Distribution of 

Radionuclides in 

Bottom Sediment of the 

Clinch River 

Eastern Tennessee

GEOLOGICAL SURVEY PROFESSIONAL PAPER 433-H

Prepared in cooperation with the

U.S. Atomic Energy Commission and the

Oak Ridge National Laboratory
Distribution of 

Radionuclides in 

Bottom Sediment of the 

Clinch River 

Eastern Tennessee

By R. J. PICKERING

TRANSPORT OF RADIONUCLIDES BY STREAMS

GEOLOGICAL SURVEY PROFESSIONAL PAPER 433-H

Prepared in cooperation with the

U.S. Atomic Energy Commission and the

Oak Ridge National Laboratory

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1969
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

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

Washington, D.C. 20402 - Price 40 cents (paper cover)
CONTENTS

Page Variation of radionuclide content with depth in cores Page

Abstract_ ________________________________________ HI Continued

Introduction_______________________________________ 1 Relationship of vertical distribution to annual

Acknowledgments____________________________ 3 releases... __________________________________ Hll

Previous work__________________________________ 4 Physicochemical composition of selected core samples--. 13

Methods and equipment_--__---_______-_______-_____ 5 Physical characteristics.-.-__________________ 13

Core sampling________________________________ 5 Mineralogical characteristics-________________ 16

Core counting__________________________________ 5 Chemical characteristics_________________________ 19

Physicochemical analysis of sediment______________ 6 Correlations of physicochemical characteristics and

Core sampling results_______________________________ 7 radionuclide content___________-______________ 19

Variation of radionuclide content with depth in cores__ 7 Discussion_____________________________________ 20

Gross gamma core scanning______________________ 7 Conclusions_____________--___________________-____- 23

Gamma-ray spectrum core scanning_____________ 10 References cited___-____-_--_______-_--__---______-_ 24

ILLUSTRATIONS

Page 

FIGURE 1. Map of study reach showing locations of core-sampling sections_---__-----_-------------_--------_-------- H2

2. Diagrammatic representation of core scanner__________________________________________________________ 6

3. Cross section at CRM (Clinch River mile) 7.5 showing results of core sampling and analysis. _________________ 8

4. Graphical comparison of gross gamma radioactivity in four cores to variations in annual releases of cesium-137

to the Clinch River_______________________________________________________________________________ 9

5. Graphs showing variations in contents of cesium-137, cobalt-60, and ruthenium-106 with depth in hole 6, CRM 7.5_ 11

6. Diagrams showing results of particle-size analyses of selected samples from hole 7-2, CRM 7.5, and from hole 2,

CRM 14.0_____-_-__-_--_____________________________________-___-__--_-____________---_-______- 15

7. Diagram showing results of particle-size analyses of composite samples of the radioactive parts of 45 cores of

Clinch River bottom sediment__________________________________________________________________ 17

TABLES

TABLE 1. Yearly discharges of radionuclides to the Clinch River______________________-_-________________________ H9

2. Coefficients of correlation for comparison of vertical distribution of gross gamma radioactivity in sediment cores

with annual releases of radionuclides_-___________-___--__--_-__-__-___-_--__---_-__ ___________ 10

3. Fractional contributions of cesium-137, cobalt-60, and ruthenium-106 to total gamma-ray radioactivity of selected

Clinch River sediment cores_-__--__-_-_--_--_--_---_--__---------------------------_--_---__-_--- 10

4. Relationship of cobalt-60 to cesium-137 in selected bottom-sediment cores from the Clinch River______________ 11

5. Physical and chemical characteristics of selected samples of bottom sediment from the Clinch River.__________ 14

6. Particle-size analyses of selected samples of bottom sediment from the Clinch River ______________________ 16

7. Cation-exchange capacities of clay-, silt-, and sand-size fractions of selected samples of Clinch River bottom

sediment-____________________________________________________________________________________ 16

8. Mineralogical composition of selected samples of Clinch River bottom sediment----------------------------- 18

9. Coefficients of correlation for constituent pairs, hole 7-2, CRM 7.5_________---------------_------_-------- 21

10. Coefficients of correlation for constituent pairs, hole 2, CRM 14.0-__---------__--------------------_-----_ 22

ill

TRANSPORT OF RADIONUCLIDES BY STREAMS

DISTRIBUTION OF RADIONUCLIDES IN BOTTOM SEDIMENT 

OF THE CLINCH RIVER, EASTERN TENNESSEE

By E. J. PICKERING

ABSTRACT

Radioactive bottom sediment in the Clinch River in eastern 

Tennessee was investigated through a study of the distribution 

of radioactivity in sediment cores. The cores were taken from a 

21-mile-long reach of river downstream from Oak Ridge National 

Laboratory. Low-level-radioactive liquid wastes are released 

from the Laboratory to the Clinch River via Whiteoak Creek.

In the upper 8 miles of the reach, radioactive sediment is 

found only along the sides of the stream channel, but in the 

lower 13 miles of the river, it extends out into the main part of 

the channel as well and attains its greatest thicknesses. Several 

sediment cores from the lower part of the river showed the same 

general pattern of variation of gross gamma radioactivity with 

depth. This pattern resembled the pattern of annual releases of 

cesium-137 from the Oak Ridge National Laboratory. Statistical 

comparison of the patterns confirmed the similarity.

Measurements of the vertical distribution of the major gammaray-emitting radionuclides in nine cores showed that approximately 81 percent of the gamma radioactivity was due to cesium137, 12 percent to cobalt-60, and 7 percent to ruthenium-106. The 

vertical distribution of cobalt-60 correlated strongly with that 

of cesium-137.

It is concluded that cesium-137 and cobalt-60 were incorporated in Clinch River bottom sediment by deposition of suspended 

radioactive solids which entered the river from Whiteoak Creek. 

The two radionuclides are not necessarily associated with the 

same solids, and cobalt-60 in the bottom sediment probably represents only a small fraction of that released to the river.

A study of the physical and chemical compositions of sediment samples from two cores showed that cation-exchange properties of the sediment are controlled largely by its content of 

mica and clay minerals. These minerals are found primarily in 

the finest sediment fraction, but can occur also in the coarser 

fractions in the form of mineral aggregates and shale particles. 

Calcium and magnesium are the major leachable cations in the 

sediment; potassium and sodium are not present in measurable 

quantities. The effects of chemical and physical properties of the 

sediment on its radionuclide content are obscured as a result of 

variations in annual releases of the radionuclides and as a result of dilution of radioactive sediment by nonradioactive sediment in the river. Compositional effects were discernible only 

after corrections were made for variations in annual releases of 

radionuclides.

INTRODUCTION

This report describes one of several contributions of 

the U.S. Geological Survey to the Clinch Eiver Study. 

