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See detailTowards a better understanding of ephemeral stream morphodynamics during the last 100 ka in the vicinity of the prehistoric site of Ifri n’Ammar (Morocco)
Bartz, Melanie; Rhixon; Khel, Martin et al

Conference (2016, April 17)

Our study focusses on the ephemeral stream deposits of Wadi Selloum to reconstruct the palaeoenvironmental evolution in direct vicinity of the rock shelter Ifri n’Ammar. As one of the oldest settlement ... [more ▼]

Our study focusses on the ephemeral stream deposits of Wadi Selloum to reconstruct the palaeoenvironmental evolution in direct vicinity of the rock shelter Ifri n’Ammar. As one of the oldest settlement sites of anatomically modern humans (AMH) in North Africa, Ifri n’Ammar documents periodical occupations since ~170 ka. Since these discontinuous settlement dynamics may be related to or influenced by landscape changes and climate forcing, our study aims (i) to identify phases of morphodynamic activity and stability in the deposits of Wadi Selloum by using micromorphological (sixteen thin sections), sedimentological (laser diffractometry, loss on ignition, magnetic susceptibility), geochemical ( XRF and Scheibler method) and mineralogical (X-ray diffractometry) proxies. Furthermore, (ii) a robust chronology for the ephemeral stream deposits is established by applying a combination of optically stimulated luminescence (OSL) and post infrared stimulated luminescence (pIRIR290) dating. Additionally, one collected pottery shard was dated by thermoluminescence (TL) dating for an inter method comparison. The application of luminescence dating techniques to Wadi Selloum deposits yielded burial ages between 1.3 ± 0.2 ka and 102 ± 8 ka covering different phases of morphodynamically stable and active phases. Enhanced aggradation is evident between ~100 and 60 ka, ~21 and 14 ka and during the Holocene. Overbank fines are distinguished by high amounts of allochthonous minerals such as quartz, muscovite, K-feldspar and plagioclase which give rise to higher eolian activity. This leads to the suggestion that morphodynamical activity was dominant during more arid phases. Landscape stability was observed in form of one palaeosol (2B-2C-sequence; OIS 3) and a recent soil (Ap/Ah-Bw-Bk-BC-C-sequence; after LGM), both attributed to the Calcisol group. Pedogenenesis is evident in thin sections by well-developed subangular blocky peds. The main soil forming process is secondary carbonate precipitation in subsoil horizons, supported by pedofeatures such as calcite infillings and hypocoatings. Holocene deposits (6.4 ± 4 to 1.3 ± 0.2 ka) seem to be affected by short-termed changes between landscape stability and hydromorphic activity due to strong variations in its mineralogical and geochemical characteristics. This is supported by a homogeneous and sterile stratigraphy, as well as an insignificant differentiation in soil horizons with only weakly developed pedofeatures. The sediment characteristics present a weak Ap-C-sequence of a calcaric Fluvisol. After ~1.3 ± 0.2 ka fluvial discharge was reduced and incision took place in the Wadi Selloum. Our study provides first insights in the palaeoenvironment around Ifri n’Ammar during the last glacial interglacial cycle and gives first suggestions about climatic conditions during the time of human occupation in Ifri n’Ammar. [less ▲]

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See detailSoil apparent conductivity measurements for planning and analysis of agricultural experiments: A case study from Western-Thailand
Rudolph, Sebastian; Wongleecharoen, Chalemchart; Lark, Murray et al

in Geoderma (2016), 267

In experimental trials, the success or failure of agricultural improvements is commonly evaluated on the agronomic response of crops, using proper experimental designs with sufficient statistical power ... [more ▼]

