Denise Terroso

Certification and quality criteria of peloids used for therapeutic purposes

Abstract The empirical application of muds for therapeutic purposes is widely known. This is called pelotherapy and consists of the local or generalized application of a mixture of a solid phase and a liquid phase (peloid) for the recovery of arthro-rheumatic issues, bone-muscle traumatic damage and dermatological pathologies. During the time of mixing (maturation process) the mud is progressively colonized by thermophilic microorganisms that contribute to improvements in the peloid quality and endow the mud with organic substances. Several studies report diatoms as the main agent of thermal muds capable of producing anti-inflammatory sulphoglycolipid which renders the mud suitable for this use. The effect of the temperature is also considered important for therapeutic purposes. Recent studies assessed physical, chemical and technological properties of some peloids in use at spa centres. Some maturation surveys have also been performed in recent years. The need for quality criteria establishment and certification of clayey products intended to be used currently is evident, especially for peloids which have therapeutic action. Consequently, this study aims at the compilation and analysis of some characteristics of peloids from the literature in order to contribute to a major database that allows the establishment of regulations and quality criteria for suitable applications of peloids.

Early diagenesis and clay mineral adsorption as driving factors of metal pollution in sediments: the case of Aveiro Lagoon (Portugal)

This work aims to define the factors driving the accumulation of metals in the sediment of the lagoon of Aveiro (Portugal). The role of initial diagenetic processes in controlling trace metal retention in surface sediment is traced by mineralogy, magnetic susceptibility and geochemical analyses. Although several studies have focused on the metal distribution in this polihaline and anthropized coastal lagoon, most of them have been solely focused on the total metal concentrations. This study instead represents the first attempt to evaluate in a vast area of the Aveiro Lagoon the role of biogeochemical processes in metal availability and distribution in three extracted phases: exchangeable cations adsorbed by clay and elements co-precipitated with carbonates (S1), organic matter (S2) and amorphous Mn hydroxides (S3). According to the sediment guideline values, the sediment is polluted by, for instance, As and Hg in the inner area of the Murtosa Channel, Pb in the Espinheiro Channel, Aveiro City canals and Aveiro Harbour, and Zn in the northern area of the Ovar Channel. These sites are located near the source areas of pollutants and have the highest total available concentrations in each extracted phase. The total available concentrations of all toxic metals are however associated, firstly, with the production of amorphous Mn hydroxides in most of the areas and, secondly, with adsorption by organic compounds. The interplay of the different processes implies that not all of the sites near pollution sources have polluted surface sediment. The accumulation of metals depends on not only the pollution source but also the changing in the redox state of the sediments that may cause alterations in the sediment retention or releasing of redox-sensitive metals. Results of this work suggest that the biogeochemical processes may play a significant role in the increase of the pollutants in the sediment of the Aveiro Lagoon.

Diatom assemblages of thermal and mineral waters from volcanic environments in São Miguel Island, Azores

Volcanic areas are hostile environments where the release of toxic gases is added to the low pH and high temperature, subjecting living organisms to extreme conditions. High-temperature environments, particularly those associated with volcanic activity have been evolving on earth throughout time. The aim of this study is to contribute to increasing knowledge of these high-temperature events and describe their associated diatom assemblages. The fumarolic fields of São Miguel Island in the Azores Archipelago were selected as a case study due to its particular characteristics and were studied seasonally during 2007. Temperature, pH and conductivity variables were measured in situ. Other environmental data were available in the literature. Diatom diversity, assessed using the Shannon–Wiener Index (H′), ranged between 0.02 and 4. Statistical analyses revealed that temperature is a significant driver for the distribution of diatom species. Achnanthidium exiguum Grunow, Nitzschia cf. thermalis var. minor (Hilse) Grunow, Pinnularia joculata (Manguin) Krammer, P. trivialiformis Lange-Bertalot & Metzeltin and P. subcapitata Gregory were prominent with relative abundance above 40% of diatom assemblages. Some diatom taxa with high relative abundance, such as N. cf. thermalis and P. joculata may be considered representative of thermal springs and may be considered important biological indicators of geochemical changes induced by volcanic activity.

