Solubility of uranium and thorium from a healing earth in synthetic gut fluids: A case study for use in dose assessments

Internal dose assessment of 238U contaminated soils based on in-vitro gastrointestinal protocol

“…The solutions were stored frozen until measured with inductively coupled plasma mass spectrometer (ICP-MS) [14][11][15] [9]. Table 2 represents the measured chemicals and enzymes used for 0.5 g of soil [15]. S2 S3 S4 S1 …”

“…Lower pH of the stomach increases the soluble fraction of 238 U leading to higher concentration values for all the following soils [11]. Hӧllriegl et al [15] highlighted that the solubility behaviour of 238 U was influenced by medium change from acidic to alkaline condition. Even though each soils present decreasing mean concentration of 238 U in gastrointestinal phase, the extraction of uranium from soil occur as carbonate ion added formed water-soluble uranyl carbonate complexes.…”

“…Fundamentally, absorption of uranium from the digestive tract into the systemic circulation mainly occur in the small intestine. Hence, the dose assessment in gastrointestinal phase will play the role to indicate the realistic approach for the estimation of internal dose [15]. Although the internal dose values were significantly lower, once uranium is taken into the body, it can results in both chemical and radiological toxicity.…”

“…In this study, German standard DIN procedure was used as a test system for mobilising pollutants in contaminated materials using synthetic digestive juices [14]. Analysis techniques using X-ray Fluorescence (XRF) was used to measure total 238 U concentrations of the samples prior digestion meanwhile Inductive Coupled Plasma Mass Spectrometry (ICP-MS) was used to measure 238 U concentrations after digested with synthetic gastrointestinal solutions [15]. Concentrations obtained will be used for internal radiation dose calculations.…”

Solubility of 238U radionuclide from various types of soil in synthetic gastrointestinal fluids using “US in vitro” digestion method

“…Based on Hollriegl et al [8], the risk of exposure from consumption of soil that has been contaminated with 238U radionuclide is measured by the method of determining the solubility of 238U radionuclide which reacts with synthetic gastric fluid stomach and small intestine synthetic liquid using in vitro gastrointestinal extraction. Solubility is defined as the fraction of pollutants discharged from the soil into the gastrointestinal fluids synthetic, it is the maximum amount of contaminants found in the soil that represents the absorption in the gut and into the blood transfer [9].…”