La zone non saturée joue un rôle clé sur le transfert des pesticides et la qualité des eaux souterraines. Les connaissances sur les processus d’écoulement et de rétention dans les matériaux géologiques de la zone non saturée au-delà des sols sont toutefois parcellaires. Le transfert du glyphosate et du S-métolachlore (SMOC), et de leurs métabolites AMPA, ESA-métolachlore (MESA) et OXA-métolachlore (MOXA) est étudié en colonne pour deux matériaux fluvio-glaciaires issus d’un aquifère de l’Est lyonnais : un sable, S-x, et un mélange bimodal de graviers et de sables, Gcm,b. Pour des conditions de non-saturation en eau, l’écoulement dans les colonnes est fractionné en deux zones, eau mobile et eau immobile, d’importance variable suivant le solide. La sortie du SMOC est retardée par rapport au traceur de l’eau ; son bilan de masse déficitaire traduit une rétention de la molécule lors de son transfert. A l’inverse, le MESA et le MOXA se comportent comme le traceur de l’eau. Le glyphosate et l’AMPA sont très peu mobiles dans la colonne de Gcm,b (seul matériau étudié) avec des quantités éluées inférieures à 1% de la quantité appliquée. La modélisation montre que le transfert des molécules est affecté de manière variable suivant le matériau par la cinétique physique d’échange entre les zones d’eau mobile et immobile et par la cinétique chimique des molécules. Cette cinétique chimique est décrite par des expérimentations complémentaires de sorption en batch. La caractérisation des matériaux révèle la présence d’oxydes et de minéraux argileux qui pourrait expliquer leur forte réactivité, qui s’avère parfois supérieure à celle des sols de la zone d’étude. / Vadose zone play a key role in pesticides transfer and groundwater quality. Knowledge’s about leaching and retention processes in the vadose zone below the shallow soil zone are still poorly understood. Transfer of glyphosate, S-metolachlor (SMOC), and their metabolites AMPA, ESA-metolachlor (MESA) and OXA-metolachlor (MOXA) is studied in unsaturated columns filled with two glaciofluvial materials collected in the East of Lyon: a sand, S-x, and a bimodal gravel, Gcm,b. Experiments show water fractionation into mobile and immobile compartments with variable importance according to material column. SMOC outflow is delayed compared to the conservative tracer. SMOC mass balance is in deficit revealing retention in columns. At the opposite, complete mass elution associated with retardation factors close to unity shows that there is no adsorption of MESA and MOXA in either lithofacies. Glyphosate and AMPA mobility is very low in the one Gcm,b column studied with amounts in leachates inferior to 1% of applied. Modelling show pesticides and metabolites transfer is affected by both flow regionalisation and non-equilibrium sorption. Chemical kinetic of sorption mechanisms is studied with complementary batch experiments. The high glaciofluvial materials reactivity, in some cases upper than soil reactivity from the study site, could be attributed to oxides and clay minerals.

In this work, I aim to clarify the mechanism that allows steel to attain higher chloride threshold as it is cathodically polarized. Specifically, I seek to provide empirical information on whether an intrinsic (predominantly interfacial effects of polarization) or an extrinsic (predominantly concentration changes due to polarization) mechanism may be dominant in the beneficial effect of polarization. I carried out this experiment with 12 identical concrete specimens, each with a cast-in steel plate, constantly exposed them to high-chloride environment. The specimens were divided into 4 triplicates and polarized at 4 different level from OCP, -200, -300 to -400 mVSCE The specimens were closely monitored for signs of corrosion. When corrosion was detected in a specimen, it was demolished to gain access to steel-concrete interface. Measurements of pH using a novel procedure and chloride ion concentration were done on the interface using an adapted in-situ pH measurement and a Florida Department of Transportation procedure respectively. The pH and chloride ion concentrations obtained in this study favor to some extent a dominant intrinsic mechanism interpretation, while the evidence in support of a dominant extrinsic mechanism interpretation remains elusive.

