A general review of soils in Virginia counties bordering the Chesapeake Bay reveals that coastal plain soils, especially those most agriculturally productive, are dominantly sandy texture in the subsurface horizon, and have shallow water tables. Considering the high amounts of pesticides used in the coastal plain region and the porous nature of sandy texture soils, there is a great potential for pesticide leaching and subsequent contamination of surface and groundwater sources. This is of great concern because of the potential detrimental effects these agrochemicals represent on aquatic and animal life in the Chesapeake Bay, the largest and most productive estuary in the United States. / Master of Science

This study compared the effects of soil texture, soil depth, and additional treatment, by constructed wetland (CW) and recirculating sand filter (RSF) systems, on wastewater renovation in a texture group 2 (loam) and a texture group 3 (clay loam) soil. The soils with depths of 15, 30, and 45 cm were placed in the columns with a Gidding's hydraulic soil probe in order to retain the soils structure <i>in situ</i>. The texture group 2 columns were dosed with septic tank eflluent (STE), constructed wetland effluent (eWE), and recirculating sand filter effluent (RSFE) at 685 cm³ per day and the texture group 3 columns were dosed at 670 cm³ per day with the same effluents. These dosing events were split into 2 separate (12 h) events. The leachate from both groups of soil columns were analyzed for fecal coliforms (FC), biochemical oxygen demand (BODs), ammonium (NH₄-N), nitrate (NO₃-N), phosphate (PO₄-P), pH, total dissolved solids (TDS), electrical conductivity (EC), and chloride. In the texture group 2 soil the reduction in fecal coliform numbers was 88% and 99%, respectively, for the CW and the RSF and, in the texture group 3 soil was 91% and 99%, respectively, for the CW and the RSF. There was a reduction in BODs concentrations of 32% and 69% ,respectively, for the CW and the RSF. There was a 42% and 84% decrease in NH₄ concentrations, respectively, for the CW and the RSF. These reductions show that treatment of STE by CW or RSF can be substituted for soil depth in texture group 2 and 3 soils and will improve drainfield performance. Texture group 2 soils are less effective at STE renovation than texture group 3 soils at all soil depths. This was evidenced by higher FC counts and concentrations of BOD, N, and P in the leachates from these columns. / Master of Science

Thesis (M. Sc. (Geology)) -- University of Limpopo, 2021 / Mining activities for mineral resources over the years have, according to certain people, resulted in soil damage in the Atok area because of huge amounts of waste earth and rock that was brought to the surface, this waste often becomes toxic when it comes into contact with air and water. However, the geology of the area which is mafic in composition has caused major damage to the soil in the area as well. Due the removal process of desired mineral materials, soil textures have been destroyed, various nutrient cycles disturbed, and microbial communities altered, changing the vegetation and leading to the format of land in the area. Therefore, soil restoration of mining lands became a very important part of sustainable development strategies and also prescribed by law in South Africa. The geochemistry and mineralogy of soil samples taken from the area of Atok were studied using X-Ray Fluorescence (XRF) and physio-chemical parameter analysis. These methods are used for investigating the element and mineral associations and the distribution of heavy metals in these soils around the mine. The chemical and mineralogical data from soil and tailings were collected from each of the following areas around Atok: (Sefateng, Moonametsi, Mohlahlaneng, Sefateng Tailing Dam and Mafeo), the samples were collected at various depths; at each sampling points. The results of XRF analysis indicated that the soils are rich in MgO, CaO and Fe2O3 with minerals such as pyroxenes, plagioclase feldspar and occasional olivine being dominant. An excess of these minerals caused the soil to be infertile. The physio-chemical analysis showed that the soil texture is sandy, therefore this is the reason that the soil has low water holding capacity (27%) and low soil moisture (1.2%), the pH (8.50) and EC (<0.50 dS/m). Keywords: Soil composition, chemical properties, heavy metal, contamination.

