Tritium environmental samples

Mass Spectrometer. The mass spectrometer is the principal analytical tool of direct process control for the estimation of tritium. Gas samples are taken from several process points and analy2ed rapidly and continually to ensure proper operation of the system. Mass spectrometry is particularly useful in the detection of diatomic hydrogen species such as HD, HT, and DT. Mass spectrometric detection of helium-3 formed by radioactive decay of tritium is still another way to detect low levels of tritium (65). Accelerator mass spectroscopy (ams) has also been used for the detection of tritium and carbon-14 at extremely low levels. The principal appHcation of ams as of this writing has been in archeology and the geosciences, but this technique is expected to faciUtate the use of tritium in biomedical research, various clinical appHcations, and in environmental investigations (66). 

Pointurier, F., N. Baglan, and G. Alanic (2004) A method for the determination of low-level organic-bound tritium activities in environmental samples. Applied Radiation and Isotopes. 61,293-298. 

Moghissi, A. A., Bretthauer, E. W., and Compton, E. H. 1973. Separation of water from biological and environmental samples for tritium analysis. Anal Chem 45, 1565-1566. Momyer, F., Jr. 1960. The Radiochemistry of the Rare Gases. National Academy of... 

A widely used instmment for air monitoring is a type of ionization chamber called a Kaimn chamber. Surface contamination is normally detected by means of smears, which are simply disks of filter paper wiped over the suspected surface and counted in a windowless proportional-flow counter. Uptake of tritium by personnel is most effectively monitored by urinalyses normally made by Hquid scintillation counting on a routine or special basis. Environmental monitoring includes surveillance for tritium content of samples of air, rainwater, river water, and milk. 

After extensive effort to perfect the method, it was found that environmental water and memory effects occurred in the bomb reactors. Since the reactor had to be opened to change the zinc and add the water sample, environmental water was adsorbed in the reactor. Neither the environmental contamination nor memory effects could be removed completely by evacuating the reactor within a reasonable time. This technique is promising, but further work must be done to eliminate these problems before it can be used routinely for low level tritium analysis. 

Konno, T. and Suguro, H., A method for the determination of tritium in environmental water samples by electrolytic enrichment. Radioisotopes 35 1 (1986) 1-8. 

The primary focus of this study was to address the basic question - How consistent are the radionuchde concentrations in bee samples If one of the primary objectives is to eventually use data collected from honey bees as part of an environmental monitoring program, or more importantly, as input into an ecological risk assessment model, then one would hope there is a certain degree of consistency between samples. In other words, if 25 samples were collected from a beehive, and each one was analyzed for tritium, one would assume there would be relative consistency between the radiochemical analytical results. A large disparity in the concentrations of tritium in bee samples would make the results suspect. In this study, first the consistency of bee samples collected from a single colony was examined. Second, the consistency of samples collected from several colonies in the same location was assessed. 

ROUTINE ANALYSIS OF AMBIENT TRITIUM LEVELS IN ENVIRONMENTAL WATER SAMPLES... 

The measurement of low-level tritium concentrations in discrete environmental water samples has been routinely accomplished by applying standard liquid scintillation counting techniques directly to a small aliquot of the original sanple or to a portion of the sample which has been pretreated. Two of the more common sample preparation methods are simple distillation at atmospheric pressure and electrolytic enrichment with a subsequent increase in the tritium content of the sample. 

Recently, the Yankee Atomic Electric Company, Environmental Laboratory, has determined the tritium levels in water samples from the environs of several nuclear generating facilities in the New England area by liquid scintillation analysis of high purity tritiated benzene prepared from the water samples to be quantified. A commercially available unit was utilized to facilitate the synthesis of benzene by reacting the water sample with calcium carbide to form tritiated acetylene which is subsequently trimerized on a vanadium catalyst to high purity tritiated benzene. 

This paper addresses two methods available for the routine analysis of aqueous tritium samples at the 100-200 pCi/1 level or greater. The development of these methods are particularly timely considering the recent Nuclear Regulatory Commission (NRC) Guide 4.8 (1975) which sets the Minimum Detectable Concentration (MDC) for tritium in environmental waters surrounding nuclear generating stations at 330 pCi/1. These two methods not only meet this MDC for tritium values encountered in varied aquatic environs but also qualify in three other areas (a) ease of sample preparation, (b) capability to... 

Three methods of tritium analyses were reviewed by the Yankee Atomic Environmental Laboratory (YAEL) prior to selection of a preferred method to use in their tritium analysis program. The first method considered entailed a sample preparation procedure encompassing distillation of the aqueous samples at atmospheric pressure followed by LS counting using an aqueous cocktail. The second procedure reviewed entailed elec-... 

Precise liquid scintillation counting (LSC) methods to measure environmental tritium concentrations generally require enrichment of the samples (Ampur, 1974, Brown and Grummitt, 1956, Gentry a., 1973, Sauzay and Schell, 1972, Theodorsson, 1974). Enrichment by either electrolytic or... 

A new method for measuring environmental tritium levels without enrichment was recently developed by the authors (Cawley t al , 1980). This method is basically a double isotope, external standard count procedure which eliminates the background by measuring tritium free water scimples ("dead water" samples) and applying a difference method. 

The most delicate part of the method developed to measure environmental tritium levels is the elimination of the background. A difference method has been applied for this purpose using "dead water" samples, i.e. tritium free water samples obtained from National Bureau of Standards. 

The environmental and dead water samples exhibit quenching characteristics falling into the range of 0.5 - 0.6 quenched standards (Packard Instrument Co.) for tritium and carbon-14. During each cycle an efficiency calibration using the quenched standards is made. A cycle consists of counting the 15 sample vials, 2 or more vials of dead water, and the 4 quenched standards (two carbon-14 and two tritium standards). The selected count period is 20 minutes. 

This method of measuring environmental tritium requires neither the large capital costs nor the large operating expenses of the enrichment techniques. While counting times may be long, the sample requires minimal preparation. 

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