Les principaux processus et facteurs qui influent sur le devenir du glyphosate dans les sols et le risque de contamination de la ressource en eau ont été étudiés. Son adsorption sur les sols est très rapide (Kf compris suivant le sol entre 16,6 à 34,5) et l’effet du pH sur ce processus a été confirmé : l’adsorption diminue quand le pH des sols augmente. Par contre, le glyphosate se désorbe difficilement et sa dégradation en conditions contrôlées ou naturelles est rapide, mais sa dynamique est très variable suivant l’activité biologique des sols. La dégradation conduit à la formation d’un métabolite, l’AMPA qui tend à s’accumuler dans le sol. L’expérimentation en colonnes de sol confirme la faible mobilité du glyphosate et de l’AMPA. Les résidus exportés par les percolats sur une période de 332 jours représentent moins de 0,28 % de la dose appliquée. Les propriétés hydrodynamique du sol et la pluviométrie rencontrée ont un effet important dans le lessivage des résidus. / The main processes and factors which influence glyphosate fate in soils and the risks of water resources contamination were studied. Its adsorption in the soils was very fast and intense (Kf between 16.6 to 34.5 depending on the soil) and the effect of pH on this process was confirmed: adsorption decreases when soil pH increased. In addition, glyphosate was slightly desorbed and its degradation in controlled or natural conditions was fast, but its kinetics was very variable according to the biological activity of the soils. Degradation led to the formation of the metabolite (AMPA), which tends to accumulate in the soil. The experimentation in columns of different soils confirmed the low mobility of the glyphosate and the AMPA. The residues exported by the leachates after more than 332 days represented less than 0.28% of the amount applied. The hydrodynamic properties of the soil and the pluviometry observed had a significant effect on the leaching of the residues.

No description available.

M.Tech. (Mechanical Engineering Technology) / Please refer to full text to view abstract

Lithium is one of the most strategically important minerals at the time of writing. The demand for lithium and lithium compounds to be used in lithium-ion batteries is increasing day by day. Zimbabwe possesses a considerable resource of lithium ore, estimated at 23 000 mt Li. Beneficiation of this lithium ore could indeed be a very promising business in the near future. This work focuses on processing of petalite concentrate from the Bikita deposit in Zimbabwe for production of Li2CO3, with subsequent preparation of LiF and LiCl. Analysis performed on the petalite showed that the average Li2O content is 4.10 %. The extraction method used involves roasting the pre-heated concentrate with concentrated H2SO4 followed by water leaching of the resulting Li2SO4, solution purification and precipitation of Li2CO3 with subsequent preparation of LiF and LiCl. Investigation of the roasting and leaching showed that the dissolution rates are significantly influenced by roasting temperature and stirring speed. 97.3 % optimum rate of extraction was attained at 320 rpm and roasting temperature of 300 C. Water-washed lithium carbonate with a purity of 99.21 %( metal basis) and an average particle size of 1.4 ìm was produced. Good quality LiF and LiCl can be produced with purity of 99.36 % and 99.02 % respectively. The pH, concentration and agitation have a great influence on the morphology of the precipitated LiF. Lower pH values and optimum concentration of the Li2CO3 solution results in smaller particle size. High recovery of 96.53 % LiF was realised. Anhydrous LiCl was found to absorb moisture when exposed to air at ambient temperature. The synthesised LiCl melts at 606.2 C with a corresponding enthalpy of fusion of 18.4 kJ mol-1, close to the values reported in the literature. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Chemical Engineering / unrestricted

>Magister Scientiae - MSc / Fly ash is the major waste material produced by power plants in the combustion of coal to generate electricity. The main constituents of fly ash are Si, Al, Fe and Ca with smaller amount of S, Mn, Na, K, and traces of many other elements such as Co, Cd, As, Se, Zn, Mo, Pb, B, Cu and Ni. Fly ash is usually disposed either by dry or wet disposal methods. These disposal methods have raised major environmental concerns due to the potential leaching of chemical species from the ash heap by ingress of rainfall and brine used to transport the fly ash to the dam. This study focuses on the changes in chemical composition, morphology and mineral phases due to weathering, of coal fly ash co-disposed with brine over 20 years at Sasol Secunda ash dump in Mpumalanga Province, South Africa. The design and operation of the Secunda ash dump presupposes that the ash dump may act as a sink for the salts which originated from chemicals used for normal operation in the plants. The majority of these salts come from the brines generated during desalination and raw water regeneration. The aim of this study is to ascertain if the ash dump could serve as a sustainable salt sink.Samples were drawn along the depth of two drilled cores (S1 and S3) from the weathered Secunda ash dump and analysed in conjunction with the fresh (unweathered) Secunda fly ash taken from the fly ash hoppers for comparative analysis. Scanning electron microscopy (SEM), X-ray diffractive (XRD) and X-ray fluorescence (XRF) spectrometry were employed to obtain a detailed morphological, mineralogical and bulk chemical