des métaux est optimale avec une solubili- sation de 86 % pour le Cd et 73 % pour le Cu et le Mn. La forte corrélation entre le POR, le pH et le pourcentage d'inoculum (r2 à 29, 46 et 70 heures de 0,94, 0,94 et 0,63 pour le POR et le pourcentage d'inoculum et de 0,80, 0,69 et 0,60 pour le pH et le pourcentage d'inoculum), a permis d'établir une corrélation entre le POR, le pH et la solubilisation du Cu. Les seuils trouvés permettant une solubilisation du Cu supérieure à 10 % sont un pH de 3,75 et un POR de 260 mV.L'augmentation des solides totaux (ST) semble limiter le développement des thiobacilles et diminue les rendements de solubilisation du Cd (à 21 heures) et du Zn (à 45 heures). Ainsi, pour le Cd, les pourcentages de solubilisation passent de 71 % à 24 % pour 3 et 15 % ST, alors que dans le cas du Zn, ils diminuent de 94 % à 81 % pour 3 et 15 % ST. La solubilisation du Mn serait, pour sa part, plutôt de type chimique.In the province of Québec, the St-Lawrence Seaway as well as the harbour areas undergo frequent dredging. Each year, more than 106 cubic metres of sediments must be dredged from the st-Lawrence river. The dredged sedirnents are generally dispersed in the water column. However, heavy metal contamination of these sediments may preclude open-water disposal and necessitate their confinement.The research work presented in this article applies to dredged sediments that are too contaminated for open-water disposal. In order to permit their safe disposal, it is necessary to have a method which effectively removes metals from these sediments. One of the effective methods of metal removal from contaminated sediments could be a microbial solubilization process, which was developed at INRS-Eau for sewage sludge decontamination and which has been tested on a pilot scale during the past year. In order to appty such a process to decontaminate sediments, it was necessary to study the influence of various factors affecting the microbial leaching process. This research verified the possibility of using a modified microbial leaching process to decontaminate sediments and also studied the influence of the enerry substrate, the microbial inoculum and the sediment total solids concentration on such a modified process.The experimental methodology consisted of mixing the contaminated sediment in a 500 ml Erlenmeyer flask for a period of 96 hours in the presence of thiobacillus inoculum and ferrous sulfate (FeSO4 • 7H2O) as the enerry substrate. Before each experiment sediments were adjusted to the desired total solids concentration with deionized water and were acidified with sulfuric acid to obtain the starting pH conditions.The solubilization of Cd, Cu, Zn and Mn was monitored at regular intervals in order to evaluate the influence of the various factors studied. Subsamples were removed, the sediments were digested and the metals were analyzed by inductively coupled plasma atomic emission spectrophotometry (ICP-AES). The elements analyzed were Al, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb,Zn as well as S, P and C. All the digestions and analyses performed made according to the APHA guidelines. The total solids, both volatile and inert, were also determined according to APHA method no.209F (APHA, 1985).Regarding the influence of the ferrous sulfate concentration on the application of the microbial leaching process, the removal rates of Cd, Zn and Mn did not vary more than 12 %. For all experiments, the final pH value approached 2,5. The oxidation-reduction potential (ORP) varied for all experiments from 462 to 560 mV. An energy source could therefore be present in the sediments, which would support the growth of thiobacillus bacteria.During the experiments conducted to study the influence of inoculum concentration on the microbial leaching process, it was found that the pH decreased from 3.5 to 2.4 and the ORP increased from 284 to 593 mV when the inoculum addition increased from 0 to 30 % (v/v). This tendency was also observed during the removal of Cd and above all, Cu. Between 0 and 20 % (v/v) inoculum concentration, Cd removal increased from 64 to 86 % whereas Cu removal increased from 20 to73 %. However, these two metals did not show any appreciable increase in solubilization when the inoculum was increased from 20 to 30 % (v/v). In the case of Mn, it was not possible to determine the solubilization pattern since the inoculum concentration did not influence the solubilization of this element, Between 0 and 30 % inoculum, the Mn removal varied from 56 to 73 %. Hence the microbial influence on Mn solubilization may be negligible.The study on the influence of total solids content on the microbial leaching process showed that the total solids concentration had an influence on pH and ORP. The final pH increased from 2.43 to 3.32 and ORP decreasedfrom 492 to 321 mV when the total solids content was varied from 3 to 15 % . The percent solubilization of Cd after 21 h was 7l %, 69 %, 43 %, 44 % and, 24 % at 3, 5, 7, 10 and 15 % total solids respectively, On the other hand, Zn solubilization after 45 h was 94 %, 90 %, 84 %, 97 % and 8l % for the same concentrations of total solids. An increase in total solids content decreased the solubilization efficiency of Cd (at t=2l h) and, to a lesser extent, Zn (att=48h). However,in the case of Mn, the maximum solubilization was achieved right at the beginning and varied little with time. Its solubilization varied between 61 and 70 % for 3 % total solids, between 67 and, 79 % for 5 % total dolids, between 52 and,62 % for 7 % totaf solids, between 57 and, 75 % for l0 % total solids and tretween 40 and 63 % for 15 % total solids. In general, for the sediments studied here, total solids content has little influence on Mn solubilization.In conclusion, use of a microbial leaching process to remove metals from contaminated sediments seems to be less complex than for sewage sludges, since the maximum removal of metals is achieved in less than 48 h in a bench-scale experiment. The average metal solubilization was above 80 % for Cd, 73 % for Cu, 90 % for Zn and 65 % for Mn. The development of thiobacillus does not seem to be dependent upon the presence of an added energy substrate. Only a minimal quantity of substrate, say 5 % ferrous sulfate (dry wt./dry wt.), is required in order to assure optimal conditions for thiobacillus growth. It is probable that with time, without ferrous sulfate, the microbial conditions would deteriorate due to exhaustion ofthe enerry substrate. A 20 % microbial inoculum seems to be enough to assure an efficient metal solubilization process. Except for Mn, the increase in total solids concentration had a negative influence on the metal solubilization. It is hence preferable to work with a total solids concentration of less than 5 %. Nevertheless, it should be noted that this percentage is more than that used for sewage sludge decontaminaton (around 2 % total solids)