As argamassas para assentamento e revestimento de alvenarias, empregadas nas regiões metropolitanas de vários estados do Brasil, são tradicionalmente constituídas de cimento e areia com adições de argilominerais, denominados de saibro ou arenoso. Essas adições fornecem à argamassa trabalhabilidade, retenção de água e plasticidade semelhantes às da argamassa mista (cimento e cal). Apesar 40 uso, pouco se conhece quanto às características do saibro para seu emprego em argamassas. A escolha do saibro para uso em argamassa é realizada de forma empírica, ocasionando muitas vezes, patologias nos revestimentos. O objetivo deste trabalho foi analisar amostras de saibro para utilização em argamassas de cimento e saibro (ACS). Foram coletadas 62 amostras de saibros em 24 jazidas, em suas maiorias exploradas comercialmente na Região Metropolitana do Recife (RMR). Foram realizados 21 ensaios de caracterização química na totalidade das amostras de saibros. Foi proposto um índice de qualidade de saibro para argamassa (IQSA) e selecionadas 9 amostras de saibro para utilização em argamassas. Foram realizadas análises em argamassas frescas e ensaios mecânicos em argamassas endurecidas com dois traços. Os resultados foram analisados estatisticamente pela análise de componentes principais (PCA). Os resultados da caracterização química mostraram que os Saibros da RMR de melhor qualidade para argamassas de alvenaria foram coletados na área Norte. As principais características químicas dos Saibros que influenciaram positivamente a qualidade das ACS foram: pH, Capacidade de Troca de Cátions (CTC < 27 cmolc kg-l), Superfície específica (SE < 10 m2g-I), Percentagem de óxido de silício e Percentagem de água no extrato de saturação. Os indicadores que envolvem características químicas e físicas são fundamentais para qualificar o desempenho de argamassas.

Made available in DSpace on 2017-06-01T17:57:24Z (GMT). No. of bitstreams: 1 pre-textuais.pdf: 5777516 bytes, checksum: 35995ebd7e6e4cb8d83e00e62aa66616 (MD5) Previous issue date: 2008-12-18 / The mortars used in many parts of Brazil to set blocks or to cover masonry are normally prepared with cement and sand with clay minerais additions, called "saibro" or "arenoso" (a clayey sand). These additions provide workability, water retention and plasticity to the mortars, similarly as in the mixed mortars (cement, sand and lime). The properties of "saibro" are poorly known, in spite of its large use. Therefore, the choice of "saibro" to use in mortars has been empirical, and the mortars quality is not guaranteed, what may cause some pathology in the masonry covers. The objective of this work was to analyze "saibro" samples to be used in cement and "saibro"mortars (CSM). Sixty two samples of "saibro" were collected from 24 ofthe most commercially explored fields in the Recife's Metropolitan Area. Chemical "saibro" characterization tests, with 21 determinations, were applied to ali samples. A quality index of "saibro" for mortars (QISM) was proposed and nine samples of "saibro" were selected to be used in mortars. Chemical analysis for fresh mortars and mechanical tests for the hardened ones were provided for two different compositions. The results were statistically analyzed by principal components analysis (PCA). The chemical characterization tests showed that the best "saibros" for masonry mortars were collected in the northern part of the studied region. The "saibro" maio chemical characteristics that influenced positively the quality of the CSM were: pH, Cations Exchange Capacity (CEC < 27 cmoic kg-1), Surface Area (SA < 102 m2g-1), Silicon Oxide Percentage and Water Percentage in the Saturation Extract. The physical and chemical indicators are fundamental to qualify the mortars performance. / As argamassas para assentamento e revestimento de alvenarias, empregadas nas regiões metropolitanas de vários estados do Brasil, são tradicionalmente constituídas de cimento e areia com adições de argilominerais, denominados de saibro ou arenoso. Essas adições fornecem à argamassa trabalhabilidade, retenção de água e plasticidade semelhantes às da argamassa mista (cimento e cal). Apesar 40 uso, pouco se conhece quanto às características do saibro para seu emprego em argamassas. A escolha do saibro para uso em argamassa é realizada de forma empírica, ocasionando muitas vezes, patologias nos revestimentos. O objetivo deste trabalho foi analisar amostras de saibro para utilização em argamassas de cimento e saibro (ACS). Foram coletadas 62 amostras de saibros em 24 jazidas, em suas maiorias exploradas comercialmente na Região Metropolitana do Recife (RMR). Foram realizados 21 ensaios de caracterização química na totalidade das amostras de saibros. Foi proposto um índice de qualidade de saibro para argamassa (IQSA) e selecionadas 9 amostras de saibro para utilização em argamassas. Foram realizadas análises em argamassas frescas e ensaios mecânicos em argamassas endurecidas com dois traços. Os resultados foram analisados estatisticamente pela análise de componentes principais (PCA). Os resultados da caracterização química mostraram que os Saibros da RMR de melhor qualidade para argamassas de alvenaria foram coletados na área Norte. As principais características químicas dos Saibros que influenciaram positivamente a qualidade das ACS foram: pH, Capacidade de Troca de Cátions (CTC < 27 cmolc kg-l), Superfície específica (SE < 10 m2g-I), Percentagem de óxido de silício e Percentagem de água no extrato de saturação. Os indicadores que envolvem características químicas e físicas são fundamentais para qualificar o desempenho de argamassas.

