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The general population is increasingly exposed to cerium (Ce), which is contained in industrial products or is present as nuclear Ce fission products. Some studies suggested a link between elevated Ce levels and endomyocardial fibrosis. Since breast milk is the optimal, and directly after birth, usually the sole nutrition for newborns, exposure of females to Ce and its transfer to infants by breast-feeding is of concern in neonate protection. Consequently, the transfer rate of Ce from blood to breast milk is of interest for elucidating the Ce exposure of infants. Biomonitoring of paired serum and breast milk samples provides such information about Ce transfer to human milk. Therefore, this study is aimed at clarification of the relationship between Ce in human milk and serum from respective mothers for elucidating Ce enrichment in human milk with possible nutritional risk for newborns. As a prerequisite a strictly quality-controlled Ce determination method applicable to very low Ce concentration was developed, and its figures of merit were determined and found to be sufficient for our purpose. It turned out that Ce concentration in milk from Munich (Germany) and Madrid (Spain) showed a median of 13 ng/L. Ce concentrations in serum were at limit of quantification (LOQ) 10 ng/L (Munich) or 21.6-70.3 ng/L (Madrid), suggesting a higher Ce intake in Madrid. No enrichment from blood to milk was seen, and no elevated nutritional risk for breast-fed babies from Ce was found. Ce in serum, but not in milk, could indicate environmental Ce. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to evaluate the relationship between cerium content in human breast milk and blood plasma or serum. Blood samples and breast milk at various stages of lactation, from 5 days to 51 weeks post partum, were donated by 42 healthy breast-feeding mothers from Munich, Germany and by 26 lactating Spanish mothers from Madrid at 4 weeks post partum. Inductively coupled plasma mass spectrometry was applied for the determination of cerium in the biological samples. Cerium concentration in the digested milk samples from Munich showed low values and the arithmetic mean values ranged between the quantification limit of 5ng/L up to 65ng/L. The median value amounted to 13ng/L. The cerium concentrations in the Spanish breast milk samples amounted to similar low values. The data were about a factor of eight lower than values found in a former study of samples from an eastern German province. All cerium concentrations in the German plasma samples, except for two, were at the quantification limit of 10ng/L. Interestingly, the serum samples of the Spanish mothers showed cerium values ranging between 21.6 and 70.3ng/L; these higher data could be explained by an enhanced intake of cerium by humans in Madrid. This could be caused by increased cerium concentrations in particulate matter due to a higher traffic volume in Madrid compared to Munich. The results obtained in this study contribute to setting reference baseline values of cerium in human breast milk and blood plasma/serum and indicate a varying cerium amount depending on the cerium environmental pollution. Possibly, the cerium content in plasma/serum could be an indicator for environmental cerium, which is not valid for breast milk. [Copyright &y& Elsevier]

Abstract: The main aim of this study was to determine and evaluate urinary excretion values of uranium in members of the public of Southwest Nigeria living in areas of low environmental uranium. As several uranium mines are running in Nigeria and the operations could be a risk of contamination for the workers as well as for the members of the public, biomonitoring of urine could provide information about the exposure to uranium for the subjects. Therefore, baseline values of uranium in urine are needed from subjects living in areas without mining activities. Volunteers of both genders (age range 3 to 78years) were asked to collect 24h-urine samples. The concentration measurements of uranium in urine were performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In addition, urinary creatinine values were determined for normalization of the renal uranium relative to the creatinine concentrations. The urinary uranium concentrations and their creatinine normalized values ranged from <10.4 to 150ngL−1 (median 13.8ngL−1) and from 2.52 to 252.7ngg−1 creatinine (median 33.4ngg−1 creatinine), respectively, for adult subjects above 15years of both genders. An increased uranium excretion value of 61.6ngL−1 (median), and of 76.0ngg−1 creatinine, respectively, were found in young subjects below 15years. The median of daily excreted uranium was estimated to be 14.2ngd−1 for adults and of 45.1ngd−1 for children, respectively. The uranium excretion from males and females living in Nigeria in a non-mining area was comparable to reference values reported from other countries with low level of environmental uranium. The data can be considered as baseline values of urinary uranium in unexposed subjects in Nigeria. [Copyright &y& Elsevier]

Abstract: The aim of this case study was to estimate the bioaccessibility of uranium (238U) and thorium (232Th) from a healing earth by analysing the solubility of these radionuclides in synthetic gastric and intestinal fluids. An easy applicable in vitro test system was used to investigate the fractional mobilization of the soil contaminants being potentially available for absorption under human in vivo conditions. These findings provided the basis for a prospective dose assessment. The solubility experiments were performed using two different in vitro digestion methods. The concentrations of 238U and 232Th in the solutions extracted from the soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). The dissolved fractions in the synthetic gastrointestinal fluid ranged in average from 10.3% to 13.8% for 238U and from 0.3% to 1.6% for 232Th, respectively, depending on the digestion method. Subsequently, the committed effective doses from intake of 238U and 232Th after ingestion of the healing earth during 1 year were evaluated for adult persons. Thereby ingestion dose coefficients calculated as a function of bioaccessibility were used. The dose assessments ranged between 4.3×10−7–1.9×10−6 Sv y−1 for 238U and 5.6×10−7–3.3×10−6 Sv y−1 for 232Th, respectively. On the basis of the assumptions and estimations made, the present work indicates a relatively low radiation risk due to 238U and 232Th after internal exposure of the healing earth. [ABSTRACT FROM AUTHOR]