The Health Risks from Exposure to Uranium: Advanced Biochemical and Biophysical Aspects (original) (raw)
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Jacobs Journal of Epidemiology and Preventive Medicine Uranium Epidemiology
Editorial Cite this article: Busby C. Uranium Epidemiology. J J Epidemiol Prevent. 2015, 1(2): 009. The anomalous biological effects of exposure to Uranium are discussed and relevant studies are cited and shown to underpin the belief that Uranium represents an important health hazard whose assessment through the concept of absorbed dose has resulted in significant harm to human populations. The Editorial calls for a new realization of the hazards of Uranium exposure and for further studies to estimate the true coefficients of harm.
Cancer Causes & Control, 2011
Objective To study the cancer risk related to protracted, low-dose exposure to different industrial uranium compounds, paying attention to their isotopic composition and solubility. Methods Two thousand and ninety-seven workers employed at the AREVA NC uranium processing plant (France) were followed up for mortality from 1960 to 2006. Historical exposure to uranium and other carcinogenic chemical and physical pollutants was assessed on the basis of the plant-specific job-exposure matrix. For each type of uranium, Cox regression models stratified on sex and calendar period, and adjusted for socioeconomic status and potentially confounding co-exposures were used to estimate hazard ratios (HRs) for mortality from lung cancer (53 deaths) and lymphatic and hematopoietic tissue malignancies (21 deaths). Results We observed that exposure to reprocessed uranium entails increasing risks of mortality from lung cancer and lymphatic and hematopoietic malignancies (the most significant HR being respectively 1.14 (95% CI: 1.00-1.31) and 1.20 (95% CI: 1.01-1.43) per unit of a time-lagged log-transformed continuous exposure scores), and that the HRs tend to increase with decreasing solubility of the compounds. Conclusion Our results suggest that uranium carcinogenicity may depend on isotopic composition and solubility of uranium compounds. This study is the first to show the carcinogenic effect of slowly soluble reprocessed uranium on two uranium target organs. This finding is consistent with data from epidemiological and experimental studies on similar compounds but need to be confirmed in the more powerful dose-response analysis.
A quantitative comparison of the chemo- and radiotoxicity of uranium at different enrichment grades
Toxicology Letters, 2019
The radiotoxic effects of uranium are often in the focus of the public fears but the chemical toxic effects of uranium are reported to surpass radiation effects. As there is no uranium isotope that is not radioactive, it is not possible to study chemical effects fully independently from radiation effects. In order to quantitate and compare radio-and chemotoxicity, we determined the median lethal doses of uranium due to its chemical toxicity and calculated the absorbed radiological doses resulting from the ingestion or inhalation of corresponding amounts depending on the isotopic enrichment grade. Committed effective doses over 50 years are related to the stochastic health effects like cancer occurrence and can be converted to a loss of statistical life time (mean loss 0.4 day / mSv). The equivalent doses absorbed within a short time frame permits conclusion on the induction of deterministic effects (e.g. acute radiation sickness). Method: Simulations were based on the biokinetic models of the International Commission for Radioprotection and performed using Integrated Modules for Bioassay Analysis software. Results were compared with the doses given by the calculator of the WISE uranium project. The fractions of the total doses absorbed within different time periods were derived from the respective areas under the activity-time curves in the whole body. Results: The distribution of the total dose on the organs and tissues depends on the invasion pathway and the solubility of the compound. In the case of inhalation, the absorption of the total dose is more protracted than after ingestion. The incorporation of depleted or natural uranium in lethal amounts due to nephrotoxicity does not lead to deterministic radiation effects and is associated with committed effective doses reaching at most about 200 mSv (proposed possible threshold for therapeutic interventions after accidental radionuclide incorporation). The inhalation of low enriched uranium leads to higher effective doses up to 690 mSv, but they are still insufficient to cause acute deterministic effects. Even highly enriched uranium seems not to induce radiation nephropathy, but deterministic effects on the hematopoetic system cannot be excluded in particularly sensitive patients. But the equivalent doses to the lungs associated with the inhalation of poorly soluble compounds of highly enriched uranium are in a range that may induce radiation pneumonitis. Conclusion: Our findings give clear evidence that for depleted and natural uranium chemical toxicity is much more marked than radiotoxicity. However, this conclusion must not be drawn for enriched and in particular highly enriched compounds that besides stochastic effects may even cause deterministic radiation effects.
