.
.
•
...
I OFI
ORNL P.
1239
-
;
.
.
.
.
E
|| 1.1
12.0
||1:25 .1.4 1.16
MICROCOPY RESOLUTION TEST CHART
NATIONAL BUREAU OF STANDARDS - 1963
1.
A
LEGAL NOTICE
This report was prepared as an account of
Government sponsored work. Neither the
United States, nor the Commission, nor any
person acting on behalf of the Commission:
A. Makes any warranty or representa-
tion, expressed or implied, with respect to
the accuracy, completeness, or usefulness
of the information contained in this report,
or that the use of any information, appa-
ratus, method, or process disclosed in this
report may not infringe privately owned
rights; or
B. Assumes any liabilities with respect
to the use of, or for damages resulting from
the use of any information, apparatus,
method, or process disclosed in this report.
As used in the above, “person acting on
behalf of the Commission” includes any em-
ployee or contractor of the Commission, or
employee of such contractor, to the extent
that such employee or contractor of the
Commission, or employee of such contractor
prepares, disseminates, or provides access
to, any information pursuant to his employ-
ment or contract with the Commission, or
his employment with such contractor.
.
+
LAT
197
ORNA-P-1839
DUPA
doo
CONF-650523
MAY 1 7 1968
ORNI - AIC - OINICIAL
MOVEMENT OF ICS BY RUNOFF, EROSION, AND INFILTRATION
ON THE ALLUVIAL CAPTINA SIIT LOAMA
A. S. Rogowski and Tsuneo Tamra
|
-
- '.
...
Health Physics Division
Oak Ridge National Laboratory
Oak Ridge, Tennessee
,
334
* . + 1
ABSTRACT

Five millicuries of 'Cs were applied in the form of spray to the
5-m? plots of the Captina soil in Tennessee under bare, clipped meadow,
and tall meadow cover conditions. During the initial 81-day period agree-
ir
.
137
.
ki
.
int
1.
W
.
ment was observed between predicted and experimental soil 1088. Linear
relationship on a full log scale was found between the soil and +31C8 2088.
On the plots with vegetation, it was found that practically all of
the 37Cs applied to the areas covered with vegetation was initially on
the plant and litter material. The leaching of +37€8 from the vegetation
began to level off towards the end of the study period (20.5 cm of rain).
At the end of the 81-day period, the bare plot had lost 11.9% of the cesium
while the clipped meadow and tall meadow plots had lost 5.1% and 2.6% of
their cesium respectively.
.
.
ra
PATENT. CLEARANCE OBTAINED. RELEASE TO
THE PUBLIC IS APPROVED. PROCEDURES
ARE ON EILE IN THE RECEIVING SECTION,
mi
Si
.
***
Research sponsored by the U. S. Atomic Energy Commission under
contract with the Union Carbide Corporation.
- LEGAL NOTICE -
ORNI - AC - OFFICIAL