Speciation of rare earth elements in surface sediments of Lagoon of Aveiro (N Portugal)

ABSTRACT Martins, V.A., Dias, J.A., Laut, L.M., Sobrinho, F., Santos, J.F., Rodrigues, M. A., Frontalini, F., Miranda, P., Terroso, D., Fernández-Fernández, S., Bernardes, C., Figueira, R., Sousa, S., Amaral, P., Mahiques, M., Bernabeu, A., Rey, D., Rubio, B., and Rocha, F., 2013. Speciation of rare earth elements in surface sediments of Lagoon of Aveiro (N Portugal). The goal of this work is to determine the distribution of the rare earth elements in the surface sediments in the Ria de Aveiro (N Portugal) coastal lagoon. Concentrations of REE (La, Ce, Nd, Sm) and related elements (Th, Y and Sc) were evaluated by total digestion of sediments in the fine fraction of 33 grab-samples of surface sediments. The same method was followed for Al, Ca, S and Zr, related to terrigenous sources, but also, in the cases of Ca and S, to biogenic and quimiogenic processes. Concentrations of REE and related elements were additionally assessed by a three-step sequential chemical extraction (E1-3) procedure coupled with ICP MS determination. The geochemical results were processed by statistical analysis combining textural and mineralogical data (XRD techniques). The results show that mobile La, Ce, Nd, Sm and Y are mostly adsorbed by amorphous Mn hydroxide (E3), secondly associate with organic matter (E2) and only in a very small extent are adsorbed on clay mineral structural sheets or associated with carbonates (E1). Thorium and Sc are almost exclusively linked with E2. Ytrium shows a very high percentage of availability, whilst Ce, La, Sc and Th are by far less mobile. Results of cluster analysis reveals that sediments are enriched in: i) quartz, feldspars and anhydrite in the most hydrodynamic areas with good connection with the ocean, where tidal currents are stronger and water is salty and well-oxygenated; ii) mud, TOC, phyllosilicates, siderite, pyrite and S in low hydrodynamic areas. In these areas, pyrite and siderite can result from reducing bacterial activity in subsurface sediments. Early diagenetic changes in the sediments would also influence the elements adsorption to clay minerals and their co-precipitation with carbonates (E1). The highest values of REE, in E1, occur in distal locations in relation to the mouths of rivers and streams. The retention of the elements in this phase may occur mainly in the lagoon, depending on the availability of carbonates and clay minerals and their assemblages composition. Concentrations of REE and related elements adsorbed by organic matter (E2) and by amorphous Mn hydroxide (E3) tend to rise near the rivers mouths and may be related to geochemical processes that take place upstream in the course of the rivers before the entry of sediments into the lagoon. Elemental concentrations retained in the structure of mineral phases (R), also tend to reach high values near the rivers mouths but in low hydrodynamic areas. There is some fractionation between Th and the light REE which is more evident in the Murtosa channel that is fed mainly by the Antuã river.

The ITRAX core scanner, a useful tool to distinguish anthropic vs. climatic influences in lagoon of Aveiro (N Portugal)

ABSTRACT Martins, V. A., Dias, J. A., Bernardes, C., Rubio, B., Bernabeu, A., , Rey, D., Soares, A.M., Sobrinho, F., Laut, L.M., Frontalini, F., Terroso, D., Miranda, P., Fernández-Fernández. S., Rodrigues, M.A., Figueira, R., Sousa, S.M., Amaral, P. Mahiques, M. and Rocha, F., 2013. The ITRAX core scanner, an useful tool to distinguish anthropic vs climatic influences in lagoon of Aveiro (N Portugal). The main goal of this work is to distinguish anthropic and climatic influences in sediments from the lagoon of Aveiro (Portugal). This study is based on a core (240-cm long) collected in Murtosa Channel. Optical and X-radiographic images and high-resolution elemental profiles were acquired with ITRAX micro-X-ray fluorescence (XRF) core scanner. Samples collected at each ≈3 cm along the core were analysed for grain size and total organic carbon. Furthermore, the fine fraction of selected layers was subjected to geochemical analysis by ICP-MS, after total acid digestion of the sediments, and mineralogical analysis, by XRD techniques. A radiocarbon age was determined by AMS, using molluscs shells collected at a depth of 90 cm. Sediments along the core are composed by fine and medium sand, with several mud layers. Sediments composing the first 100-cm may have been deposited after 1950, as it is indicated by the radiocarbon data, the increasing trend of Zn/Al, Pb/Al and Cu/Al and total concentrations of Zn, Pb, Cu, V, Cr, As and Ni in this interval that therefore might be linked with industrial activities of Chemical Complex of Estarreja. The progressive increase of Si/Al, Cl/Al, Rb/Al, K/Al and Br/Al and reduced Al concentrations, from the base to the top of this core, are interpreted as being related to higher marine influence and greater differences in tidal currents with longer exposition to air of the sediments with the consequent formation of brines favouring minerals precipitation in the area (e.g. anhydrite). These results seem to be a consequence of several works developed over time like: i) dredging to improve the navigation access to the harbour, located in the external sector of the lagoon; ii) the control of the course of some rivers influencing the supply of sediments. The tendency of sea level rise may have also emphasized the gradual increase of marine influence in this area. Fine-grained sections, related to an increase in Al, phyllosilicates, organic matter, pyrite and siderite contents would be attributed to phases of greater supply of fine-sediments during heavy rainfall events by the nearby Antuã river and other streams during negative phases of North Atlantic Oscillation. Higher deposition of organic matter enhanced diagenetic changes with pyrite and siderite formation. In the bottom of the core another record of pollution was unveiled to mining activities at the beginning of 20th century.