The Clinch Eiver Study was a multiagency effort to 

evaluate the past, present, and future use of the Clinch 

Eiver for disposal of low-level-radioactive liquid waste 

from the Oak Eidge National Laboratory, which is in 

eastern Tennessee (Morton, 1961,1962b, 1963; Pickering 

and others, 1965; Struxness and others, 1967) and is 

operated by the Union Carbide Corp. for the U.S. 

Atomic Energy Commission. The agencies that participated in the study are: Oak Eidge National Laboratory 

(OEKL); Tennessee Game and Fish Commission; 

Tennessee State Department of Public Health, Stream 

Pollution Control Board; Tennessee Valley Authority 

(TVA); U.S. Atomic Energy Commission (AEC); 

U.S. Geological Survey (USGS); and U.S. Public 

Health Service (PHS).

When the study was begun in 1960, the following objectives were established by the Clinch Eiver Study 

Steering Committee, an advisory group composed of 

representatives of each of the participating agencies 

(Morton, 1963, p. 1) :

1. To determine the fate of radioactive materials currently being discharged to the Clinch Eiver.

2. To determine and understand the mechanisms of 

dispersion of radionuclides released to the river.

3. To evaluate the direct and indirect hazards of current 

disposal practices in the river.

4. To evaluate the overall usefulness of the river for 

radioactive waste disposal purposes.

5. To provide appropriate conclusions regarding longterm monitoring procedures.

Work described in this report was part of a cooperative program with the Health Physics Division, OENL;

Hi
H2 TRANSPORT OF RADIONUCLIDES BY STREAMS

the Oak Ridge Operations Office, AEC; and the Division of Reactor Development, AEC.

The release of low-level-radioactive liquid waste to 

the Clinch River via Whiteoak Creek (fig. 1), which 

drains the Oak Ridge National Laboratory area, was 

begun soon after establishment of the Laboratory in 

1943 for the processing of radioactive materials. Radioactive liquids have entered Whiteoak Creek as a result 

of direct releases of processed waste water from the 

Laboratory, seepage from liquid-waste holdup pits, and 

drainage from solid-waste-disposal trenches (Browder, 

1959). This waste-disposal practice has resulted in the 

incorporation of some of the introduced radionuclides 

(Glasstone, 1958, p. 213) in bottom sediment in the reach 

of river downstream from the mouth of Whiteoak Creek 

(Cottrell, 1959; Pickering and others, 1966).

Throughout most of the Laboratory's history, the 

waters of Whiteoak Creek have been impounded in 

Whiteoak Lake by Whiteoak Dam, which is located 

0.6 mile upstream from the mouth of the creek. The 

lake was created as a holdup facility for the radioactive 

waste carried in the creek water. Radioactive waste 

waters in Whiteoak Creek flow into the Clinch River at 

a point 3.3 miles downstream from the Laboratory area. 

The diluted wastes in the Clinch River flow into the 

Tennessee River 20.8 miles downstream from the entry 

of Whiteoak Creek.

The continuous release of radioactive wastes to the 

Clinch River during nearly 20 years of Laboratory 

operations has provided a unique opportunity for studying the effects of such releases on the river and the effects of physical, chemical, hydrologic, and biological 

characteristics of the river on the fate of the radioactive 

materials.

A knowledge of the amount, distribution, and nature 

of the radioactive sediment was needed for determining 

the fraction of the released radionuclides that is being 

retained in the river system, and the locus and duration 

of retention. With such information, an estimate can 

be made of present and potential radiation hazards 

resulting from the use of the river for disposal of radioactive wastes. An evaluation of the advisability of continued use of the river for such disposal can be made 

also. Knowledge of the physical, mineralogical, and 

chemical composition of the radioactive sediment was 

required for an understanding of the mechanisms 

whereby the various radionuclides were incorporated in 

the sediment.

A series of core samples of radioactive bottom sediment was taken at 14 sampling sections in the Clinch 

River and at two sampling sections in each of two 

tributary streams Poplar Creek and the Emory River 

(fig. 1), by means of a Swedish Foil Sampler. Sampling 

sections were selected for adequate coverage of the study 

reach and, wherever possible, were made to coincide with 

sediment ranges used by TVA for periodic measurements 

of bottom-sediment accumulation or erosion. Two sampling sections were located just upstream and just downstream from the mouth of Poplar Creek to assess the 

effect of that tributary on bottom-sediment radioacN

TENNESSEE RIVER

EXPLANATION

Sampling section; distance upstream from river mouth, 

-j '- 3 in miles 

+ 2 Distance upstream from river mouth, in miles

1 »/2 0 1 MILE

FIGURE 1. Study reach and locations of bottom-sediment core-sampling sections.
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H3

tivity. The most downstream sampling section was at 

CEM (Clinch River mile) 1.3 and the most upstream 

section was at CEM 22.8. The abbreviation GEM followed by a number has been used in this report to designate distance, in miles, upstream from the mouth of the 

river. This terminology is consistent with prior usage 

in the Clinch Eiver Study (Morton, 1961).

Eadioactive waste enters the Clinch Eiver via Whiteoak Creek at CEM 20.8. The entire study reach of the 

Clinch Eiver is part of Watts Bar Lake, which is formed 

by Watts Bar Dam on the Tennessee Eiver.

Initially, 10 coring sites were selected in each of the 

six sampling sections in the Clinch Eiver downstream 

from CEM 13. Five sites were selected in each of the 

eight sections upstream from CEM 13 and in the four 

sections in the two tributary streams. Coring sites were 

selected on the basis of known sediment thicknesses calculated by TVA from sediment-range surveys, and the 

results of sediment-probe measurements and a survey 

of sediment-surface radioactivity which were made at 

each sampling section just prior to core sampling.

The vertical distribution of gross gamma radioactivity and of the major gamma-ray-emitting radionuclides 

in the cores was measured by means of a device, known 

as a core scanner, which was developed especially for 

that purpose.

The chemical forms and associations of radionuclides 

in the bottom sediment were investigated through a program of detailed analyses of 23 sediment samples from 

two cores. The two cores were obtained from areas in 

which the accumulated radioactive sediment was several 

feet in thickness. The samples consisted of alternate 

2-inch-thick slices of sediment taken from the two 

cores. A series of physical and chemical tests, as well as 

radionuclide analyses, were performed on the 23 samples in order to characterize their compositional variability. Properties measured were the mineralogy, 

particle-size distribution, cation-exchange capacity, 

leachable-cation content, free aluminum oxide content, 

free iron oxide content, inorganic and organic carbon 

contents, and the amounts of potassium, rubidium, 

cesium, and strontium in each of the samples. Correlations of variations in concentration with depth for each 

core were determined for selected constituent pairs by 

means of a digital computer program in an effort to 

determine what properties of the sediment were responsible for the presence of each of the radionuclides.