.
*
VN WERDEN
This raport me prepared us an account of over mest podmored work. Nolther tye vallad
stats., oor the Commisolon, por kay pornoo actlog oo bobull of the Conosolon:
A. Makes by wartenty or repentation, expresved or loplied, with respect to the accu-
racy, completopeds, or whalni of the Information contained to the report, or at the wo
of any laformation, appuntue, method, or proces. diaclound In we report may not jofringe
printly oro. ridu; ori
B. Ainner may liabilua th respect to the um of, or for demago. reswing from the
use of way fuoruation, appardelene melbod, or proces, disclosed in this report
Ao waod in the above, "perko acting on behall of the Commun" Includes wy on
ployee or contractor of the Conclusion, or employee of such contractor, to the extoot that
auch employee or contractor of the Commission, or employm el much coolractor preparos,
dienominator, or provides accouto, way Information purnaal to do soployment or contract
with the Complu.100, or die employment with such contractor.
y la formation or bon respect to Woo... disclosed isiko Laclude.net that
Annars have courable sound on behalf or such cootracto Taclos prepare
of wood in the above the connesson, of clon. or epaployer to be comployment
.
.
-.
The major long-term objective of the soil studies at the Oak Ridge
OINI - AIC - OSPICIAL
di
National Laboratory is to obtain information from field and laboratory
d..
studies on the behavior of radionuclides in soils and to synthesize this
irformation to enable predictions of the fate of radionuclides released
to the soil environment. One aspect of this study includes following
''
the movement of radionuclides off the soil surface by runoff and erosion
for selected soils in Southeastern United States.'
Studies of fission product movement by runoff and erosion have been
concerned with fallout contamination, particularly with attention to radio-
strontium. -,2 Menzel, working with soils from Wisconsin and Georgia, found
that up to 30 times more 90sr was associated with soil particles in runoff
than in the original soil. He noted that 25% of the Po Sr deposited at a
given time by fallout can be lost by runoff and erosion from plots in corn
and oats in Wisconsin. Frere and Roberts concluded that as much as two-thirds
of the Sr deposited by fallout had been lost by runoff and erosion from a
cultivated watershed in Ohio. Graham also noted the importance of seasonal
variations in his studies on a Missouri soil. He reported that more loss of
ossr and 13 I occurred in the 1961 season than in the 1960 season and inferred
that the difference was due to the higher soil moisture conditions during
1961 which increased runoff.
Very little information is available on the movement of 137C8 by
runoff and erosion; indeed the high sorption of this element by most soils.
.
.Di
..
.him.-
..
*
: -
..
.
...
..rita ini.
..
S
W
ER
suggests immediate fixation and stabilization in the surface soil.
ONI - ABC - OSSICIAL
ORNI - AIC - OFFICIAL
It was felt that the concentration of 137cs at or very near the surface
of the soil would contribute to movement by runoff and erosion because
ORNI - AIC - OPTICIAL
the surface particles are more susceptible to movement by these mechanisms.
Furthermore, the use of long-lived radiocesium would permit following the
behavior of radionuclide over a long time span.
In this paper the movement of tCs on a Captina soil in East Ten-
nessee under different cover conditions is reported for the 81-day period
following the spray application. The higher rate of application than
those used by Graham, 3 the different soil and plant characteristics, and
the different rainfall pattern in East Tennessee suggested the need for
close attention to the movement of this radionuclide during the early
stages following application. This paper is concerned with the movement
of 13'cs during this period.
Methods and Materials
Soil Description
The experimental area is located on the alluvial plain of the north
bank of the clinch River at the Oak Ridge reservation. The soil belongs ::
to the Captina series which occupies low to intermediate areas along the
Clinch River. These areas were subject to flooding during high flood
crests prior to the RVA flood control program. The alluvial deposits
are a mixture of materials derived from sandstone, limestone, and shale.
Sandstone and shale predominate in the upper 5 ft of the deposit. Dur-
ing exploratory drilling coarse, sandy material was encountered in the
experimental area at about 12 ft, containing the permanent water table
at approximately the level of Clinch River.,
ORNI - A&C - ORT!CIAL

ORNI - AIC - OFFICIAL
In Fig. 1 a profile of Captinu silt loam 18 shown. In the experi-
mental area about 4 in. of highly permeable (8 in. of water per hour).
top soil (A) rests on a massive 4-in.-thick former plow pan (Az). Water
movement through this Az layer is restricted and takes place largelja
through the root cracks at the rate of 1.5 in. per hour. Below this
layer are the B, and B, horizons with a vertical permeability of 0.3 in.
per hour and horizontal permeability of 0.2 in. per hour. Below B,
starting at 21 to 24. in. a fragipan layer occurs. Although occasionally
highly permeable sand lenses appear in the By M portion of the fragipan,
the soil is very massive and virtually impermeable (0.02 in. per hour)
below the 40-in. depth (B, M). As a result of the fragipan layer, water-
logged conditions prevail in the upper 4 ft of the profile during most
of fall, winter, and spring. The composite infiltration rate of up to
15 in. per day and drainage rate of 4 in. per day has been observed ex-
perimentally under field conditions. With a temporary water table close
to the ground surface, occurring during the late fall, winter, små spring,
the soil is subject to erosion, even by minor storms during these seasons.
Experimental Area Description
The experimental portion of the area is covered with a mixture of
crabgrass and fescue with crabgrass predominating. Using a point samplerº
there is on the average 73% surface plant cover and 8.9% basal plant cover
with 300 to 500 g of plant material (on the dry basis) per square meter
of surface. The slopes found in the field range from 2 to 15%. Three
experimental plots were chosen for tagging with+'cs. In the first plot
the vegetation was removed (Fig. 2a); in the second plot the meadow was
clipped and the litter was left on the ground (Fig. 2b); and in the third
ORNL - AEC - OSSICIAL
CRNI - AIC - OINICIAL
Fig. 1. Profile of Captina Silt Loam Soil.
ORNE - AIC - OFFICIAL
.

