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The Morrón de Mateo bentonite deposit (Cabo de Gata region, Spain) has been studied as a natural analogue of the thermal and geochemical effects on the clayey barrier in a deep geological repository of high level radioactive wastes. This deposit was intruded by a volcanic dome inducing an increase of temperature and supplying Fe–Mg-rich solutions, which were responsible for the alteration of the previously bentonitised pyroclastic materials (white tuff formation). The textural, mineralogical and crystallochemical features of the smectites located within the vicinity and away from the dome have been studied in order to elucidate the intrusion effects on these smectites. The results obtained show that distal smectites are Al-montmorillonites, similar to those from other bentonite deposits in the Cabo de Gata region; whereas proximal smectites are a mixture of Al-montmorillonites, Fe-rich montmorillonites and beidellites, and intermediate smectites between beidellite and Fe-rich-saponite. The textural relationships between these smectites indicate that smectites with intermediate composition come from the transformation of Al-montmorillonite, through gradual steps, consisting of increasingly Mg and Fe-rich smectites. This transformation process is confirmed when the structural formulae of proximal smectites are plotted on the MgVIvs (Al + Fe3 +)VI diagram. Thus, a gradual transition from dioctahedral smectites to smectites with an intermediate chemical composition is observed, which tend toward trioctahedral smectites. These observations suggest that the transformation of dioctahedral smectites into an intermediate term between di- and trioctahedral Fe-rich smectites could be originated under natural conditions. This transformation can be considered as an analogue process to that expected in the bentonite barrier from a deep geological repository of radioactive wastes whether the two following conditions would occur: i) an increase of temperature due to the radioactive, ENRESA/CIEMAT, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, FALSE, pub

The determination of surface soil properties is an important application of remotely sensed hyperspectral imagery. Moreover, different soil properties can be associated with erosion processes, with significant implications for land management and agricultural uses. This study integrates hyperspectral data supported by morphological and physico-chemical ground data to identify and map soil properties that can be used to assess soil erosion and accumulation. These properties characterize different soil horizons that emerge at the surface as a consequence of the intensity of the erosion processes, or the result of accumulation conditions. This study includes: 1) field and laboratory characterization of the main soil types in the study area; 2) identification and definition of indicators of soil erosion and accumulation stages (SEAS); 3) compilation of the site-specific MEDiterranean Soil Erosion Stages (MEDSES) spectral library of soil surface characteristics using field spectroscopy; 4) using hyperspectral airborne data to determine a set of endmembers for different SEAS and introducing these into the support vector machine (SVM) classifier to obtain their spatial distribution; and 5) evaluation of the accuracy of the classification applying a field validation protocol. The study region is located within an agricultural region in Central Spain, representative of Mediterranean agricultural uses dominated by a gently sloping relief, and characterized by soils with contrasting horizons. Results show that the proposed method is successful in mapping different SEAS that indicate preservation, partial loss, or complete loss of fertile soils, as well as down-slope accumulation of different soil materials.

The Morrón de Mateo bentonite deposit (Cabo de Gata region, Spain) has been studied as a natural analogue of the thermal and geochemical effects on the clayey barrier in a deep geological repository of high level radioactive wastes. This deposit was intruded by a volcanic dome inducing an increase of temperature and supplying Fe–Mg-rich solutions, which were responsible for the alteration of the previously bentonitised pyroclastic materials (white tuff formation). The textural, mineralogical and crystallochemical features of the smectites located within the vicinity and away from the dome have been studied in order to elucidate the intrusion effects on these smectites. The results obtained show that distal smectites are Al-montmorillonites, similar to those from other bentonite deposits in the Cabo de Gata region; whereas proximal smectites are a mixture of Al-montmorillonites, Fe-rich montmorillonites and beidellites, and intermediate smectites between beidellite and Fe-rich-saponite. The textural relationships between these smectites indicate that smectites with intermediate composition come from the transformation of Al-montmorillonite, through gradual steps, consisting of increasingly Mg and Fe-rich smectites. This transformation process is confirmed when the structural formulae of proximal smectites are plotted on the MgVIvs (Al + Fe3 +)VI diagram. Thus, a gradual transition from dioctahedral smectites to smectites with an intermediate chemical composition is observed, which tend toward trioctahedral smectites. These observations suggest that the transformation of dioctahedral smectites into an intermediate term between di- and trioctahedral Fe-rich smectites could be originated under natural conditions. This transformation can be considered as an analogue process to that expected in the bentonite barrier from a deep geological repository of radioactive wastes whether the two following conditions would occur: i) an increase of temperature due to the radioactive

Quantitative phase analysis (QPA) of clayey materials using X-Ray diffraction data has always been a challenge. While quantitative methods based on Rietveld analysis offer excellent results for non-clay minerals, they become problematic when high crystallochemical and order degree variations are present in the phases, as is the case of most clay minerals. In the summer of 2014, the Spanish Clay Society (Sociedad Española de Arcillas, SEA) proposed a collective QPA experiment to its members. The aim was to compare the results obtained in different clay laboratories studying the same samples by X-Ray diffraction. This comparative study is a starting point for a long-term work focused on the development of an optimized QPA guide for clay minerals adapted to modern equipment and software. The results presented in this talk are those from the 2014 preliminary study in which the 22 participant laboratories analyzed three samples following their own laboratory routines. The only condition was not to use other complementary techniques for the quantification (e.g. IR spectroscopy, thermal or chemical analysis). The samples were mixtures of nearly pure quartz, feldspar, calcite, alunite, and different clays. Clay minerals included two different smectites (with low and high crystallinity), sepiolite, kaolinite and palygorskite. The set of procedures, technical characteristics of the equipment, and software used in each laboratory was very different and, as a consequence, comparison of the results is not straightforward. The results were classified into "Reflecting Powers Method" (RPM) and “Relative Intensity Ratio (RIR) – Rietveld methods” groups. As it is well known RPM is based on the peaks areas while RIR is based on the peak intensities. As expected, a high dispersion of the results was found both globally and per group. At first glance, RPM returned, on average, better approximations to the true composition of the samples. Interestingly that trend was clearer in samples w