Composite samples of 45 additional cores were analyzed for particle-size distribution. The radionuclide 

content of these cores had been determined previously 

(Carrigan, 1969; Carrigan and Pickering, 1967).

| ACKNOWLEDGMENTS

The help and support of E. G. Struxness, Assistant 

Division Director, Health Physics Division, OENL; 

F. L. Parker, Section Chief, Eadioactive Waste Disposal Section, Health Physics Division, OENL, and coordinator of the Clinch Eiver Study; and P. H. Carrigan, Jr., chief of the USGS project for the Clinch Eiver 

Study, are gratefully acknowledged. Tsuneo Tamura 

and D. G. Jacobs, OENL, have discussed the results of 

their research and the general concepts in this report at 

length with the author and have thereby contributed 

greatly to the author's knowledge of sorption mechanisms in aluminosilicate minerals. Similar thanks 

are due to V. C. Kennedy and E. A. Jenne, USGS, and 

E. W. Andrew, Jr., PHS.

E. E. Eastwood, OENL, prepared the samples used 

in the study and assisted1 in tabulation and inspection 

of data. He also performed most of the gross gamma and 

gamma spectrum scanning of the sediment cores and 

assisted in the field while coring was in progress. He 

was assisted in the core scanning by J. E. Jackson, 

OENL, and W. E. Parker, OENL and USGS; B. P. 

Glass, OENL, assisted with coring operations.

Construction of the core scanner was under the direction of P. N. Hensley, OENL. W. P. Bonner, OENL, 

acted as consultant on the use of the 512-channel pulseheight analyzer in conjunction with the core scanner. 

Advice on gamma spectrum analysis was furnished also 

by C. L. Burros, Analytical Chemistry Division, OENL.

The digital computer program used for the analysis 

of gamma spectra of the sediment samples was developed by Ernest Schonfeld, Chemical Technology Division, OENL, who also contributed his personal services and advice in the handling of the raw data and in 

the evaluation of analytical results.

Analysis of sediment samples for content of Strontium-90 was performed at the Low Level Eadiochemistry Laboratory, Analytical Chemistry Division, 

OENL. Particle-size analyses were made at the Water 

Quality Laboratory, USGS, Ealeigh, N.C. Cationexchange capacity, leachable-cation content, and 

mineralogical analyses were performed at the Denver, 

Colo., laboratories of the Branch of Analytical Laboratories, USGS. Determinations of free iron oxide content, 

adsorbed water content, and contents of mineral, organic, and total carbon were performed at the same Denver laboratories. Analyses of minor and trace elements 

in the sediment samples were performed at the Laboratory for X-ray and Spectrochemical Analysis, Analytical Chemistry Division, OENL.
H4 TRANSPORT OF RADIONUCLIDES BY STREAMS

The digital computer program used for correlation of 

gross gamma core scans was conceived by P. H. Carrigan, Jr., USGS, and written by M. T. Harkrider, 

OENL Mathematics Division. Other computer programs used in interpreting the data reported here were 

written by M. T. Harkrider and by E. P. Leinius and 

A. M. Craig, Jr., ORNL Mathematics Division.

Data on sediment deposition in the Clinch River were 

provided by J. W. Beverage and James Smallshaw, 

TVA. Information concerning the distribution of radioactivity in the upper part of Clinch Eiver bottom sediment was obtained through H. H. Abee and W. D. Cottrell, Applied Health Physics Section, Health Physics 

Division, OENL.

Eussell Lenker and Leon Dowdy, Jr., employees of 

Sprague and Henwood, Inc., drilling contractor for 

coring of the bottom sediment, provided much helpful 

information and instruction on the use of the Swedish 

Foil Sampler. Sprague and Henwood, Inc., constructed 

the special cutting shoe with basket core retainer which 

was designed during the coring operations and used to 

obtain increased recovery of cores consisting of rather 

fluid sediment. Contractual arrangements for drilling 

were under the supervision of F. L. Parker, Section 

Chief, Eadioactive Waste Disposal Section, OENL.

Figures 1,2, and 3 were prepared by the Graphic Arts 

Services, ORNL.

PREVIOUS WORK

Uptake of chemical constituents from liquid systems 

by sediment-forming minerals has been investigated 

extensively during the past several years, but the specific 

processes involved in the uptake of radioactive materials 

by stream sediment are for the most part not precisely 

known. For this reason, the general term "sorption" has 

been used in this paper; for an explanation of the term 

see Sayre, Guy, and Chamberlain (1963, p. 11) and 

McBain (1950, p. 38). Sorption of radionuclides by 

river sediment has been studied by Carritt and Goodgal 

(1953), Barker (1958), Jacobs (1960), Jacobs and 

Tamura (1960), and others. The importance of radiocesium uptake by the clay minerals has been well established, and Tamura and Jacobs (1960) have shown that 

cesium is selectively sorbed by the micas and the 2:1- 

layer clay minerals (minerals that have an aluminumoxygen layer between two silicon-oxygen layers; Grim, 

1953, p. 65) which have a layer-to-layer spacing of 10 A 

(angstroms). Tamura (1963) has further shown that 

hydrous iron oxides and aluminum oxides, common 

minor constituents in many sediments, selectively sorb 

strontium in neutral and basic solutions. Work on radionuclide uptake by river sediments has been summarized

by Sayre, Guy, and Chamberlain (1963), Kornegay, 

Vaughan, Jamison, and Morgan (1963), and Eobinson 

(1962).

Sorathesn, Bruscia, Tamura, and Struxness (1960) 

measured the capacity of a sample of Clinch Eiver bottom sediment to sorb cesium and found it to be quite 

high. This they attributed to the high illite content of 

the sediment. The higher-than-expected sorption capacity for cobalt-60 and strontium-90 in one sample of 

Clinch Eiver bottom sediment was attributed to organic 

matter in the sediment.

Jenne and Wahlberg (1965) have noted that during 

the progressive extraction of iron and manganese oxides 

from bottom sediment from Whiteoak Creek, cobalt-60 

was also extracted. A study of extraction rates has indicated that more of the cobalt-60 occurs in association 

with manganese oxides than with iron oxide.

E. W. Andrew, Jr. (PHS, written commun., 1964) 

noted a correlation between particle size and content of 

cesium-137 and cobalt-60 in sediment samples from the 

Clinch Eiver and the Tennessee Eiver when the claysize fraction was divided into fine (less than 0.2 micron) 

and coarse (0.2-2.0 microns) subfractions. The content of ruthenium-106 correlated best with the content 

of fine clay in samples from the Clinch Eiver, but the 

content of organic matter provided the best correlation 

in the Tennessee Eiver. Organic matter correlated also 

with the contents of cesium-137, cobalt-60, and strontium-90 in the Tennessee Eiver. Through the use of 

multiple correlation techniques, Andrew determined 

that 50 to 90 percent of the observed variation in the 

radionuclide content of bottom-sediment samples from 

the Tennessee Eiver could be explained on the basis of 

particle size and content of organic matter in the samples. Less than 50 percent of the variation in samples 

from the Clinch Eiver was explained by the same 

variables.

