Rapid detection of enriched uranium in food.

We have developed a quadrupole ICP-MS method for detecting sub-picogram quantities of 235U in contaminated foods. Notable features included elimination of the requirement for possessing licensed nuclear materials so that non-radiochemical laboratories may perform this analysis in the event of a large-scale nuclear or radiological emergency calling for high sample surge capacity, elimination of several extremely hazardous reagents in sample analysis e.g. aqua regia and hydrofluoric acid, and the method was developed for applying a moderately priced, and widely used quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS). This method could be quickly implemented at many laboratories to increase emergency response capability.

Uranium in drinking-water: a unique case of guideline value increases and discrepancies between chemical and radiochemical guidelines.

BACKGROUND: Uranium represents a unique case for an element naturally present in the environment, as its chemical guideline value in drinking water significantly increased from 2 µg/L in 1998 up to 15 µg/L in 2004 and then to 30 µg/L in 2011, to date corresponding to a multiplication factor of 15 within a period of just 13 years. OBJECTIVES: In this commentary we summarize the evolution of uranium guideline values in drinking-water based on both radiological and chemical aspects, emphasizing the benefit of human studies and their contribution to recent recommendations. We also propose a simpler and better consistency between radiological and chemical values. DISCUSSION: The current chemical guideline value of 30 µg/L is still designated as provisional because of scientific uncertainties regarding uranium toxicity. During the same period, the radiological guideline for (238)U increased from 4 Bq/L to 10 Bq/L while that for (234)U decreased from 4 Bq/L to 1 Bq/L. These discrepancies are discussed here, and a value of 1 Bq/L for all uranium isotopes is proposed to be more consistent with the current chemical value of 30 µg/L. CONCLUSION: Continuous progress in the domains of toxicology and speciation should enable a better interpretation of the biological effects of uranium in correlation with epidemiological human studies. This will certainly aid future proposals for uranium guideline values.

NUSIMEP-7: uranium isotope amount ratios in uranium particles.

The Institute for Reference Materials and Measurements (IRMM) has extensive experience in the development of isotopic reference materials and the organization of interlaboratory comparisons (ILC) for nuclear measurements in compliance with the respective international guidelines (ISO Guide 34:2009 and ISO/IEC 17043:2010). The IRMM Nuclear Signatures Interlaboratory Measurement Evaluation Program (NUSIMEP) is an external quality control program with the objective of providing materials for measurements of trace amounts of nuclear materials in environmental matrices. Measurements of the isotopic ratios of the elements uranium and plutonium in small amounts, typical of those found in environmental samples, are required for nuclear safeguards and security, for the control of environmental contamination and for the detection of nuclear proliferation. The measurement results of participants in NUSIMEP are evaluated according to international guidelines in comparison to independent external certified reference values with demonstrated metrological traceability and uncertainty. NUSIMEP-7 focused on measurements of uranium isotope amount ratios in uranium particles aiming to support European Safeguards Directorate General for Energy (DG ENER), the International Atomic Energy Agency's (IAEA) network of analytical laboratories for environmental sampling (NWAL) and laboratories in the field of particle analysis. Each participant was provided two certified test samples: one with single and one with double isotopic enrichment. These NUSIMEP test samples were prepared by controlled hydrolysis of certified uranium hexafluoride in a specially designed aerosol deposition chamber at IRMM. Laboratories participating in NUSIMEP-7 received the test samples of uranium particles on two graphite disks with undisclosed isotopic ratio values n((234)U)/n((238)U), n((235)U)/n((238)U) and n((236)U)/n((238)U). The uranium isotope ratios had to be measured using their routine analytical procedures. Measurement of the major ratio n((235)U)/n((238)U) was obligatory; measurement of the minor ratios n((234)U)/n((238)U) and n((236)U)/n((238)U) was optional. Of the twenty-four institutes that registered for NUSIMEP-7, 17 have reported their results achieved by different analytical methods. The results of NUSIMEP-7 confirm the capability of laboratories in measuring n((234)U)/n((238)U), n((235)U)/n((238)U) and n((236)U)/n((238)U) in uranium particles of the size below 1 µm diameter. Furthermore, they underpin the recent advances in instrumental techniques in the field of particle analysis. In addition, feedback from the measurement communities from nuclear safeguards, nuclear security and earth sciences was collected in view of identifying future needs for NUSIMEP interlaboratory comparisons.

Certified reference materials and reference methods for nuclear safeguards and security.