composition of all the samples. Pore water analysis was used to determine the pH, EC and moisture content of fly ash samples. A five step sequential chemical extraction procedure was used to establish the geochemical association of particular elements with various mineral phases. The total acid digestion test was also used to determine the total elemental compositions of the Secunda fly ash samples. The SEM results showed that the fly ashes consist of irregular and numerous spherically shaped particles. Changes (encrustations, etchings and corrosion) in the morphologies of the weathered ash particles were also observed. The XRD results revealed quartz, mullite, lime and calcite as the major mineral phases. Other minerals identified in very minor quantities in the drilled Secunda ash core that were dried prior to analysis were halite, kaolinite, nitratine, bassanite, microline. and hydrophitte. These phases may have formed during sample handling. XRF investigation revealed that the major oxides present in the dumped ash samples were SiO₂, A₂2O₃, CaO, Fe₂O₃, MgO, Na₂O, TiO₂ and the minor elements present were K₂O, P₂O₅, SO₃ and MnO. The sum of the mean values of the % composition of SiO₂, Al₂O₃, and Fe₂O₃ was 70.19 %, and 72.94 % for the two drilled ash core samples (S1 and S3) respectively, and 78.67 % for the fresh ash which shows the significant alteration of the Si, Al and Fe content in the ash matrix over time. The fly ash is classified as Class F using the ASTM C 618 standards. The loss on ignition (LOI) which is an indication of unburned carbon or organic content was 4.78 %, 13.45 % and 8.32 % for the fresh ash, drilled ash cores S1 and S3 respectively. The high LOI values for the drilled ash cores could indicate high hydrocarbon content in the ash dump because of co-disposal practises where hydrocarbon waste are included in the brine stream for disposal on the ash. While the ash samples from the surface appeared dry, moisture content (MC) analysis showed that there is considerable water entrained in the fly ash dump. The fresh ash MC was 1.8 % while core S1 ranged from 41.4 – 73.2 %; core S3 ranged from 21.7 – 76.4 %. The variations in the MC values can be attributed to uneven flow paths due to inconsistent placement conditions or variations in ambient weather conditions during placement. The fresh fly ash (n=3) had a pH of 12.38±0.15, EC value of 4.98±0.03 mS/cm and TDS value of 2.68±0.03 g/L, the pH of the drilled ash core S1 (n=35) was 10.04 ±0.50, the EC value was 1.08±0.14 mS/cm and the TDS value was 0.64 ±0.08 g/L. Core S3 (n=66) had pH of 11.04±0.09; EC was 0.99 ±0.03 and TDS was 0.57 ± 0.01. The changes in pH values can be attributed to the dissolution and flushing out from the dump basic alkaline oxides like CaO and MgO These variations in pH values shows that the fly ash is acidifying over time and metal mobility can be expected under these conditions. The large decrease of EC in the drilled ash cores S1 and S3 compared to the fresh ash indicated a major loss of ionic species over time in the ash dump. The sequential extraction scheme revealed that the elements Al, Si, Ca, Mg, Ba, Sr, Fe, Mn, Na, K, As, Pb, Cr, Mo, Cu, Ni and Zn are present in Secunda fresh and weathered fly ash and are partitioned between the water soluble, exchangeable, carbonate, iron and manganese, and residual fractions of the coal fly ash. It also showed that the trace elements As, Pb, Cr, Mo, Cu, Ni and Zn do not show permanent association with particular mineral phases as a continuous partitioning between different mineral phases was observed in the weathered drilled core. Generally, all the elements had the highest concentration in the residual fraction. But it was evident that the labile phase (water soluble, exchangeable and carbonate fractions) had fairly high concentrations of Si (± 6.5 %), Al (± 6.5 %), Ca (±10 %), Mg (± 5.5 %), Ba (± 7.5 %),Sr (± 7.5 %), Na (± 12 %) and K (± 12 %) for the Secunda drilled ash core (S1 and S3) and fresh fly ash samples. This indicates that these species can leach easily upon water ingress and could pose a danger to the environment. Na and K had the highest concentrations leached out in the labile phase in all the ash samples. The amount of Na leached out of the drilled Secunda ash core in the labile phase was 13.21 % of 18584.26 mg/kg in the five geochemical phases of core S1; and 9.59 % of 11600.17 mg/kg in the five geochemical phases of core S3 while the fresh Secunda fly ash leached out 11.28 % of 16306.30 mg/kg of Na in the five geochemical phases. This study provided significant insight into the pore water chemistry, morphology, mineralogy and chemical composition and the elemental distribution pattern of the major and trace elements in the Secunda fly ash and weathered drilled Secunda ashm core S1 and S3. Though results from XRF analysis and the sequential extraction scheme shows that Na, K, S, Ca and Mg were slightly captured from the co-disposed brine by the Secunda fly ash, these species were however released in the labile phase. Hence there was no significant retention of these species in the ash dump. The amount of these species retained in the weathered ash were (0.26 % and 0.55 %) for Na, (0.02 % and 0.34 %) for K, (0.08 % and 0.06 %) for S, (0.94 % and 0.01 %) for Ca and (0.37 % and 0.96 %) for Mg in drilled ash cores S1 and S3 respectively. This poor retention of Na K, S, Ca and Mg which are major components of Sasol Secunda brine in the drilled ash cores S1 and S3 clearly shows the unsustainability of the Secunda fly ash dump as a salt sink.

