Role of Certain StreamSediment Components in 

Radioion Sorption

GEOLOGICAL SURVEY PROFESSIONAL PAPER 433-F
Role of Certain StreamSediment Components in 

Radioion Sorption

By E. A. JENNE and J. S. WAHLBERG

TRANSPORT OF RADIONUCLIDES BY STREAMS

GEOLOGICAL SURVEY PROFESSIONAL PAPER 433-F

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1968
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 20 cents (paper cover)
CONTENTS

Abstract____________________________________

Introduction. _________________________________

Acknowledgments___ ________________________

Approach and objectives______________________

Experimental methods_______________________

Calculations________________________________

Results____________________________________

Mineralogy. _______________________________

Soluble and extractable (exchangeable) cations . 

Strontium. ________________________________

'age 

Fl

1

?,

?,

?,

R

6

6

8

9

Results Continued

Cobalt _____ __________

Rare eartns_.-_____ ____________

Ruthenium. ___ _________________

Future studies _ _ ______ __

References cited__ ____________ __

Page 

__-____.___-_- F10

__________ 11

___ 11

____ 12

. _________ 12

.-___-__ ____ 13

. __________ 14

. ____ _ ____ 15

ILLUSTRATIONS

FIGURE 1. Index map showing location of Whiteoak Creek, Tenn____________________ __._ _..

2. X-ray diffraction powder patterns of sized Whiteoak Creek sediment __ ________ ___ ______ _.

3. X-ray diffraction patterns of parallel-oriented specimens of Whiteoak Creek sediment-___ _________________

4. Graph showing generalized curve for the desorption of a radiocation from multiple-phase earth-material specimen.

TABLES

Page 

F3

6

7

14

TABLE 1. Major soluble cations in the stream water, major extractable (exchangeable) stable cations, and cation exchange 

capacities of the sized Whiteoak Creek sediment________ ________ ________________________________

2. Distribution and selectivity coefficients for strontium-90 sorption by Whiteoak Creek sediment-_______________

3. Ratio of strontium-90 to calcium plus magnesium in ammonium acetate and ammonium chloride extracts of Whiteoak Creek sediment_______________________ _____ ______ 

4. Percentage of total radioactivity removed from Whiteoak Creek sediment by ammonium acetate plus ammonium 

chloride extractions______________ ____ _____ ____ _________________

5. Distribution and selectivity coefficients for cesium-137 sorption by Whiteoak Creek sediment-----_____________

6. Distribution and selectivity coefficients for cobalt-60 sorption by Whiteoak Creek sediment ________________

7. Natural distribution and selectivity coefficients for rare-earth sorption by Whiteoak Creek sediment.______--_ 

m

Page

F8 

9

10

10

11

12

TRANSPORT OF RADIONUCLIDES BY STREAMS

ROLE OF CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION

By E. A. JENNE and J. S. WAHLBEEG

ABSTRACT

"Natural" and laboratory "dialysis" mass-action selectivity 

coefficients were determined for the < 60-mesh «0.25 mm) and 

the 9- to 60-mesh (2-0.25 mm) sediment fractions to evaluate 

the comparability of these two types of selectivity coefficients 

and the effectiveness of nonclay components in controlling the 

distribution of radioions between solid and liquid phases.

Stream water and surficial bed sediment were sampled in 

Whiteoak Creek, Tenn., from a small stilling basin. This creek 

carries low-level-radioactive waste waters from Oak Ridge National Laboratory to the Clinch River. Appropriate mass-action 

selectivity coefficients were calculated following determination 

of the soluble radioions in the water and the exchangeable 

radioions on the sediment. Portions of the size-fractionated sediment were air dried and used for 2-day radioion dialysis sorption 

experiments.

Sorption of strontium-90 was controlled by in situ precipitated 

carbonates. The solubility of the precipitated carbonates was 

sufficient in ammonium acetate and ammonium chloride leaches 

to yield selectivity coefficients which were high for the natural 

as compared with the dialysis values 9.6 versus 1.2 for the 

<60-mesh fraction. The carbonate solubility was sufficient to 

preclude determination of dialysis selectivity coefficients with 

sodium as the competing cation owing to the compounding 

effects of calcium plus magnesium. Cobalt-60 sorption was 

controlled by manganese and iron oxides and yielded high 

natural selectivity coefficients for the < 60-mesh fraction owing 

to partial dissolution of the oxides in the extracting solution. 

The dialysis selectivity coefficients were greater for the 9- to 

60-mesh fraction, where the oxides were most abundant. Sorption 

of cesium-137, in contrast to strontium-90 and cobalt-60, was 

controlled by the clay minerals. The observed higher natural 

selectivity coefficients for cesium-137, as compared with laboratory selectivity coefficients, are attributed to the slow diffusion 

of cesium into the interlayer spaces of illite and vermiculite, the 

dominant layer silicates.

Precipitation of cerium-144 during dialysis precluded determination of laboratory selectivity coefficients. Exchangeable and 

soluble zirconium-95 and niobium-95 were below detection level.

The results of the study indicate that nonclay minerals control 

the distribution between the solid and the liquid phases of two 

out of the three dominant radioions in Whiteoak Creek. Natural 

and laboratory selectivity coefficients were not comparable in 

many instances. This is attributed to partial dissolution of finegrained carbonates and of manganese and iron oxides, and in

part to the largely irreversible nature of cobalt-60 and cesium137 sorption. The laboratory and the natural selectivity coefficients for cesium-137 agreed within a factor of 2.

INTRODUCTION

Thousands of laboratory radioion distribution coefficients have been determined in recent years as a 

part of governmental radiological safety programs. 

These radioion sorption determinations have been made 

on soils and various types of rocks near sites proposed 

for nuclear detonations or radioactive-waste disposal. 

Similar studies have been made on reference clays. 

The usefulness of these data for predicting radioion 

sorption by stream sediments is quite limited for 

several reasons. These data, although extensive, are 

scattered and remain unsummarized. To be generally 

useful, the distribution coefficients must be transformed 

into mass-action selectivity coefficients. This is not 

generally possible, as the equilibrium aqueous phase 

concentration of the principal competing cations must 

be known. This information is very scarce in the 

distribution-coefficient literature. There is almost a 

total lack of data on the radioion-sorption properties 

of the nonclay minerals that occur in stream sediments. 

The sparse data available indicate that certain of the 

nonclay minerals, as well as organics, may be rather 

highly selective cation sorbers (Hechter and others, 

1959; Tamura, 1962; Jenne and Wahlberg, 1965). A 

further limitation of the application of available 

selectivity-coefficient data is that drying and storage 

effects such as desiccation of biota, irreversible dehydration of hydrous oxides, oxidization of reduced 

metal ions and organics, and precipitation of sparingly 

soluble salts and trace metals are to be expected. It 

is not known whether these changes will alter the mean 

cation (and anion) selectivity of the earth material 

enough to seriously affect the usefulness of the laboratory data for field application. In addition, quantitative

Fl
F2 TRANSPORT OF RADIONUCLIDES BY STREAMS

clay mineralogy, which is required if the sorption 

characteristics of a sediment are to be predicted, is 

neither simple nor easy to obtain. Finally, the similarity 

of chemical properties of "reference clays" (often 

incorrectly referred to as "standard clays") to those 

of clays occurring in stream sediments is questionable.

Dissimilar chemical properties of reference and 

stream-sediment clays should be expected. The literature indicates that clay minerals in soils and recent 

sediments are commonly (1) poorly crystallized; (2) 

mixed-layer rather than discrete mineral species; (3) 

interlayered with aluminum (and less commonly 

magnesium, iron, or organics); and (4) physicochemically admixed with organic matter and (or) the oxides 

of aluminum, silicon, iron, or manganese.

Physicochemical responses in soils and sediments 

such as cesium, potassium, ammonium, and phosphate 

fixation as well as liming requirements (for soils), are 

different for poorly crystalline and intergrade layer 

silicates than for the reference clays.

The clay minerals in stream sediments have been 

reported as being poorly crystalline (Gorbunova, 1961; 

Clanton, 1963). The effect of varying degrees of 

crystallinity of the layer silicates on their chemical 

properties is known for only relatively few minerals. 

Ormsby, Shartsis, and Woodside (1962) have shown, 

for kaolins, that crystallinity decreases with decreasing 

particle size, whereas surface area and cation excharige 

capacity increase. Other studies have shown that prolonged grinding (hours) reduces the degree of crystal 

perfection of clays with concomitant increase in surface 

area, cation exchange capacity, and phosphate fixation.

Natural 14-A (angstrom) layer silicates, which have 

properties intermediate between those of typical 

chlorites and typical vermiculites or montmorillonites 

and which form as a result of weathering, are common 

in soil clays and have been reported by numerous investigators during the last 15 years. (See, for example, 

Weed and Nelson, 1962, and Carstea, 1965.) Rich 

(1960) concluded that the presence of interlayer hydroxy-aluminum compounds resulted in a marked 

decrease in the capacity of vermiculitic soil clays to 

irreversibly sorb ammonium and, presumably, other 

large fixable cations such as cesium.