© 2015 Elsevier B.V. Hypoderma larvae are tissue invading parasites which spend several months migrating within the host tissues before completing their development in the sub-dermal tissues of the back. Subcutaneous stages of the parasite produce an inflammatory reaction in the skin called >warbles>, as well as holes through which larvae breathe. In order to elucidate the microscopical structure of the warbles, three hides from warbled cows were collected in a slaughterhouse in Lugo (NW, Spain) between March and May 2012. A total of 60 skin samples, including warbles at different phases of development, were chosen for histopathological and immunohistochemical examination. Microscopic lesions were classified into three groups, according to the predominance and distribution of different cell populations. In warbles containing living or recently dead larvae with apparently well preserved cuticle (type 1), plasma cells were observed in high number. However, macrophages and lymphocytes were the predominant cells in granulomas (type 2) formed in relation to remnants of the dead parasite, containing or not remains of the altered cuticle. Scars (type 3) were characterized by granulation tissue. Immunohistochemistry showed that B lymphocytes and IgG+ cells were predominant in the lesions, as long as the cuticle of the larvae is intact. On the other side, CD3+ lymphocytes increased once cuticle is destroyed and a granuloma is formed. Macrophages, revealed by CD68+, MAC387+ and lysozyme immunolabelling, were detected in all types of lesions, but they were more abundant in type 2 and scarce in scars. These cells appeared isolated around the intact larvae or forming aggregates around its remains in the granuloma. Moreover, a strong immunolabelling against MAC387 antibody was registered in the squamous epithelium covering the breathing pore. This finding may be associated with the expression of calprotectin, a molecule involved on the healing process of the skin after larvae out

We have identified a clonal complex of Mycobacterium bovis isolated at high frequency from cattle in Uganda, Burundi, Tanzania, and Ethiopia. We have named this related group of M. bovis strains the African 2 (Af2) clonal complex of M. bovis. Af2 strains are defined by a specific chromosomal deletion (RDAf2) and can be identified by the absence of spacers 3 to 7 in their spoligotype patterns. Deletion analysis of M. bovis isolates from Algeria, Mali, Chad, Nigeria, Cameroon, South Africa, and Mozambique did not identify any strains of the Af2 clonal complex, suggesting that this clonal complex of M. bovis is localized in East Africa. The specific spoligotype pattern of the Af2 clonal complex was rarely identified among isolates from outside Africa, and the few isolates that were found and tested were intact at the RDAf2 locus. We conclude that the Af2 clonal complex is localized to cattle in East Africa. We found that strains of the Af2 clonal complex of M. bovis have, in general, four or more copies of the insertion sequence IS6110, in contrast to the majority of M. bovis strains isolated from cattle, which are thought to carry only one or a few copies., Centro de Vigilancia Sanitaria Veterinaria (VISAVET), TRUE, pub

[EN] The paper summarises the studies that have been performed in Spain as regards the selection and characterisation of clays suitable for sealing and backfilling of radioactive waste repositories. This research began in the 80’s under the auspices of ENRESA, the Spanish agency for nuclear waste management, and started by a survey of apt clay deposits and suppliers. The characterisation of the clays and the criteria followed for their further selection were those already accepted by the international community: mineralogical purity, retention properties, plasticity, low permeability, high swelling pressure and thermal conductivity. These initial studies resulted in the selection of deposits from the Cabo de Gata region (Almería) and the Tertiary Basin of Madrid (Toledo), whose detailed characterisation was carried out by several laboratories. The Cortijo de Archidona deposit (Almería) was finally selected and the bentonite taken there has been the object of various research projects that have ended in this bentonite being one of the best characterised from the mineralogical, thermal, hydraulic, mechanical, geochemical and alterability points of view. Besides, and more recently, the behaviour of the bentonite under the conditions of a repository has been studied at laboratory and natural scale, and the long-term evolution of the barrier is being analysed by natural analogues studies in the Cabo de Gata area.S, [ES] El artículo resume los estudios que se han llevado a cabo en España para la selección y caracterización de arcillas aptas como material de sellado y relleno en almacenamientos de residuos radiactivos. La investigación comenzó en los años 80 bajo el patrocinio de ENRESA, la agencia española para la gestión de residuos nucleares, con la búsqueda de yacimientos de arcilla apropiados. El tipo de caracterización realizado y los criterios seguidos para la selección estaban ya aceptados por la comunidad internacional: pureza mineralógica, propiedades de retención, plasticidad, baja permeabilidad, elevada presión de hinchamiento y conductividad térmica. Estos estudios iniciales dieron lugar a la selección de yacimientos de la región de Cabo de Gata (Almería) y de la Cuenca Terciaria de Madrid (Toledo), cuya caracterización detallada fue realizada por varios laboratorios. Finalmente se seleccionó el yacimiento de Cortijo de Archidona (Almería), y la bentonita procedente de él ha sido objeto de varios proyectos de investigación que han hecho que esta bentonita sea una de las más intensamente caracterizadas en sus aspectos mineralógico, térmico, hidráulico, mecánico, geoquímico y de alterabilidad. Además, posteriormente se ha estudiado el comportamiento de esta bentonita en condiciones similares a las de un almacenamiento a escala de laboratorio y natural, y la posible evolución a largo plazo de la barrera se ha analizado mediante estudios de análogos naturales en la región de Cabo de Gata.

Development of Neostrongylus linearis larvae was studied in the snail intermediate hosts Oestophora (Oestophora) barbula, Oestophorella buvinieri, Cepaea nemoralis and Helix (Cryptomphalus) aspersa. The molluscs of each species, all adults, were divided into groups of 40 for infection purposes. The infection doses for the first two snail species were 90 and 50 first stage larvae (L1) of N. linearis, respectively. For C. nemoralis two batches were tested: one with 200 L1 kept at 19 degrees C and the other with 250 L1 at a temperature of 21 degrees C. The same was done with Helix (C.) aspersa with 200 L1 at a temperature of 21 degrees C, on the one hand and 300 L1 at 24 degrees C on the other. One or two molluscs of each species were killed in series from the 6th day post-infection (p.i.) until the 44th. Percentage values for total larvae (1, 2 and 3) and L3 were higher with the lower dose for C. nemoralis, whilst the same was true with the higher dose in Helix (C.) aspersa. In both cases, the higher temperature appeared to contribute to cycle acceleration. Using one way analysis of variance, statistically significant differences were detected between the species of molluscs tested concerning percentages of L1 which penetrated, total larvae and L3. According to our results, the decreasing order of susceptibility of these species of molluscs as experimental intermediate hosts of N. linearis is: O. buvinieri, Oestophora (O.) barbula, C. nemoralis and Helix (C.) aspersa. It is the first time that Oestophora (O.) barbula and Oestophorella buvinieri have been named as experimental intermediate hosts of N. linearis.