Confidence in comparability and reliability of measurement results in nuclear material and environmental sample analysis are established via certified reference materials (CRMs), reference measurements, and inter-laboratory comparisons (ILCs). Increased needs for quality control tools in proliferation resistance, environmental sample analysis, development of measurement capabilities over the years and progress in modern analytical techniques are the main reasons for the development of new reference materials and reference methods for nuclear safeguards and security. The Institute for Reference Materials and Measurements (IRMM) prepares and certifices large quantities of the so-called "large-sized dried" (LSD) spikes for accurate measurement of the uranium and plutonium content in dissolved nuclear fuel solutions by isotope dilution mass spectrometry (IDMS) and also develops particle reference materials applied for the detection of nuclear signatures in environmental samples. IRMM is currently replacing some of its exhausted stocks of CRMs with new ones whose specifications are up-to-date and tailored for the demands of modern analytical techniques. Some of the existing materials will be re-measured to improve the uncertainties associated with their certified values, and to enable laboratories to reduce their combined measurement uncertainty. Safeguards involve the quantitative verification by independent measurements so that no nuclear material is diverted from its intended peaceful use. Safeguards authorities pay particular attention to plutonium and the uranium isotope (235)U, indicating the so-called 'enrichment', in nuclear material and in environmental samples. In addition to the verification of the major ratios, n((235)U)/n((238)U) and n((240)Pu)/n((239)Pu), the minor ratios of the less abundant uranium and plutonium isotopes contain valuable information about the origin and the 'history' of material used for commercial or possibly clandestine purposes, and have therefore reached high level of attention for safeguards authorities. Furthermore, IRMM initiated and coordinated the development of a Modified Total Evaporation (MTE) technique for accurate abundance ratio measurements of the "minor" isotope-amount ratios of uranium and plutonium in nuclear material and, in combination with a multi-dynamic measurement technique and filament carburization, in environmental samples. Currently IRMM is engaged in a study on the development of plutonium reference materials for "age dating", i.e. determination of the time elapsed since the last separation of plutonium from its daughter nuclides. The decay of a radioactive parent isotope and the build-up of a corresponding amount of daughter nuclide serve as chronometer to calculate the age of a nuclear material. There are no such certified reference materials available yet.

[Improvement of the organization of oncological aid under conditions of specific technogenic load on the population].

Social and economic disbenifits due to mortality from malignant neoplasms were estimated taking into account the losses of man-years of work, mean life expectancy for the sick, losses from temporary disablement and invalidization caused by malignancies, and the cost of oncological aid. The study was based at an area in Uzbekistan subjected to pollution by industrial wastes from an uranium-extracting enterprise. A special purpose-oriented program has been elaborated for the correction of oncological aid currently provided to the workers of the Navoi mining and metallurgical works and the local population. Its implementation resulted in a 13% reduction of standardized mortality from malignant neoplasm in 2004 compared with 1999 and another 24% in 2009. The disbenefit prevented by the reduction of mortality at active ages is estimated at 60,6 mln rubles.

pH dependent separation of uranium by chelation chromatography using pyridine 2,6-dimethanol as a chelator: single crystal X-ray structural confirmation of the chelated uranium complex.

A very effective sorbent material which exhibits exceptional capture of hexavalent uranium from other actinides and lanthanides at microg g(-1) level, features pyridine 2,6-dimethanol immobilized onto alumina. The maximum sorption capacity for dioxouranium(VI) was found as 1.96 mmol g(-1) at pH 3.0. The adsorbed uranium complex was eluted completely by 0.05 mol L(-1) (NH(4))(2)CO(3) solution and the concentration of hexavalent dioxouranium ion was monitored spectrophotometrically using Arsenazo III. The structure of the chelated uranium complex has been confirmed by single crystal X-ray structure analysis and Fourier transform infrared red (FTIR) spectroscopy. Thermo gravimetric analysis/differential thermo gravimetric analysis (TGA/DTG) of the chelated uranium complex was performed. The method is reproducible with a relative standard deviation (RSD) of 1.2% (N=10) and the three sigma detection limits (N=15) 1.2 microg mL(-1) respectively. A pre-concentration factor, almost 500, for uranium was achieved. Interferences from Th(4+), Mn(2+), Ni(2+) and Cu(2+) ions were masked with ethylene diamine tetra acetic acid (di-sodium salt) (Na(2)EDTA) in the aqueous phase. The developed method has been tested for uranium recovery and estimation in some certified reference materials and environmental samples.

The use of pencil lead as a matrix and calibrant for matrix-assisted laser desorption/ionisation.