In experimental trials, the success or failure of agricultural improvements is commonly evaluated on the agronomic response of crops, using proper experimental designs with sufficient statistical power. Since fine-scale variability of the experimental site can reduce statistical power, efficiency gains in the experimental design can be achieved if this variation is known and used to design blocking, or some proxy variable is used as a covariate. Near-surface geophysical techniques such as electromagnetic induction (EMI), which describes subsurface properties non-invasively by measuring soil apparent conductivity (ECa), may be one source of this information. The motivation of our study was to investigate the effectiveness of EMI-derived ECa measurements for planning and analysis of agricultural experiments. ECa and plant height measurements (the response variable) were taken from an agroforestry experiment in Western Thailand, and their variability was quantified to simulate multiple realizations of ECa and the residuals of the response variable from treatment means. These were combined to produce simulated data from different experimental designs and treatment effects. The simulated data were then used to evaluate the statistical power by detecting three orthogonal contrasts among the treatments in the original experiment. We considered three experimental designs, a simple random design (SR), a complete randomized block design (CRB), and a complete randomized block design with spatially adjusted blocks on plot means of ECa (CRBECa). Using analysis of variance (ANOVA), the smallest effect sizes could be detected with the CRBECa design, which indicates that ECa measurements could be used in the planning phase of an experiment to achieve efficiencies by improved blocking. In contrast, analysis of covariance (ANCOVA) demonstrated that substantial power improvements could be gained when ECa was considered as a covariate in the analysis. We therefore recommend that ECa measurements should be used to characterize subsurface variability of experimental sites and to support the statistical analysis of agricultural experiments. [less ▲]

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See detailLa ligne et la boucle. Michel Strogoff ou l'involution
Durand, Pascal ULg

Conference (2016, April)

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See detailConstruire un programme de formation pédagogique pour les enseignants
Poumay, Marianne ULg

in Daele, Amaury; Sylvestre, Emmanuel (Eds.) Comment développer le conseil pédagogique dans l’enseignement supérieur ? (2016)

En s’appuyant sur quelques expériences européennes et notamment celle de l’Université de Liège, pionnière en matière d’obligation de formation pour les encadrants du supérieur en Belgique, ce chapitre ... [more ▼]

En s’appuyant sur quelques expériences européennes et notamment celle de l’Université de Liège, pionnière en matière d’obligation de formation pour les encadrants du supérieur en Belgique, ce chapitre tente d’éclairer les défis majeurs qui attendent les enseignants ou conseillers pédagogiques au détour de leur conception d’un programme de formation pour enseignants. Il aborde tout d’abord l’intérêt d’étudier les besoins ou en tout cas de définir un cap institutionnel clair et partagé en matière de formation des enseignants en interne. Il propose quelques réflexions quant au choix du public-cible de ces formations, de leurs contenus et méthodes, de leur durée et de leurs animateurs. Il aborde ensuite les questions des incitants à la participation des enseignants et de l’impact de ces formations avant d’ouvrir sur quelques pistes de discussion. [less ▲]

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See detailLes théories représentationnelles de l'esprit
Gauvry, Charlotte ULg

Conference (2016, April)

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See detailL'imagination. Une pratique normée chez Wittgenstein
Gauvry, Charlotte ULg

Conference (2016, April)

Contrairement aux empiristes anglais, Wittgenstein récuse l’idée d’après laquelle les actes d’imagination sont définis par leur « contenu », à savoir une « image mentale » qui ne différerait que par son ... [more ▼]