El propósito de este estudio fue establecer el modelo epidemiologico de las bronconeumonias verminosas ovinas en la montaña de León. Con este fin, se han realizado investigaciones parasitológicas en los hospedadores definitivos (ovinos) e intermediarios (moluscos) durante 2 años.

Se estudió mensualmente, desde Marzo 1986 a Febrero 1987, la eliminación de larvas I (L-I) de Protostrongylidae y Dictyocaulidae en ovinos explotados en régimen de pastoreo extensivo, procedentes de 4 localidades de la cuenca del Porma...

Se ha estudiado la idoneidad de Oestophora (Oestophora) barbula (R0SSMSSLER, 1838), Oestophorella buvinieri (MICHAUD, 1841), Cepaea nemoralis (LINNAEUS, 1758) y Helix (Cryptompha lus) aspersa MULLER, 1774, como moluscos hospedadores intermediarios (H.I.) experimentales de Neostrongylus linearis (MAROTEL, 1913) GEBAUER, 1932, — parásito broncopulmonar de pequeños rumiantes. Los moluscos de cada especie (adultos) se agruparon, para su infestación por el método KASSAI, en lotes de 40 ejemplares.

The purpose of this study was to stablish the epidemiological pattern of ovine verminous bronchopneumonia in the mountain region of León. So, parasitological research on definitive (ovine) arid intermediate (mollusc) hosts bave been carried out for two years. Nevertheless, only the data referring to monthly larvae 1 elimination by the sheep in the first year of sampling are summarized in this paper...

[EN] This is the first study on the experimental susceptibility of the following species of molluscs: Cernuella (X.) cespitum arigonis, Helicella (H.) itala, Helicella ordunensis, Cochlicella barbara, Cepaea nemoralis and Helix (C.) aspersa, as intermediare hosts for the combination of both C. ocreatus and M. capillaris, pulmonary parasites in ruminants. Furthermore, the larval development of C. ocreatus and N. linearis, the two taken together, has been followed in Cernuella (X.) cespitum arigonis, H. ordunensis and C. nemoralis. Approximately 40 specimens of each of the above-mentioned species of molluscs were infected with the parasites listed. Bearing in mind the results obtained, we believe that while Cernuella (X.) cespitum arigonis, H. ordunensis, C. nemoralis, C. barbara and Helicella (H.) itala are suitable intermediate hosts for the larval combination of C. ocreatus and M. capillaris, the same cannot be said of Helix (C.) aspersa. Likewise, the first 3 species of molluscs quoted are ideal for the joint larval development of C. ocreatus and N. linearis. It seems that double infections favour larval development., [GER] Dies ist die erste Studie zur experimentellen Empfänglichkeit folgender Schneckenarten als Zwischenwirte für die Kombination von C. ocreatus/M. capillaris (Lungenparasiten von Wiederkäuem): Cernuella (X.) cespitum arigonis, Helicella (H.) itala, H. ordunensis, Cochlicella barbara, Cepaea nemoralis und Helix (C.) aspersa. Weiter wurde die kombinierte Larvalentwicklung von C. ocreatus und N. linearis in Cernuella (X.) cespitum arigonis, H. ordunensis und C. nemoralis verfolgt. Etwa 40 Exemplare jeder der genannten Schneckenarten wurde mit den erwähnten Parasitenkombinationen infiziert. Auf Grund der Ergebnisse nehmen wir an, daß Cernuella (X.) cespitum arigonis, H. ordunensis, C. nemoralis, C. barbara und Helicella (H.) itala empfängliche Zwischenwirte für die larvale Kombination von C. ocreatus und M. capillaris sind, während dies für Helix (C.) aspersa nicht zutrifft. Die ersten 3 genannten Schneckenarten sind dabei ideal für die kombinierte Larvalentwicklung von C. ocreatus und N. linearis. Es scheint, daß Doppelinfektionen die Larvalentwicklung begünstigen.

En 186 ejemplares de Cernuella (C.) virgata de 12 localidades, la parasitación por metacercarias de Brachylaemidae fué de 403% en invierno y 16’8% en otoño. Metacercarias por caracol: 1—32 (media 6’1). El 2’2% de los moluscos de primavera contenian esporocistos de Dicrocoelidae. En 116 ejemplares de Cernuella (Microxeromagna) vestita de 5 localidades, recolectados en primavera y otoño, se encontró parasitado por metacercarias de Brachylaemidae, 12’4 y 5’3% respect. Metacercarias por caracol: 1—14 (media 52). Esporocistos de Dicrocoelidae en el 2’1% en primavera y 15’ 8% en otoño. En 1282 ejemplares de Cernuella (Xeromagna) cespitum arigonis de 88 lugares, los parasitados por metacercanias de Brachylaemidae fueron 23’8% en otoño, 18’7% en invierno, 12’5% en verano y 3’5% en primavera. Metacercarias por caracol: 1—138 (media 9’55). Los parasitados por esporocistos de Dicrocoelidae fueron 12’1% en invierno, 5’4 en primavera, 1’0 en otoño y 1´1 en verano. Los esporocistos de 0’2% en otoño eran Brachylaemidae. En 373 caracoles de Helicella leiolema de 61 localidades, había metacercarias de Brachylaemidae en 18’5% en verano, 10’8% en invierno, 2’2% en primavera y 2’1% en otoño. Metacercarias por caracol:1—17 (media 4’27). Parasitados por esporocistos de Dicrocoelidae: 7’4% en verano, 4’2% en invierno y 1’1% en primavera.