11
1
i
och
LE
1
.
C
fii
Tu
.
.
.
•
!
1
11:
"OSJ01.win
a
89
:12
22 21 22 i 211 it i* : 10.4
4 !5
ra
.
.
.
.
26
CARINA
W
.
$
;
...
WINT
.
.
.
.
.
i
.
-.
ORNI - AIC - OFFICIAL
Fig. 2. Cover Conditions on the Experimental Plots: (a) Bare
Soil (Plot 1), (b) clipped Meadow (Plot 2), and (c) Tall Meadow (Plot 3).
ORNL - AEC - OFFICIAS

Nwaunvoto NW un am.
hodnih danauluihihukummilumlului

-
1
-
SY
M
Nwauno@onwaua
u hudud:1111mililililoulouloulouluntului

i
-
•
:.;
Ano @ VINWA
:
.
.
1
.
PHOTO 6 S194
-
-
-
-
-
-
-
.
-
-
-
ORNI - AIC - OKSICIAN
plot the meadow was fertilized and allowed to grow tall (Fig. 20).
In Table 1 pertinent data for each piot are given, and in Fig. 3.
a general view of the experimental plot locations is shown. Each of
the experimental plots (as shown in Fig. 3), which was surrounded by
a 2.5 by 2.5 meter pen, was enclosed by a 15 cm wide metal strip sunk
to a depth of 7 cm into the ground. A fourth plot was kept in reserve
for future studies. At the lowest corner of each piot a runoff catch-
ment sink was cemented in place and connected by means of a rubber hose
encased in galvanized pipe to the runoff catchment pans. Each catch-
ment pan (also shown in Fig. 3) was equipped with calibrated drums and
WAS
water level recorder. A recording rain gauge, a runoff disposal pit
(not shown in Fig. 3), and a runoff transfer water pump were included
as a permanent part of the experimental setup.
The information from the recording rain gauge on duration, intensity,
and amount of rainfall for each storm was used in computing the erosion
index: (ET) value. It was also correlated with the runoff rates, amounts,
and starting times obtained with the water level recorders for each
plot.
Tagging
Application of 1510s tag (Fig. 4) was carried out using a modified
orchard sprayer at constant pressure of 50 psi, under the direction of
H. D. Waller, Radiation Ecology Section. Five milicuries of 137cs were
diluted to 4000 ml volume in a weak Hcl solution (pH 4.0). This quantity
was sufficient for five complete spray passes. Alternate sprayings were
made in the direction at right angles to the previous application. Cesium-
137 tag was applied under dry soil conditions. The first rain was recorded
was
ORNL - AEC - OFFICIAL
6 days after tagging.
8
.
Table 1. Effective Aree, a slope, slope Length, Canopy Cover, Basal Cover
and Plant Matter on the Dry Basis on the Experimental Plots
at the Oak Ridge National Laboratory
Plot Number
and
Description
Effective
Area
Average
Slope
Average
Slope
Length
Canopy
Cover
Basal
Cover
Dry Plant
Matter
(€/m2;
2. – Bare
Soil
5.54
2.95
2.19
0
0
7.4
5.33
2 - Clipped
Meadow
4.63
2.04
74.00
374.0€
61.0
13.0
3 - 012
5.40
5.40
13.38
13.38
3. Tall
Meadow
1.98
1.98
76.0
76.0
34
9.4
406.04
Effective area is contained inside the metal border strip, exclud-
ing catchment sink.
The first number represents total per cent of canovy cover; the
second number represents total per cent of litter cover; and the third
number represents the total per cent of plant cover.
This value includes both litter and plant material. An average
value on the basis of two samplings gives 30.7% plant material and 69.3%
litter material.
"Average value on the basis of three samplings.
ORNL - AEC - Ornicia
9
.
· ORMI - AIC - OFFICIAL
Fig. 3. View of Experimental Area Showing Plot and Runoff Catch-
ment Pans Locations.
ORI! - AEC - OFFICIAL

:
:
hans
.
{
.
on
:
P
MER:1123H
TE
RECETTETITSI
BESARE.
21
:
ALAS
.
RADIONICE
MOVEMENT
2015 man!
ni
D
.
ka
****
:
STRA
:
IN
7
1:
un
in
.
.
.
VI
.
.
.
....
.
***
.
.
.
.
.
is
.
ment Used in Tagging.
Fig. 4. Application of 15lCs to an Experimental Plot Showing Equip-
ORNE - AIC - OINICIAL
ORNI - ALC - OINICIAL