Contrairement aux empiristes anglais, Wittgenstein récuse l’idée d’après laquelle les actes d’imagination sont définis par leur « contenu », à savoir une « image mentale » qui ne différerait que par son degré d’intensité d’un contenu cognitif (Cf. Hume, Traité de la nature humaine, I, i, 3 ; Wittgenstein, F §621). Parallèlement, Wittgenstein récuse l’hypothèse selon laquelle un « œil mental » ou « œil interne » nous fournirait ces images (cf. e.g. RPP II §66). De fait, les nombreux exemples des Recherches philosophiques comme des textes plus tardifs (cf. e.g. RP §§6, 19 ; F §§98, 571) mettent en scène l’imagination d’un langage, d’une hypothèse, d’un usage, d’un contexte, etc. – autant de choses que l’on ne « voit » pas par l’œil de l’esprit. En adoptant une position assez proche de celles de Reid, Ryle ou Sartre (cf. Glock 1996), Wittgenstein défend alors l’hypothèse d’une imagination sans imaginaire. Ce faisant, Wittgenstein présente l’imagination comme un acte, ou plutôt une « pratique ». Or Wittgenstein dissocie cette pratique de celle de la perception (F §§621-637). Selon le §625 des Fiches, il existe bien un « rapport » entre ces deux jeux de langage, mais pas de « ressemblance ». À titre de premières indications, il semble que les deux pratiques diffèrent pour au moins trois raisons : - Premièrement, Wittgenstein affirme que l’imagination, à la différence de la perception, est assujettie à la volonté (e.g. F §621). Si nous recevons ce que nous percevons, nous pouvons en revanche répudier ou rechercher certaines images. - Qui plus est, en tant que pratique volontaire, l’imagination est soumise aux mêmes règles que celles qui régulent toutes les pratiques. C’est donc une pratique normée : en situation, certaines représentations sont possibles alors que d’autres pas (cf. e.g. RP, §651 : « je ne peux pas imaginer le contraire »). - Il semble enfin que l’imagination, à la différence de la perception, soit une pratique créatrice. Wittgenstein rapproche en effet l’imagination du « voir comme » et non du voir (RP II, 11, RPP §543). Elle joue à ce titre un rôle méthodologique fondamental dans l’économie de la vision synoptique que Wittgenstein appelle de ses vœux. [less ▲]

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See detailContrasted accumulation patterns of persistent organic pollutants and mercury in sympatric tropical dolphins from the south-western Indian Ocean
Dirtu, Alin; Malavannan, Govindan; Das, Krishna ULg et al

in Environmental Research (2016), 146

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the ... [more ▼]

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the contamination with persistent organic pollutants (POPs) and total mercury (T-Hg) of spinner (Stenella longirostris, n=21) and Indo-Pacific bottlenose dolphins (Tursiops aduncus, n=32) sampled from the coastal waters of La Réunion (south-western Indian Ocean). In addition, seven co-occurring teleost fish species were sampled and analyzed as well. Blubber samples from living dolphins and muscle from teleosts were analyzed for polychlorinated biphenyls (PCBs), DDT and metabolites (DDTs), chlordanes (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), and polybrominated diphenyl ethers (PBDEs). Methoxylated PBDEs (MeO-PBDEs), reported as having a natural origin, were also analyzed. T-Hg levels were measured in blubber and skin biopsies of the two living dolphin species. δ13C and δ15N values were determined in skin of the dolphins and in the muscle of teleosts. For PCBs, HCHs and T-Hg, concentrations were significantly higher in T. aduncus than in S. longirostris. For other POP levels, intra-species variability was high. MeO-PBDEs were the dominant compounds (55% of the total POPs) in S. longirostris, while PCBs dominated (50% contribution) in T. aduncus. Other contaminants showed similar profiles between the two species. Given the different patterns of POPs and T-Hg contamination and the stable isotope composition observed among analyzed teleosts, dietary and foraging habitat preferences possibly explain the contrasted contaminant profiles observed in the two dolphin species. Levels of each class of contaminants were significantly higher in males than females. Despite their spatial and temporal overlap in the waters of La Réunion, S. longirostris and T. aduncus are differently exposed to contaminant accumulation. [less ▲]

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See detailMicrowave-assisted extraction of pectin from unutilized pumpkin biomass
Košťálová, Zuzana; Aguedo, Mario ULg; Hromádkováa, Zdenka

in Chemical Engineering and Processing: Process Intensification (2016), 102

Microwave-assisted extraction was employed to extract polysaccharides from pumpkin biomass and compared to the usual extraction by conventional heating. The effect of microwave heating time, liquid/solid ... [more ▼]