En 186 ejemplares de Cernuella (C.) virgata de 12 localidades, la parasitación por metacercarias de Brachylaemidae fué de 403% en invierno y 16’8% en otoño. Metacercarias por caracol: 1—32 (media 6’1). El 2’2% de los moluscos de primavera contenian esporocistos de Dicrocoelidae. En 116 ejemplares de Cernuella (Microxeromagna) vestita de 5 localidades, recolectados en primavera y otoño, se encontró parasitado por metacercarias de Brachylaemidae, 12’4 y 5’3% respect. Metacercarias por caracol: 1—14 (media 52). Esporocistos de Dicrocoelidae en el 2’1% en primavera y 15’ 8% en otoño. En 1282 ejemplares de Cernuella (Xeromagna) cespitum arigonis de 88 lugares, los parasitados por metacercanias de Brachylaemidae fueron 23’8% en otoño, 18’7% en invierno, 12’5% en verano y 3’5% en primavera. Metacercarias por caracol: 1—138 (media 9’55). Los parasitados por esporocistos de Dicrocoelidae fueron 12’1% en invierno, 5’4 en primavera, 1’0 en otoño y 1´1 en verano. Los esporocistos de 0’2% en otoño eran Brachylaemidae. En 373 caracoles de Helicella leiolema de 61 localidades, había metacercarias de Brachylaemidae en 18’5% en verano, 10’8% en invierno, 2’2% en primavera y 2’1% en otoño. Metacercarias por caracol:1—17 (media 4’27). Parasitados por esporocistos de Dicrocoelidae: 7’4% en verano, 4’2% en invierno y 1’1% en primavera.

En este trabajo se ha seguido experimentalmente el desarrollo larvario de Neostrongylus linearis, Muellerius capillaris y Cystocaulus ocreatus (en infestaciones puras o pluriespecíficas), en diversas especies de Helicidae de la provincia de León, mantenidas en el laboratorio o en condiciones controladas de campo. En el primer caso se estudió la receptividad a dichos parásitos, en infestación monoespecífica y en sus posibles combinaciones multiespecíficas, de 3240 moluscos (agrupados en lotes de 40) pertenecientes a 23, 13 y 8 especies de Helicidae, respectivamente. Al mismo tiempo se llevó a cabo un estudio similar, pero en condiciones controladas de campo, con 2400 ejemplares de Cernuella (Xeromagna) cespitum arigonis agrupados en lotes de 100. En todas las infestaciones se determinó el porcentaje de penetración de las Larvas I (L-I) en cada molusco y, posteriormente, para seguir el desarrollo larvario, se sacrificaron seriadamente los caracoles de cada lote, desde el día 6º hasta el 40º- 50º día post-infección (p.i.). Se anotó siempre el número de larvas (I + II + III) y de L-III hallado en cada molusco. Teniendo en cuenta estos números, y basándonos en las larvas que habían penetrado, se calcularon los correspondientes porcentajes de evolución y de L-III. También se anotaron los días de observación de los distintos estadios larvarios. En las infestaciones monoespecíficas realizadas con N. linearis o M. capillaris, en las que se infestaron y mantuvieron dos lotes, en cada caso, de la misma especie de caracol a distinta temperatura, se comprobó, mediante “Ji cuadrado”, la influencia de la temperatura respecto a la penetración y posterior evolución larvaria de N. linearis, pero no de M. capillaris. De igual modo, al tener en cuenta la edad de los moluscos, se obtuvieron diferencias estadísticamente significativas para las dos variables en N. linearis y sólo para la penetración en M. capillaris. Tanto en las infestaciones monoespecíficas como en las pluriespecíficas, En general, se observaron diferencias estadísticamente significativas (“Ji“ cuadrado) en la evolución de los tres parásitos, cuando se compararon las infestaciones pluriespecíficas con las monoespecíficas. No se apreciaron marcadas diferencias en los días de observación de las L-II, pero sí de las L-III entre las especies de parásitos utilizadas en las infestaciones puras y triples. Si tenemos en cuenta los criterios de receptividad establecidos por nosotros (número total de larvas y de L-III/molusco, porcentajes de penetración y L-II, así como los días de observación de los distintos estadios larvarios), en general, las especies de caracoles, más adecuadas como hospedadoras intermediarias para los tres parásitos y sus posibles combinaciones fueron: Cernuella (Xeromagna) cespitum arigonis, Cochicella barbara, Monacha (Asfordia.) granulata y Cernuella (Cernuella) virgata. Tanto en las infestaciones puras como en las pluriespecíficas de los caracoles mantenidos en el laboratorio, el mayor desarrollo larvario correspondió a M. capillaris, seguido de N. linearis y de C. ocreatus. También en los moluscos mantenidos en condiciones controladas de campo, se desarrolló mejor el primer parásito que el segundo, lo que podría explicar el mayor porcentaje de infestación por M. capillaris en los ovinos de nuestra provincia. En el trabajo realizado en la finca experimental, se observó una mayor mortalidad en los lotes de C. (X.) cespitum arigonis, infestados monoespecificamente con M. capillaris o N. linearis, que en los testigos. Al mismo tiempo se apreció que el desarrollo larvario fue más lento en los meses más fríos (aunque nunca se detuvo por completo) que en los más cálidos, hecho más acentuado en N. linearis. Al tener en cuenta los valores alcanzados en el desarrollo de ambos Protostrongylidae, los máximos fueron similares, mientras que los mínimos de N. linearis fueron siempre inferiores a los de M. capillaris. Tanto el porcentaje como el número de L-III de M. capillaris y

El papel de los moluscos como hospedadores intermediarios (H. I.) en el ciclo biológico de los Protostrongyliae fue denunciado por primera vez por HOBMAIER & HOBMAIER (1929, 1930) (cit. por CHITWOOD & CHITWOOD, 1937) para Muellerius capillaris (MUELLER, 1889) CAMERON, 1927....

La importancia del ganado ovino en España y la frecuencia de las parasitosis que requieren un molusco terrestre como Intermediario...

4,625 snails (11 spp. of Helicidae) were studied — for natural infection by Protostrongylinae. 7 Cernuella & Helicella spp. were found infected by C.o., M.c., N.l. & Protostrongylus spp. Experimentally the most convenient hosts were: Cernuella (C.) virgata for C.o.; Monacha (A.) granulata for M.c.; Cochlicella barbara for N.l...

This is a summary of the experimental infection and the subsequent development of two species of ovine Protostrongylinae (Muellerius capillaris (MÜLLER, 1889) and Neostrongylus linearis (MAROTEL, 1913) in the species Candidula intersecta (POIRET, 1801), Cernuella (Microxeromagna) vestita (RAMBUR, 1868), Cochlicella barbara(L., 1958), Helicella jamuzensis GITTENBERGER & MANGA, 1977, and Monacha (Ashfordia) granulata (ALDER, 1830) (Mollusca, Hei— cidae), intermediate host of these parasites...

Se han infestado 560 caracoles, en lotes de ca.40 ejemplares, mantenidos a temperaturas de l7—25º C y sacrificados seriadamente a partir del 6º día p.i. Muellerius capillaris se ha desarrollado óptimamente en Cernuella (C.) virgata seguida de Cepaea nemoralis y, con pocas diferencias, en Helicella 1eiolema y Cernuella (X.) cespitum arigonis...