Iron and manganese oxide coatings are extensive in 

sediments, and Sumner (1962) has shown that the iron 

oxides increase the number of positive exchange sites 

and have a variable effect on the number of negative 

sites depending on the pH of the system. The degree 

of crystallinity, as well as the crystallographic form of 

iron oxide coatings, has been shown to influence the

anion and cation exchange capacity of earth materials 

(Sumner, 1963). Because the physicochemical interaction of iron and organic matter in soils having a high 

iron oxide content sometimes precludes the complete 

oxidization of organic matter with hydrogen peroxide 

without prior iron removal, not all of the cobalt-60 

associated with organic matter is available for cation 

exchange. Baas Becking and Moore (1959) concluded 

that most of the iron in sediments exists in complexes, 

chiefly with organic matter. Similarly, Berg (1960) 

noted that, when ferric chloride was hydrolyzed in the 

presence of clays, iron precipitated on the surface of 

clay particles until some maximum value (which appeared to vary with the surface area of the clay) was 

reached, and then it precipitated as discrete particles.

ACKNOWLEDGMENTS

Appreciation is expressed to W. M. McMaster for 

his assistance in obtaining the samples, to Pauline 

Dunton for running the X-ray diffraction patterns, and 

to Vance Kennedy for the thin-section examinations 

and a detailed review of a preliminary draft of the 

manuscript. Reviews by Ronald Tidball, Ronald 

Malcolm, R. J. Pickering, and W. M. McMaster also 

contributed greatly to the clarity of this report.

APPROACH AND OBJECTIVES

The release of low-level-radioactive waste by the 

Oak Ridge National Laboratory into Whiteoak Creek 

provided a suitable opportunity to obtain samples 

with which to make appropriate comparisons between 

natural and laboratory selectivity coefficients. Whiteoak 

Creek, a small tributary of the Clinch River, has a 

mean annual discharge at the sample-collection point 

of about 9.5 cfs (cubic feet per second). (See fig. 1.)

The objectives of this study were to compare the 

natural radioion distribution in a stream with that 

obtained by the conventional laboratory (dialysis) 

technique of air-drying, storing, and equilibrating 

portions of the sediment with artificial solutions; and 

to evaluate the role of nonclay stream-sediment 

minerals in radioion sorption.

EXPERIMENTAL METHODS

In August 1963, about 40 liters of stream water and 

3 liters of surface bed sediment were collected from 

a stilling basin above the Cipolletti weir, 1.1 miles 

below Oak Ridge National Laboratory and 1.6 miles 

above the Clinch River. The water sample was obtained by lowering 18-liter plastic bottles into the 

shallow pool above the weir. The bottles were filled
ROLE OP CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION F3

FIQUBE 1. Locatioa of Whiteoak Creek, Tenn. Drawing courtesy of Oak Ridge National Laboratory.

with additional water dipped from the pool. Although 

the stream water was quite clear at the time of sampling, the turbulence resulting from the sampling 

procedure caused some of the fine-grained bed sediment 

to become suspended. The surface bed sediment in 

the pool was sampled by scraping with a plastic beaker 

to a depth of approximately one-third inch. The sediment samples were taken to Denver by air and refrigerated. No preservatives were added to either the 

water or the sediment. The water sample was shipped

by Railway Express. The stream discharge was almost 

constant at 0.662 cfs for a 6-hour period prior to the 

time of sample collection.

When the water sample reached the laboratory 

10 days after sampling the water, containing a considerable amount of suspended sediment, and the 

slurry of surficial stream-bed sediment were combined. 

The combined material was then equilibrated for about 

24 hours, and the solid and liquid phases were quantitatively separated. There was no observable color or
F4 TRANSPORT OF RADIONUCLIDES BY STREAMS

odor change between the time of sampling and the 

time of sediment separation. The sediment was size 

fractionated into >9-mesh C>2 mm in diameter), 9- 

to 60-mesh (2-0.25 mm), and <60-mesh «0.25 mm) 

fractions. The >9- and the 9- to 60-mesh fractions 

were separated by wet sieving, and the <60-mesh 

fraction was recovered by passing the slurry at a rate 

of 300 millimeters per minute through a continuousflow Servall SS-1 superspeed centrifuge at 15,000 

revolutions per minute. Approximately equal amounts 

of the sediment were found in each of the three size 

fractions. The ^>9-mesh fraction was not used because 

of the difficulty in obtaining representative subsamples. 

The clear centrifugate was acidified( ~ pH 3) to decrease the probability of precipitation, biological 

growth, and adsorption on polyethylene containers.

Natural selectivity coefficients, K^j,1 were calculated using the quantities of the radioions extracted 

from portions of the sized sediment and in the stream 

water. The exchangeable cations were extracted from 

the undried 9- to 60-mesh and <60-mesh sediment 

fractions in a Buchner funnel by leaching with a volume 

of 2N (normal) ammonium acetate (pH 7) such that 

the total milliequivalents of ammonium exceeded the 

exchange capacity of the sediment by approximately 

40 times. A total contact time of 24 hours between 

leachate and sediment was maintained. A second leach 

of similar volume and contact time was conducted with 

2N ammonium chloride (pH 3).

Ammonium acetate was used as the primary extractant of the exchangeable cations because it is the most 

commonly used salt for this purpose, and it can be 

volatized at reasonably low temperatures, as can 

ammonium chloride (with fuming nitric acid). Twoliter aliquots of the leachates were concentrated by 

evaporation to volumes of 10-15 milliliters. This degree 

of concentration would not have been possible if other 

commonly used salts, such as potassium chloride or 

calcium chloride, had been used to displace the exchangeable ions.

An appropriate carrier that is, a nonradio active 

material isotopic with the radioion was added to 

separate aliquots of stream water and sediment leachates following the evaporation step. This procedure was 

repeated for each radioion whose presence was anticipated (Morton, 1961). The aliquots were than evaporated to dryness. Dissolved organic matter as well as 

the ammonium chloride and ammonium acetate were

i i=fth exchangeable ion, j=jfh competing ion, and S or AT=cation exchange site 

(where the bar over the X signifies that the site is assumed to be of a monovalent 

nature).

destroyed by adding fuming nitric acid and again 

evaporating to dryness. Chemical separations were 

made as follows: Cesium by a silicotungstic perchlorate 

method (Glendenin and Nelson, 1951), strontium by 

carbonate precipitation followed by a fuming nitric 

acid separation method (Beaufait and Lukens, 1952), 

cobalt by an a-nitroso /S-naphthol chloroform extraction 

method (Sandell, 1959), ruthenium by a distillation 

method (Glendenin, 1951), cerium and rare earths by 

fluoride precipitation followed by an oxalate precipitation method (Ballou, 1951), zirconium and niobium by 

oxalate precipitation followed by a phenylarsonic acid 

extraction procedure (Steinberg, 1951). In the last procedure, oxalate was decomposed by fuming with 

sulfuric acid instead of boiling with potassium chlorate 

as in the reference. The amount of each radioion was 

determined by comparison of its count rate with that 

of Nuclear Chicago 2 standards.

Dialysis selectivity coefficients, ^i+j, for strontium, 

cesium, cerium, and cobalt were determined for comparison with the natural selectivity coefficients, K&+J. Four 

hundred milligrams of sized and air-dried sediment was 

transferred into a 2-ounce polyethylene bottle. Twenty 

milliliters of a solution containing tracer quantities 

(approximately lO^W) of one of the radiocations and 

known concentrations of calcium chloride or sodium 

chloride were also added to the bottle. Twenty milliliters 

of the identical solution were sealed in a cellulose dialysis 

casing (by tying knots in the ends) and inserted in the 

same 2-ounce bottle. The bottle was then placed on a 

slow-speed shaker and the contents allowed to equilibrate for 2 days. Experiments with reference clays 

indicate that 95-97 percent as much strontium is sorbed 

in 2 days as in 4 days. Since Whiteoak Creek sediment 

contains rock fragments, it may not have approached 

equilibrium as closely in 2 days as did the reference 

clays. However, when equilibration times of 4 days or 

more are used, appreciable biotic growth occurs. In 

addition, the dissolution of slightly soluble phases 

becomes an increasing problem with extended equilibration time, as discussed later for carbonates.

Immediately after the equilibration period, the 

dialysis tube was removed from the bottle and opened, 

and duplicate 1-milliliter aliquots of solution from inside the dialysis tube were pipetted to counting tubes. 

This technique avoided the problem of incomplete 

separation of solid and liquid phases by centrifuging. 