Microwave-assisted extraction was employed to extract polysaccharides from pumpkin biomass and compared to the usual extraction by conventional heating. The effect of microwave heating time, liquid/solid (L/S) ratio and extraction temperature on the yield and molecular mass of extracted pectin from the seeded oil pumpkin biomass was investigated. Heating times ranged from 2 to 10 min, L/S ratio from 30/1 to 50/1 and temperature from 80 to 120 °C. The response surface methodology was used to optimize the effects of processing parameters to isolate pectin with medium molecular weight and with the highest yield. The retained conditions were as follows: liquid/solid ratio 50/1, microwave heating time of 10 min and a temperature of 102.2 °C. Among the studied factors, the liquid/solid ratio had the greatest influence on yield and molecular mass, respectively. Application of microwave heating in the extraction of pumpkin biomass gave a pectin with medium Mw and dramatically reduced extraction time in comparison to traditional hot acid extraction. Microwave is an excellent tool for extraction and modification of polysaccharides in one step. [less ▲]

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See detailInsertion professionnelle et parcours enseignants : mise en perspective
Simons, Germain ULg

in Didactiques en pratique (2016), (2),

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See detailEffective soil hydraulic conductivity predicted with the maximum power principle
Westhoff, Martijn ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

Conference (2016, April)

Drainage of water in soils happens for a large extent through preferential flowpaths, but these subsurface flowpaths are extremely difficult to observe or parameterize in hydrological models. To ... [more ▼]

Drainage of water in soils happens for a large extent through preferential flowpaths, but these subsurface flowpaths are extremely difficult to observe or parameterize in hydrological models. To potentially overcome this problem, thermodynamic optimality principles have been suggested to predict effective parametrization of these (sub-grid) structures, such as the maximum entropy production principle or the equivalent maximum power principle. These principles have been successfully applied to predict heat transfer from the Equator to the Poles, or turbulent heat fluxes between the surface and the atmosphere. In these examples, the effective flux adapts itself to its boundary condition by adapting its effective conductance through the creation of e.g. convection cells. However, flow through porous media, such as soils, can only quickly adapt its effective flow conductance by creation of preferential flowpaths, but it is unknown if this is guided by the aim to create maximum power. Here we show experimentally that this is indeed the case: In the lab, we created a hydrological analogue to the atmospheric model dealing with heat transport between Equator and poles. The experimental setup consists of two freely draining reservoirs connected with each other by a confined aquifer. By adding water to only one reservoir, a potential difference will build up until a steady state is reached. From the steady state potential difference and the observed flow through the aquifer, and effective hydraulic conductance can be determined. This observed conductance does correspond to the one maximizing power of the flux through the confined aquifer. Although this experiment is done in an idealized setting, it opens doors for better parameterizing hydrological models. Furthermore, it shows that hydraulic properties of soils are not static, but they change with changing boundary conditions. A potential limitation to the principle is that it only applies to steady state conditions. Therefore the rate of adaptation of hydraulic properties should be faster than the rate of change in boundary conditions. [less ▲]

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See detailDoes the Budyko curve reflect a maximum power state of hydrological systems? A backward analysis
Westhoff, Martijn ULg; Zehe, Erwin; Archambeau, Pierre ULg et al

Conference (2016, April)

Almost all catchments plot within a small envelope around the Budyko curve. This apparent behaviour suggests that organizing principles may play a role in the evolution of catchments. In this paper we ... [more ▼]

Almost all catchments plot within a small envelope around the Budyko curve. This apparent behaviour suggests that organizing principles may play a role in the evolution of catchments. In this paper we applied the thermodynamic principle of maximum power as the organizing principle. In a top-down approach we derived mathematical formulations of the relation between relative wetness and gradients driving runoff and evaporation for a simple one-box model. We did this in an inverse manner such that when the conductances are optimized with the maximum power principle, the steady state behaviour of the model leads exactly to a point on the asymptotes of the Budyko curve. Subsequently, we added dynamics in forcing and actual evaporations, causing the Budyko curve to deviate from the asymptotes. Despite the simplicity of the model, catchment observations compare reasonably well with the Budyko curves subject to observed dynamics in rainfall and actual evaporation. Thus by constraining the – with the maximum power principle optimized – model with the asymptotes of the Budyko curve we were able to derive more realistic values of the aridity and evaporation index without any parameter calibration. [less ▲]