Pencil lead is shown to be an effective matrix and calibrant in matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry. Various groups of analytes, including peptides, polymers and actinide metals, can be readily ionised using MALDI when deposited onto a pencil lead matrix. The matrix is seen to have advantages in sample preparation relating to its hydrophobic properties and almost complete suppression of the matrix during analysis. Using pencil lead as a matrix is a quick and convenient method of qualitative analysis and has been shown to be quantitative for the isotope ratio analysis of actinide metals.

Performance assessment model development and parameter acquisition for analysis of the transport of natural radionuclides in a Mediterranean watershed.

This paper describes the methodology developed to construct a model for predicting the behaviour of the natural radioisotopes of U, Th and Ra in a Mediterranean watershed. The methodology includes the development of the performance assessment model, obtaining water flow and radiological parameters based on experimental data and analysis of results. The model, which accounts for both water flows and mass balances of the radionuclides in a semi-natural environment, provides assessments of radionuclide behaviour in grassland and agricultural soils, rivers and reservoirs, including the processes of radionuclide migration through land and water and interactions between both. From field and laboratory data, it has been possible to obtain parameters for the driving processes considered in the model, water fluxes, source term definition, soil to plant transfer factors and distribution coefficient values. Ranges of parameter values obtained have shown good agreement with published literature data. This general methodological approach was developed to be extended to other radionuclides for the modelling of a biosphere watershed in the context of performance assessment of a High Level Waste (HLW) repository under Mediterranean climate conditions, as well as for forecasting radionuclide transport under similar Mediterranean conditions that will occur in the future in other areas. The application of sensitivity and uncertainty analysis was intended to identify key uncertainties with the aim of setting priorities for future research. The model results for the activity concentration in the reservoir indicate that for (238)U and (230)Th the most relevant parameter is the initial concentrations of the radionuclides in the reservoir sediments. However, for (226)Ra the most important parameter is the precipitation rate over the whole watershed.

Uranium, radium and radon exhalation studies in geological samples belonging to some areas of punjab, using track etching technique.

With a view to prospect the uranium, radium and radon concentration and related health risk assessments in areas of Muktsar and Ferozepur districts in Punjab, the fission track registration technique has been used for the analysis of water and soil samples. Uranium content in water ranged from 5.47 to 10.19 microg/l(-1) and 6.28 to 11.74 microg/l(-1) for Muktsar and Ferozepur respectively. Uranium content in soil samples of Muktsar and Ferozepur ranged from 1.14 to 1.90 mg/kg(-1) and 1.26 to 2.44 mg/kg(-1) respectively. Radium concentration in these soil samples has been found to vary from 3.97 to 15.94 bq/kg(-1) and 7.24 to 24.14 bq/kg(-1) for Muktsar and Ferozepur respectively. The radon exhalation values were calculated in terms of area (E(A)) and mass (E(M)). The values of E(M) ranged from 4.9 to 20.6 (mbqkg(-1) hr(-1)) for Muktsar and 9.4 to 31.3 (mbqkg(-1)hr(-1)) for Ferozepur and values of E(A) ranged from 173 to 728 (mbqm(-2)hr(-1)) for Muktsar and 330 to 1102 (mbqm(-2)hr(-1)) for Ferozepur district. These values in general are low and not significant from health hazard point of view. The values of uranium concentration in water samples of these areas are lower than those reported for soil and water samples of Himachal Pradesh. These values are also lower than those reported by Singh et al. for the rocks belonging to uranium and copper mines of Bihar.

Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides.

Daily dietary intakes of two naturally occurring long-lived radionuclides, 232Th and 238U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of 232Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of 238U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for 232Th and 12.7 mBq for 238U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 ug) 232Th and 23.6 mBq (1.9 ug) 238U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq 232Th and 15.6 mBq 238U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of 232Th and 238U were calculated to be 0.34 and 0.20 microSv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 microSv to man from the natural radiation sources as proposed by UNSCEAR.

A simplified method to create quantitative, "fixed" uranyl-contaminated metal coupons.

A method was developed and validated to quantitatively apply and "fix" uranyl contamination onto a metal surface (steel). Simple approaches are needed to create test surfaces in order to quantify contaminant removal or "decon" methods. We used steel discs sized to allow direct and accurate alpha counting in a Ludlum scanner from radioactive contaminants. A typical 3.8-cm-diameter coupon had a depleted uranyl loading of about 0.1 mg U cm with a count of 980 dpm. The resulting alpha radiation was measured with a precision of >97% for the same coupon. The alpha concentration on replicate coupons differed by as much as 9% (standard deviation). This method, based on earlier methods, required a uranyl solution to be dried but lowers the baking temperature to less than 100 degrees C to increase safety in a typical radiological laboratory. A dike was used to provide a uniform coating of the uranyl solution.