. به
.
:" .
,
و
ا
==
..
.
.
.
:
مه
:
من
هم
.و با
:
-
1
مہ
:::
:
من
:
.
:
.
. . "
: : : :
:
: : :
" : ما
: : :
.
"
. ::
:
:
:
م
:
"
... .
د '
: :
. .
.
.
.
.
*
عنا
.
عام
و ۱۰۰
-
.
-
.
.
:
:
:
1
ا
.
:.
.:
.. . .
ترنج
:
ا
RADIATION .
.
. .
. . .: .:
..
10NI
.
ا
=
.
.
1!
ا
*
ا
..
.
ا
. .
ا ا
لا
*
..
:
*
..
همه
ا
.
. ان
ا
..
م
ه
ء
:
.
مدم
. ...
.
4
.
.
::
مر
ا
*
.
!
.
. .
. .....
. .
.. .. .... ----- ....
..
..
. .
.
.
.. .
هه
.
.
.
.
.
. .
ORNI - AIC - OINICIAL
Sampling
Following each storm the runoff collected was stirred and mixed
thoroughly. Exactly 500 ml was sampled and centrifuged at 2400 rpm with
1 ml of 1 M Cacıy. The supernate was decanted, the solids dried, weighed
on the analytical balance, and multiplied by a proportionality factor
to give the soil loss in grams per plot. It should be pointed out that
all liandling and sampling equipment consisted of polyethylene laboratory
ware to prevent sorption of SYCs by glass or metal surfaces.
A further 31-ml sample was obtained and used in the 19"Cs loss de-
termination. The sample was centrifuged for 15 min prior to counting
on a multichannel analyzer; following the counting, sufficient Caci, was
added to make the solution 1 M with respect to Caci,. The flocculated
clay was centrifuged and recounted. A 15-ml sample of the supernate was
removed and counted separately. This counting procedure was established
when it was found that the bulk of the activity was associated with the
solid particles in the runoff and that the cesium associated with the
particles was not significantly desorbed by addition of Cacin. The
15-ml supernate count served to verify this conclusion and also served
Was
as a check of the procedure.
Results
Study Period
The study period reported here covers 81 days between October 20,
1964, and January 9, 1965. In Table 2 total rainfall for the months
covering the study period is given and compared with the normal rainfall
for the same time. In Table 3 maximum observed 24-hr rain and its
ORNI - AIC - OFFICIAL
ORNI - AIC - OFFICIAL
expected return period for maximum rains during the 81-day study period
is given, and in Table 4 observed erosion index (EI) values for the study
period are compared with expected and maximum average annual EI values
for the experimental area. The El value is a numerical evaluation of
the capacity of a specific rainfall pattern to erode soil from the un-
protected fields. It is the product of rainfall energy, and its maximum
30 min intensity?
Analyzing the information given in Tables 2, 3, and 4, we conclude
that although the total rainfall was generally below normal during the
study period, storms of higher-than-average energies and intensities were
observed. It should be noted that soil loss and +31Cs loss values are
given for the time of year when the soil is generally in wet and water-
logged conditions and when the vegetation is dead.
Soil Loss
.
.
.
.
.
..
.
....
2
.
In Fig. 5 actual soil loss values in grams per square meter observed
on the experimental plots are plotted for each type of cover conditions a-
gainst the erosion index (ET) value in (ergs/cm?) (cm/sec). The straight
lines drawn through the experimental points represent the theoretical loci
of points expected for the rainfall pattern, soil type, area slope, slope
length, and cover conditions that prevailed on the respective plots during
the study period. The curves were calculated from the erosion equation given
by Wischmeier and Smith,? Wischmeier et al., Wischmeier, 9 and data listed
in reference 10. Considering the short study period, the agreement of theo-
retical predictions and experimental results is considered satisfactory.
.
.
.
wios.
2
m
'
.
A 15-cm-wide border of bare soil surrounded Plot 2. The contribution
*....
ORNI -AIC - OFFICIAL
.
*
','
S
www
13
ORNI - ALC - OFFICIAL
Table 2. Total Rainfall" for Months Covering the Study Period
as Compared to the Normalb Rainfall for the Same Time
Observed Rain
(in.)
Normal Rain
(in.)
Departure
From Normal
October
1.94
- 0.62
- 1.02
November
2.82
3.49
5.22
2.47
4.73
4.71
December
0.49
January
5.24
- 0.53
A The total rainfall for 81 days of the study period was
11.69 in.