Se estudia la receptividad a la infestación con C. ocreatus/N. linearis de 4 especies de Helicidae (Mollusca: Stylommatophora), para lo cual se utilizaron lotes de 40 a 50 moluscos de cada especie, que se sacrificaron seriadamente desde el día 6º al 43º p.i....

N.l. vive varios años en el pulmón ovino desde donde elimina L1 de forma irregular, con frecuentes períodos “mudos”. En ausencia de fenómenos inmunitarios protectores, los ovinos de más edad son quienes eliminan mayor n°. de larvas (0—123 l/g), con ritmo estacional bicuspidal, siendo los máximos en marzo y agosto...

The susceptibility to Cystocaulus ocreatus of 358 mollusos belonging to 8 species of the Helicidae family was studied under experimental conditions. The molluscs, divided into batches of approximately 40 specimens, were killed in series between the 6th and 49th day p.i...

This work summarizes facts about natural infection by Protostrongylinae of the 8 Heicella spp. which, according to studies by GITTENBERGER & MANGA (1977) and MANGA (1977) are to be found in the province of León. These species belong to the Helicellinae Subfamily...

El trabajo se realizó entre Diciembre de 1979 y Enero de 1981. Los caracoles utilizados en el experimento (2.400) se recolectaron en el mismo lugar, después de comprobar la ausencia de infestación natural por Protostrongylidae. En la 1ª quincena de cada mes, se trasladaron a la finca experimental 100 moluscos, inmediatamente después de infestados con 200 larvas cada uno, y otros 100 como testigos...

The experimental larval development of Neostrongylus linearis (Marotel, 1913) has been studied in the following molluscs, collected in the province of León, Spain: 48 Portugala inchoata (Morelet, 1845), 40 Hygromia (Pyrenaearia) cantabrica cantabrica (Hidalgo, 1873), 40 Hygromia (P.) cantabrica covadongae (Ortiz de Zarate, 1956), 39 Ponentina ponentina (Morelet, 1845) and 40 Euomphalia (Mengoana) brigantina (Da Silva Mengo, 1867). The absence of the natural infection, by the Protostrongylidae larvae, was proved by examining 10% of the snails of each sample...

In this work (between December 1979 and January 1981), the larval development of M. capillaris (Müller, 1889) was studied in Cernuella (X.) cespitum arigonis (Schmidt, 1853) experimentally infected and kept outdoors under controlled conditions...

Una vez realizadas infestaciones puras con Muellerius capillaris (MUELLER, 1889) CAMERON, 1927 (1,2) y con Cystocaulus ocreatus (RAILLET & HENRY, 1907) MIKACIC, 1939 (3) en diversas especies de moluscos, creimos conveniente infestar estos caracoles con una mezcla de ambos parásitos, para establecer las posibles influencias mutuas de estos nematodos a nivel de los moluscos hospedadores intermediarios...

Es la primera vez que se estudia el desarrollo larvario conjunto de Muellerius capillaris y Neostrongylus linearis (nematodos broncopulmonares de pequeños rumiantes) en Cernuella (Xeromagna) cespitum arigonis, Helicella ordunensisy Helix (Cryptomphalus) aspersa (moluscos hospedadores intermediarios). También se ha seguido dicho desarrollo en Helicella (Helicella) itala, Cochlicella barbara y Cepaea nemoralis...

A total of 264 molluscs were infected (KASSAI method) with M. capillaris larvae (L)...

El estudio se ha llevado a cabo sobre 2613 ejemplares de moluscos recogidos, en su mayoría, entre 1979 y 1984, pertenecientes a diversas especies de los géneros Candidula (108), Cernuella (642), Helicella (178), Cochlicella (218), Monacha (203), Portugala (lo), Hygomia (69), Ponentina (54), Euomphalia (28), Oestophora (86), Cepaea (118) y Helix (236) (Helicidae), y los géneros Arion (77), Deroceras (568), Lehmannia (8) y Milax (16) (Pulmonados desnudos). Los muestreos se realizaron al azar y en su mayor parte en la provincia de León...

Se han infestado experimentalmente con una mezcla de larvas de dichos nematodos, las siguientes especies de Helicidae: Cernuella (Xeromagna) cespitum arigonis, Helicella (Helicella) itala, Helicella ordunensis, Cochli— cella barbara, Cepaea nemoralis y Helix (Cryptomphalus) aspersa...

En 149 ejemplares de Cernuella (C.) virgata de 9 localidades, sin datos de verano, se encontró un 1’7% de parasitados, solo en el invierno, siendo doble la parasitación por Müellerius capillaris que por Cystocaulus ocreatus. Nº de larvas por caracol: 3. En 137 ejemplares de Cernuella (Microxeromagna) vestita de 3 localidades, recolectados en primavera y otoño, se halló, en la 1ª un 0’8% de Neostrongylus linearis. Nº de larvas por caracol: 1. En 880 moluscos de Cernuella (Xeromagna) cespitum arigonis de 66 localidades, se encontró en la primavera un 0’8% parasitados, pero solo se identificó un 20% de las larvas, que fueron de N. linearis. El % de moluscos parasitado, en el verano, fue 1’8 y el de larvas identificadas de 50, siendo 57’1% M. capillaris, 28´6% de N. linearis y 14’3% C. ocreatus. En el otoño, el % de moluscos parasitados fue 4’9 y el de larvas identificadas de 40, 43’2% de M. capillaris, 40’5% de N. linearis, 10’8% de C. ocreatus y 5’4% de Protostrongylus spp. En el invierno el % de infestados fue 0’6 de Protostrongylus spp. Nº de larvas por caracol: 1—38 (media 9’8). En 357 ejemplares de Helicella leiolema de 37 localidades, se halló 3’3% moluscos infestados, en el otoño, habiendose identificado el 80% de las larvas, siendo mitad de C. ocreatus y mitad de M. capillaris. Nº larvas por caracol: 14 (media 2’5).

