| December 2014
The local organising institution of the 31st International Conference of the SEGH in 2015 – was established in 1940 and performs the tasks of the State Geological Survey of the Slovak Republic. continue reading...
SEGH was established in 1971 to provide a forum for scientists from various disciplines to work together in understanding the interaction between the geochemical environment and the health of plants, animals, and humans. We recognise the importance of interdisciplinary research. SEGH members represent expertise in a diverse range of scientific fields, such as biology, engineering, geology, hydrology, epidemiology, chemistry, medicine, nutrition, and toxicology.
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| November 2014
Pre-Hispanic metallurgical activities released enough metals to be transported throughout the entire South American continent. continue reading...
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Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health
High-Fâˆ’ groundwater is widely distributed in Xiji County, which endangers the safety of drinking water. In order to evaluate the key factors controlling the origin and geochemical mechanisms of Fâˆ’ enrichment in groundwater at Xiji County, one hundred and five groundwater samples and sixty-two sediment samples were collected. Fluoride concentration in the groundwater samples ranged from 0.2 to 3.01Â mg/L (mean 1.13Â mg/L), with 17Â % exceeding the WHO drinking water guideline value of 1.5Â mg/L and 48Â % exceeding the Chinese drinking water guideline value of 1.0Â mg/L. High-Fâˆ’ groundwaters were characterized by hydrochemical types of Naâ€“HCO3 and Naâ€“SO4Â·Cl, which were found in Quaternary sediment aquifer and in Tertiary clastic aquifer, respectively. Conditions favorable for Fâˆ’ enrichment in groundwater included weakly alkaline pH (7.2â€“8.9), low concentration of Ca2+, and high concentrations of HCO3 âˆ’ and Na+. Calcite and fluorite were the main minerals controlling Fâˆ’ concentration in groundwaters. The hydrolysis of F-bearing minerals in aquifer sediments was the more important process for Fâˆ’ release in Tertiary clastic aquifer, which was facilitated by long residence time of groundwater, in comparison with Quaternary sediment aquifer. Cation exchange would also play important roles, which removed Ca2+ and Mg2+ and led to more free mobility of Fâˆ’ in groundwater and permitted dissolution of fluorite, especially in Tertiary clastic aquifer. However, evapotranspiration and competing adsorption of B and HCO3 âˆ’ were the more important processes for Fâˆ’ enrichment in Quaternary groundwater. Groundwater in Lower Cretaceous aquifer had relatively low Fâˆ’ concentration, which was considered to be the potential drinking water resource.
The primary objective of this study was to investigate the effect of biochar, produced from wheat residue at different temperatures, on the adsorption of diesel oil by loess soil. Kinetic and equilibrium data were processed to understand the adsorption mechanism of diesel by biochar-affected loess soil; dynamic and thermodynamic adsorption experiments were conducted to characterize this adsorption. The surface features and chemical structure of biochar, modified at varying pyrolytic temperatures, were investigated using surface scanning electron microscopy and Fourier transform infrared analysis. The kinetic data showed that the adsorption of diesel oil onto loess soil could be described by a pseudo-second-order kinetic model, with the rate-controlling step being intraparticle diffusion. However, in the presence of biochar, boundary layer control and intraparticle diffusion were both involved in the adsorption. Besides, the adsorption equilibrium data were well described by the Freundlich isothermal model. The saturated adsorption capacity weakened as temperature increased, suggesting a spontaneous exothermic process. Thermodynamic parameter analysis showed that adsorption was mainly a physical process and was enhanced by chemical adsorption. The adsorption capacity of loess soil for diesel oil was weakened with increasing pH. The biochar produced by pyrolytic wheat residue increased the adsorption behavior of petroleum pollutants in loess soil.
The objective of this study was to examine whether a single model could be used to predict the bioaccessibility of heavy metals in soils in two adjacent areas and to determine the feasibility of using existing data sets of total metal concentrations and soil property parameters (e.g., pH, total organic carbon, and soil texture) when predicting heavy metal bioaccessibility. A total of 103 topsoil samples were collected from two adjacent areas (Baotou and Bayan Obo). A total of 76 samples were collected from Baotou, and 27 were collected from Bayan Obo. The total and bioaccessible concentrations of arsenic (As), copper (Cu), lead (Pb), and zinc (Zn) were measured following complete composite acid digestion and a simple bioaccessibility extraction test. The average total concentrations of As, Cu, Pb, and Zn were 8.95, 27.53, 28.40, and 79.50Â mg/kg, respectively, in Baotou and 18.12, 30.75, 38.09, and 87.62Â mg/kg in Bayan Obo. Except for As, these values were similar in both areas. The average bioaccessible heavy metal concentrations (Bio-HMs) for each target HM were also similar. In Baotou, the average Bio-HM values for As, Cu, Pb, and Zn were 1.16, 3.76, 16.31, and 16.10Â mg/kg, respectively, and 1.26, 2.51, 14.31, and 8.68Â mg/kg in Bayan Obo. However, the relative bioaccessibilities for each HM in Baotou were greater than those in Bayan Obo, with mean values for Pb, Zn, Cu, and As of 57, 20, 17, and 12Â %, respectively, in Baotou and 40, 11, 9, and 8Â % in Bayan Obo. In both areas, prediction models were successfully created using heavy metal concentrations and soil physicochemical parameters; however, models of the same target element differed between the areas, which indicated that a common model for both sites does not exist. Bio-HMs were highly affected by soil properties, which were found to differ between the adjacent areas. In addition, soil properties with large variations played major roles in the predictive models. This study highlights the importance of incorporating physical and chemical parameters that vary greatly when building predictive models of heavy metal bioaccessibility in soil. A similarity in soil properties between areas might be a prerequisite for the creation of a common predictive model for soil Bio-HMs.