"Normal rain is for Oak Ridge iocal climatological data
with comparative data for 1964. ..
ORNL - AIC - OFFICIAL
Table 3. Maximum Observed 24-Hour Rain and Its Expected Return Period
for Maximum Rains During the 81-Day Study Period
Maximum Observed 24-Hour Rain
Month .
Plot Study
in, in.)
Return Per
(precip. days)
Probability
of Occurrence
(return period)
Average .
Number of
(precip. days)
Probability a
of Occurrence
(return period)
October
0.68
33 times/yr
Twice every
October
November
1.40
Every 2 yr
1.86€
December
January
8 times/yr
4 times/yr
Every 2 yr
3.30
13
13
250
Every 2 yr
Every 19 yr
Data comuted from ORO-99, A Meteorological Survey of the Oak Ridge Area, 1948-1952, Fig. 49.
"Probability of such a rain occurring again, assuming 133 precipitation days (precipitation ?
0.01 in. of rain). See ORO-99, Table 18c.
Data from ORO-99, Fig. 47c.
'Probability of such a rain occurring again in the same month.
Observed maximum intensities in December and January were 3.60 in. per hour for 10 min, 2.04 in.
per hour for 5 min, and 1.80 in. per hour for 10 min. Return period for such intensities is equal to
or less than 2 yr (rainfall-intensity-duration frequency curves for Knoxville, Tennessee, published
by V. S. Weather Bureau).
ORNI - AIC - OFFICIAL
ORNI - AIC - OFFICIAL
'
,
'.-
'-. '
.
..
....
..
7
-
,
.
Y-
LL
WINNO SN-INIO
Table 4. Observed Erosion Index (EI) Values for the Study Period:
Compared with Expected and Maximum Average Annual EI
Description
.
(ergs/cm2)(cm/sec)&
% of Annual
Cumulative EI observed:
10/20/64 to 1/9/65
1968
20%
1183
Cumulative EI expected:
20/20 to 1/96
Maximum expected:
6/1 to 9/10
4872
&0.473 (ergs/cm?)(cm/sec) = 1 EI unit in (ft - T/A)(in./hr).
"Soil Loss Es öimation in Tennessee, Unpublished Proceedings
of Soil Loss Prediction Conference, University of Tennessee, Knox-
ville, Tennessee, 1959.
ORNI – AEC - OFFICIAL
16
to the soil and +57Cs loss from this area was found to be considerable
and was taken into account in the calculations. The theoretical curve
for Plot 2 in Fig. 5 represents the soil loss as a function of erosion
index from the clipped meadow plot with 80% of the total area covered by
ORNI - AS - OFFICIAL
vegetation and 20% of the total area consisting of a bare soil border
.
strip.
In Table 5 the total observed soil loss during the study period is
compared with the soil loss predicted from the erosion equation given
by Wischmeier and Smith.' The erosion equation had been derived on the
basis of a large number of observations with a subsequent statistical
treatment of the variables.
The agreement shown in Table 5 on the basis
of relatively few observations is considered satisfactory.
Cesium-137 Loss from Soil
In Fig. 6 cumulative +5'cs loss in per cent is plotted as a function
of cumulative soil loss in grams per square meter on a full log scale.
The dashed lines for Plot 1, "Plot 2 plus border," and Plot. 3, represent
extrapolations to the very low readings (data not shown in Fig. 6) ob-
tained during the initial runoff producing rain. For example, 1.6 g/m2
soil loss on Plot 1 accounted for 0.006% of 15°Cs loss. The curve for
"Plot 2 less border" represents estimated loss of +5°Cs from the vegeta-
tion covered portion of Plot 2. The curve for "Plot 2 plus border"
represents the observed +57Cs loss values from the whole plot, including
the border bare soil covered strip. In Fig. 6 initial concentratious of
-5°Cs are given. These concentrations assume a uniform application of
5 mc of +Cs per plot and are computed using effective areas for respec-
tive plots listed in Table 1.
ORNI - ARC - OFFICIAL
ORNI - AIC - OFFICIAL
...
.-wrino woo
Fig. 5. Experimenta). Soil Loss as a Function of Erosion Index
(EI) for the Bare Soil (Plot 1), Clippe Meadow (Plot 2), and Tall
Meadow (Plot 3). Solid lines give predicted values. Predicted curve
for Plot 2 is corrected to include loss from bare soi), border.
..
..
ORN - Aić - OFFICIAL
- -..
-
-
-
-
ORNL DWG. 65-3823
100
50
50
PLOT 3 : TALL MEADOW
ixol
for PLOT 2:CLIPPED MEADOW
PLOTI: BARE SOIL
EI VALUE IN (ergs con-2)(cmsec') x102
Ō
00
0
RAINFALL ENERGY X MAX30 min. INTENSITY
4
PREDICTED VALUES
EXPERIMENTAL I
EXPERIMENTAL 2
EXPERIMENTAL 3
2

