Contamination of Plant Follage with Radioactive Fallout

Romney, E. M.; Lindberg, R. G.; Hawthorne, H. A.; Bystrom, B. G.; Larson, K.H.

doi:10.2307/1932181

Cited by 51 publications

(19 citation statements)

References 11 publications

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“…Measurements made at the Nevada Test Site indicate that particles larger than 40 , are not likely to be retained on plant leaves. Larger particles may lodge tenaciously in leaf axils, leaf sheaths, and bases of grasses, but most particles produced by desert detonations and intercepted by vegetation were in the range of 0.5 to 5.0 ,u (18).…”

Section: Foliar Uptake Of Fallout Radionuclidesmentioning

confidence: 99%

Accumulation of Radionuclides by Plants as a Monitor System

Koranda¹,

Robison²

1978

Environmental Health Perspectives

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The accumulation of radionuclides by plants acting as a monitoring system in the environment may occur by two modes; foliar absorption by the leaves and shoot ofthe plant, or by root uptake from the soil. Data on plant accumulation of radionuclides may be obtained from studies of fission product radionuclides deposited as worldwide fallout, and from tracer studies of plant physiology.The epidermal features of plant foliage may exert an effect upon particle retention by leaves, and subsequent uptake of radionuclHdes from the surface. The transport of radionuclides across the cuticle and epidermis of plant leaves is determined in part by the anatomy of the leaf, and by physiological factors.The foliar uptake of fallout radionuclides, "'Sr, 131I, and 137Cs, is described with examples from the scientific literature. The environmental half-life of 131I, for example, is considerably shorter than its physical half-life because of physical and biological factors which may produce a half-life as short as 0.23/day. 9'Sr and 137Cs are readily taken up by the leaf, but '37Cs undergoes more translocation into fruit and seeds than "°Sr which tends to remain in the plant part in which it was initially absorbed.Soil-root uptake is conditioned primarily by soil chemical and physical factors which may selectively retain a radionuclide, such as '37Cs. The presence of organic matter, inorganic colloids (clay), and competing elements will strongly affect the uptake of 9°Sr and 137Cs by plants from the soil.The role of plants as monitors of radionuclides is twofold: as monitors of recent atmospheric releases of radionuclides; and as indicators of the long-term behavior of aged deposits of radionuclides in the soil.

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Section: Foliar Uptake Of Fallout Radionuclidesmentioning

confidence: 99%

Accumulation of Radionuclides by Plants as a Monitor System

Koranda¹,

Robison²

1978

Environmental Health Perspectives

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“…The concentration of a radionuclide on fallout-contaminated foliage, C(t), as a function of time after fallout is usually approximated by C ( t ) = c; e--1pt ( 3 ) where ?.fi is the effective decay constant for the radionuclide and is equal to 0.693/T,. The effective half-life, T,, of the radionuclide on foliage is given by…”

Section: Romney Et Al(3)mentioning

confidence: 99%

Retention of a Fallout Simulant Containing 134Cs by Pine and Oak Trees

Witherspoon¹,

Taylor²

1969

Health Physics

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Small white pine (Pinus strobus) and red oak (Quercus rubra) trees were contaminated in the field with a fallout simulant consisting of 88-175 ,u dia. quartz particles containing 134Cs. Whole plants were harvested at intervals up to 33 days after application of the simulant, and the lacs retention by each species was determined.The initial fraction of the simulant retained by foliage was higher in the oaks (0.35) than in the pines (0.24). However, after 1 hr, the broad leaved oaks had lost 90.5% of the initial 134Cs concentrations while the pines had lost only about 10%. These early retention differences are related to the effects of wind on the two distinct foliage types.Effective half-lives were calculated for both species at intervals of 0-1 day, 1-7 days and 7-33 days. For pine trees these values were 0.25, 4.53 and 20.66 days, respectively. For oaks they were 0.12, 1.41 and 24.86 days. Loss of particles (13%s) was due, primarily, to the weathering action of wind and rain during the study. The effects of wind and the first rain following contamination accounted for a large percentage of the total radionuclide loss during the study.

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“…Particles < 50A in diameter are more readily trapped on plant foliage than are particles of larger diameter and these smaller particles are (32) The radionuclides contained in fallout particles may enter plant tissue via roat absorption (29,30) (27,34) (33) , foliar absorption , or stem-base absorption Because these processes are relatively slow or because the amount of activity involved is small in relation to the activity of external deposits, the actual assimilation of radionuclides by plants is of little significance in -regard to the early food-chain kinetics in a fallout-contaminated ecosys tem.…”

Section: Disclaimermentioning

confidence: 99%

“…. Studies now in progress (32) (26) show that nearly all the ·radioactive particles on the foliage of plants in the Sedan fallout field were < 50K in diameter, and about half were < 20g in diame ter.…”

Section: An Evaluation Of the Model's Performancementioning

confidence: 99%