[ES] La infestación experimental de 419 ejemplares de 2 Candidula spp. y 7 Helicella spp. (Mollusca) con L-I de Neostrongylus linearis (Nematoda), obtenidas de heces ovinas, ha demostrado que hay diferencias altamente significativas entre las nueve especies de caracoles, en lo que respecta a los porcentajes de larvas que invaden el pie, evolucionan y alcanzan el estadio de L-III, así como el número de días requeridos para ello. Los métodos estadísticos utilizados fueron el análisis de la varianza (una vía), la «t de Student», el coeficiente de correlación y la Ji-cuadrado. Las especies más receptivas, en orden decreciente, son: H. ordunensis, H. itala, H. zaratei, H. corderoi, C. rocandioi, H. madritensis, C. intersecta, H. jamuzensis y H. bierzona. Por primera vez se comprueba experimentalmente la receptividad de C. rocandioi, H. bierzona, H. corderoi, H. itala, H. madritensis y H. zaratei a Neostrongylus linearis.

[ES] Se han llevado a cabo infestaciones experimentales monoespecíficas con larvas I de Muellerius capillaris y Neostrongylus linearis, empleando 203 ejemplares de Cernuella (Xeromagna) cespitum arigonis, 163 de Cernuella (Cernuella) virgata y 69 de Cernuella (Microxeromagna) vestita. En cada sistema parásito/hospedador se determinó el porcentaje de larvas que penetraron, que evolucionaron y que llegaron al estadio infestante (L-III), así como los días post-infestación en que aparecían las primeras L-II y L-III y el período en el que ya eran L-III todas las evolucionadas. Para cada fase de desarrollo se estudian las medidas de las estructuras que permiten su diagnóstico. Se han calculado las rectas de regresión correspondientes a la fase de penetración, y a la relación entre el número de L-I y L-III en los diversos sistemas parásito- hospedador considerados. C. (X.) cespitum arigonis, ampliamente distribuida en la región leonesa y muy receptiva a ambos nematodos estudiados, se considera que puede influir considerablemente en la epizootiología de estas protostrongilinosis. C. (M.) vestita se ha estudiado experimentalmente por primera vez, considerándose la menos adecuada para la evolución de estos nematodos., [EN] Monospecific experimental infestations were carried out with larvae I of Muellerius capillaris and Neostrongylus linearis, using 203 specimens of Cernuella (Xeromagna) cespitum arigonis, 163 of Cernuella (Cernuella) virgata and 69 of Cernuella (Microxeromagna) vestita. In each host parasite relationship the percentages of larvae which penetrated, developed and reached the infesting stage (L-III) were established. The length of time after infestation that it took the first L-II and L-III to appear, and the period when all the larvae that developed reached the L-III stage were also calculated. The structures used in diagnosis during each stage of development are also analized. The regression lines belonging to the penetration stage were calculated, as well as the relationship between the number of L-I and L-III in the different host parasite systems observed. It is believed that C. (X.) cespitum arigonis, widely distributed in the León region and very receptive to both the nematodes studied, can considerably influence the epizootiology of these protostrongyline infestations in sheep. C. (M.) vestita is studied for the first time under experimental conditions, although it was considered to be the least favorable for the development of these nematodes.

[EN]The susceptibillty of eight species of Helicidae molluscs to C. ocreatus was studied under experimental conditions. The statistical study was based on analysis of variance of the % of penetration, evolution and L III, and subsequently the corresponding correlation coefficient was obtained between them. Student’s “t” was used to find out the existence or not of significative differences between the averages of the above mentioned parametres for each species. We took into account fundamentally the evolution and L III percentages, the days when the first L III appeared and when all had reached this final stage. The following list shows, in decreasing order, the most adequate species as intermediate hosts: C. (C.) virgata, M. (A.) granulata, H. ordunensis, C. (X.) cespitum arigonis, y C. barbara. In our opinion H. itala, O. (O.) barbula and C. nemoralis are not favourable I.H., [ES]Se estudia la receptividad experimental a C. ocreatus de ocho especies de moluscos de la familia Helicidae. El estudio estadístico se basó en el análisis de varianza del % de penetración, evolución y L III, entre los que se estableció, en cada caso, el correspondiente coeficiente de correlación. Se empleó la “t” de Student para la constatación de la existencia o no de diferencias significativas, entre las medias de los parámetros anteriormente mencionados, para cada especie de molusco. Considerando fundamentalmente el % de evolución y el de L III, así como el día de aparición de las primeras L III y, aquel en el que todas se encontraban en este estado, se pueden considerar como especies más adecuadas, en orden decreciente: C. (C.) virgata, M. (A.) granulata, H. ordunensis, C. (X.) cespitum arigonis, y C. barbara. A nuestro juicio, no se pueden señalar como H.I. adecuados a H. itala, O. (O.) barbula y C. nemoralis.

Five species of Helicidae found in the province of León were infected with ovine Protostrongylinae larvae under experimental conditions. The most receptive molluscs to infection were, in decreasing order: Cochlicella barbara, Monacha (A.) granulata, Cernuella (M.) vestita, Candidula intersecta and Helicella jamuzensis for Neostrongylus linearís, and Monacha (A.) granulata, Cochlicella barbara and Cernuella (M.) vestita for Muellerius capillaris. This is the first time that M. (A.) granulata, C. (M.) vestita, C. intersecta and H. jamuzensis have been used in connection with the above mentioned parasites, and the first time that C. barbara has been infected with M. capillaris.

The natural infection level of ovine Protostrongylinae in the province of León was studied. The species examined were: Helicella bierzona, H. corderoi, H. jamuzensis, H. zaratei H. itala, H. madritensis, H. ordunensis and H. valdeona. Information about soil types, phytosociology, altitude, and map references concerning the collection places are given. The first four species showed no signs of parasite infection. Amongst the other species, the percentage of infection was, in decreasing order: H. madritensis, H. valdeona, H. itala, and H. ordunensis. This is the first time that H. madritensis and H. ordunensis have been found infected with larvae of Cystocaulus ocreatus, Neostrongylus linearis and Muellerius capillaris.

The larval development of Neostrongylus linearis was studies in a total of 1,200 specimens of Cernuella (Xeromagna) cespitum arigonis, infected monthly (throughout one year) with 200 L-I, and kept outdoors under controlled conditions. ln the parasitological study of each mollusc, the degree of development, the percentage of L-III, the total number of larvae (I + II + III)and of L-III, was taken into account, and likewise the d when L-II and L-III first appreared. The development of the infection was optimum between the end of spring and autumn. The percentage and total number of L-III are, generally, related in a positive way to the thermic integral, but an obvious connection with the relative humidity was not observed. It was in the May-September and in the June-August experiments, when the period of staged development from L-I and L-II and from L-II to L-III was the shortest, respectively. There were not statistically significant differences between the mortality rate of the infected molluscs and that of the control snails.