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See detailEspace, temps et angoisse psychotique : à propos d'un cas magistral
Englebert, Jérôme ULg

Scientific conference (2016, March 26)

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See detailThymus and Type 1 diabetes: Where are we now?
Geenen, Vincent ULg

Scientific conference (2016, March 24)

Our studies have demonstrated that the thymus programs central self-tolerance to neuroendocrine functions through transcription of neuroendocrine-related genes in thymic epithelial cells (TECs). However ... [more ▼]

Our studies have demonstrated that the thymus programs central self-tolerance to neuroendocrine functions through transcription of neuroendocrine-related genes in thymic epithelial cells (TECs). However, thymic neuroendocrine precursors are not secreted but processed as the source of neuroendocrine self-antigens that are presented by thymic proteins of the major histocompatibility complex (MHC). This process, highly specific of the thymus, has allowed an integrated and harmonious coevolution of the neuroendocrine and immune systems when recombination-activating genes and the subsequent adaptive immune response have emerged in cartilaginous fishes some 450-500 millions years ago. All the members of the insulin gene family are expressed in murine TECs under the control of AutoImmune Regulator (AIRE) according a precise hierarchy: Igf2 >Igf1>Ins2>Ins1. Igf2 transcription is defective in TECs of autoimmune diabetes-prone BB rats, and tolerance to insulin is severely impaired in Igf2-/- mice as well as in Igf2-loxP/Foxn1-cre mice with Igf2 deletion targeted in TECs. In addition, the diabetogenic coxsackievirus B4 (CV-B4) is able to persistently infect human and murine TECs and to inhibit Igf2 transcription and IGF-2 synthesis in a murine medullary TEC line (coolaboration with D. Hober, Laboratory of Virology, CHRU and University of Lille 2, France). These studies show that: 1° IGF-2 is the dominant tolerogenic precursor of the family and mediates cross-tolerance to insulin; 2° a thymus dysfunction plays a crucial role in the development of the diabetogenic autoimmune response; and 3° a thymic infection by CV-B4 is implicated in type 1 diabetes (T1D) pathogenesis. Most probably due to its very low level of expression in the thymus, the protein insulin is highly immunogenic and is the primary autoantigen tackled in T1D. On the basis of the tolerogenic properties of IGF-2, we are currently working on the development of a negative/tolerogenic self-vaccine against T1D. [less ▲]

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See detailVoyage[s] through the thymus, the small central 'brain' of the adaptive immune system
Geenen, Vincent ULg

Scientific conference (2016, March 24)

Our studies have demonstrated that the thymus programs central self-tolerance to neuroendocrine functions through transcription of neuroendocrine-related genes in thymic epithelial cells (TECs). However ... [more ▼]

Our studies have demonstrated that the thymus programs central self-tolerance to neuroendocrine functions through transcription of neuroendocrine-related genes in thymic epithelial cells (TECs). However, thymic neuroendocrine precursors are not secreted but processed as the source of neuroendocrine self-antigens that are presented by thymic proteins of the major histocompatibility complex (MHC). This process, highly specific of the thymus, has allowed an integrated and harmonious coevolution of the neuroendocrine and immune systems when recombination-activating genes and the subsequent adaptive immune response have emerged in cartilaginous fishes some 450-500 millions years ago. All the members of the insulin gene family are expressed in murine TECs under the control of AutoImmune Regulator (AIRE) according a precise hierarchy: Igf2 >Igf1>Ins2>Ins1. Igf2 transcription is defective in TECs of autoimmune diabetes-prone BB rats, and tolerance to insulin is severely impaired in Igf2-/- mice as well as in Igf2-loxP/Foxn1-cre mice with Igf2 deletion targeted in TECs. In addition, the diabetogenic coxsackievirus B4 (CV-B4) is able to persistently infect human and murine TECs and to inhibit Igf2 transcription and IGF-2 synthesis in a murine medullary TEC line (coolaboration with D. Hober, Laboratory of Virology, CHRU and University of Lille 2, France). These studies show that: 1° IGF-2 is the dominant tolerogenic precursor of the family and mediates cross-tolerance to insulin; 2° a thymus dysfunction plays a crucial role in the development of the diabetogenic autoimmune response; and 3° a thymic infection by CV-B4 is implicated in type 1 diabetes (T1D) pathogenesis. Most probably due to its very low level of expression in the thymus, the protein insulin is highly immunogenic and is the primary autoantigen tackled in T1D. On the basis of the tolerogenic properties of IGF-2, we are currently working on the development of a negative/tolerogenic self-vaccine against T1D. [less ▲]

