The transport, dispersion, and cycling of tritium in the environment. [Contains Bibliography]

Murphy, C.E. Jr.

doi:10.2172/6324878

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…Apple fruit was taken from each of the trees, peeled, pitted, and stored in sealed glass containers. Apple fruit tissue sampling is based on the following simplifying assumptions: (a) Transpiration tritium signal is conserved in the fruit tissue, albeit at lower fractions of total hydrogen incorporated than the component moving through the plant as tritiated water (Kramer, ; Murphy, ); (b) Majority of tritium (as tissue‐free water tritium) in the fruit tissue comes from the soil (IAEA, ); and (c) There is negligible to nil water loss via the fruit tissue as any cuticular water loss (5–10%) is theoretically possible only via the plant leaf (Boyer et al, ).…”

Section: Methodsmentioning

confidence: 99%

Tritium analysis shows apple trees may be transpiring water several decades old

Zhang

Evaristo

et al. 2017

Hydrological Processes

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Recent work has shown evidence of ecohydrological separation whereby plants appear to use a less mobile soil water pool that does not mix with more mobile soil water, groundwater, and streamflow. Although many elements of this two water worlds hypothesis remain to be tested and challenged, one key question is “how old might the less mobile water used by plants be?” Such a question is methodologically difficult to answer: stable isotope tracing makes it difficult to resolve any water age older than a few years since the signal gets so damped. Tritium—a useful radiogenic isotope and age dating tool, is now difficult to use in natural systems because most bomb tritium has washed out of soil profiles. Here, we leverage new data from an unusually deep, homogenous soil profile that preserves the mid‐1960s tritium bomb signal. We sample the Fuji apple trees (Malus pumila Mil) growing on this site that have root systems that penetrate over 15 m and utilize water from within the bomb peak soil water distribution (extracted via cryogenic extraction). Our data show that water used by these trees is on average 29 years old. Bayesian mixing analysis suggests that 40 ± 30% of fruit tissue water came from depths between 4 and 9 m within the soil profile (36 ± 9 years old); 60 ± 29% was equally divided between 0 and 4 m and 9–15 m ranges (13 ± 5 years old). These findings suggest that trees can use quite old less mobile water, highlighting the separation in ages between more mobile soil water and water in transit in sap flow.

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Section: Methodsmentioning

confidence: 99%

Tritium analysis shows apple trees may be transpiring water several decades old

Zhang

Evaristo

et al. 2017

Hydrological Processes

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“…is about 5% lower (Murphy 1990). In general, the circulation of H-3 would be expected to closely follow that of water.…”

Section: L2 Tritium Submodelsmentioning

confidence: 97%

User's manual for RESRAD version 6.

Yu¹,

Zielen²,

Cheng³

et al. 2001

114

161

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In 1993, a manual on using Version 5 of the RESRAD code to implement the U.S. Department of Energy's (DOE's) residual radioactive material guidelines was released. Since then, as part of the RESRAD quality assurance (QA) program, the RESRAD code has undergone extensive review, benchmarking, verification, and validation. The manual and code have been used widely by DOE and its contractors, the U.S. Nuclear Regulatory Commission, U.S. Environmental Protection Agency (EPA), U.S. Army Corps of Engineers, industrial firms, universities, and foreign government agencies and institutions. New features, some in response to comments received from users, have been incorporated into the code to form RESRAD 6. These improvements have increased RESRAD's capabilities and flexibility and enabled users to interact with the code more easily. With the improvements, the code has become more realistic in terms of the models and default parameters it uses. RESRAD 6 represents the sixth major version of the RESRAD code since it was first issued in 1989. The RESRAD code can now perform uncertainty/probabilistic analyses with an improved probabilistic interface. 1 It uses a preprocessor and a postprocessor to perform probabilistic dose and risk analyses. 2 It incorporates default parameter distributions (based on national average data) for selected parameters. The code can provide analysis results as text reports, interactive output, and graphic output. The results of an uncertainty analysis can be used as a basis for determining the costeffectiveness of obtaining additional information or data on input parameters (variables). 3 The RESRAD code now allows users to calculate the time-integrated dose and risk at userspecified times. The instantaneous dose/risk can be calculated by setting the time integration point to one. The other major changes in the code are a new external exposure model, new area factor xii model for the inhalation pathway, and New Dose Conversion Factor (DCF) Editor. The DCF Editor gives users the ability to change dose conversion factors, transfer factors, and slope factors. Moreover, the RESRAD database was updated. It now includes inhalation and ingestion dose conversion factors from the EPA's Federal Guidance Report No. 11 (FGR-11), direct external exposure dose conversion factors from FGR-12, risk slope factors primarily from the latest health effects and summary tables, and radionuclide half-lives from International Commission on Radiological Protection Publication 38. The risk coefficients from FGR-13 are also available in the code. Version 6 of RESRAD incorporates many improvements made since Version 5 was released. These include the addition of seven new radionuclides: selenium-79, zirconium-93, neodymium-93m, barium-133, curium-245, curium-246, and curium-247. The code was also modified to account for radioactive decay and ingrowth during food storage times. The code now has an improved groundwater model to ensure convergence for K d calculations when water concentrations are known; has an improved radon pa...

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“…Laboratory techniques for doing these analyses were perfected inCY84 [Gr85], and the techniques are documented in the Radiological Environmental Monitoring Laboratory Handbook[REML90]. These baselines are being established because surface soils and vegetation are among the best indicators of tritium deposition after a release[Jo74],[Mu77],[Mu82],[Mu90]. The present, measured concentrations are consistent with those of tritium in the environment.…”

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confidence: 77%

Princeton Plasma Physics Laboratory (PPPL) annual site environmental report for calendar year 1990

Stencel¹,

Finley²

1991

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The transport, dispersion, and cycling of tritium in the environment. [Contains Bibliography]

Cited by 6 publications

References 9 publications

Tritium analysis shows apple trees may be transpiring water several decades old

Tritium analysis shows apple trees may be transpiring water several decades old

User's manual for RESRAD version 6.

Princeton Plasma Physics Laboratory (PPPL) annual site environmental report for calendar year 1990

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