The relative quantity of a given radioion in the solution 

inside the dialysis casing was compared with that of an 

equal-volume aliquot of input solution to determine the

* Nuclear Chicago Corp., 333 East Howard Ave., Des PMnes, HI.
ROLE OF CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION P5

fraction of radioion sorbed by the sediment. The 

quantity of added radioion was sufficiently greater than 

that already on the sediment so that the contribution 

of the latter could safely be ignored. Both calcium plus 

magnesium and sodium were used as competing cations.

Sodium and potassium were determined on a flame 

photometer, and calcium plus magnesium was determined by versene titration (Rainwater and Thatcher, 

1960). Cation exchange capacities were determined with 

IN cesium chloride spiked with cesium-137 (Beetem 

and others, 1962) using two 4-hour and one overnight 

equilibration periods. After removing the free salt with 

ethanol, the oven-dry sample weight and the count 

rate of the cesium-137 sorbed by the sample were 

obtained. Comparison of the count rates (counts per 

minute per milliequivalent) of 1 milliequivalent of the 

IN cesium chloride solution with the count rate of the 

sample made possible the calculation of the cation 

exchange capacity of the sample.

The layer-silicate clay minerals were disaggregated and concentrated in a <^2jz (micron) fraction. 

Five-gram portions of the <60- and the 9- to 60-mesh 

fractions were suspended in distilled water and disaggregated in a Waring Blendor. After blending for 1 minute, 

the suspension was poured onto a 44ju screen and washed 

with distilled water. The sediment remaining on the 

screen was again blended with distilled water for 1 

minute and then sized. This cycle was repeated until 

the filtrate was almost clear. The <C44jLt material was 

separated at 20^ by decantation, and the 20-44|z 

material alternatively blended and sized until the 

decantate was almost clear. The <C20/i material was 

fractionated at 2p. without further blending.

CALCULATIONS

The distribution coefficient, Kd, is a common means 

of expressing the exchange sorption of a cation. If fs 

represents the fraction of radiocation which is adsorbed 

by the sediment and I /, represents the fraction 

remaining in solution, then

J.V (1)

where V is the solution volume, in milliliters, and M 

is mass of the sediment, in grams. It is apparent 

that the absolute amount of a radioion in either solid 

or liquid phase need not be known to calculate the Ka. 

One needs to know only the relative count rate for a 

particular radioion sorbed on M grams of sediment 

and that for V milliliters of equilibrium solution (or 

alternatively, the count rate for V milliliters of both the

294-242 68 2

original and the equilibrium solutions). The distribution coefficient then has units of milliliters per gram.

The relationship between Kd and JK^+j, the massaction selectivity coefficient, is quite simple. Consider the 

reaction describing the equilibrium exchange of Cs+ 

(cesium) in solution for exchangeable Ca++ (calcium):

(2)

(3)

Solving for K&M yields

From equation 1 it is apparent that

K^ (fraction sorbed/fraction unsorbed) (V/M) =

(CsX)/(Cs+); thus, equation 3 may be rewritten as

(4)

where (Cs+) and (Ca++) represent solution concentrations, in milliequivalents per milliliter, and terms 

(CsX) and (Ca!Z2) represent the quantity of exchangeable cations, in milliequivalents per gram.

The selectivity-coefficient equations in this paper are 

all written as in equation 3, where the radiocation is 

uniformly taken to be the jth competing cation. Hence, 

the greater the K%+i value, the greater is the selectivity 

of the sediment for the radiocation relative to the 

selectivity of the sediment for the competing cation (s).

Equation 4 is applicable in the presence of one, 

two, or several competing cations. Therefore, to calculate ~Kix+j from a particular Kdj, only the concentration 

of the competing cation of specific interest on the 

exchanger (sediment) and in the liquid phase (stream 

water) need be known.

Ion exchange reactions of reference clay minerals 

are rapid for the most part that is, of the order of 

minutes (Kennedy and Brown, 1966) and they are 

reversible. However, in dealing with earth materials 

in general and stream sediments in particular, extended 

times are often required to reach an apparent equilibrium because of (1) slow diffusion rates into the interstices of rock fragments and cemented secondary 

aggregates due to (a) extreme tortuosity, (b) doublelayer salt sieving (Kemper, 1960), and (c) edge collapse 

(pinching of particle edges) of expansible layer silicates 

of high-charge density (Walker, 1959, 1963); and (2) 

secondary reactions such as (a) fixation due to collapse 

of an expanded or partially expanded layer silicate 

mineral to a spacing of approximately 10 A, (b) pre-
F6 TRANSPORT OF RADIONUCLIDES BY STREAMS

cipitation for example, Co++ +2OH~4=»Co(OH) 

and (c) isomorphous substitution of the type

Some of the secondary reactions noted above are 

not readily reversible; hence, an apparent, rather than 

true, equilibrium is obtained. Most of the values of 

K&+J reported in the literature for earth materials 

exhibit a dependence on the concentration of the 

competing cation(s) as a result of secondary reactions 

of the types noted.

Another reason why K&+j values reported in the 

literature show the influence of the concentration of the 

competing cations is the use of concentrations rather 

than activities. To obtain thermodynamically valid 

KU+J values, which by definition are invariant with 

competing cation activities, ion activities rather than 

ion concentrations must be used. Activities can readily 

be calculated for salts in the aqueous phase (however, 

the accuracy decreases markedly for solutions whose 

ionic strength is greater than O.L/V). Currently there are 

major uncertainties in assigning values for the activities 

of solid-phase (exchangeable) cations.

The use of the term "mass-action equilibrium constant" is generally reserved for those reactions where (1) 

activities of the reacting ions can be unambiguously calculated or determined, (2) reversibility of the exchange 

reaction is demonstrated or can reasonably be expected 

to occur, and (3) secondary reactions of the types noted 

above are unlikely to occur. Under these conditions, 

selectivity coefficients and mass-action equilibrium constants are equivalent.

RESULTS 

MINERALOGY

Grain thin sections made from the 9- to 60-mesh 

fraction were examined through a petrographic microscope, and the composition was estimated: quartz, 40- 

50 percent; chert, 10-15 percent; and rock fragments, 

30-35 percent. Mica, chlorite, and feldspar grains were 

very rare.

Several X-ray diffraction patterns were obtained for 

randomly oriented powder specimens. Representative 

patterns are shown in figure 2. The powder patterns 

indicate the dominance of quartz, and the presence of

w

FULL S(

SEC ER 

z co

UJ I 

o z

a: 3

uj o

Q- o

Ca=calcite 

cl=clay 

D=dolomite 

F=feldspar 

Q=quartz

1.377 1.540 1.757 2.06 2.49

'ANGSTROMS

3.18 4.44 7.37 22

72 68 64 60 56 52 48 44 40 36 32 28 24 20 16 12

26, IN DEGREES

FIGUEE 2. X-ray diffraction powder patterns of sized Whiteoak Creek sediment [ground to 100 mesh; Cu Ka radiation].
ROLE OF CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION F7

clay at 10.10 A, 4.98 A, 2.56 A, and 1.50 A, and some feldspar 

at 3.24 A. One weak calcite and two very weak dolomite 

reflections were found in the diffraction patterns of the 

<60-mesh fraction. These reflections were not apparent 

in all the powder patterns. The maximum intensity of 

the calcite (3.02 A) and dolomite (1.78 A and 2.89 A) 

reflections was 7 and 5 percent above background, 

respectively. Neither calcite nor dolomite reflections 

could be identified in the 9- to 60-mesh fraction. The 

calcite and dolomite reflections disappeared entirely 

upon treatment of the sample with ammonium acetate 

and ammonium chloride. No iron oxides were identified 

in the powder patterns, although total iron, calculated 

as Fe2O3 , was 3.6 and 6.1 weight percent in the <60- and 

the 9- to 60-mesh fractions, respectively.

The Waring Blendor was very effective in breaking 

down the shale fragments, and it facilitated the concentration of the clays in the <2j* fraction, as shown 

by the absence of layer-silicate reflections in the X-ray 

powder patterns of the >44.u or 20-44ju separates of 

both the <60- and 9- to 60-mesh fractions (patterns 

not shown). In fact, only a minor amount of clay was 

found in the parallel-oriented slides made from the 

2-20ju separates (fig. 3), indicating that the clay had 

been successfully concentrated in the <2,u fraction. 

The size distribution resulting from the Waring Blendor 

disaggregation process was 28.4, 21.0, 36.0, and 11.1 

weight percent for the >44M, 20-44-u, 2-20ju, and <2ju 

separates of the <60-mesh fraction, respectively. The 

size distribution for the 9- to 60-mesh fraction was 

62.3, 11.8, 18.6, and 6.3 weight percent for the <44M , 

20-44ju, 2-20ju, and <2j* separates, respectively. Sample 

loss in the fractionating process amounted to 3.5 and 

0.9 weight percent for the <60- and the 9- to 60-mesh 

fractions, respectively.