A critical review of experimental data for the half-lives of the uranium isotopes 238U and 235U.

The existing experimental data for the half-lives of the uranium isotopes 238U and 235U have been scrutinised in detail because of their significant practical importance, in particular for geochronogical use and for the assay of standard samples used for neutron fluence and cross-section measurements. The most accurate measurements by Jaffey et al. (Phys. Rev. C 4 (5) 1889) with 1sigma uncertainties of 0.054% (238U) and 0.068% (235U), are not confirmed by other measurements of comparable accuracy. In this work, we take a critical look at the 238U and 235U half-life measurements in the literature. Although we find that the Jaffey et al. data are concordant with other reliable results, generally much higher uncertainties of the latter cannot prove or disprove the Jaffey et al. results. Therefore, at this time, we do not recommend new half-life values. Instead, we call for new measurements of these two half-lives with accuracies comparable to the work of Jaffey et al.

Beverages: bottled water. Direct final rule.

The Food and Drug Administration (FDA) is amending its bottled water quality standard regulations by establishing an allowable level for the contaminant uranium. As a consequence, bottled water manufacturers are required to monitor their finished bottled water products for uranium at least once each year under the current good manufacturing practice (CGMP) regulations for bottled water. Bottled water manufacturers are also required to monitor their source water for uranium as often as necessary, but at least once every 4 years unless they meet the criteria for the source water monitoring exemptions under the CGMP regulations. FDA will retain the existing allowable levels for combined radium-226/-228, gross alpha particle radioactivity, and beta particle and photon radioactivity. This direct final rule will ensure that the minimum quality of bottled water, as affected by uranium, combined radium-226/-228, gross alpha particle radioactivity, and beta particle and photon radioactivity, remains comparable with the quality of public drinking water that meets the Environmental Protection Agency's (EPA's) standards. FDA is issuing a direct final rule for this action because the agency expects that there will be no significant adverse comment on this rule. Elsewhere in this issue of the Federal Register, FDA is publishing a companion proposed, rule under the agency's usual procedure for notice-and-comment rulemaking, to provide a procedural framework to finalize the rule in the event the agency receives any significant adverse comments and withdraws this direct final rule. The companion proposed rule and direct final rule are substantively identical.

The 1999 Lauriston S. Taylor lecture--back to background: natural radiation and radioactivity exposed.

I am profoundly grateful for being chosen as the twenty-third presenter of the Lauriston S. Taylor Lecture, and I share this honor with a list of distinguished scientists, including my husband, who pay tribute to the premier leader in radiation protection. In 1938, Laurie was working for the National Bureau of Standards and chaired the Advisory Committee on X-ray and Radium Protection, a group of 8 persons, who set the pace for all forthcoming radiation standards. NBS had, since 1913, been standardizing essentially all of the radium offered for sale in the U.S., and the problem arose to revise the handbook on proper conditions for handling radium based on the then current knowledge. This resulted in Handbook 23 (1938) superseding the 1934 work. At the time Laurie was a scientist working in the measurements side of radiation and though he contributed much to that field, his name is inseparably linked with guidance in radiation protection. Today we pay tribute for his leadership that he carried out with intelligence, grace, and personal warmth. My talk today deals mostly with measured data for naturally occurring internal radiation emitters and how these data can be used for predictive purposes in estimating the dose and risk from internal body contamination. This stresses the "and Measurements" part of the Council's title. The topic of this year's NCRP Annual Meeting is "Radiation Protection in Medicine: Contemporary Issues." I believe that physicians and State and Federal agencies will have to cope with complaints following various exposure situations resulting from the cleanup of background radionuclides during closure at nuclear facilities, military use of radioactivity, and occurrences of high natural background in some locations. They will find comfort in the knowledge that existing background radiation data can be the basis for predictions of realistic dose and risk in most situations.

Nephrotoxic limit and annual limit on intake for natural U.

Our experience with a U-intoxicated patient and human data in the literature suggest the kidney U burden should not be allowed to exceed 0.26 micrograms g-1. The Annual Limit on Intake (ALI) for natural U was calculated from the chemical toxicity of U and was found to be lower than that reported previously.