Orientador: Bruno Coraucci Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-27T11:56:27Z (GMT). No. of bitstreams: 1 Marinho_LuccasEricksondeOliveira_D.pdf: 1543396 bytes, checksum: 1b79be871162aa959b39c2fd84188cc0 (MD5) Previous issue date: 2015 / Resumo: Apesar da baixa eficiência, em relação aos sistemas convencionais de tratamento de esgotos, aproximadamente 12 milhões de famílias utilizam tanque séptico, fazendo deste sistema o segundo método de tratamento de esgoto mais utilizado em nosso país. A destinação do lodo residual que é gerado nestas unidades de tratamento é um grande problema ambiental para as empresas de saneamento, públicas ou privadas. O gerenciamento destes resíduos interfere, direta e indiretamente, na vida de toda a sociedade, principalmente pela necessidade de se dar um destino mais nobre para este abundante resíduo. O presente estudo teve como premissa a geração de tecnologia de uso social de baixo custo, direcionado para ser utilizado em pequenas comunidades. Foi utilizado um lodo de tanque séptico, do tipo coletivo, que faz o tratamento de efluente de uma pequena comunidade no interior do estado de São Paulo. Para o desaguamento desse lodo foram utilizados contentores de geotêxtil de três aberturas aparentes diferentes, em que o processo de desaguamento ocorreu com três enchimentos desses contentores. A redução da massa de lodo foi avaliada em diferentes tempos e ao final de 60 dias não houve diferença estatística significativa quando comparado a eficiência na redução de massa. Essa redução foi de 62 a 64%. Após o deságue o lodo retido nos contentores foi homogeneizado e avaliado quanto ao seu potencial uso na agricultura. As análises laboratoriais demonstraram que o lodo poderia suprir toda a demanda de nitrogênio das roseiras, embora não fosse suficiente quanto ao fósforo e potássio. Foram utilizados cinco tratamentos distintos para a avaliação da aplicação do lodo séptico no solo em um período de 18 meses. Houve um aumento na produtividade de rosas em 31% nos canteiros em que o lodo séptico foi aplicado junto a uma adubação complementar contendo fósforo e potássio. O solo de cultivo avaliado não apresentou risco de acúmulo de metais potencialmente tóxicos e demais compostos que poderiam ser prejudiciais as culturas agrícolas. Os resultados demonstraram também que o manejo convencional da cultura de roseiras com o adubo mineral (NPK) apresenta maiores riscos de lixiviação de nitrato do que quando o lodo séptico é utilizado. As rosas colhidas que foram cultivadas com lodo e adubação complementar apresentaram ganhos na qualidade comercial e durabilidade do produto final o que representa um ganho econômico em escala real / Abstract: Despite the low efficiency compared to conventional wastewater treatment systems, approximately 12 million households use septic tank, making this system the second sewage treatment method most used in our country. The allocation of residual sludge that is generated in these treatment facilities is a major environmental problem for sanitation companies, both public or private. The management of these residues interferes, directly and indirectly, in the life of the whole society, especially for the need to give a nobler destiny for this abundant residue. This study was premised on the generation of social use of low-cost technology, targeted for use in small communities. For this study it was used a collective type septic tank, which provide the effluent treatment from a small community in the state of São Paulo. For sludge dewatering it were used geotextile containers with three apparent openings,. The reduction of sludge mass was evaluated at different times and at the end of 60 days there was no statistically significant difference when compared the efficiency of mass reduction. This reduction was 62-64%. After the outflow sludge retained in the container was homogenized and assessed for their potential use in agriculture. Laboratory tests showed that the sludge could supply all the nitrogen demand of roses, though not sufficient in phosphorus and potassium. Five different treatments were used for evaluating the implementation of septic sludge into the soil over a period of 18 months. There was an increase in productivity rose by 31% in the beds where the septic sludge was applied to a supplementary fertilizer containing phosphorus and potassium. The rated tillage showed no risk of potentially toxic metal accumulation and other compounds that could be harmful agricultural crops. The results also showed that the conventional management of the culture rose with mineral fertilizer (NPK) nitrate leaching presents greater risk than when the septic sludge is used. Roses were harvested and cultured with supplementary fertilization sludge showed gains in commercial quality and durability of the final product which is a full-scale economic gain / Doutorado / Saneamento e Ambiente / Doutor em Engenharia Civil