Koughly equivalent intensities of illite (10 A) and 

vermiculite (14 A) reflections were obtained upon 

magnesium saturation and glyceration of the <2ju 

separate of the <60-mesh fraction (fig. 3). As was 

expected, there was less vermiculite in the <\2ju separate 

from the 9- to 60-mesh fraction than from the <60- 

mesh fraction. The high diffraction intensity in the 

region between the 10-A and 14-A peaks indicated 

that random mixed-layered illite-vermiculite was also 

present in addition to their occurrence as separate 

minerals.

Potassium saturation and air drying resulted in considerable enhancement of the 10-A illite peak and a 

concomitant decrease in the 14-A vermiculite peak. 

There did not appear to be any decrease in intensity 

in the 12-A to 13-A region as might have been expected,

A. <2n SEPARATE FROM 

<60-MESH FRACTION

C. <2» SEPARATE FROM 

9- TO 60-MESH FRACTION

Mg+AIR DRY 

- Mg+GLYCEROLB. 2- SEPARATE FROM

<60-MESH FRACTION

 Mg+AIR DRY- - 

 Mg+GLYCEROL __

 K+AIR DRY .^

 K+550°C ,

7.1 10 1418 7.1 10 1418

ANGSTROMS

14 12 10 8 6 4 14 12 10 8 6 4 

20, IN DEGREES

FIGUEE 3. X-ray diffraction patterns of parallel-oriented specimens of Whiteoak 

Creek sediment. [The <60- and 9- to 60-mesh fractions were separated by wet 

sieving. The <2^ and 2-20ji separates were obtained by physical disaggregation 

of the sized sediment in a Waring Blendor. Cu Ka radiation.]

because of collapse of part of the vermiculite to 10 A. 

The 10-A peak was sharpened by heating the sample 

to 300° Celsius (centigrade) because further dehydration and collapse of the vermiculite component occurred. 

The absence of discrete montmorillonite was indiated by the failure of a 17-A to 18-A reflection to 

occur upon glyceration. However, in the <2/u separate 

of the <.60-mesh fraction, glycerol solvation caused a
F8 TRANSPORT OF RADIONUCLIDES BY STREAMS

small reduction in the intensity of the 14-A reflection 

relative to that of the 10-A reflection. This would 

indicate that something in excess of 10 percent of the 

layers yielding the 14-A reflection were irregularly 

interstratffied montmorillonite.

A small amount of kaolinite in the <2/x separates 

was indicated by a 7-A peak, which was unaffected 

by cation saturation, glyceration, or heating to temperatures of up to 350°C for 1 hour. The 7-A reflection 

completely disappeared after the sample was heated 

at 550°C for 1 hour. A small amount of halloysite 

was indicated by a broad peak, or sometimes by a 

plateau, from about 7.1 A to 7.9 A, with a tendency 

for discrete peaks in the 7.4 A-7.9 A region. The intensity of the variable peaks in the latter region was not 

perceptibly influenced by free iron oxide removal, 

whereas the intensity of the 7-A peak was increased. 

The increased intensity of the 7-A peak was ascribed 

to removal of iron oxide coatings; this removal allowed 

more complete orientation of the kaolinite platelets 

parallel to the plane of the glass slide. The halloysite 

occurred predominantly in the <2/x fraction.

The absence of discrete chlorite was indicated by 

(1) no decrease in intensity of the 14-A reflection 

upon heating the sample at 550°C, as compared to 

350°C, for 1 hour; (2) the broad 14-A reflection in 

most patterns, often ranging from 12.6 A to 14.2 A; 

and (3) complete loss of the 7-A reflection at 550°C.

The 2-20/x separates showed a small amount of 

illite and a trace of kaolinite. The intensity of the illite 

reflection was enhanced by the heat treatments. The 

7-A kaolinite reflection was eliminated by heating the 

sample to 550°C.

No indication of hydroxy interlayers was found from 

either X-ray-diffraction or cation-exchange-capacity 

measurements made before and after free iron oxide 

removal.

SOLUBLE AND EXTBACTABLE (EXCHANGEABLE) 

CATIONS

Studies of the Clinch River downstream from the 

mouth of Whiteoak Creek (Morton, 1961) have shown 

that, as of 1958, the relative abundance of radioisotopes 

in the surface bed sediments of the Clinch River and, 

hence, presumably of Whiteoak Creek was cesium137> cerium-144 > cobalt-60 > rare earths plus 

yttrium-90]> strontium-90. However, according to 

Morton (1962), cesium-137, cobalt-60, strontium-90, 

and ruthenium-106 were considered to be of primary 

importance with regard to health safety on the basis of 

their low maximum permissible concentrations in drinking

water, relatively high abundance, and long half lives 

(cesium-137=30 yr, cobalt-60=5.24 yr, strontium-90= 

28 yr, ruthenium-106=371 days). Our analyses for 

cesium-137, cerium-144, cobalt-60, rare earths, strontium-90, ruthenium-106, and zirconium-95 plus niobium-95 revealed the presence of cesium-137, strontium-90, cobalt-60, and rare earths in both the stream 

water and leachates. Ruthenium-106 was found only 

in the stream water. If present, cerium-144 and zirconium-95 plus niobium-95 were below our detection 

levels.

Soluble calcium plus magnesium was slightly more 

than twice the value for soluble sodium in the stream 

water (table 1). As KNa£+Ca for clays is of the order of 

3-9 (Wahlberg and others, 1965), it could be predicted 

that most of the cation exchange sites of the clays 

present in the stream sediment would be saturated with 

calcium plus magnesium.

The extractable cations (exchangeable plus those 

dissolved from carbonates) were found to be predominantly calcium plus magnesium (table 1) as anticipated. 

The sum of the extracted cations is greater than the 

cation exchange capacity by a factor of about 4 for the 

<60-mesh fraction, whereas the two values are equivalent for the 9- to 60-mesh fraction (table 1).

The excess of extractable calcium plus megnesium 

over the cation exchange capacity for both size fractions 

indicates that some solid phase containing calcium and 

magnesium was dissolved. The discrepancy is greater 

for the < 60-mesh fraction than for the 9- to 60-mesh 

fraction. Several lines of evidence indicate that in situ 

precipitated carbonates were the source of the dissolved 

calcium plus magnesium.

TABLE 1. Major soluble cations in the stream water, major 

extractable (exchangeable) stable cations, and cation exchange 

capacities of the sized Whiteoak Creek sediment

Extractant

Calcium Cation

Sodium Potassium plus exchange

magnesium capacity

Stream water f (me/ml)

12X10-* 0.69X10-* 27X10-

< 60 mesh (me/g)

2.5 X10-* 

.42X10-*

2.2 X10-* 

.31X10-* 0.16

.068

0.11

9-60 mesh (me/g)

NH4C2H3 02................ 1.9 X10-*

NH4C1..................... .37X10-*

1.4 X10-* 

.18X10-*

0.081

.008

0.083

t The conductance of the stream water (after centrifugation) was 1.0X10* /»mho 

cm at 25°C. The pH of the water (before centrifugation) was 7.14.
ROLE OF CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION F9

Field observation (R. J. Picketing, oral commun., 

1965) indicates that carbonates are presently precipitating in Whiteoak Creek. This is in accordance with the 

greater amount of calcium plus magnesium extracted 

from the <60-mesh than the 9- to 60-mesh fraction 

by the ammonium acetate and ammonium chloride 

leaches. A marked decrease in the calcium plus magnesium in the ammonium chloride extract of both fractions 

as compared with the ammonium acetate extract (pH 3 

versus pH 7) may indicate that the carbonates present 

were largely removed during the course of the ammonium acetate extraction. Serial IN ammonium acetate 

pH 5 extractions (Jackson, 1956) of portions of the 

ammonium acetate plus ammonium chloride leached 

sediment yielded a small additional amount of calcium 

plus magnesium from both fractions in the first two 

30-minute extractions, but none was detected in 

subsequent extractions.

STRONTIUM

Strontium desorbed from the 9- to 60-mesh fraction 

with ammonium acetate gave a Kc$j+8r value of 1.9 

compared with 1.1 for the dialysis experiment. However, the KC^J+ST values for the <^60-mesh fraction 

were eight times that of the laboratory value. The 

larger values of K^+ST than KC$+B, are attributed to dissolution of (Ca,Sr90)CO3 by the ammonium 

acetate (and ammonium chloride) leach yielding strontium-90 in addition to the strontium-90 that was 

exchangeable.

The dialysis experiment yielded KC^+ST values 

(table 2) for both size fractions that are essentially 

identical with those obtained for sorption of strontium 

by reference clay minerals (Wahlberg and others, 

1965). This would not have occurred if the concentration of calcium in the starting solution had been used 

in the calculation, since appreciable calcium plus magnesium dissolved from the sediment in the course of 

the 2-day equilibrium period. The use of strontium-85 

for the dialysis experiments was also fortunate because 

of the release of strontium-90 by the dissolving carbonates. Whether strontium-85 and strontium-90 were 

in exchange equilibrium or not is immaterial, since a 

cation at the trace level (<^W~8N) competes with the 

dominant competing cation, not with other cations 

present in trace concentrations.