Annual monitoring surveys by the Applied Health 

Physics Section, OENL, have shown that most of the 

radioactivity in Clinch Eiver bottom sediment is due 

to cesium-137. The remainder of the radioactivity is 

primarily due to cobalt-60, ruthenium-106, certain rare 

earths of the lanthanide series, and strontium-90. The 

annual surveys have also shown that concentrations of 

the major radionuclides in the surface layer of sediment vary with changes in radionuclide loads released 

by the Laboratory (Morton, 1965, p. 30). However, 

the longitudinal pattern of distribution of gross gamma 

radioactivity at the surface of the sediment in the 

Clinch Eiver has remained much the same since the 

first survey was made in 1951. Strong similarities in 

the longitudinal distributions of cesium-137, cobalt-
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H5

60, ruthenium-106, and certain rare earths in the surface layer of the sediment, observed in 1961, suggested 

that similar mechanisms controlled the distribution of 

those radionuclides. The observed rates of decrease in 

concentration of the radionuclides with distance downstream were much greater than rates calculated on the 

basis of flow dilution alone. This evidence has been 

interpreted to mean that the mechanism controlling the 

distribution pattern may be a sedimentation process. 

The longitudinal distribution pattern of strontium-90, 

which was different from the distribution patterns of 

the three other radionuclides, suggests that a different 

mechanism may be controlling the distribution of 

strontium-90 (Morton, 1965, p. 65).

A series of bottom sediment cores was collected from 

the Clinch River in 1960 by ORNL personnel, but the 

coring device that was used failed to penetrate the full 

thickness of radioactive sediment (Morton, 1962a, p. 

45-57). Analysis of the cores showed that cesium-137 

was the predominant radionuclide at all sampling sections. The relative abundances of cesium-137, cobalt60, and strontium-90, which were much the same 

throughout the study reach, suggest that the same, or 

at least concurrent, processes governed the deposition 

of the three radionuclides in the riverbed (Morton. 

1962a,p.53).

METHODS AND EQUIPMENT

CORE SAMPLING

Relatively undisturbed cores of bottom sediment were 

obtained by means of a Swedish Foil Sampler. The 

Swedish Foil Sampler is a 2^-inch-diameter, pistontype sampler in which thin axial metal strips (foils) 

are used to decrease friction between the sample tube 

and the sediment while coring is proceeding (Pickering, 1966). As the sampler is pushed into the sediment, 

the foils unroll and form a sheath that encloses the core 

and prevents its contact with the interior of the sample 

tube. The core does not move relative to the foil strips, 

and the only friction in the sample tube is the metalto-metal friction between the foils and the interior of 

the tube. Compaction and blocking of the core due to 

friction between the sediment and the walls of the tube 

is thus prevented.

Core recovery, at coring sites where radionuclides 

were believed to be present throughout the full thickness of the sediment penetrated, generally ranged from 

80 to 100 percent. When a satisfactory core recovery 

was not obtained, a second coring attempt was made. 

At a few locations, satisfactory cores could not be obtained with the unmodified sampler. Use of a cutting 

shoe containing a basket-type core retainer generally 

produced adequate samples.

Sediment cores were transferred in the field from 

the sample tube to plastic storage tubes and were then 

frozen to facilitate handling and to suppress biological 

and chemical action prior to processing of the samples.

CORE COUNTING

Variations of radionuclide content with depth in the 

intact sediment cores were measured with a core scanner 

which was designed and constructed at ORNL. The 

scanner consists of a 3- by 3-inch, thallium-activated 

sodium iodide scintillation crystal and a matched 

photomultiplier tube housed in one end of a 4-inchthick cylindrical lead shield. In the other end of the 

shield is a cylindrical hole, or core well, whose axis is 

perpendicular to that of the lead cylinder and through 

which the cores, still encased in their plastic tubes and 

foils, can be moved. A 2-inch-long, 2- by 2-inch collimator channel extends from the face of the scintillation 

crystal to the core well. A diagrammatic representation 

of the core scanner is shown in figure 2.

The use of a 2-inch-long collimator channel in the 

core scanner represented a compromise between the 

desire for high collimation of the gamma-ray emission 

from the 2-inch-thick increment of core opposite the 

channel opening and the desire for minimum dropoff 

of total gamma-ray radioactivity due to the distance 

between the scintillation crystal and the sediment core. 

With the chosen channel length, gamma-ray radioactivity was high enough for adequate measurement, but a 

certain amount of this radioactivity represented emission from parts of the core above and below the 2-inchthick increment being measured. Each incremental 

gamma-ray radioactivity measurement was corrected 

for the effect of this extraneous radioactivity by means 

of a calibration curve based on measurements of plane 

sources of radioactivity. The correction was applied by 

means of a digital computer program, which also was 

used for plotting the corrected incremental radioactivity 

against depth in the core for gross gamma scans.

For counting of gross gamma radioactivity, the photomultiplier-tube output was routed through a sealer 

and automatic timer-printout system. The number of 

seconds required for the accumulation of a preset number of counts (usually 2,048 counts) from the 2-inchthick increment of core opposite the collimator channel 

was recorded, the core was automatically raised 2 inches 

by means of a calibrated hoist, and counting of the next 

increment of core was begun.

326-270 69-
H6 TRANSPORT OF RADIONTJCLIDES BY STREAMS

4-in.-thick 

lead shield

3-by 3-in. Nal crystal and 

photomultiplier tube

Multichannel

analyzer 

and punched 

tape readout

Sealer 

and printed 

tape readout

* Stepping pulley 

mechanism

Stepping interval 

control

FIGURE 2. Diagrammatic representation of core scanner.

Core in 

plastic tube

2-by2-by2-in. 

collimator

For gamma-ray-spectrum scanning, the photomultiplier-tube output of the core scanner was routed through 

a 512-channel pulse-height analyzer, and the analyzer 

output (gamma-ray spectrum) for each 2-inch-thick 

increment of core was recorded. The output data were 

then examined for analyzer malfunctions by means of 

a computer program. The gamma-ray spectrum produced by each 2-inch-thick increment of the cores was 

analyzed through the use of a computer program developed at ORNL (Schonfeld and others, 1965). The 

results of each analysis, which included specific activities 

with computed standard deviations for eight radionuclides, were corrected for imperfect collimation and 

plotted for visual inspection by means of a third computer program. The eight radionuclides used in the 

gamma-ray-spectrum analysis included the nuclearfission products cesium-137, ruthenium-106, cesium-134, 

europium-152, europium-154, cerium-144, zirconium-95, 

niobmm-95, the neutron-activation product cobalt-60, 

and the naturally occurring radionuclide potassium-40.