A podridão floral dos citros (PFC), causada por Colletotrichum acutatum, induz a abscisão de frutos jovens, podendo causar perdas de até 100%. A presença de inóculo viável na forma de conídios e/ou apressórios quiescentes na planta justifica a ocorrência generalizada da doença. Em períodos de chuva a PFC é agravada, possivelmente, em função de substâncias lavadas das diferentes partes da planta, as quais contêm metabólitos que estimulam o desenvolvimento do fungo. Diante do exposto, objetivou-se verificar o efeito das águas de lavagem brutas (ALBs) de flores, botões, folhas velhas (FV) e folhas novas (FN) e mistura destas sobre conídios, apressórios e hifas quiescentes de C. acutatum (isolados 61A e 142) in vitro e in vivo e sobre a severidade da PFC, bem como identificar substâncias presentes nas ALBs, exibindo a atividade biológica de interesse. Além disso, buscou-se verificar variações na composição das ALBs. O efeito de compostos voláteis brutos (CVBs) e os identificados a partir de laranjeira Valência (linalol, limoneno, mirceno, nonanal e a mistura destes) sobre o desenvolvimento do patógeno também foi avaliado. Todas as frações das ALBs estimularam a germinação dos conídios do fungo, sendo que a ALB de flores apresentou o maior estímulo para ambos os isolados. Para apressórios quiescentes (isolado 61A), o maior estímulo foi verificado nos tratamentos com ALBs de botões e da mistura e para conídios no tratamento mistura. Os maiores valores para comprimento do tubo germinativo foram observados nos tratamentos mistura, FN e botões. Para as estruturas quiescentes, o efeito das ALBs foi mais significativo para o isolado 142. Não foi observado efeito das ALBs sobre o micélio quiescente. Houve estímulo da germinação de conídios e ramificação de hifas in vivo, principalmente, em resposta ao tratamento com ALB de botões. A aplicação da ALB da mistura em flores resultou em maior severidade da PFC. Por sua vez, os CVBs apresentaram efeito inibitório. A exposição do isolado 61A aos voláteis (CVs) linalol, nonanal e mistura, resultou em germinação apenas na menor dose. O mirceno manteve a germinação semelhante a testemunha em todas as doses testadas, assim como limoneno nas doses de 0,005 a 0,25 µL mL-1. Todos os voláteis reduziram o comprimento do tubo germinativo. Para o isolado 142, houve redução em todas as variáveis para todas as doses dos CVs. Houve variações na composição das ALBs nas diferentes coletas, o que explica em parte a variação na capacidade de estímulo em alguns testes. Na ALB de flores, identificou-se a presença de cafeína, dos flavonóides glicosilados hesperidina e naringina, além de compostos glicosilados e peptídeos. Nas partes vegetais de laranjeira Valência foram identificados 54 CVs. As ALBs apresentam efeito estimulatório sobre conídios e apressórios quiescentes de C. acutatum in vitro e in vivo, bem como sobre a severidade da PFC. Os CVs linalol, limoneno, mirceno, nonanal e a mistura destes são, de forma geral, inibitórios ao desenvolvimento de C. acutatum. / The postbloom fruit drop of citrus (PFDC), caused by Colletotrichum acutatum, induces abscission of young fruits, and it may cause losses up to 100%. The presence of viable inoculum in the form of conidia and/or quiescent appressoria on the plant justifies the widespread occurrence of the disease. Under rain, the PFDC is increased, possibly due to substances washed from different parts of the plant, which contain metabolites that stimulate the development of the fungus. Therefore, we aimed to determine the effect of watery washing (WWs) of flowers, flower buds, old leaves (OL) and young leaves (YL) and the mixture of them on quiescent conidia and hyphae of C. acutatum (isolates 61A and 142) in vitro and in vivo and on the severity of the PFDC, and to identify substances in the WWs, exhibiting the biological activity of interest. In addition, variations in the composition of WWs were determinated. The effect of crude volatile compounds (CVCs) and those identified from Valencia sweet orange (linalool, limonene, myrcene, nonanal and the mixture of them) on the development of the pathogen was also evaluated. All fractions of WWs stimulated spore germination, and the flower WW exhibited the highest effect for both isolates. For quiescent appressoria (isolate 61A), the highest stimulus was observed in treatments