Examination of grain thin sections from air-dried 

unextracted sediment failed to reveal any discrete 

carbonate particles in either size fraction. However, 

detrital carbonates may exist as cement in some of the 

numerous rock fragments. The results of Clanton (1963)

TABLE 2. Distribution and selectivity coefficients for strontium-90 

sorption by Whiteoak Greek sediment

[Strontium-85 was used in the dialysis sorption studies; strontium-90 concentration 

in the stream water was found to be 1,200 pc/l (picoeuries per liter)]

Extractant

Natural Dialysis

K,

< 60 mesh

NH4C2H3O2 _

f NH4C1* __ .

405

527

9.6

12. 5 -.

1.2

9-60 mesh

NH4C2 H3O2 57

67

1.9 

2.2

1. 1

t-KS+y for the reaction H(CaXi + Mg-STa) + Sr+^SrXa + H(Ca«- + Mg++). 

*The total strontium-90 from both ammonium acetate and ammonium chloride 

extracts was used in this K?" and Kd calculation.

IX+J

indicate that significant exchange of strontium-90 in 

solution for the calcium plus magnesium of wellcrystallized carbonates is not likely to occur within a 

day or two. He demonstrated that sorption of strontium90 by detrital calcite plus dolomite was very slow. The 

average strontium-90 sorption (in what was initially 

distilled water spiked with strontium-90) only increased 

from 52.8 percent after 1 hour to 55.4 percent after 7 

days. Hence, the nature of the carbonate present in a 

stream sediment may be much more significant than 

the quantity of the phase present, as it affects the rate 

of the reaction CaCO3+Sr++^SrCO3 -l-Ca++.

Ratios of strontium-90 to calcium plus magnesium 

in the extracts are presented in table 3. The similarity 

of values for a given size fraction calculated for the 

two leaches indicates a relatively constant content of 

strontium-90 in the calcium plus magnesium phase 

dissolved. That it is a carbonate phase which is being 

dissolved is indicated by the disappearance of the calcite 

and dolomite reflections in the X-ray patterns following 

the ammonium acetate plus ammonium chloride leaches. 

That this carbonate phase is an in situ precipitate is 

indicated by the rapid rate at which it dissolves.

TABLE 3. Ratio of strontium-90 to calcium plus magnesium in 

ammonium acetate and ammonium chloride extracts of Whiteoak 

Creek sediment

[(pc Sr««/g)/(me Ca+Mg/g)]

Extractant

Size fraction

<60 mesh 9-60 mesh

NH4Cl

5,500

2,200

900

1,400
F10 TRANSPORT OF RADIONUCLIDES BY STREAMS

CESIUM

The predominantly irreversible 3 nature of cesium 

sorption by Whiteoak Creek sediment is indicated by 

the data in table 4, which show that only a small 

portion of the cesium-137 present was removed by 

the two 24-hour extractions. It is noteworthy that 

the percentage of cesium-137 extracted by ammonium 

acetate and ammonium chloride from the 9- to 60- 

mesh fraction was appreciably less than from the 

<60-mesh fraction. This difference is ascribed to the 

higher illite content of the coarser size fraction (fig. 3, 

A and G}. However, the absolute amount of cesium-137 

extracted from the two size fractions was not sufficiently different, when compared with the concentration in the stream water, to yield markedly different 

 Koat+08 values.

TABLE 4. Percentage of total radioactivity removed from Wh&eoak Creek sediment by ammonium acetate plus ammonium 

chloride extractions

<60 mesh_ ____ _____

9-60 mesh__ ___________

__._ 32

__ 14

Gamma

Cs»

17

4

count

Co*

12

Both size fractions sorbed equivalent quantities of 

cesium in the dialysis experiment. The K0;$+Cs values 

are of the same order of magnitude, although higher 

than those determined from the cesium-137 content of 

the leachate and stream water (Kcas+cs)- Since the 

combined ammonium acetate plus ammonium chloride extraction time was equivalent to the sorption time 

in the dialysis experiment (48 hr), &2 must be greater 

than ki, where ki and k% are the rate constants for reactions 5 and 6, respectively:

__

» 2CsX+K(Ca+++Mg+-»-).

(6)

Thus, perhaps a dialysis equilibrium tune of 1 day 

might have resulted in a KcS+os value identical with 

that obtained after the 48-hour desorption period.

The Conasauga Shale is one of the principal formations in the area drained by Whiteoak Creek, which 

presumably accounts for the illitic nature of the sediment. Reference samples of illite commonly continue

* Where irreversible sorption Is understood to pertain to that portion of the element 

not desorbed within the time interval of the experiment.

to sorb additional quantities of cesium for several 

days, at a decreasing rate. Thus, after only a 2-day 

equilibrium period, therate of cesium uptake in dialysis 

experiments may still have been fairly rapid. Thus, 

in comparing these data with other literature values, 

variable time factors must be taken into account. 

Release of cesium from interlayer sorption sites of 

illite is essentially a diffusion process, so that one 

might expect that considerably more cesium would 

have been removed from the sediment if the extraction 

time had been prolonged. This is indicated in table 5, 

where it is shown that 20-30 percent of the total cesium137 extracted was removed in the second 24-hour 

extraction period. This is in accordance with findings 

of various investigators that the displacement of a 

readily exchangeable portion of the total potassium 

is followed by a slow release of interlayer potassium 

(or cesium) from micas and illites, as indicated by the 

amount of potassium extracted or by increased cation 

exchange capacity values. (See, for example, Schnepfe, 

1960; Mortland and Lawton, 1961.)

TABLE 5. Distribution and selectivity coefficients for cesium-187 

sorption by Whiteoak Creek sediment

[Cesium-137 concentration in the stream water was found to be 670 pcA]

Natural Dialysis

xiiAtxauuauu

NH4C8H3O2

NH^HsOa+NHiCl*...

KdCa

> 60 mesh

. ___ 814

. __ 1,030

to,'

16, 000

25, 000 ..

to,'

56, 000

9-60 mesh

642 13,000

786 20,000

57, 000

tK£+j for the reaction J^(CaXj+]Vfe5j)+2Cs+ ^± 2Cs.Y+J£(Ca+++Mg«-). 

"The total cesium-137 from both ammonium acetate and ammonium chloride

extracts was used in this JBT^* and Kt calculation.

Previous laboratory studies (Wahlberg and Fishman, 

1962) on several reference layer-silicate minerals yielded 

^oat+cs values ranging from 2.8 X103 (kaolinite) to 

4X107 (illite) 4 for tracer-level («10-10_V) cesium in the 

presence of 0.003 AT calcium chloride. The same authors 

found KC&+CS values of 2-4.4 X104 and 0.9-1.2X10* 

for American Petroleum Institute montmorillonites No. 

11 and 21 respectively. This range in Kcaf+cs values 

(0.9-4.4 X104) for montmorillonite encompasses the 

range found for the stream sediment (2.0-2. 9 X104)

«J. S. Wahlberg, unpub. data;
KOLE OF CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION Fll

and is similar to the range obtained by dialysis (5.6- 

5.7 X104) in this study.

The question arises as to why the sediment, which 

X-ray diffraction shows to be principally illite and 

vermiculite, behaves chemically toward cesium like 

montmorillonite, yielding Kcas+cs values of the order 

of 104 instead of 107. One possibility is that coatings of 

organic matter, iron, manganese, and possibly aluminum and silicon on the primary particles present a 

diffusion barrier; thus, the equilibration time used in 

these experiments may simply have been inadequate. 

Rock fragments have been found to require up to twice 

as much time as reference clays to reach equilibrium in 

ion exchange reactions.5 In view of the considerable 

portion of rock fragments present in this stream sediment, inadequate equilibration time seems certain to 

be a contributing factor to the discrepancy. Further 

credence is given to this possibility by the significant 

amount of cesium-137 removed in the second 24-hour 

extraction (ammonium chloride) of the undried sediment (table 5).

COBALT

Some type of an essentially nonreversible mechanism 

is indicated for the sorption of cobalt-60 by Whiteoak 

Creek sediment. Table 4 illustrates that ammonium 

acetate plus ammonium chloride extractions removed 

practically none of the cobalt-60 from the 9- to 60- 

mesh fraction. In fact, so little cobalt-60 was displaced 

from this fraction that the KA and KCaZ+co values can 

be considered as indicative only. Clinch River status 

reports have suggested that sorption of cobalt-60 from 

solution was due primarily to organics (Morton, 1961, 

1962). However, manganese and iron oxides have 

recently been established as the primary scavenging 

agents in Whiteoak Creek sediment (Jenne and Wahlberg, 1965), organic matter being of secondary importance. Analysis of the ammonium acetate and ammonium chloride extracts for manganese and iron 

revealed that considerable manganese, but very little 

iron, had been dissolved. Thus, a large portion of the 

cobalt-60 extracted is presumed to have been released 

by dissolution of manganese oxides.