X lo
©
X
100
150
50
SOIL LOSS IN g/m?
ORNI - AIC - OFFICIAL
Fig. 6. Cumulative bics Loss as a Function of Soil Loss for the
Bare Soil (Plot 1), clipped Meadow (Plot 2, plus border), Tall Meadow
(Plot 3), and Clipped Meadow Corrected to Exclude Border (Plot 2, minus
border).
ORNI - AEC - OFFICIAL
ORNL DWG.65- 3821
3
6
10
30 60 100 300
Тт тТт тТт тТ-
137CS INITIAL
[ 0.903 mc/m2
2 0.937 mc/m?
3 0925 mc/ m2
ooo
CUMULATAIVE "Cs LOSS IN PERCENT

pos---A---az--s-
• PLOT I
O PLOT 2 + BORDER
A PLOT 2 - BORDER
X PLOT 3
1
0.6
---*
0.3
للللللللللللللل
3 6 10 30 60 , 100
CUMULATIVE SOIL LOSS g/m
300
19
.
· ORNI - AIC - OFFICIAL
Table 5. Observed Total Soil Loss on the Runoff Plots Compared
with the Soil Loss Predicted by the Use of Erosion Equation
for the Study Period October 20, 1964, to January 9, 1965
Soil L088 in Grams per Plot
Plot
Number
Description
Observed
Predicted
Bare Soil
1488
1648
Clipped Meadow
340
2826
Tall Meadow
93
101
Wischmeier and Smith (1958).
Corrected for bare soil border present.
-
'..tu
..
ORMI - AEC - OFFICIAL
1
.-i
:
20
: ORNI - ACC - OINICIAL
In Table 6 average specific concentrations of +/Cs in the runoff
for the initial and final part of the study period are given. It should
be pointed out that in Fig. 6 the second points on the lower part of the
curve for Plot 1 and "Plot 2 plus border," and the first point of the
curve for Plot 3 represent cumulative per cent of +\Cs lost during the
initial part of the study period (up to December 5, 1964). The relation-
ship between the data in Table 6 and in Fig. 6 is as follows: If the
solid lines in Fig. 6 for Plot 1, 2, and 3 were to be extrapolated back
at the same relative slope (and not at a steeper slope shown by dashed
lines in the figure), the specific concentrations for the initial part
of the study period would have been 0.7, 1.8, and 0.9 mc per gram of
soil for Plots 1, 2, and 3, respectively. The data in Table 6 show on
the average a higher specific +91C8 concentration. It is felt therefore
that the extrapolations to the low values shown by dashed lines in Fig. 6
are valid and that the steeper slopes reflect a faster rate of initial
loss
Cesium-137 Loss from the Plant Material
Following the application of 137Cs on the plots with vegetation (Plot
2 and 3), it was found that practically all of the +57Cs applied to the
Areas
areas covered with vegetation was on the plant and litter material. The
data obtained in the subsequent sampling of the vegetation is presented
in Fig. 7.
On the basis that all of the 15Ycs was on the vegetation initially,
Fig. 7 gives the per cent of 15Ycs leached from the vegetation as a
::
4. D. Waller, Radiation Ecology Section, ORNI, 1964
ORNI - A1C - OFFICIAL
22
ORNI - AIC - OINICIAL
Table 6. Specific Concentration of +5 Cs in the Runoff in uc/8 of
Soil Lost for the Initial and Final Part of the Study Period
Specific Concentration (uc/8)
Plot 1
Plot 2
Plot 3
Period
0.91
October 26 to
December 5
2.74
2.008
0.42
1.26
December 14 to
January 9
1.25
"Estimated value. No appreciable soil. 1088 was observed on
Plot 3 until December 24, 1964.
4
ORNI - AIC - OFFICIAL
ORNI - AIC - OFFICIAL
Fig. 7. Leaching Loss of+Cs as a Function of Total Rain for
Plot 2 (litter), Plot 2 (plant), and Plot 3 (plant).
ORNI - AIC - OFFICIAL
CON
ORNL DWG.65- 3824
0
10
20
30
40
50
Toox
OX
I
PERCENT OF INITIAL "37CS LEACHED OUT
* PLOT 2 CLIPPED MEADOW:LITTER
O PLOT 2 CLIPPED MEADOW:PLANT
O PLOT 3 TALL MEADOW: PLANT
2018

