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Bioavailability of arsenic in the mine waste in Kaňk near Kutná Hora
Raus, Karel ; Drahota, Petr (advisor) ; Vítková, Martina (referee)
Summary: Arsenic relative bioavailability (RBA) in mine wastes is always lower than 100%. Total concentration of As at Kaňk varied between 87 and 15500 mg.kg-1 in collected samples of road dust, urban soil and mine waste, however the bioaccessible amount of arsenic obtained with SRBC-G method was much lower (6-795 mg.kg-1 ). Crucial factors influencing arsenic bioaccessibility are pH value and solubility of mineral phases which are stable under given conditions of the sample. Although the highest total As concentrations were found in the mine wastes (9250-15500 mg.kg-1 ), these samples displayed the lowest As bioaccessibilities (5,1 ± 1,3%). This is probably due to the prevalence of poorly soluble Fe- arsenates and As-sulfides in the low-pH mine wastes. In the near-neutral samples of road dust and urban soil the As bioaccessibility showed slightly higher values (7,5 ± 2,6%; 8,2 ± 2,6% respectively). From the chemistry and mineralogy of the samples it is possible to recognize the mine wastes as the main source of As contamination in soil and road dust at the Kaňk village. The bioaccessibility of arsenic and other pollutants from the specific site provides more accurate data for the health risk assessment, although the valid in vivo/in vitro comparison doesn't seem to be revealed.
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Geomaterials from mining and hydrometallurgical processing of Zn ores at Skorpion (Namibia): bioaccessibility of dust particles and variability in Zn isotope signal
Raus, Karel ; Ettler, Vojtěch (advisor) ; Vaněk, Aleš (referee)
This study is focused on the bioavailability of contaminants in dust particles from geomaterials from the extraction and hydrometallurgical processing of non-sulphide Zn ores at the site of Skorpion (Namibia) and the change of isotope signal in geomaterials and drill core samples. Mineralogical composition and bioaccessibility of contaminants were studied with RTG, SEM / EDS, EPMA and simple in vitro leaching test in simulated gastric fluid for fractions <48 μm and <10 μm representing the dust particles. Based on results from chemical analysis, Cd, Cu, Pb and Zn were identified as the main contaminants and their concentrations also significantly increased in the finer fractions compared to the original samples. The bioaccessible fraction (BAF) values ranged from 36-97% for Cd, 17-78% for Cu, 2-100% for Pb and 27-100% for Zn. Daily intake via oral exposure, calculated for an adult (70 kg, ingestion 100 mg / day), exceeded tolerable daily intake (TDI) limits for Cd (up to 1.95), Pb (up to 21.96) and Zn (up to 2.02). Ores originating from Turkey and Taiwan, used to adjust feed ore Zn concentration, were identified as the most hazardous materials. The bioavailability of contaminants depends on the mineralogical composition of the geomaterials and the particle size, but the risks for humans are...
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Bioavailability of arsenic in the mine waste in Kaňk near Kutná Hora
Raus, Karel ; Drahota, Petr (advisor) ; Vítková, Martina (referee)
Summary: Arsenic relative bioavailability (RBA) in mine wastes is always lower than 100%. Total concentration of As at Kaňk varied between 87 and 15500 mg.kg-1 in collected samples of road dust, urban soil and mine waste, however the bioaccessible amount of arsenic obtained with SRBC-G method was much lower (6-795 mg.kg-1 ). Crucial factors influencing arsenic bioaccessibility are pH value and solubility of mineral phases which are stable under given conditions of the sample. Although the highest total As concentrations were found in the mine wastes (9250-15500 mg.kg-1 ), these samples displayed the lowest As bioaccessibilities (5,1 ± 1,3%). This is probably due to the prevalence of poorly soluble Fe- arsenates and As-sulfides in the low-pH mine wastes. In the near-neutral samples of road dust and urban soil the As bioaccessibility showed slightly higher values (7,5 ± 2,6%; 8,2 ± 2,6% respectively). From the chemistry and mineralogy of the samples it is possible to recognize the mine wastes as the main source of As contamination in soil and road dust at the Kaňk village. The bioaccessibility of arsenic and other pollutants from the specific site provides more accurate data for the health risk assessment, although the valid in vivo/in vitro comparison doesn't seem to be revealed.
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