The results obtained show that KC&+CO from the 

<60-mesh fraction was 7.5 times greater than the 

comparable value determined by the dialysis technique 

(table 6), in spite of the fact that only 12 percent 

of the total cobalt-60 content of the <60-mesh fraction 

was removed (table 4).

* E. A. Jenne, and V. C. Kennedy, unpub. data.

TABLE 6. Distribution and selectivity coefficients for cobalt-60 

sorption by Whiteoak Creek sediment

[Cobalt-60 concentration In the stream water was found to be 47 pc/1]

Extractant

Natural Dialysis

< 60 mesh

NH4C2H3O2 _ ________

NH4C2H3O2 +NH4C1*.

1,400

2,400

33

57

4.3

9-60 mesh

NH4C2H3O2 +NH4C1*. 113

JO. 4 

1-4

17

IKS* for the reaction J_(Ca"xi+Mg"Xs)+Co-^^Co'^j+}.(Ca+++]Vfe^).

"The total cobalt-60 from both ammonium acetate and ammonium chloride extracts 

was used in this K£+j and Kd calculation.

{Quantity determined was extremely close to detection level; hence, values are 

only approximate.

Cobalt sorption by reference clays in the presence of 

dilute concentrations (0.1-0.001AO of calcium or 

sodium is of similar magnitude to that of strontium 

(data not presented). Cobalt sorption equivalent to 

that of strontium was also indicated by Sorathesn, 

Bruscia, Tamura, and Struxness (1960) for distilledwater systems and by Graham and Killion (1962) for 

0.013M (molar) calcium chloride systems. In the 

presence of organics (peat), the cobalt selectivity is 

much enhanced relative to strontium (Graham and 

Killion, 1962). Because little cobalt-60 was found in 

the organic fraction of this stream sediment (Jenne and 

Wahlberg, 1965), the J5.ggl.oo value of 4.3 «60-mesh 

fraction) indicates scavenging of the cobalt-60 from the 

solutions by manganese and iron oxides, in addition to 

sorption on exchange sites of the silicate minerals. 

The greater laboratory sorption by the coarse, as compared with the fine, sediment fraction reflects the 

greater amount of manganese and iron oxides present 

in this fraction. In contrast, the jKc^+co value is higher 

in the <^60-mesh fraction because the ammonium 

acetate plus ammonium chloride extractants dissolved 

a greater portion of the fine-grained manganese and iron 

oxides.

BABE EARTHS

Dialysis sorption experiments yielded highly erratic 

results ranging from 63 to >99 percent uptake of 

tracer-level cerium-144 (originally trivalent) in competition with 10~3-10~W calcium chloride. The extent of 

cerium sorption was not obviously related to competing 

cation concentrations. The count rates of different 

aliquots of the original input solutions were also noted 

to be erratic. Three separate series of aliquots were
F12 TRANSPORT OF RADIONUCLIDES BY STREAMS

taken, from the original input solutions after these 

solutions had been stored for several days. Aliquots 

were taken with a minimum of disturbance, after 

vigorous shaking, and after acidification of the solutions. 

This sequence of aliquots yielded increasing count rates, 

indicating that precipitation or radiocolloid formation 

had occurred. Thus, the laboratory sorption data were 

invalidated and are therefore not presented here.

If precipitation occurred in the cerium dialysis experiments (average pH of 7.6 with extremes of 7.3 and 7.8), 

as it apparently did, then a similar process might be 

expected to occur in Whiteoak Creek. If rare earths were 

present in the sediment as precipitates which were 

insoluble in the ammonium acetate plus ammonium 

chloride leachates, the low K^+Ce values shown in 

table 7 would be explained. The higher concentration 

of rare earths in the solution phase, relative to the 

exchangeable phase, may be due to organic complexing 

agents in the stream. In fact, the fraction of the rare 

earths present which was removed by the ammonium 

acetate leach may have been combined with organics 

and, thus, may have escaped inorganic precipitation in 

the stream.

The selectivity constant approach does not appear 

to be applicable for cerium except in acid waters. Bensen 

(1960) noted that the uptake of cerium was essentially 

100 percent at pH above 5 for a calcareous soil regardless of the initial valence of the cerium. Similar results 

were obtained with yttrium. The reversibility of the 

uptake was not reported for either element.

RUTHENIUM

From the presence of 230 picocuries of ruthenium-106 

per liter in the water and the absence of ruthenuim-106 

from the leachates, one would conclude that ruthenium is

TABLE 7. Natural distribution and selectivity coefficients for 

rare-earth sorption by Whiteoak Creek sediment

[Rare-earth (R.E.) concentration in the stream water was found to be 44 pcfl as 

cerium-144; rare-earth concentration in the ammonium chloride extracts was 

below detection]

Extractant Kc iZ+j t

<60 mesh

Do.

180

140

0.5 

.3

9-60 mesh

NH4C2H8O2*. 

Do......

89

73

0.3 

.2

the reaction 3(CaXi+Mg"£2)+2(R.E.)+8^2(R.E.)"£3+3(Ca+++Mg++). 

Concentrations found were extremely close to detection levels; hence, values are 

only approximate.

either irreversibly sorbed or not sorbed at all. Failure 

of the sediment to sorb ruthenium was indicated by an 

insufficient amount present in the sediment to be identified in the gamma spectrums. Other investigators 

(Bensen, 1960; Friend and Porcella, 1962; Story and 

Gloyna, 1963) also indicated that ionic uncomplexed 

ruthenium is only slightly sorbed by earth materials. 

As information on the valence state of ruthenium 

(which varies form 0 to +8) in Whiteoak Creek was 

not available at the time of the present study, the 

laboratory determination of distribution coefficients on 

the sediment was somewhat pointless.

In contrast to the findings in the present study, 

Pickering, Carrigan, Tamura, Abee, Beverage, and 

Andrew (1966) reported the presence of 16 curies of 

ruthenium-106 in Clinch River bed sediments as of 

July 1, 1962. Lomenick and Gardiner (1965) reported 

1,038 ±88 curies of ruthenium-106 in the bed of White 

Oak Lake as of December 1962. The latter authors noted 

that the ruthenium-106 is concentrated in a small area 

of the upper lake bed which roughly coincides with 

inlets of two surface streams which drain the intermediate-level-radioactive liquid-waste seepage-pit area. 

They stated that most of the ruthenium-106 is retained 

in the upper few inches of soil whereas a portion of the 

ruthenium migrates underground. Pickering, Carrigan, 

Tamura, Abee, Beverage, and Andrew (1966) suggested 

that the ruthenium-106 in the Clinch River bed sediment is in the form of nitrosyl ruthenium hydroxide, 

RuNO(OH) 3 (H2O) 2 . Both ion exchange and physical 

sorption would be involved in the retention of this 

rather large ion by sediments.

DISCUSSION

It is believed that the soluble and exchangeable 

radioions were essentially in equilibrium at the time of 

separation of the sediment and aqueous phases for several 

reasons. First, about 40 days had elapsed since the last 

rain of sufficient magnitude to cause significant sediment 

movement. Hence, the sediment in the stilling basin 

would have been in the process of equilibrating with the 

low-level waste from the Oak Ridge National Laboratory for this period of time. Second, the time of travel 

of the creek water from the Oak Ridge National Laboratory to the stilling basin, a distance of 1.1 miles, was 

approximately 2% hours at the discharge rate which 

prevailed (W. M. McMaster, written commun., 1966). 

In conjunction with the shallow nature of the creek 

and the coarse-textured highly permeable stream bed, 

this time and distance of travel is adequate to smooth 

out any short-time fluctuations in radioisotope dis-
ROLE OF CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION F13

charge from the laboratory. Thus, changes in the radioisotope concentration in the stilling basin in response 

to releases from the laboratory would occur slowly over 

a period of many hours. Third, upon receipt of the water 

in the U.S. Geological Survey's Denver laboratory 

about 10 days after collection, the slurry of surficial bed 

sediment was mixed with the water and allowed to 

equilibrate further for 24 hours before separation. 

Since the permeability of the polyethylene bottles to 

oxygen and carbon dioxide is appreciable, and because 

there was no detectable change in the odor of the water 

as a result of transport, there is reason to believe that 

the biological population of the water would not have 

changed sufficiently during transit to have affected the 

radioion distribution.

The data presented indicate strongly that ammonium 

acetate "extractable" strontium, cobalt, and cesium 

are not identical with the quantity of these ions that 

is "exchangeable" that is, sorbed reversibly onto 

electrostatic exchange sites. This situation results from 

the dissolution of significant amounts of solid phases 

containing strontium and also cobalt, and from the 

diffusion-controlled release of cesium from the micaceous minerals. Thus, the amount of these radioions 

extracted is partly dependent on the duration of the 

extraction and the solid to solution ratio utilized. 