PHYSICOCHEMICAL ANALYSIS OF SEDIMENT

Comprehensive particle-size analyses of aliquots of 

23 sediment samples were made by wet sieving and by 

bottom-withdrawal tube (U.S. Inter-agency River 

Basin Committee, 1953). Size ranges, determined in 

microns, were: <2, 2-4, 4-8, 8-16,16-31, 31-62, 62-125, 

125-250, 250-1000, >1000. The method of size analysis 

used involves dispersal of the sediment particles by 

chemical as well as mechanical means and can be expected to break up aggregates of clay minerals which 

existed in the bottom sediment as silt- or sand-size 

masses. The method thus results in a determined particle-size distribution which is not necessarily fully representative of the actual distribution of particle sizes in 

the natural environment. However, it gives a measure 

of the primary size distribution, which is useful in some 

hydraulic studies of sediment movement and in mineralogical studies of sediment composition.

Particle-size separations of aliquots of the same samples were performed by wet sieving and by centrifugation after the samples had been initially dried. Dispersal 

was by hand stirring or, for some samples, by ultrasonic 

agitation. Size ranges, determined in microns, were: <2, 

2-62, >62. This method of separation tended to preserve 

aggregates of smaller particles, but additional aggregates may have formed as a result of the attachment of 

clay-size particles to sand- and silt-size particles when 

the samples were dried. Leaf fragments and twigs 

tended to be concentrated in the >62-micron-si2;e fraction, and finer, lightweight organic material was decanted with the <2-micron-size fraction following 

centrifugation. Determinations of cation-exchange capacities and mineralogical composition were made of the 

three size fractions.

The significance of the two methods of sizing in 

respect to the analysis of the physico-chemical characteristics of the sediment is discussed in another section 

of this report.
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H7

Cation-exchange capacities were determined by means 

of an ammonium chloride leach followed by measurement of the sorbed ammonium after extraction by distillation. The content of leachable cations in the raw 

sediment samples was determined through a chemical 

analysis of the leachates obtained as a result of the 

cation-exchange-capacity determinations. Mineralogical 

determinations were made by X-ray diffractometer.

The content of free alumina in the samples was determined by extraction in a 0.5 N solution of sodium hydroxide (Hashimoto and Jackson, 1960) and colorimetric analysis by the "aluminon" method (Jackson, 

1958, p. 296-300). Free iron oxides were extracted in a 

buffered dithionate-citrate solution (Mehra and Jackson, 1960) and analyzed by the potassium thiocyanate 

method (Jackson, 1958, p. 168-169). The extraction 

methods used are believed to have caused very little dissolution of silicate minerals present in the sediment.

The 'content of organic carbon in each of the sediment 

samples was determined as the difference between the 

total amount of carbon, determined through combustion 

of the sample at 1350°C (Tourtelot and others, 1964, p. 

D74), and the carbonate-derived (mineral) carbon, determined by the gas-evolution method of Rader and 

Grimaldi (1961, p. 33). Analysis of the samples for 

minor and trace elements was performed by flame spectrophotometric methods in which recently developed 

precision methods for the determination of strontium 

(Rains and others, 1962) and cesium (Feldman and 

Rains, 1964) were used.

The content of the gamma-ray-emitting radionuclides 

in each sample was determined by analysis of the 

gamma-ray spectrum obtained by means of a 512-channel pulse-height analyzer. The detection system consisted of a 4- by 4-inch thallium-activated sodium iodide 

scintillation crystal housed in a cadmium-lined lead 

shield which was 4 inches thick. Gamma-ray spectra 

were analyzed by means of a digital computer program 

developed at ORNL (Schonfeld and others, 1965). The 

content of strontium-90 in each sample was determined 

by "wet" chemical separation methods and by countingof the beta-ray radioactivity of the purified sample.

CORE SAMPLING RESULTS

A total of 163 bottom-sediment cores (including cores 

resulting from repeated attempts at a single coring site) 

were obtained at 135 coring sites. Sediment thicknesses 

measured with a sediment probe were generally confirmed by core sampling. At sampling sections which 

coincided with TVA sediment ranges, coring results 

generally agreed with TVA measurements of sediment 

thicknesses.

In the Clinch River upstream from CRM 13.0, 

periodic high discharges have swept the central part of 

the stream channel relatively free of all sediment except 

pebbles and boulders, and accumulation of finer sediment is confined largely to the sides of the channel. 

Downstream from CRM 13.0, fine sediment extends over 

a considerable part of the channel bottom, but is generally thickest on the less steep side of the stream channel. At the sampling sections at CRM 10.0, 11.9, and 

12.1, fine sediment from a few inches to several feet 

thick extends across almost the entire width of the 

channel. The depositional pattern of the sediment in 

the study reach probably reflects the distribution of 

velocity in the river channel and, at four cross sections 

in the Clinch River, is consistent with the measured 

velocity distribution (Morton, 1962a, p. 81-85).

VARIATION OP RADIONUCLIDE CONTENT WITH 

DEPTH IN CORES

GBOSS GAMMA COEE SCANNING

Scanning the bottom-sediment cores for variations in 

gross gamma radioactivity with depth revealed the general pattern of variation in each core and provided a 

basis for determining the thickness of radioactive sediment at each coring site. As used in this report, gross 

gamma radioactivity refers to the measured quantity of 

radioactivity given off by all gamma-ray-emitting nuclides in the sample. The fraction of the total radioactivity detected depends on the design and sensitivity 

of the analytical equipment used.

Variations in gross gamma radioactivity in the cores 

were great enough to permit the base of the radioactive 

zone to be picked from plots of the gross gamma scans 

and to encourage attempts at gamma spectrum core 

scanning. In addition, the results of gross gamma core 

scanning indicated that the entire thickness of radioactive sediment had been sampled in most cores.

The greatest thicknesses of radioactive sediment occur 

in the lower part of the river, downstream from CRM 

13.0. The core showing the greatest thickness (8.7 feet) 

of radioactive sediment was obtained at CRM 7.5.

In accord with the general pattern of sediment accumulation in the river, the layer of radioactive sediment 

is thickest along the sides of the stream channel, but in 

sections downstream from CRM 13.0 it extends out into 

the main part of the channel as well. Near the mouth of 

Poplar Creek at CRM 12.0, radioactive sediment extends 

across the entire width of the river channel. The effect 

of this wider distribution of radioactive sediment in the 

cross section on the average cross-sectional radioactivity level at the sediment surface can be seen in the
H8 TRANSPORT OF RADIONUCLIDES BY STREAMS

results of annual measurements made by the Applied 

Health Physics Section, ORNL. This average, which 

represents the mean of all sediment-surface radioactivity readings at a cross section, has been highest for cross 

sections in the vicinity of CKM 12.0 in several annual 

surveys (Morton, 1962b, p. 62).