[ES] Debido a la frecuencia con que se encuentran en la naturaleza moluscos albergando dos o más especies de Protostrongylidae, se han probado experimentalmente y de forma simultánea con larvas de Muellerius capillaris y Neostrongylus linearis, 6 especies de moluscos Helicidae. Para seguir el desarrollo larvario conjunto de ambos parásitos, se utilizaron sobre 40 moluscos adultos de cada especie, que se mataron seriadamente a partir del 6º día pi. De los resultados obtenidos referentes a las larvas I que penetraron en cada molusco, y las que de ellas prosiguieron a L-ll y L-lll, así como los períodos de tiempo que requirieron para ello, consideramos que el orden de idoneidad de las especies de moluscos probadas, para el desarrollo larvario conjunto de M. capillaris y N. linearis, fue: Cernuella (Xeromagna) cespitum arigonis, Cochlicella barbara, Helicella ordunensis, Cepaea nemoralis, Helicella (Helicella) itala y HeIix (Cryptomphalus) aspersa. Parece que M. capillaris y N. linearis evolucionan mejor en las infestaciones dobles que en las monoespecíficas., [EN] Due to the fact that molluscs harbouring two or more species of Protostrongylidae are frequently found in natural habitats, 6 species of Helicidae molluscs were experimentally infected on with Muellerius capillaris and Neostrongylus linearis larvae. Approximately 40 adult molluscs of each species were proved and killed in series from the 6th day post-infection, so that the joint larval development of both parasites could be followed. The results referring to the larvae I which penetrated each mollusc and those of them which reached to L-ll and L-lll, as well as the time required to do so, make us think that, from amongst the molluscs species investigated, the most suitable for the joint larval development of M. capillaris and N. linearis are in decreasing order: Cernuella (Xeromagna) cespitum arigonis, Cochlicella barbara, Helicella ordunensis, Cepaea nemoralis, Helicella (Helicella) itala and HeIix (Cryptomphalus) aspersa. It seems that M. capillaris and N. linearis evolve better in double infections than in the monospecific one.

The experimental susceptibility of Portugala inchoata, Euomphalia (M.) brigantina, Ponentina ponentina, Hygromia (P.) cantabrica cantabrica and Hygromia (P.) cantabrica covadongae to Neostrongylus linearis larvae were studied for the first time. The total number of molluscs used in the infections was 207 and they were killed in series between day 6 and 5O post-infection. In order to define the suitability of the molluscs as intermediate hosts for this parasite, the number of L-I that penetrated the foot and developed to L-I, L-II and L-III has been taken into account, as well as the first days on which the different stages were observed. One way analysis of variance showed statistically significant differences for the penetration and development of the larvae among the species of molluscs examined. Statistically significant differences concerning the susceptibility of the adult and young examples of P. inchoata and E. (M.) brigantina to N. linearis were confirmed by using the chi-square test. The most susceptible species of molluscs to N. linearis using experimental infections were in decreasing order: P. inchoata, E.(M.) brigantina, H.(P.) cantabrica covadongae, P. ponentina and H.(P.) cantabrica cantabrica.

The larval development of Muellerius capillaris was studied in samples of 1200 Cernuella (X.) cespitum arigonis. The molluscs, distributed in groups of 100, were infected in the laboratory at monthly intervals (for one year) with 200 L-I and kept, together with the same number of controls, under controlled conditions on an experimental farm. The snails were killed every 7 or 15 days p.i. In the parasitological study we considered: the total number of larvae (I + II + III), of L-III per mollusc and their respective percentages, as well as the days on which the first L-II and L-III were obtained and when all of them reached the third stage. In general, it was observed that the average and percentage of the total number of larvae were similar in the infections carried out in the coldest, wettest months (October–March) and in the wannest, driest months (April–September), but the average and percentage of the total L-III were lower in the first case. The shortest period before observing the third larval stage for the first time corresponded with the infections carried out from June to October. The total numbers of L-III and their percentage are, in general, positively related to the thermal integral and not to the average relative humidity. There are no statistically significant differences between the mortality rate of infected molluscs and that of the controls.

[EN] In this study we have tested for the first time the susceptibiliiy of Ponentina ponentina, Euomphalia (M.) brigantina, Oestophora (O.) barbula, as potencial intermediate hosts of Muellerius capillaris. At the same time, the development of the above mentioned parasite in Cepaea nemoralis and Helix (C.) aspersa was followed. The total number of molluscs used in the infections was 268. The dose of M. capillaris L-I used ranged between 65 and 838 larvae per mollusc. Once the snails had been infected, 1 or 2 examples from each species were killed every day between day 6 and 46 post-infection, to study the larval development of the parasite. In order to define the suitability of the molluscs as intermediate hosts for this parasite, the number of L-I that penetrated the foot of each snail and developed to L-II and L-III has been taken into account, as well as the first day on which the different stages were observed. The analyses of variance (one way) showed statistically significant differences among the specics of molluscs tested, concerning the percentages of penetration, total amount of larvae and L-III. The correlation coefficient showed that there was a relationship between the last two percentages. According to our results the species: C. nemoralis, P. ponentina, Euomphalia (M.) brigantina and Helix (C.) aspersa can be considered as suitable intermediate hosts for M. capillaris, whilst Oestophora (O.) barbula cannot be considered so., [FR] Dans ce travail, on recueille les données sur l’infestation expérimentale avec larves I de Muellerius capillaris des espèces de mollusques suivantes : Ponentina ponentina, Euomphalia (Mengoana) brigantina, Oestophora (Oestophora) barbula, Helix (Cryptomphalus) aspersa et Cepaea nemoralis. Le nombre des mollusques employé pour l’infestation a été 268. Une fois que les mollusques sont infestés, on a sacrifié 1 ou 2 exemplaires par jour (de chacune des espèces), dès le 6º jour jusqu’au 46° jour post-infestation, pour suivre le développement larvaire ou parasite. On a calculé le nombre de larves I qui a pénétré dans chaque mollusque durant son infestation et, d’après ce nombre, les pourcentages de larves totales (I, II, III et de leurs combinations) et de larves III. On a également tenu compte des jours où l’on a observé les différents stades larvaires. Les analyses de variance à un critère de classificatioin ont montré des différences statistiquement significatives entre les espèces de mollusques testés pour les pourcentages de pénétration, total de larves et de L-III. Avec le coefficient de corrélation, on a observé que les deux derniers pourcentages étaient en relation. Les espèces de mollusques, C. nemoralis, P. ponentina, Euomphalia (M.) brigantina et Helix (C.) aspersa se sont comportés comme des hôtes intermédiaires adéquats pour le développement de M. capillaris.