However, this does not invalidate equation 3 because 

the strontium in the in situ precipitated carbonate, 

the cobalt in the hydrous manganese and iron oxides, 

and the interlayer cesium in illite are in equilibrium 

with the stream water. However, the accuracy of the 

resultant selectivity coefficients is adversely affected 

because the optimum extraction time is unknown.

Carbonates present a twofold problem. First, ammonium acetate, even at pH 7, dissolves an appreciable 

quantity of fine-grained carbonates (Hanna and Reed, 

1948; Bower and others, 1952); hence, where strontium 

is a component of stream carbonates, either through 

coprecipitation or by isomorphous substitution for 

calcium or magnesium in detrital carbonates, the 

amount of exchangeable strontium as well as calcium 

plus magnesium will be overestimated. Secondly, 

during the equilibration of strontium with the sediment 

in the dialysis technique, carbonates also dissolve 

when the solution is undersaturated with respect to 

calcium carbonate (as would commonly be the situation), yielding additional strontium to the solution 

but, more importantly, depressing strontium sorption 

by increasing the concentration of competitive divalent 

cations (calcium plus magnesium). Thus, calcium plus 

magnesium is not constant, but increases during the

equilibration period. Strontium sorption in the presence 

of sodium as the competing ion (data not presented) 

revealed that in the <60-mesh fraction the calcium 

plus magnesium concentration increased from 0 to 

2-5X10~W. Here, the strontium-90 that came into 

solution caused no problem, as the dialysis experiments 

were carried out with strontium-85. Also, the amount 

of strontium dissolved was insignificant in comparison 

with the calcium plus magnesium concentration. That 

is, the sorption of a cation present at the trace level 

is controlled by the selectivity of the exchanger for it 

and the dominant cation(s) on the exchange complex, 

not by other trace elements. This situation is illustrated 

for cesium in the report of Wahlberg and Fishman 

(1962).

The large amount of fixed, relative to exchangeable, 

cobalt-60 led to a companion study (Jenne and Wahlberg, 1965) where an attempt was made to identify 

the agent(s) in the sediment responsible for scavenging 

of cobalt-60. Metal oxide reduction treatments (Jackson, 1956) with interspersed organic-matter oxidization 

revealed that most of the cobalt-60 was in the reducible 

metal oxide fraction. It was concluded that 95 percent 

of the cobalt-60 was distributed between these two 

scavenging agents, and that much more was in the 

manganese than in the iron oxide fraction, even though 

the sediment contains 30 times more iron than manganese.

The sorption and desorption of strontium, cesium, 

and cobalt were shown to be significantly time dependent. Thus, the rates at which these reactions occur 

may be of equal or greater significance than the ion 

exchange capacity, as regards the retention of radioions.

FUTURE STUDIES

Many problems are inherent in the accurate prediction of field uptake of radioions on the basis of laboratory sorption measurements. The time dependency of 

many sorption and other concomitant reactions is the 

source of several problems.

Ideally, a complete in situ separation of the stream 

water and sediment should be made immediately after 

sampling, followed by size separation of the sediment, 

displacement of the exchangeable ions, and determination of the major cations. Ammonium chloride appears 

to be the most suitable extractant, as carbonates and 

manganese oxides are believed to be less soluble in 

ammonium chloride than in ammonium acetate. The 

use of a nonvolatile salt is precluded by the need to 

concentrate the extract.
F14 TRANSPORT OF RADIONUCLIDES BY STREAMS

The ammonium chloride used to displace exchangeable cations should be adjusted to a pH such that, 

after leaching through the sample, the leachate pH 

is identical with that of the stream water. Alternatively, 

the extractant pH could be adjusted to the pH of the 

stream water. However, the former is preferable because the 

higher salt concentration of extractant displaces hydrogen 

ions from the exchange sites, increasing the solution-phase 

activity of hydrogen so that it can attack carbonates. 

Thus, to maintain the pH of the extractant in contact 

with the sample at the pH of the stream water, it may 

be necessary to start with the ammonium chloride 

solution at a slightly higher pH than that of the stream 

water.

Portions of extracted and unextracted sediment could 

then be dried immediately. The clarified stream water 

and ammonium chloride extracts should be acidified to 

pH 2-3 to reduce biotic growth, container sorption, and 

precipitation, especially where waters may be supersaturated with respect to calcium carbonate. The stream 

water would be clarified by filtration through a O.OSju 

filter. If significant amounts of suspended sediment were 

present, the water could first be passed through a 

continuous flow centrifuge to reduce filtration time.

The next steps would entail the transfer of appropriate aliquots of the sediment-free stream water to 

plastic bottles, addition of known amounts of appropriate carriers to duplicate aliquots, and capping of the 

bottles for return to the laboratory for concentration, 

radiochemical separations, and quantitative radioactivity assay.

It would be necessary to treat the various aliquots 

of stream water so as to insure the same oxidization 

state for both the carriers and radioions. Errors in the 

estimation of the concentration of a given element in 

the stream water, due to container sorption or radiocolloid formation, would be essentially eliminated by 

the above procedures, inasmuch as the addition of a 

known amount of a carrier allows the percentage recovery of a given element to be determined. Changes in the 

quantity of radioions in the liquid and solid phases due 

to changes in redox potential, temperature, and biota 

during transport could thus be avoided. The determined 

radioion distribution would be very nearly that which 

actually existed in the stream at the time of sampling.

It would be desirable to extract a portion of the sediment with sodium chloride or some other highly soluble 

salt in which organics, manganese oxides, and carbonates 

would be less soluble than in ammonium chloride. The 

difference in the calcium, magnesium, manganese, and 

iron concentrations in this extract and in the ammonium

chloride extract would indicate the extent to which 

minor phases were being dissolved in the ammonium 

chloride extract. However, the use of a nonvolatile salt 

is precluded for determining the amount of trace-level 

radioisotopes because extract volumes of the order of 

liters must be concentrated to volumes of the order of 

milliliters.

In any future studies of this type, it would be essential to determine the rates of the sorption-desorption 

reactions. The leachate might well be collected in 

several sequential portions so that the fraction of each 

radioion removed could be determined as a function of 

leaching time. Sorption-desorption curves of the type 

illustrated in figure 4 may be expected for any radioion 

where a portion of the sorption is irreversible (that is, 

within the time interval of the experiment). In addition 

to furnishing a best estimate of the amount of exchangeable ion, the time curves indicate the degree of 

permanence with which the radiocation has been fixed 

and permit an estimate of the time required for the 

nonexchangeable portion to be extracted. If a leaching 

solution were used which was similar in composition 

to the stream water, except for the absence of the 

radiocation, the time required for the radiocation content of the sediment to drop to background, when and if 

its source to the stream were cut off, could be estimated.

A mobile field laboratory would be essential for such 

a study in view of the amount of work which should 

be performed on site.

CONCLUSIONS

In situ precipitated carbonates controlled the sorption 

of strontium-90, the hydrous oxides of manganese and

z 

o

a: o

0 5

(/) o

LJ O

O

-Amount initially present

Nonexchangeable

Exchangeable

TIME, IN MINUTES

FIGTJBE 4. Graph showing generalized curve for the desorption of a radiocation 

from multiple-phase earth-material specimen.
ROLE OF CERTAIN STREAM-SEDIMENT COMPONENTS IN RADIOION SORPTION F15

iron controlled the sorption of cobalt-60, and illite 

controlled the sorption of cesium-137 in Whiteoak Creek 

(Oak Ridge, Term.) sediment. Rare earths precipitated at the neutral pH of the stream water, whereas 

ionic, uncomplexed ruthenium was sorbed only very 

slightly by the sediment.

Agreement between "natural" and "laboratory" selectivity coefficients (nonequilibrium mass-action constants) for the <60-and the 9- to 60-mesh fractions of 

the sediment was only fair. High values for the natural 

selectivity coefficients for strontium-90 and cobalt-60 

are attributed to the dissolution of fine-grained carbonate and hydrous manganese and iron oxides, 

respectively, in the ammonium acetate and ammonium 

chloride leachates. High laboratory selectivity coefficients for cobalt-60 in the 9- to 60-mesh fraction is 

believed to be due to the greater quantities of the 

hydrous oxides in this size fraction. The larger cesium137 laboratory selectivity coefficient (by a factor of 2) 

is believed to be due to more rapid rates of cesium-137 

sorption than desorption by illite, the dominant clay 

mineral in the sediment. Much less cobalt-60 was 

desorbed from the 9- to 60-mesh than from the <60- 

mesh fraction of the sediment owing to the lesser 

amount of hydrous oxides of manganese and iron 

present in the coarser fraction. Much less cesium-137 

was desorbed from the coarser fraction owing to the 

slower diffusion of cesium-137 out of the larger illite 

particles.