The results of gross gamma scanning of core samples 

from CEM 7.5 are shown in figure 3. Sediment deposition, and therefore accumulation of radioactive sediment, has been largely confined to the more gently sloping left half of the stream channel which constituted 

the side of the former stream channel and a part of the 

flood plain of the stream prior to inundation by Watts 

Bar Lake. (Note that the vertical exaggeration of the 

cross section plot is 10:1). Parts of the cross section 

showing a water depth of less than 6 feet are not submerged during low winter lake levels. The resulting 

nondeposition of sediments and erosion probably account for the very thin layer of radioactive sediment 

found in cores from such sites (cores 1 and 2).

Cores 4, 5, 6, and 7-1 in figure 3 show a persistent 

general pattern of variation of gross gamma radioactivity with depth. Similar distribution patterns of gross 

gamma radioactivity were observed in several cores 

from other sampling sections in the part of the study 

reach downstream from CUM 18. The general pattern 

which they exhibit is strikingly similar to the pattern 

of annual releases of cesium-137 to the Clinch River as 

measured at Whiteoak Dam (table 1). This similarity 

is illustrated in figure 4 for several of the cores. The zone 

of highest radioactivity in each of the four cores is assumed to correspond to the period during which releases 

of cesium-137 were highest that is, 1956 (Cottrell, 1959, 

p. 39).

The patterns of variation of gross gamma radioactivity with depth in the sediment cores were compared by 

means of a digital computer program. With this program, the variation of radioactivity in a core of any 

length could be compared to that in any other core, 

provided two reference points at different depths could

SEDIMENT SURFACE ACTIVITY

40

45

0 100 

*(CPM)= COUNTS PER MINUTE

200 300 400 500 

DISTANCE FROM LEFT BANK, IN FEET

600 700 800

FIGURE 3. Cross section at CRM 7.5 showing penetration, recovery, and gross gamma radioactivity variations with depth for 1962 bottomsediment core samples (vertical exaggeration 10:1).
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H9

ACTIVITY, IN COUNTS PER SECOND 

10 20 30 -5 0 10 20

CRM 14.0 HOLE 2-2 CRM 10.0 HOLE 7

CURIES 

5 10 15.

T~1961

1956

 1949

1944

Pattern of annual release of 

Cs137 from Whiteoak Lake 

corrected for decay to 

1962. Dashed where 

estimated

ACTIVITY, IN COUNTS PER SECOND 

0 10 20 30 -50 10 20 30

CRM 7.5 HOLE 4 CRM 1.3 HOLE 6-3

FIGURE 4. Graphical comparison of patterns of variation of gross gamma radioactivity with depth in four bottom-sediment cores to variations

in annual releases of cesium-137 to the Clinch River.

TABLE 1. Yearly discharges of radionuclides to the Clinch River 

[Results in curies. From Cowser and Snyder (1966). TRE ( Ce), trivalent rare earths excluding cerium; Nd, not determined]

Year Gross beta Cs»« Sr«o TRE (-Ce) Zr«« 1151 Co««

1949 _____ .

1950 _____ .

1951 _____ .

1952 ____ ..

1953 ___ ..

1954 __ ....

1955 __ .. 

1956 _____ .

1957 _____ .

1958-_---._.

1959 __ ....

1960 _____ .

1961 _____ .

1962 _____ .

1963 _____ .

718

191

101

214

304

384

437

582

.... 397

544

937

2, 190

2,230

1,440

470

77

19

20

9.9

6.4

22

63

170

89

55

76

31

15

5. 6

3. 5

110

23

18

15

26

11

31

29

60

42

520

1,900

2,000

1,400

430

150

38

29

72

130

140

93

100

83

150

60

28

22

9.4

7.8

77

30

11

26

110

160

150

140

110

240

94

48

24

11

9.4

18

Nd

Nd

23

6.7

24

85

59

13

30

48

27

4.2

1.2

1.5

180

15

4,5

19

7.6

14

5.2

12

23

6.0

27

38

20

2.2

.34

22

42

2. 2

18

3.6

9. 2

5.7

15

7. 1

6. 0

30

45

70

7.7

.71

77

19

18

20

2 1

3.5

7.0

3. 5

1.2

8.2

. 5

5.3

3.7

.36

.44

Nd

Nd

Nd

Nd

Nd

Nd

6.6

46

4.8

8.7

77

72

31

14

14

be assigned as corresponding to the same parts of the 

patterns in each of the cores compared. Core lengths 

were adjusted for the comparison on the basis of the 

distance between the two reference points picked for 

each core. A series of correlations were attempted for 

each pair of cores, a different adjustment factor being 

used in each correlation attempt. The output of the 

program included the coefficients of correlation and regression for the best correlation attempted with each 

pair of cores.

By means of the computer program, gross gamma 

scans of 27 cores which exhibited a similar pattern of 

variation of gross gamma radioactivity with depth were 

compared with the pattern of annual releases of cesium137 to the Clinch River, the releases being corrected for 

decay to the date of sampling (table 2). Coefficients of 

correlation ranged from 0.60 to 0.90 and had a mean of

0.76. When annual releases of cobalt-60 were added to 

those of cesium-137 and correction was made for the 

relative gamma-ray emission of the two nuclides, the 

comparison showed improved correlation with the cores 

and resulted in a mean coefficient of correlation of 0.80 

and a range of 0.64 to 0.98. When the annual releases of 

ruthenium-106 were added to those of cesium-137 and 

cobalt-60, after making corrections for relative gamma 

ray emission, the correlation was not as good, giving a 

mean coefficient of correlation of 0.68 and a range of 

0.44 to 0.97.

