Geostatistical analysis of the influence of textural, mineralogical and geochemical parameters on the geotechnical behaviour of the ‘Argilas de Aveiro’ Formation (Portugal)

Galhano, C.; Rocha, Fernando; Gomes, Celso

doi:10.1180/000985599545966

Cited by 57 publications

(20 citation statements)

References 4 publications

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“…Qualitative and semiquantitative mineralogical analyses followed the criteria recommended by Schultz (1964), Thorez (1976) and Mellinger (1979). For the semiquantification of the identified principal minerals, peak areas of the specific reflections were calculated and weighted by empirically Galhano et al (1999) and Oliveira et al (2002). Crystallinity is a measure of the lattice ordering, and the crystallite size of clay minerals is often used to assess the degree of maturation of a residual soil.…”

Section: Methodsmentioning

confidence: 99%

Assessing the control exerted by soil mineralogy in the fixation of potentially harmful elements in the urban soils of Lisbon, Portugal

et al. 2011

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The main purposes of this study are the textural, chemical and mineralogical characterization of the urban soils of Lisbon and the identification of probable relations between the several soil properties. The results are used to infer which soil properties control the superficial dispersion of potential harmful elements to human health. Soil sampling was carried out in 51 selected sites all through the city, under the criterion that such sites should be spaces usually frequented by children. The concentrations of 42 elements in the [2 mm soil size fraction were determined at a commercial laboratory in Canada (ActLabs, LTD), by ICP-MS/ICP-OES after an acid digestion with aqua regia. The soil mineralogy was determined by X-ray diffraction in the \2 and \62 lm size fractions. The results indicate that the urban soils have mainly a sandy texture and a main mineralogical assemblage of quartz, K-feldspar, plagioclase and calcite. In terms of clay minerals, smectite, illite and kaolinite are the main clays in the soil. Smectite and illite show a dichotomy in their distribution, with the smectites prevailing in the soils of the volcanic complex of Lisbon, which are classified as being residual, and illite prevailing in the remaining soils, which are considered mainly as man-made soils. Smectite seems to exert an important role in the fixation of Ni and Cr. The results of the geochemical study show that Ni and Cr have concentrations above the soil guideline value established to the UK and pose a probable risk to human health.

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Section: Methodsmentioning

confidence: 99%

Assessing the control exerted by soil mineralogy in the fixation of potentially harmful elements in the urban soils of Lisbon, Portugal

et al. 2011

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“…Soil organic matter (SOM) was determined by loss-on-ignition (LOI), at 430ºC for about 16 h (Schumacher 2002 The semi-quantitative mineralogical analysis of a sub-set of samples (seven soil samples in total) was carried out by X-ray diffraction, following the criteria of Schultz (1964), Thorez (1976), Galhano et al (1999) and Oliveira et al (2002). The clay fraction (<2 µm) was obtained by sedimentation according to the Stoke's law.…”

Section: Analysesmentioning

confidence: 99%

Geochemistry, mineralogy, solid-phase fractionation and oral bioaccessibility of lead in urban soils of Lisbon

Reis

Patinha

Wragg

et al. 2014

Environ Geochem Health

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An urban survey of Lisbon, the largest city in Portugal, was carried out to investigate its environmental burden, emphasizing metallic elements and their public health impacts. This paper examines the geochemistry of lead and its influence on human health data. A total of 51 soil samples were collected from urban recreational areas used by children to play outdoors. The semi-quantitative analysis of lead was carried out by inductively coupled plasma mass spectrometry after an acid digestion. X-ray diffraction was used to characterise the soil mineralogy. The solid phase distribution of lead in the urban soils was investigated on a sub-set of 7 soils, out of a total of 51 samples, using a non-specific sequential extraction method coupled with chemometric analysis. Oral bioaccessibility measurements were obtained using the Unified BARGE Method developed by the Bioaccessibility Research Group of Europe. The objectives of the study are: (i) investigation of lead solid-phase distribution; (ii) interpretation of lead oral bioaccessibility measurements; (iii) integration of metal geochemistry with human health data; (iv) understanding the influence of geochemistry and mineralogy on oral bioaccessibility. The results show that the bioaccessible fraction of Pb is lower when major metal fractions are associated to less soluble soil phases such as Fe-oxyhydroxides, and more elevated when the metal is in the highly soluble carbonate phase. However, there is some evidence that the proportion of carbonates in the soil environment is also a key control over the oral bioaccessibility of Pb, irrespective of its solid phase fractionation.

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“…The analysis of the different clay characteristics i.e., mineralogical and chemical compositions can be interpreted as follows: White clay displays the highest plasticity index and the highest smectite content; indeed, high plasticity values are associated with increased smectite contents [42]. Delamination, and lower plasticity indexes occur in illite clay types and higher contents of illite were found in the Red soil, with smaller differences in the Yellow and Black soils.…”

Section: Resultsmentioning

confidence: 99%

Analysis of the Influence of the Fiber Type in Polymer Matrix/Fiber Bond Using Natural Organic Polymer Stabilizer

2014

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This research study compares the effect of polypropylene and wool fibers on the mechanical properties of natural polymer based stabilized soils. Biocomposites are becoming increasingly prevalent and this growth is expected to continue within a number of sectors including building materials. The aim of this study was to investigate the influence of different fiber reinforced natural polymer stabilized soils with regards to mechanical properties and fiber adhesion characteristics. The polymer includes alginate, which is used in a wide range of applications but has not been commonly used within engineering and construction applications. In recent years, natural fibers have started to be used as an ecological friendly alternative for soil reinforcement within a variety of construction applications. Test results in this study have compared the effects of adding natural and synthetic fibers to clay soils and discussed the importance of an optimum soil specification. A correlation between the micro structural analysis using scanning electron microscope (SEM), fiber typology, fiber-matrix bonds and the mechanical properties of the stabilized soils is also discussed.

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Geostatistical analysis of the influence of textural, mineralogical and geochemical parameters on the geotechnical behaviour of the ‘Argilas de Aveiro’ Formation (Portugal)

Cited by 57 publications

References 4 publications

Assessing the control exerted by soil mineralogy in the fixation of potentially harmful elements in the urban soils of Lisbon, Portugal

Assessing the control exerted by soil mineralogy in the fixation of potentially harmful elements in the urban soils of Lisbon, Portugal

Geochemistry, mineralogy, solid-phase fractionation and oral bioaccessibility of lead in urban soils of Lisbon

Analysis of the Influence of the Fiber Type in Polymer Matrix/Fiber Bond Using Natural Organic Polymer Stabilizer

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