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See detailThe Islamic coinage of Barqa from the conquest up to the advent of the Fatimids
Bauden, Frédéric ULg

Conference (2016, March 19)

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See detailDepressive symptomatology and the influence of the behavioral avoidance and activation: A gender-specific investigation
Wagener, Aurélie ULg; Baeyens, Céline; Blairy, Sylvie ULg

in Journal of Affective Disorders (2016), 193

BACKGROUNG: Depression is a highly prevalent disorder which is usually considered as differentially experienced depending on gender. Behavioral theories of depression pinpoint the importance of the ... [more ▼]

BACKGROUNG: Depression is a highly prevalent disorder which is usually considered as differentially experienced depending on gender. Behavioral theories of depression pinpoint the importance of the behavioral avoidance in the maintenance of depression. However, little is known about the specific impact of the behavioral avoidance and activation on each depressive symptom as well as on gender differences on the behavioral features of depression. METHODS: This study’s aim was two-fold: (1) to assess the presence of gender differences on the BDI-II; (2) to investigate the respective predictive value of behavioral avoidance and of behavioral activation on each depressive symptom assessed by the BDI-II depending on gender. Community adults and adults attending mental healthcare composed the sample. RESULTS: Results showed differences in symptomatology profiles depending on gender (e.g. higher scores of sadness, self-criticalness in women, higher scores of past failure and loss of pleasure in men). Behavioral avoidance positively predicted almost all depressive symptoms in women and in men while behavioral activation negatively predicted almost all symptoms in both gender. Nevertheless, the strengths of these relationships were different for some symptoms (e.g. pessimism). LIMITATIONS: The use of self-report instruments; the lack of assessment of causal or precipitating factors of the depressive symptomatology; the higher number of women in the sample. CONCLUSIONS: Results are discussed with respect to previous findings and present clinical implications: (1) to underline the relevance of the combination of gender-specific assessment tools; (2) to highlight the need of tailored psychological intervention. [less ▲]

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See detailEvaluation des charges polluantes (domestiques et industrielles) arrivant au lac Kivu dans la ville de Bukavu, RD. Congo
Lina Aleke, Alex ULg

Doctoral thesis (2016)

Dans les pays en développement (PED) en général, et plus particulièrement en République Démocratique du Congo (RDC), le développement des villes et l'augmentation des populations urbaines se font avec une ... [more ▼]