Toxicological risk assessment of protracted ingestion of uranium in groundwater
Environmental Geochemistry and Health, 2018
Groundwater samples have been collected from far-reaching locations in Solan and Shimla districts of Himachal Pradesh, India, and studied for uranium concentration using LED fluorimetry. In this region, uranium in groundwater varies from 0.12 to 19.43 lg L-1. Radiological and chemical toxicity is accounted for different uranium isotopes. The average mortality risk for uranium isotopes 234 U, 235 U, and 238 U are 2.6 9 10-12 , 3.5 9 10-10 , and 5.9 9 10-8 , respectively. Similarly, the mean morbidity risk for 234 U, 235 U and 238 U are 4.1 9 10-12 , 5.6 9 10-10 and 9.5 9 10-8 , respectively. An attempt has also been made to calculate doses for different age-groups. Highest doses, ranging from 0.30 to 48.23 lSv year-1 , are imparted to infants of 7-12 months of age which makes them the most vulnerable group of population. Using Hair Compartmental Model for uranium and mean daily uranium intake of 3.406 lg for 60-year exposure period, organspecific doses due to uranium radioisotopes, retention in prime organs/tissues and excretion rates via urine, feces and hair pathway are estimated. In this manuscript, the transfer coefficients for kidney, liver, skeleton, GI tract, soft tissues, urinary bladder, and blood are analyzed. Hair compartment model and ICRP's biokinetic model are compared in terms of uranium load in different organs after 60 years of protracted ingestion. The study on biokinetic behavior of uranium is the first of its kind in the area which is dedicated to environmental and social cause. Keywords Uranium biokinetics Á LED fluorimetry Á Hazard quotient Á Lifetime average daily dose Á Ageadjusted dose Á Organ-specific dose Á Transfer coefficients
Jacobs Journal of Epidemiology and Preventive Medicine: , 2015
Uranium Epidemiology has shown in last 10 years that exposure to the element, especially in the form of micro and nano particles generates genetic damage and cancer far in excess of any predicted by the current radiation risk model.
BioMed Research International, 2014
Uranium level in drinking water is usually in the range of microgram-per-liter, but this value may be as much as 100 to 1000 times higher in some areas, which may raise question about the health consequences for human populations living in these areas. Our purpose was to improve knowledge of chemical effects of uranium following chronic ingestion. Experiments were performed on rats contaminated for 9 months via drinking water containing depleted uranium (0.2, 2, 5, 10, 20, 40, or 120 mg/L). Blood biochemical and hematological indicators were measured and several different types of investigations (molecular, functional, and structural) were conducted in organs (intestine, liver, kidneys, hematopoietic cells, and brain). The specific sensitivity of the organs to uranium was deduced from nondeleterious biological effects, with the following thresholds (in mg/L): 0.2 for brain, >2 for liver, >10 for kidneys, and >20 for intestine, indicating a NOAEL (No-Observed-Adverse-Effect Level) threshold for uranium superior to 120 m g/L. Based on the chemical uranium toxicity, the tolerable daily intake calculation yields a guideline value for humans of 1350 g/L. This value was higher than the WHO value of 30 g/L, indicating that this WHO guideline for uranium content in drinking water is very protective and might be reconsidered.
Uranium in drinking water: a public health threat
Archives of Toxicology, 2020
Uranium (U) has no known essential biological functions. Furthermore, it is well known for its toxicity, radioactivity, and carcinogenic potency. Impacts on human health due to U exposure have been studied extensively by many researchers. Chronic exposure to low-level U isotopes (radionuclides) may be interlinked with cancer etiology and at high exposure levels , also kidney disease. Other important issues covered U and fertilizers, and also U in soils or human tissues as an easily measurable indicator element in a pathophysiological examination. Furthermore, phosphate fertilization is known as the important source of contamination with U in the agricultural land, mainly due to contamination in the phosphate rock applied for fertilizer manufacture. Therefore, long-term usage of U-bearing fertilizers can substantially increase the concentration of U in fertilized soils. It should also be noted that U is an active redox catalyst for the reaction between DNA and H 2 O 2. This review is aimed to highlight a series on various hydro-geochemical aspects in different water sources and focused on the comparison of different U contents in the drinking water sources and presentation of data in relation to health issues.
Uranium exposure of the Swiss population based on 24-hour urinary excretion
Swiss Medical Weekly, 2020
AIM OF THE STUDY: Important regional differences in uranium exposure exist because of varying uranium concentrations in soil, water and food. Comprehensive data on the exposure of the general population to uranium is, however, scarce. Based on the 24-hour urinary excretion, the uranium exposure of the adult Swiss population was assessed in relation to age, sex, place of residence, body mass index (BMI), smoking habit and type of drinking water, as well as risk factors in relation to kidney impairment and indicators of a possible renal dysfunction. METHODS: Uranium was quantified in 24-hour urine from a nationwide population-based sample (n = 1393). The ratio 238 U/ 233 U was measured for isotope dilution calibration with a sector field inductively coupled plasma mass spectrometer (HR-ICP-MS). RESULTS: Overall median and 95th percentile were 15 and 67 ng/24 h, respectively. The place of residence significantly influenced urinary uranium excretion. However, most of the highest urinary uranium excretion levels could not be associated to areas known for their elevated uranium concentrations in the drinking water. Sources other than the local drinking water (e.g., bottled water) might be important, too. Gender as well as albumin excretion also had a significant effect on uranium excretion. The latter was, however, strongly dependent on the presence of diabetes mellitus. No association was found for age, BMI, smoking habit or the other examined kidney related variables. CONCLUSIONS: On the basis of uranium exposure, assessed via 24-hour urinary uranium excretion, and current knowledge of the toxicity of naturally occurring uranium, a substantial corresponding health risk for the general adult population is unlikely. However, as long as no specific sensitive biomarker for the biological impact of low-dose chronic uranium exposure has been identified and validated, assessing subtle health impact of such exposure will remain difficult.