Americium determination

Boulyga, S. R, Desideri, D., Meli, M. A., Testa, C., and Becker, J. S. 2003. Plutonium and americium determination in mosses by laser ablation ICP-MS combined with isotope dilution technique. Int J Mass Spectrom 226(3), 329-339. 

Spent Zirflex Process Decladdent. The basic perceived need is to devise an3 develop a simple process for selective and efficient removal of plutonium (and 21 1Am) from spent Zirflex process decladdent solution. To satisfy this need, it may be necessary--or prove beneficial—to determine, by appropriate physiochemical methods, the nature of the plutonium (and americium) species in the decladding solution. Availability of a satisfactory transuranium removal scheme may be one of the key factors in devising an alternative to storage in expensive double-shell tanks for spent Zirflex process solution at the Hanford site. 

The extent of these reactions will be determined by the reaction free energy and concentration for each of the impurities in the molten anode/electrolyte salt system. Americium can be used as an example of a very electropositive impurity ... 

Dacheux N, Aupiais J (1997) Determination of uranium, thorium, plutonium, americium, and curium ultratraces by photon electron rejecting alpha liquid scintillation. Anal Chem 69 2275-2282 Duan YX, Chamberlin EP, Olivares JA (1997) Development of a new high-efficiency thermal ionization source for mass spectrometry. Inti JMass Spectrom IonProcessesl61 27-39 Edwards RL, Chen JH, Wasserburg GJ (1987) systematics and the precise... 

Analytical Methods for Determining Americium in Biological Samples... 

If you are exposed to americium, many factors determine whether you ll be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider the other chemicals you re exposed to and your age, sex, diet, family traits, lifestyle, and state of health. 

IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN EXPOSED TO AMERICIUM ... 

Bone is divided into trabecular and cortical components, with each further divided into surface bone, bone volume, and bone cavity (marrow compartment). Deposition of americium is assumed to occur from plasma directly to bone surfaces, whereas elimination from bone occurs by transfer from the bone surface or volume to the marrow cavity, and then from the marrow cavity to plasma (Figure 3-6). Transfers of americium within the cortical or trabecular bone compartments are modeled based on assumptions about rates of bone formation and resorption, which are assumed to be vary with age, but are equal within a given age group (Leggett et al. 1982). Movement of americium to the marrow compartment is determined by the bone resorption rate, whereas, movement from the bone surface to the bone volume is assumed to occur by burial of surface deposits with new bone and is determined by the bone formation rate. During growth, bone formation and resorption are assumed to occur at different sites within bone therefore, the rate of removal of americium from the bone surface is approximated by the sum of the bone resorption rate (represented in the model by the movement of americium to the marrow compartment) and the rate of bone... 

Metabolism. As noted in Section 3.4.3, the metabolism of americium consists of binding interactions with proteins and probably complex formation with various inorganic anions such as carbonate and phosphate, and carboxylic acids such as citrate and lactate (Durbin 1973 Taylor 1973 Webb et al. 1998). Experiments have not been conducted to determine whether americium binds to metallothionein, but such binding is not likely. 

Section 104(i)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the Administrator of EPA and agencies and programs of the Public Health Service) to assess whether adequate information on the health effects of americium is available. Where adequate information is not available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the initiation of a program of research designed to determine the health effects (and techniques for developing methods to determine such health effects) of americium. 

Accuracy of in vivo and in vitro measurements of americium is determined through the use of standard, certified radioactive sources with known concentrations of americium. The primary source of certified americium standards is the National Institute of Standards and Technology (NIST). Standard solutions are available for241 Am (SRM 4322, 40 Bq/g [1.1 nCi/g]) and 243Am (SRM 4332, 40 Bq/g [1.1 nCi/g]). Standard Reference Materials for human lung (SRM 4351) and human liver (SRM 4352) are also available from NIST. 

There are methods available to quantify the total mass of americium in environmental samples. Mass spectrometric methods provide total mass measurements of americium isotopes (Dacheux and Aupiais 1997, 1998 Halverson 1984 Harvey et al. 1993) however, these detection methods have not gained the same popularity as is found for the radiochemical detection methods. This may relate to the higher purchase price of a MS system, the increased knowledge required to operate the equipment, and the selection by EPA of a-spectrometry for use in its standard analytical methods. Fluorimetric methods, which are commonly used to determine the total mass of uranium and curium in environmental samples, have limited utility to quantify americium, due to the low quantum yield of fluorescence for americium (Thouvenout et al. 1993). 

Methods for Determining Biomarkers of Exposure and Effect. Analytical methods with satisfactory sensitivity and precision are available to determine the levels of americium in human tissues and body fluids. However, improved methods are needed to assess the biological effects of americium in tissues. 

Methods for Determining Parent Compounds and Degradation Products in Environmental Media. Analytical methods with the required sensitivity and accuracy are available for quantification of americium, both total and isotopic, in environmental matrices (see Table 7-2). Knowledge of the levels of americium in various environmental media, along with the appropriate modeling (see Chapters 3 and 5), can be used to evaluate potential human exposures through inhalation and ingestion pathways. 

Bomben AM, Equillor HE, Oliveira AA. 1994. Simultaneous biphasic liquid scintillation determination of americium and plutonium. J Radioanal Nucl Chem 177(l) 27-37. 

Dacheux N, Aupiais J. 1997. Determination of uranium, thorium, plutonium, americium, and curium ultratraces by photon electron rejection a liquid scintillation. Anal Chem 69 2275-2282. 

Dacheux N, Aupiais J. 1998. Determination of low concentrations of americium and curium by photon/electron rejecting alpha liquid scintillation. Anal Chim Acta 363 279-294. 

Directorate of Fisheries Research. 1990. Determination of alpha-emitting nuclides of plutonium, americium and curium in environmental materials Pt. 1. Seawater. Lowestoft, England Directorate of Fisheries Research. NTIS/DE92614732. 

Guogang J, Testa C, Desideri D, et al. 1998. Sequential separation and determination of plutonium, americium-241 and strontium-90 in soils and sediments. J Radioanal Nucl Chem 230(l-2) 21-27. 

Hafez MB, Hafez N. 1992. Quantitative determination of americium in biological materials. J Radioanal Nucl Chem 164(2) 81-89. 

Ham GJ, Stradling GN, Breadmore SE. 1977. Determination of americium and curium in biological samples of extraction and liquid scintillation. Anal Chem 49 1268-1270. 

Jia G, Desideri D, Guerra F, et al. 1997. Determination of plutonium and americium in moss and lichen samples. J Radioanal Nucl Chem 220(1) 15-19. 

Knab D. 1979. Determination of americium in small environmental samples. Anal Chem 51(7) 1905-1907. 

Poupard D, Jouniaux B. 1990. Determination of picogram quantities of americium and curium by thermal ionization mass spectrometry (TIMS). Radiochim Acta 41(l) 25-28. 

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