10
20 30
TOTAL RAIN IN Cm
40
50
23
function of total rain. The last set of points for 52.5 cm of rain
were based on the samples of March 22, 1965; and, although this date
ORNI - AEC - OFFICIAL
extends beyond the study period, the data are included for clarity.
The set of points plotted for 20.5 cm of rain were obtained on Decem-
ber 30, 1964. The first set of points were calculated from data ob-
tained by H. D. Waller. It appears that no leaching occurred in the
litter materials after 52.5 cm of rain as compared with 20.5 cm of rain.
It is possible that the apparent lack of leaching is due to the trans-
fer of +5lCs from the plant to the underlying litter material during
leaching.
Mass Balance
In Fig. 8 the mass balance computed on the basis of soil, litter,
and plant material sampling on December 30, 1964, is given. The soil
was sampled in 2-cm increments to a depth of 10 cm. Note that by that
sampling date most of the applied +37Cs was found to be on the soil.
For Plot 2 the the 17% value given for the bare soil border 18 an estimated
value based on the results obtained for Plot 1. On the other hand the 34%
value represents the actual per cent of the total WICs found on the
soil underlying the vegetation cover. These values were computed on the
basis of unit area. Furthermore, the percentages given in Fig. 8 for
.
Plots 2 and 3 have been corrected for the amount of basal cover (Table
1).
Had the sampling been made on January 10, 1965 (following the in-
tense storm on January 9, 1965), the erosion losses would have been 12,
&H. D. Waller, Radiation Ecology Section, ORNL, 1964.
ORNI - AIC - OFFICIAL
i entos estamaisiais ----...........
ormovim
m
Pikant
TwinAin.. How
24
Sisso - JIV - INTO
9, and 3% for Plots 1, 2, and 3, respectively. The ma88 balance shows
total recovery for the bare soil. Plot 1, but is low by about 4% on Plot
2 and in excess by about 6% on Plot 3.
Discussion
No conclusions on the long-term behavior of +370s can be drawn on
the basis of the short 81-day study period. There is, however, enough
information present to point up the trends and establisk two relation-
ships to be followed up in greater detail over an extended period of
time.
The first relationship of importance is presented in Fig. 6.
The
data presented in Fig. 6 immediately raise. the question of whether or
not the straight line relationship on a full log scale between the SiCs
loss and soil loss will continue until all cesium has been removed by
erosion.
Given the same pattern of soil loss, values of the +51cs loss
should remain the same for any period. during the year. However, if
any significant movement deeper into the soil profile by infiltration
and through the plant roots takes place, the SICs loss-soil relation-
ship would reflect this change. The distribution coefficient (ka)
move
which is the ratio of adsorbed cesium per kram of soil to the unsorbed
ORNE - AEC - OMSICAL
25
ORNL - ALC - OFFICIAL
cesium per milliliter of solution 18 3 x 10 ml/8 for the A, horizon.
Since the ka for 137c8 of the Captina 18 very high, 1t 18 felt that no
appreciable amount of +31C8 would move into the profile by infiltration.
The relationship shown for Plot 1 in Fig. 6 should therefore hold for
any time during the year. Any seasonal change in the relationship for
Plot 2 and Plot 3 would suggest the translocation by plant roots of
Cs into the deeper horizons of the soil profile.
The movement of 13 Cs into the soil profile is relatively minor.
on the basis of mass balance computations, given in Fig. 8, more than
90% of the 137cs associated with the soil was found to be in the upper
2 cm of the profile at the sampling time. It is felt that a large
part of +sics found below the 2 cm depth could have been due to the
inadvertent contamination by the sampling tools. Thus the relation-
ship describing the loss of +31Cs by erosion becomes the principal
mode of transfer of this radionuclide and acquires a special signi-
ficance.
The second relationship of importance concerns the leaching of
37Cs from vegetation by rain. Based on the data presented in Fig. 7, the
loss by rainfall leaching begins to level off after about 20.5 cm of rain.
If this relationship holds the specific +37Cs concentration in the runoff
from the vegetation covered plots should decrease and approximate the
specific +31cs concentration in the runoff from the bare soil plot which
was shown to be lower (Table 6). This decrease in the specific +57Cs
concentration on the vegetation covered plots should be reflected by a
ORNI - AIC - OPSICIAL
26
OINI - AIC -OCSICIAL
Fig. 8. Cesium-137 Mass Balance for Soll, Litter, and Plant
Materials on the Bare Soil (1), clipped Meadow (2), and Tall Meadow (3)
Plots. Sampling date was December 30, 1964.
ORNI - AEC - OFFICIAL
L
ORNL-DWG. 65-3822
6.5%
EROSION
7100
39%
te weekenden men det h
INIO PLANT
andlar
10%
PERCENT TOTAL 137CS APPLIED