Dans les pays en développement (PED) en général, et plus particulièrement en République Démocratique du Congo (RDC), le développement des villes et l'augmentation des populations urbaines se font avec une rapidité telle que l'accessibilité à l'eau potable et à l'assainissement de basepose un problème croissant de sante publique et de bien-être des populations. Le manque d'expertise et des moyens techniques et/ou financiers ne permet pas de mettre en place des programmes cohérents et adaptés aux réalités et défis que connaissent ces pays. C'est dans cette optique que la présente étude qui porte sur la caractérisation des eaux résiduaires domestiques et industrielles générées dans la ville de Bukavu, a été menée en vue d'évaluer les flux des pollutions arrivant dans le lac Kivu. Différents axes de recherche ont été ainsi exploités pour répondre a cet objectif. Ce sont :l'évaluation de l'assainissement non collectif (ANC),la caractérisation des flux polluants générés par les activités domestiques et industrielles, etl'analyse critique des atouts naturels (physiques, géologiques, hydrogéologiques, etc.) de la ville de Bukavu en vue de mettre sur pied des filières permettant un assainissement correctet la protection du lac Kivu. L'évaluation de l'assainissement a été basée sur une démarche sociologique faisant appel à des techniques d'enquêtes et d'observation deterrain. Une approche d’évaluation par un indicateur découlant de la combinaison des indicateurs mis en place au prorata des trois maillons composants une filière d’ANC (amont, intermédiaire et aval) a été utilisée. Les résultats obtenus montrent un faible niveau d'accès à l'eau potable et à l'assainissement de base qui serait lié à des facteurs historiques, physiques, politiques, et socio-économiques. De plus, un effort considérable reste à faire pour la gestion du maillon aval car la gestion des boues produites se fait pour le moment de manière non conforme. Par ailleurs, la densité de la population, en pleine croissance, nécessite une politique de construction de logements bien appropriée. Réalisée au niveau des émissaires domestiques (ITFM, Rukumbuka, PIR, Nyamugo et Bagira) et des rivières (Bwindi, Tshula, Wesha et Kahwa) qui traversent Bukavu, la caractérisation des flux de pollutions domestiques a été menéeau travers des méthodes physicochimiques et microbiologiques. Elle a permisd'apprécier l'importance des risques sanitaires qu'encourent les habitants de Bukavu dans leur quotidien, ainsi que l'ampleur des pressions que subit le lac qui en est le réceptacle. De la même manière, notre étude s'est intéressée aux flux produits des pollutions industrielles brassicoles et pharmaceutiques, suivant une approche physicochimique. Il ressort de ces analyses que les émissaires domestiques constituent le cadre de premier choix adopté par les habitants pour le rejet de leurs déchets. Ce faisant, les rivières de la ville font l'objet d'importantes pollutions engendrées par les activités domestiques, et constituent des égouts à ciel ouvert. Les flux évacués et arrivant quotidiennement dans le lac vont de 2165 kg (rivière Bwindi) à 5974 kg DBO5 (riviere Kahwa) en saison sèche, et de 5303 kg (rivière Bwindi) à 14270 kgDBO5 (rivière Kahwa) en saison de pluie, correspondant aux charges totales respectives de 7468 kg DBO5 et 20244 kg DBO5. Les flux des pollutions microbiologiques ont été évalués a 2,3.109 UFC/EH DBO5 pour la rivière Bwindi et 6.109 UFC/EH DBO5 pour la rivière Kahwa en ce qui concerne les coliformes fécaux, et 2800 œufs/EH DBO5 (rivière Bwindi) et 4185 œufs/EH DBO5 (rivièreKahwa) pour les parasites.En outre, 11 taxons de parasites ont été identifiés. Ce sont : Entamoeba coli, Giardia lamblia, Entamoeba histolytica, Ascaris sp. (taxon le plus distribué), Ankylostoma sp., Strongyloides sp., Trichuris trichiura, Hymenolepis nana, Hymenolepis diminuta, Taenia saginata et Schistosoma mansoni. Recevant les eaux de 4 de 5 émissaires domestiques étudiés, la rivière Kahwa s'est avérée comme la plus polluée des rivières de Bukavu. Concernant les pollutions industrielles, pour chaque litre de boisson (bières et boissons gazeuses confondues), la société brassicole Bralima utilise entre 4,7 et 5,7 l d'eau, avec une moyenne de 5,1 l.Les pollutions spécifiques s'établissent entre 1,2 et 1,6 kg DCO/hl, et 0,2 et 0,4 kg MES/hl de produits finis, avec unecharge globale évaluée 194,1 kgDCO par jour, avant traitement. L'abattement des pollutions dans la station d'épuration de cette société brassicole devrait être amélioré en vue de réduire ses pressions sur le lac et les risques sanitaires auxquels sont exposées les populations. Quant à la Pharmakina, la charge globale des pollutions, évaluée à 1229,2 kgDCO par jour, arrive dans le lac Kivu sans aucun traitement préalable, constituant ainsi de graves menaces environnementales et écologiques imputables à sa responsabilité. [less ▲]

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