Liquid limit determination of clayey material by Casagrande method, fall cone test and EBS parameter

Abstract Casagrande and fall cone tests are standard methods widely used for liquid limit determination. This is a parameter that, in addition to the information provided by plastic limit assessment, allows the evaluation of the plasticity of soils. This study carried out the determination of liquid limit of 18 clayey samples by Casagrande and fall cone methods in order to compare them. A high correlation was found between the results of both methods. Moreover, the most recent equation proposed on literature for the comparison between methods was applied, and it seems suitable for the prediction of liquid limit assessed by fall cone test and the experimental value achieved by Casagrande device. As expected, good correlations between liquid limit, phyllosilicate amount and type of clay minerals was noticed. As complement, equivalent basal spacing (EBS) parameter was calculated and tested. Good correlations between this parameter and liquid limit measured were observed only for samples with <70% of phyllosilicate content; when the analysis is applied to the samples with higher amount of phyllosilicates, there is not a good match, suggesting that EBS calculation is not reliable in those cases.

Abrasiveness index of dispersions of Portuguese clays using the Einlehner method: influence of clay parameters

Abstract The unique properties of clays make them suitable for a large number of applications. Among the procedures that can be used to characterize clayey materials, the assessment of the abrasion and the abrasiveness index can be employed to predict the mechanical behaviour of clay samples. However, only a limited number of references to these testing procedures are available in the literature. Several Portuguese clayey samples were collected and the <63 μm fraction was analysed. The main clay minerals present are kaolinite, illite and smectite. The abrasiveness index depends on the granulometric and mineralogical compositions. A lower abrasiveness is induced by the presence of a high abundance of the <2 μm fraction, small mean particle size and a large phyllosilicate content. Kaolinite and illite show good correlation with the abrasiveness index, while smectite decreases abrasion.

Chemical Modifications and Diatom Community Development on Volcanic Clayey Sediments During an Indoor Maturation Experiment

Maturation experiments of volcanic mud samples with mineral water were followed up during 120 days at constant room temperature (20ºC) to track geochemical modifications induced by the process and, eventually, the development of diatom communities. Different abiotic conditions were tested during the experiments. Mud samples were collected in Azores and Madeira Archipelagos (Portugal) and the biological inoculum was collected from the edge of a fumarole from Azores (Portugal). The assemblages of diatoms were dominated by Nitzschia species both in the inoculum and on maturated muds. Although one of the samples from São Miguel island (Azores) was dominated by Nitzschia cf. thermalis var. minor, the mud sample from Porto Santo (Madeira) allowed the development mainly of Nitzschia communis during maturation experiments. Associations between chemical composition and samples’ mineralogical signature were established by cluster analysis. Slight enrichment on Na+ and Ca2+ was detected in samples after maturation and exchangeable cations content was improved by the process. This research includes a multidisciplinary approach that contributes to the understanding of interactions between volcanic substrates and specific diatom species and geochemical modifications induced by maturation in volcanic materials.