Coefficients of correlation resulting from a comparison 

of the distribution of radioactivity in four cores shown 

in figure 4 with annual releases of radionuclides to the 

Clinch River are included in table 2. In all four cores, 

18 increments were used for comparison.
H10 TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 2. Coefficients of correlation for comparison of vertical 

distribution of gross gamma radioactivity in sediment cores with 

annual releases of radionuclides

Annual releases were corrected for decay to date of sampling. Where releases are 

combined, correction has bean made for the relative gamma emission of the radionuclides. Dash leaders indicate correlation was not obtained]

Sampling section Core Cs«' Cs«'+Co("> Cs«7+Co6»+Ru»o«

CRM 1.3__ _ .3 0. 64 0

1.3.. ________ 5 .78

1.3__ _ ___ 6-2 . 63

1.3__ _ __ __ 6-3 .73

1.3______.___ 7 .60

1.3__ __ _ 7-2 .88

4.3___ ____ 2-2 .67

4.3__ _ _ __ 11-2 .73

7.5__________ 4 .81

7.5. __ _____ 5 .80

7.5_________. 6-1 .81

7.5____._____ 7-1 .75

7.5_____.____ 7-2 .72

10.0. _ _ . 2 .83

10.0_____ __ _ 3-3 .77

10.0_ _ 7 .83

11.9 _ _ __ 9 .76

11.9 __ _ 10 . 60

12.1.___._____ 2 .88

12.1 __ _ 6-1 . 66

12.1 _ _ _. 7 .79

12.1___ ____ _ 9 .89

14.0__. __ ___ 2-1 .82

14.0 _ __ 2-2 . 80

14.0__ _____ 3 .76

17.5. ____ ___ 3-1 .90

17.5____ ____ 3-2 .76

Mean____ __ 0. 76 0

Standard deviation ____ . 084

67 0. 68 

84 .72 

72 . 64 

78 . 78 

64 .65 

93 . 80 

83 .69 

79 .63 

82 . 62 

72 .51 

75 .49 

79 . 57 

64 . 50 

82 . 61 

90 . 81 

79 .44 

76 ____ _______

79 .71

89 .80 

82 . 80 

78 .77 

98 . 87 

85 .60 

84 . 62 

87 . 97 

79 .83 

66 . 63

80 0. 68 

083 . 126

The correlation results suggest that, in most of the 27 

cores tested, the pattern of variation in gross gamma 

radioactivity exhibited by the cores reflects not only 

the pattern of annual releases of cesium- 137 to the 

Clinch Eiver but to a minor extent that of annual releases of cobalt-60 as well.

cesium-137, cobalt-60, ruthenium-106, and potassium40. Because of its short half life (1 year), ruthenium106 was detected in only the upper parts of most of the 

cores. The presence of the naturally occurring radionuclide potassium-40 was not due to releases from 

ORNL. 

Variations in contents with depth of the three most 

abundant gamma-ray-emitting radionuclides in a core 

from hole 6, OEM 7.5 are illustrated in figure 5 ; values 

whose standard deviations represented greater than 75 

percent of the analytical values computed prior to 

collimation correction have been plotted as zero values. 

An examination of the first four plots in figure 5 

demonstrates the relative contributions of the three 

radionuclides to the total gamma-ray radioactivity of 

the core. Over 80 percent of the radioactivity is contributed by cesium-137. The contribution of radioactivity from ruthenium-106 is confined to the upper part 

of the core. (The isolated positive values for ruthenium106 below a depth of 20 inches on the plot are questionable.) Similar results obtained for the eight other 

cores that were scanned are shown in table 3.

TABLE 3. Fractional contributions of cesium-187, cobalt-60, and 

ruthenium-106 to total gamma-ray radioactivity of selected Clinch 

River sediment cores

Sampling section Core Cs137 CoM Ru>o»

CRM 1.3__--_ _ __ __ ._ 3 0 82 0 11 0 07

1.3___ _ -__. __ _- 6-3 77 13 10

7.5__ ____ --_-___ 5 81 13 16

7.5_--_. _ ___ _ __ 6 82 12 06

7.5-____ _ __ -___ 7-2 77 13 10

10.0__ _ __ ___ ___ 2 79 10 11

14.0 ______ 2 80 13 07

14.0__ ____ _ ____ 2-2 84 11 05

17.5 __ _ _______ 3-1 86 10 04

Mean value _ _ _____ 0.81 0.12 0.07

GAMMA-RAY SPECTRUM CORE SCANNING

Nine cores were selected for gamma-ray spectrum 

scanning on the basis of gross gamma scan results. 

Cores selected were those with a zone of radioactive 

sediment which was several feet thick and which showed 

the characteristic pattern of variation in gross gamma 

radioactivity with depth illustrated in figures 3 and 4.

Four gamma-ray-emitting radionuclides were present in the bottom sediment in concentrations high 

enough to provide acceptable data for the full thickness 

of the radioactive zone in each core scanned; they were

The similarity between the distributions of 

cesium-137 and cobalt-60 with depth in the core can 

be observed with the aid of the fifth plot in figure 5, 

which shows variations in cobalt-60 concentration with 

depth at an expanded scale. The same relationship was 

exhibited by the eight other cores that were gamma 

spectrum scanned. 'Statistical treatment of the relationship between cesium-137 and cobalt-60 in all nine cores 

further emphasizes the similarity in distribution of the 

two radionuclides (see table 4).
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE Hll

-10 0 

0

ACTIVITY, IN COUNTS PER SECONDS

10 20 30 40 50 -50 0 100 200

CONTENT, IN PICOCURIES PER GRAM 

300 400-500 100-500 100-100 20 40 60

100

Co«>

FIGURE 5. Variations in contents of cesium-137, colbalt-60, and ruthenium-106 with depth in hole 6, CRM 7.5.

TABLE 4. Relationship of cobalt-60 to cesium-137 in selected 

bottom-sediment cores from the Clinch River

Sampling section

CRM 1.3____ ___

1.3.__. _____

7.5.__._____

7.5.. .._.___

7.5___._.___

10.0 ________

14.0_-_-_-_.

14.0. _______

17.5._._____

Core Correlation Regression 

coefficient coefficient

. 3 0

. 6-3

. 5

. 6

. 7-2

2

2

. 2-2

_ 3-1

62 0

89 

90 

93 

91 

87 

90 

87 

99

09 

12 

13 

13 

13 

11 

13 

13 

09

Ratio of 

mean concentrations 

(Cs:Co)

7.39 

5. 83

5.77 

7.34 

5. 86 

7.83 

6.37 

7. 25 

9. 11

Mean value. 0.88 0. 12 6. 97

RELATIONSHIP OF VERTICAL DISTRIBUTION TO 

ANNUAL RELEASES

Radiochemical 'analyses of water samples collected 

weekly at Whiteoak Dam for a period of 2 years indicate that on the average nearly 70 percent of the cesium137 present in the water is associated with suspended 

solids having a diameter greater than 0.7 micron 

Churchill and others, 1965, p. 37). Cesium is known to

be preferentially sorbed by layered aluminosilioate minerals in which the 0-axis spacing is 10 A (Jacobs and 

Tamura, 1960; Tamura, 1963). Such minerals are 

abundant in Whiteoak Creek basin (Jacobs, 1960; McMaster and Waller, 1965). Furthermore, this sorption 

reaction is known to be not readily reversible. It is safe 

to assume, then, that incorporation of cesium-137 in 

Clinch River bottom sediment is primarily a result of 

sedimentation of suspended radioactive aluminosilicate 

minerals which enter the river in water from Whiteoak 

Creek.