REFERENCES CITED

Baas Becking, L. G. M., and Moore, D., 1959, The relation 

between iron and organic matter in sediments: Jour. Sed. 

Petrology, v. 29, p. 454-458.

Ballou, N. E., 1951, Determination of rare-earth activities in 

fission, 4/i Coryell, C. D., and Sugarman, Nathan, Radiochemical studies; The fission products: New York, McGrawHill Book Co., v. 3, Paper 292, p. 1673-1691.

Beaufait, L. J., Jr., and Lukens, H. R., Jr., 1952, in Handbook 

of radiochemical analysis, v. II, Radiochemical procedures: 

U.S. Atomic Energy Comm. Rept. NP-5057, p. 122.

Beetem, W. A., Janzer, V. J., and Wahlberg, J. S., 1962, Use of 

cesium-137 in the determination of cation exchange capacity: 

U.S. Geol. Survey Bull. 1140-B, 8 p.

Bensen, D. W., 1960, Review of soil chemistry research at 

Hanford: U.S. Atomic Energy Comm. TID-4500, 15th ed., 

HW-67201, 42 p.

Berg, W. A., 1960, A theory of ion exchange behavior in iron 

oxide kaolinite systems: North Carolina State Univ. Ph. D. 

thesis, 79 p.

Bower, C. A., Reitemeier, R. F., and Fireman, Milton, 1952, 

Exchangeable cation analysis of saline and alkaline soils: 

Soil Sci., v. 73, p. 251-261.

Carstea, Dumitra, 1965, Conditions of Al, Fe, and Mg interlayer formation in montmorillonite and vermiculite: Corvallis, Oregon State Univ. M.S. thesis, 73 p.

Clanton, U.S., 1963, Sorption and release of radionuclides by 

sediments: U.S. Atomic Energy Comm. TID-7664, p. 

113-125.

Friend, A. G., and Porcella, D. B., 1962, Studies of the distribution of radionuclides in the Clinch and Tennessee Rivers 

below Oak Ridge: New York, Engineers Joint Council, 

Preprint Paper 75, 24 p.

Glendenin, L. E., 1951, Improved determination of ruthenium 

activity hi fission, in Coryell, C. D., and Sugarman, Nathan, 

Radiochemical studies; The fission products: New York, 

McGraw-Hill Book Co., v. 3, Paper 260, p. 1549-1556.

Glendenin, L. E., and Nelson, C. M., 1951, in Coryell, C. D., 

and Sugarman, Nathan, Radiochemical studies; The fission 

products: New York, McGraw-Hill Book Co., v. 3, Paper 

283, p. 1642-1645.

Gorbunova, Z. N.» 1961, Properties of soils in the Klyaz'ma 

River flood plain and the mineralogical composition of 

their clay fraction: Soviet Soil Sci., v. 11, p. 48-54.

Graham, E. R., and Killion, D. D., 1962, Soil colloids as a factor 

in the uptake of cobalt, cesium, and strontium by plants: 

Soil Sci. Soc. America Proc., v. 26, p. 545-547.

Hanna, W. J., and Reed, J. F., 1948, A comparison of ammonium 

acetate and buffered barium chloride methods for determining cation-exchange properties of limed soils: Soil Sci., 

v. 66, p. 447-458.

Hechter, Oscar, Pollen, AUessandro, Lester, Gabriel, and Gregor, 

H. P., 1959, A model for cellular cation discrimination: 

Am. Chem. Soc. Jour., v. 81, p. 3798-3799.

Jackson, M. L., 1956, Soil chemical analyses Advanced course: 

Published by the author, Wisconsin Univ., Madison, Wis., 

991 p.

Jenne, E. A., and Wahlberg, J. S., 1965, Manganese and iron 

oxide scavenging of cobalt 60 in White Oak Creek sediment 

(Oak Ridge, Tenn.) (abs.): Am. Geophys. Union Trans., 

v. 46, p. 170.

Kemper, W. D., 1960, Water and ion movement in thin films 

as influenced by the electrostatic charge and diffuse layer 

of cations associated with clay mineral surfaces: Soil Sci. 

Soc. America Proc., v. 24, p. 10-16.

Kennedy, V. C ., and Brown, T. E., 1966, Experiments with a 

sodium-ion electrode as a means of studying cation exchange 

rates, in Bradley, W. F., and Bailey, S. W., eds., National 

Conference of Clays and Clay Minerals, 13th, Madison, 

Wis., 1964, Proc.: New York, Pergamon Press, p. 351-352.

Lomenick, T. F., and Gardiner, D. A., 1965, The occurrence 

and retention of radionuclides in the sediments of White 

Oak Lake: Health Physics, v. 11, p. 567-577.

Mortland, M. M., and Lawton, K., 1961, Relationship between 

particle size and potassium release from biotite and its 

analogues: Soil Sci. Soc. America Proc., v. 25, p. 473-476.

Morton, R. J., ed., 1961, Status report no. 1 on Clinch River 

study: U.S. Atomic Energy Comm. ORNL-3119, 76 p.

 1962, Status report no. 2 on Clinch River study: U.S. 

Atomic Energy Comm. ORNL-3202, 91 p.

Ormsby, W. C., Shartsis, J. M., and Woodside, K. H., 1962, 

Exchange behavior of kaolins of varying degrees of crystalUnity: Am. Ceramic Soc. Jour., v. 45, p. 361-366.
F16 TRANSPORT OP RADIONUCLIDES BY STREAMS

Pickering, R. J., Carrigan, P. H., Jr., Tamura, Tsuneo, Abee, 

H. H., Beverage, J. W., and Andrew, R. W., Jr., 1966, 

Radioactivity in bottom sediment of the Clinch and Tennessee Rivers: Internat. Atomic Energy Agency, Vienna, 

May 16-20, 1966, Symposium on the Disposal of Radioactive Wastes into Seas, Oceans and Surface Waters, 

SM-72/4, 44 p.

Rainwater, F. H., and Thatcher, L. L., 1960, Methods for 

collection and analysis of water samples; U.S. Geol. Survey 

Water-Supply Paper 1454, p. 174-176.

Rich, C. I., 1960, Ammonium fixation by two red-yellow podzolic 

soils as influenced by interlayer-Al in clay minerals: Internat. 

Gong. Soil Sci., 7th, Madison, Wis., 1960, v. 7, p. 468-475.

Sandell, E. G., 1959, Colorimetric metal analysis: 3d ed., New 

York, Interscience Publishers, Inc., p. 422.

Schnepfe, M. M., 1960, Cation exchange with vermiculite, in 

Short papers in the geological sciences: U.S. Geol. Survey 

Prof. Paper 400-B, p. 161-163.

Sorathesn, A., Bruscia, G., Tamura, Tsuneo, and Struxness, 

E. G., 1960, Mineral and sediment affinity for radionuclides: 

U.S. Atomic Energy Comm. ORNL-60-6-93, 26 p.

Steinberg, E. P., 1951, Oxalate method for determination of 

zirconium and niobium activities in fission, in Coryell, 

C. D., and Sugarman, Nathan, Radiochemical studies 

The fission products: New York, McGraw-Hill Book Co., 

v. 3, Paper 243, p. 1495-1497.

Story, A. H., and Gloyna, E. F., 1963, Radioactivity transport

in water-environmental behavior of nitrosylrutheniuin: 

Texas Univ. ORO 620, Tech. Rept. 3, 89 p. 

Sumner, M. E., 1962, The effect of sodium dithionite on the 

surface properties of clays: Agrochimica, v. 6, p. 183-189.

 1963, Effect of iron oxides on positive and negative

charges in clays and soils: Clay Minerals Bull., v. 5, p.

218-226. 

Tamura, Tsuneo, 1962, Strontium reactions with minerals:

Ground Disposal of Radioactive Wastes Conf., 2d, Chalk

River, Canada, Sept. 26-29, 1961, U.S. Atomic Energy

Comm. TID-7628, book 1, p. 187-197. 

Wahlberg, J. S., Baker, J. H., Vernon, R. W., and Dewar, R. S.,

1965, Exchange adsorption of strontium on clay minerals:

U.S. Geol. Survey Bull. 1140-C, 26 p. 

Wahlberg, J. S., and Fishman, M. J., 1962, Adsorption of

cesium on clay minerals: U.S. Geol. Survey Bull. 1140-A,

30 p. 

Walker, G. F., 1959, Diffusion of exchangeable cations in

vermiculite: Nature, v. 184, p. 1392-1393.

 1963, The cation exchange reaction in vermiculite, in 

Rosenquist, I. T., ed., Internat. Clay Conf. Proc., Stockholm, Sweden, Aug. 12-16, 1963: New York, MacMiUan 

Co., p. 177-181.

Weed, S. B., and Nelson, L. A., 1962, Occurrence of chlorite-like 

intergrade clay minerals in coastal plain, piedmont, and 

mountain soils of North Carolina: Soil Sci. Soc. America 

Proc., v. 26, p. 393-398.

O