with WWs from flower buds and the mixture and for quiescent conidia in the treatment mixture. The highest values for germ tube length were observed on the treatments mixture, YL and flower buds. For the quiescent structures, the effect of WWs was more significant for isolate 142. There was no effect of WWs on the quiescent mycelium. There was stimulation of conidia germination and hyphal branching in vivo in response mainly to treatment with WW from flower buds. The application of the mixture of WW in flowers resulted in higher severity of the PFDC. On the other hand, the CVCs showed inhibitory effect. Exposure of the isolate 61A to the volatiles (VCs) linalool, nonanal and the mixture of them, resulted in germination only at the lowest concentration. The germination on myrcene was similar to control at all doses tested as well as on limonene at doses from 0.005 to 0.25 mL mL-1. All volatiles reduced the length of the germ tube. In the case of isolate 142, a reduction in all variables for all concentration of VCs was observed. There were changes in the composition of WWs based upon times of harvesting, which partly explains the variations observed in the ability to stimulate the structures in some experiments. In flower WWs, we identified the presence of caffeine, the flavonol glycosides hesperidin and naringin, glycosylated compounds and peptides. In the plant parts of sweet orange \'Valencia\' were identified 54 VCs. The WWs have stimulatory effect on quiescent conidia and appressoria of C. acutatum in vitro and in vivo as well as in the severity of the PFDC. The VCs linalool, limonene, myrcene, nonanal and the mixture of them are, in general, inhibitory to the development of C. acutatum.

Les déchets nucléaires de haute activité, produits en France sous forme de colis de verre lors du traitement du combustible usé, sont destinés à être stockés en couche géologique profonde sur le long terme. L’arrivée de l’eau de l’environnement au contact du colis est prévue après quelques milliers d’années. De nombreuses études sur la durabilité d’un simulant non radioactif du verre industriel ont montré que le verre au contact de l’eau s’altère selon plusieurs régimes de vitesse, aboutissant à la formation d’une pellicule d’altération « passivante » et à l’instauration d’un régime de vitesse résiduelle sur le long terme. Cependant, la matrice vitreuse est soumise à la radioactivité des radioéléments qu’elle confine. Ce travail de thèse a pour objectif de se focaliser sur l’influence de l’irradiation sur la pellicule d’altération formée au cours de ce régime de vitesse résiduelle d’un point de vue structural et mécanistique. Dans ce but, la démarche choisie s’articule selon trois axes complémentaires. Des verres modèles simples non radioactifs ont été altérés et irradiés de façon externe afin d’observer les modifications engendrées par des effets électroniques (irradiations aux électrons et aux particules alpha).Le comportement à l’altération de ces mêmes types de verres, préalablement irradiés par des ions lourds, a été étudié de façon à appréhender l’impact de la dose balistique par le verre avant l’arrivée de l’eau. Enfin, l’altération d’un verre complexe dopé en émetteur alpha a été mise en œuvre afin de se rapprocher d’une situation plus réaliste. / High-level radioactive waste (HLW) remaining after spent nuclear fuel reprocessing is immobilized within a glass matrix, eventually destined for geological disposal. Water intrusion into the repository is expected after several thousand years. The alteration of a non-radioactive surrogate for nuclear glass has been extensively studied and it has been determined that successive leaching mechanisms lead to the formation of a “passivating” alteration layer and to the establishment of a residual rate regime in the long term. However, glass packages are submitted to the radioactivity of confined radioelements. This work focuses on the influence of irradiation on the alteration layer formed during the residual rate regime, in a structural and mechanistic point of view. Three focal areas have been selected. Non-radioactive simple glasses have been leached and externally irradiated in order to determine modifications induced by electronic effects (irradiations with electrons and alpha particles). The same type of glass samples have been previously irradiated with heavy ions and their leaching behavior have been studied in order to assess the impact of ballistic dose cumulated by the glass before water intrusion. Leaching behavior of a complex radioactive glass, doped with an alpha-emitter, has been studied to consider a more realistic situation.