An investigation was carried out into the thermal effect induced by the Morron de Mateo volcanic dome, Cabo de Gata volcanic region, Spain, on the adjacent bentonitised tuffaceous beds as a natural analogue of the thermal behaviour of the bentonite-engineered barrier of a geological radioactive waste repository. The bentonites consist mainly of Fe-rich smectites and were formed in equilibrium with seawater at temperatures between 75 and 95 degrees C. In contrast, bentonites from other localities in the region consist mainly of Al-smectites, formed in equilibrium with meteoric water below 25 degrees C. Distal smectites are dioctahedral Al-smectites, similar to those from other deposits in the region, while proximal smectites are Fe- and Mg-rich smectites, showing two evolutionary trends on an Fe-Mg-Al ternary diagram. Similar features were observed when their structural formulae were plotted on the muscovite-celadonite-pyrophylite diagram. They plot in the smectite domain with interlayer charge less than 1, mainly due to octahedral substitution for distal smectites and both octahedral and tetrahedral substitutions for proximal smectites. In this ternary diagram, the domains of both proximal and distal smectites partially overlap. Proximal biocalcarenites are enriched in Fe-rich dolomite compared with the distal ones. The 87Sr/86Sr and delta-13C values in carbonates and delta-D in smectites indicate equilibrium with seawater. In contrast, delta-18O values of carbonates and smectites indicate that they were transformed and re-equilibrated between 40 and 90 and between 55 and 66 degrees C, respectively, independently of their location with respect to the dome., An investigation was carried out into the thermal effect induced by the Morron de Mateo volcanic dome, Cabo de Gata volcanic region, Spain, on the adjacent bentonitised tuffaceous beds as a natural analogue of the thermal behaviour of the bentonite-engineered barrier of a geological radioactive waste repository. The bentonites consist mainly of Fe-rich smectites and were formed in equilibrium with seawater at temperatures between 75 and 95 degrees C. In contrast, bentonites from other localities in the region consist mainly of Al-smectites, formed in equilibrium with meteoric water below 25 degrees C. Distal smectites are dioctahedral Al-smectites, similar to those from other deposits in the region, while proximal smectites are Fe- and Mg-rich smectites, showing two evolutionary trends on an Fe-Mg-Al ternary diagram. Similar features were observed when their structural formulae were plotted on the muscovite-celadonite-pyrophylite diagram. They plot in the smectite domain with interlayer charge less than 1, mainly due to octahedral substitution for distal smectites and both octahedral and tetrahedral substitutions for proximal smectites. In this ternary diagram, the domains of both proximal and distal smectites partially overlap. Proximal biocalcarenites are enriched in Fe-rich dolomite compared with the distal ones. The 87Sr/86Sr and delta-13C values in carbonates and delta-D in smectites indicate equilibrium with seawater. In contrast, delta-18O values of carbonates and smectites indicate that they were transformed and re-equilibrated between 40 and 90 and between 55 and 66 degrees C, respectively, independently of their location with respect to the dome.

The deposit is being studied as a natural analogue for the thermal and geochemical effects on a bentonite barrier in a deep geological repository of high-level radioactive wastes. The mineralogical and chemical features of the clay minerals of the hydrothermally altered pyroclastic (white tuffs) and epiclastic rocks (mass flow units) in the NE sector of the deposit are described. White tuffs have a high content of phyllosilicates, mainly composed of dioctahedral smectites, while mass flow units have a higher proportion of inherited minerals, the neoformed phyllosilicates being dioctahedral smectites, and an interlayer chlorite/smectite mineral of corrensite type. The chemical composition of smectites reflects the different nature of the parent rocks, with smectites from white tuffs having a homogeneous chemical composition and montmorillonite-type structural formula, while smectites from mass flow units show more chemical variability, higher Fe and Mg contents and a mean structural formula corresponding to Fe-Mg-rich beidellite and/or to an intermediate smectite member between beidellite and saponite. The presence of corrensite in the epiclastic rocks suggests that a hydrothermal alteration process occurred after bentonite formation which transformed Fe-Mg-rich smectites into corrensite. The system could be a good natural analogue of both thermal and chemical effects on a bentonite barrier related to the radioactive decay of fission products and the interaction between the corrosion products of steel over-packs and the bentonite. The conditions would favour the transformation of the candidate Al-rich smectites into Fe-Mg-rich smectites and corrensite as steps prior to formation of chlorite. In this case all the physicochemical and mechanical properties of Al-rich smectites would disappear and the clayey barrier would fail., The deposit is being studied as a natural analogue for the thermal and geochemical effects on a bentonite barrier in a deep geological repository of high-level radioactive wastes. The mineralogical and chemical features of the clay minerals of the hydrothermally altered pyroclastic (white tuffs) and epiclastic rocks (mass flow units) in the NE sector of the deposit are described. White tuffs have a high content of phyllosilicates, mainly composed of dioctahedral smectites, while mass flow units have a higher proportion of inherited minerals, the neoformed phyllosilicates being dioctahedral smectites, and an interlayer chlorite/smectite mineral of corrensite type. The chemical composition of smectites reflects the different nature of the parent rocks, with smectites from white tuffs having a homogeneous chemical composition and montmorillonite-type structural formula, while smectites from mass flow units show more chemical variability, higher Fe and Mg contents and a mean structural formula corresponding to Fe-Mg-rich beidellite and/or to an intermediate smectite member between beidellite and saponite. The presence of corrensite in the epiclastic rocks suggests that a hydrothermal alteration process occurred after bentonite formation which transformed Fe-Mg-rich smectites into corrensite. The system could be a good natural analogue of both thermal and chemical effects on a bentonite barrier related to the radioactive decay of fission products and the interaction between the corrosion products of steel over-packs and the bentonite. The conditions would favour the transformation of the candidate Al-rich smectites into Fe-Mg-rich smectites and corrensite as steps prior to formation of chlorite. In this case all the physicochemical and mechanical properties of Al-rich smectites would disappear and the clayey barrier would fail.