Please read the abstract in the section 00front of this document / Dissertation (MSc (Soil Science))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted

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This diploma thesis focuses on the use of thermogravimetry as quick and low-cost method in the analysis of soil quality. Most of the currently used methods for analyzing some soil properties are, unlike thermogravimetry, demanding especially for pretreatment and analysis time. Previous research has shown an interesting correlation between thermogravimetry data and some soil properties, but to obtain these correlations, it is necessary to keep the analyzed soils at 76% relative humidity. The aim of this work was to determine whether similar correlations can also by achieved at lower relative humidities. Therefore, soil samples in this work were thermogravimetrically analyzed at 43% relative humidity. That humidity is closer to laboratory conditions and it is also easier to be reached by most of commercially available thermogravimeters. Next aim of this thesis was to find whether thermogravimetric data correlate with other soil properties, especially microbiological indicators of soil quality. Results showed that thermogravimetry of soil samples correlates with standard methods even at 43% humidity. Furthermore, it was found that they also correlate with selected microbiological parameters, such as anaerobic ammonification or urease activity. These results suggest the possibility of using thermogravimetry analysis at broader spectrum of soil properties, without the need for pretreatment of samples and at different (relevant) soil moisture.

For several decades, the idea of flying and landing a less-than-man-rated nuclear reactor for planetary surface applications has been considered. This approach promises significant mass savings and therefore reduction in launch cost. To compensate for the lack of shielding, it has been suggested the use of in-situ materials for providing radiation protection. This would take the form of either raw dirt walls or processed soil materials into blocks or tile elements. As a first step in determining the suitability of this approach, it is necessary to understand the neutron activation characteristics of these soils. A simple assessment of these activation characteristics was conducted for both Martian and Lunar soils using ORIGEN2.2. An average composition for these soils was assumed. As a baseline material, commonly used NBS-03 concrete was compared against the soils. Preliminary results indicate that over 2.5 times more gamma-radiation production of these soils vs. concrete took place during the irradiation phase (a baseline of 2.4 x 1011 neutrons/sec-cm2 was assumed). This was due primarily to radiative capture on Na23 and Mn55 and subsequent decay of their activation products. This is does not necessarily disqualify these materials as potential shielding material since the -radiation output was only in the order of 4.2 x 108 photons/cm3-sec. Furthermore, these soils did not show any significant activity after shutdown of the neutron source (the reactor), since all activation products had very short half lives. Their performance in this area was comparable to that of NBS-03 concrete. / text