HI LITTER
A SOIL 0-2cm
WASOIL BORDER 0-2 cm
\34%
I
2
3
SOIL 2-10 cm
BARE SOIL
CLIPPED MEADOW
TALL MEADOW
120
17%
6.5%

5%
12-30-64
2

27
decrease in slope for curves of Plots 2 and 3 in Fig. 6. Data obtained
after the study period indicate that the slope of the curves of Plots 2
ORNI - AIC - OFFICIAL
ani 3 does tend to decrease
More data however are necessary to confirm
this behavior.
In Fig. 7 the curve for leaching loss of 'Cs from the vegetation
by rain tends to level off out about 75% of +31C8 lose. The fate of the.
25% of +37Cs remaining on the vegetation is uncertain at this stage.
Slow leaching and decay of the plant material will eventually add the
entire amount to the soil. The rate of this addition should approxi-
mately equal the rate of decay of the plant residues.
The difference of the specific +37Cs concentration on the runoff
mo
from the bare sol.1 (plot 1) and vegetation covered plots (Plots 2 and 3),
shown in Table 6, has raised a question with regards to the fate of +31Cs
leached from vegetation. The specific 13/Cs concentration in the runoff
from Plots 2 and 3 is about three times as large as in the runoff from
Plot 1. One may postulate that 37Cs leached by rain from vegetation
becomes fixed on the fine fraction of the soil materials present in the
runoff water during the storm without ever reaching the soil surface.
Laboratories studies in progress show that about twice as much +31C8 is
leached from vegetation by an uncontaminated runoff containing fine frac.
-
-
tion of the soil material as 18 leached by the equivalent amount of pure
-
-
-
-
-
rain water from the same storm.
Finally, it is interesting to compare the radionuclide losses re-
ported in this study with the findings of others. Graham, 3: working in
Missouri, found that the highest loss of Osr occurred on his fallow plot,
amounting to 0.097 in the fall of 1960 and 0.982% in the fallo f 1961. The lowest
ert:-
..
..
C
ORNI ~ AEC - OFFICIAL
.
...
...
...
.
.
.
.
. .
ORNI - AC - OFFICIAL
. .
loss occurred on a fescue meadow plot and amounted to 0.037% in 1961.
In our studies with 137C8 the fallow plot (bare so11) showed a 1088 of
11.86%, and the fescue-crabgrass meadow plot (tall meadow) showed a loss
of 2.57% for the study period. The differences are 11kely due to the
. .
-
.. -
'.
higher rainfall in East Tennessee as compared with Missouri, to the
higher energy and intensity rains which feil here and to the nature of
the radionuclide. Faster movement of strontium downward into the profile
as compared to the downward cesium' movement could result in a relatively
lower loss of strontium by erosion. Although a steeper slope (13.4%) 18
present in our tall meadow plot, as compared to 3% in the Missouri plot,
the high loss of 15%Cs on our clipped meadow plot (5.10%) with only 4.6%
slope (Plot 2 less border in Fig. 6) reduces the probability that the
slope factor was the only reason for the higher losses in our tall meadow
plot.
Frere and Roberts? report that between 1/3 to 2/3 of the posr de-
posited by fallout up to 1960 was lost on cultivated watershed in Ohio
with an average slope of 13%. Even if the +57Cs loss rate were to re-
main constant on our tall meadow plot, it would lose approximately 10%
of the radiocesium on a similar slope in about 8 months time. Further
speculation is premature at this time. The widely differing results
obtained by investigators on radionuclide movement strongly suggest the
need to continue these studies to define ** the parameters af-
fecting radionuclide movement by runoff and erosion
quantitatively.
ORNI - AIC - OFFICIAL
· ORNI - AIC - OFFICIAL
References
1.
R. G. Menzel, Science 131, 499 (1960).
2. M. H. Frere and M. Roberts, Jr., Proceedings, So:11 Science Society
of America 27, 82 (1963).
3. E. R. Graham, Water and Sewage Works 110, 407 (1963).
L. Fredericksson, B. Ericksson, B. Rasmuson, B. Gahne, K. Edvarson,
and K. Low, Proceedings of Second International Conference on Peace-
ful Uses of Atomic Energy 18, 449 (1958).
---... -
J. R. Miller and R. F. Reitemeier, Proceedings, Soil Science Society
of America 27, 141 (1963).
-
-
. .
.
D. Brown, Methods of Surveying and Measuring Vegetation. Comon-
wealth Bureau of Pasture and Field Crops, Bulletin 42, Aurley, Berks,
1954.
-.-..-.e
7. W. H. Wischmeier and D. D. Smith, Transactions American Geophysical
Union 39, 285 (1958).
wie
indica
8. W. H. Wischmeier, D. D. Smith, and R. E. Uhland, Agricultural Engi-
neering 39, 458 (1958).
9. W. H. Wischmeier, Proceedings, Soil Science Society of America 24,
322 (1960).
utk.
1.
Soil Loss Estimation in Tennessee, Unpublished Proceedings from Soil
Loss Prediction Conference, University of Tennessee, Knoxville, Ten-
nessee (1959).
-
-
.
-
-
.
-
-
ev
-
-
-
..
.
e
rice
.
uni
c
e..........
.iti
ORNI - AIC - OFFICIAL
u
...t
hacia
•
iet.
2-
X
.
*'
.
---
! : -www
.
..
.
w
END
DATE FILMED
8 / 26 /65
TY-
-
-
.
.
.
-



- --- -----





------