The year of highest release of cesium-137 to the 

Clinch River was 1956. This high release resulted from 

the draining of Whiteoak Lake during the latter half of 

1955 (Cottrell, 1959, p. 39) and from the exposure to 

the air of the accumulation of fine sediment on the 

lake bottom. Rapid erosion of the exposed radioactive 

lake sediment during the subsequent period of high 

winter rainfall resulted in an increase in the quantity 

of radioactive sediment entering the Clinch River and 

in higher content of cesium-137 in bottom sediment 

deposited in the river during 1956. Through the operation of processes such as this, variations in annual releases of cesium-137 have been recorded as variations
H12 TRANSPORT OF RADIONUCLIDES BY STREAMS

in the vertical distribution of the cesium-137 in the bottom sediment in parts of the river where fairly regular 

and persistent deposition of sediment has taken place.

The pattern of variation in the content of cobalt-60 

in the sediment does not strongly resemble the pattern 

of annual releases of cobalt-60 to the Clinch River (see 

table 1). Some effect of annual releases is implied, however, by the improved correlation which resulted when 

annual cobalt-60 releases were taken into account in 

the comparison of gross gamma core scan patterns described previously. The most striking feature of the 

pattern of cobalt-60 variation in the cores gamma 

spectrum scanned is its great similarity to the pattern 

of cesium-137 variations (see fig. 5 and table 3). This 

similarity suggests that cobalt-60, like cesium-137, was 

incorporated in Clinch Kiver bottom sediment primarily by sedimentation of suspended solids which had 

obtained their content of cobalt-60 before entering the 

Clinch Kiver. It also suggests that a rather small fraction of the total cobalt-60 released to the river became 

incorporated in Clinch Kiver bottom sediment; otherwise, distribution of cobalt-60 in the cores would resemble the pattern of annual releases of cobalt-60 to 

the river. This second suggestion is supported by the 

results of water sampling which show that only about 

20 percent of the cobalt-60 released from Whiteoak 

Creek is associated with suspended sediment with a 

diameter greater than 0.7 micron (Churchill and others, 

1965, p. 52). Although the results of water sampling do 

not preclude 'association of the remaining 80 percent 

of the cobalt-60 with smaller diameter suspended solids, 

some of which might be deposited in the Clinch River, 

it is possible that the nuclide may be present in Whiteoak Creek water also in a second form, such as ,a dissolved ion. The presence of two chemical forms of 

cobalt-60 in Whiteoak Creek water does not conflict 

with the results of gamma-ray spectrum core scanning 

if it is assumed that the ratio of dissolved cobalt-60 to 

solids-associated cobalt-60 in the water did not remain 

constant during the period in which the sampled sediment was deposited.

The suggestion that some of the cobalt-60, like most of 

the cesium-137, is associated with suspended solids when 

it enters the Clinch River from Whiteoak Creek does not 

necessarily imply that the two radionuclides are associated with the same type of solid. It is assumed that 

cesium-137 is primarily associated with layered aluminosilicate minerals. Leaching experiments (Morton, 

1965, p. 60) have indicated that cobalt-60 may be present in the bottom sediment as a hydrated oxide. The 

studies further indicate that cobalt-60, like cesium-137 

and ruthenium-106, is not readily removed by leaching

after it becomes associated with the bottom sediment. 

Other studies have indicated that cobalt-60 in the sediment is associated with iron and manganese oxides 

(Jenne and Whalberg, 1965).

The contribution of ruthenium-106 to gamma radioactivity in the upper part of the sediment cores studied 

is much less than one would expect if its relative retention in the sediment were as great as that of cesium-137. 

It can be assumed, then, that a relatively small fraction 

of the total amount of ruthenium-106 that has been released to the Clinch River has become incorporated in 

the bottom sediment. This assumption has been confirmed by the results of an inventory of radioactivity in 

Clinch River bottom sediment (Carrigan, 1969).

Too little is known about the chemical form of ruthenium-106 in the Clinch River to permit definite 

inferences concerning the manner in which it is incorporated in Clinch River bottom sediment. The ruthenium-106 content of annual samples of the surface layer 

of Clinch River bottom sediment has been shown to 

reflect the amount of ruthenium-106 released to the river 

during the preceding year (Morton, 1965, p. 30). Analyses of water samples from Whiteoak Lake indicate that 

less than 10 percent of the ruthenium-106 released to the 

Clinch River is associated with suspended sediment 

greater than 0.7 micron in diameter (Churchill and 

others, 1965). Even with the benefit of this information, 

it can be stated only that the mechanism by which ruthenium-106 is incorporated in the sediment may be one or 

more of the following: (1) Sedimentation of radioactive solids suspended in Whiteoak Creek water, (2) 

precipitation of a ruthenium-bearing compound from 

Clinch River water, (3) an ion-exchange reaction between Clinch River water and bottom sediment in the 

river. It has been suggested (Morton, 1965, p. 60; 

Lomenick, 1963, p. 844) that some of the ruthenium-106 

in bottom sediment may be present in the form of nitrosyl ruthenium hydroxide RuNO(OH) 3 (H2O) 2. 

This compound, which is presumed to have been formed 

as a result of the high nitrate content of the original 

waste solutions, is not easily decomposed.

The general pattern of variation in gross gamma 

radioactivity with depth that occurs in many of the 

longer sediment cores taken from the Clinch River 

implies a similar history of sediment deposition at each 

of those coring sites. Furthermore, the resemblance of 

the pattern, which is due primarily to the cesium-137 

content of the sediment, to variations in the annual release of cesium-137 from Whiteoak Creek to the Clinch 

River, implies fairly regular, persistent deposition at 

those coring sites.

Regular, persistent deposition at certain coring sites
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H13

in a cross section does not necessarily require regular, 

persistent deposition over the entire cross section. Periodic short-term net sediment losses for the cross section 

are possible. However, a long-term net gain for the 

entire period of deposition of radioactive sediment is 

implied for all cross sections at which cores showing the 

characteristic pattern were collected. This sedimentation 

model is confirmed by TVA's record of sedimentation 

for the reaches of the Clinch Biver from which the cores 

were collected. The record shows net losses for some of 

the reaches downstream from CKM 13 for some of the 

5-year intervals between surveys, but a net increase in 

sediment was computed for all reaches for the entire 

period of record. This net accumulation of sediment 

in the downstream reaches of the Clinch Kiver is no 

doubt the result of readjustment of channel shape caused 

by the filling of Watts Bar Lake, which began at about 

the same time as release of radioactivity to the Clinch 

Kiver was started by ORNL (U.S. Geological Survey, 

1958, p. 228).

It should be emphasized that regular and persistent 

sediment deposition can occur without continual sediment deposition. Because the radioactive part of the 

sediment cores represents a sedimentation history of approximately 20 years, conclusions pertaining to sedimentation are at best valid for time intervals of a year or 

more. Annual sedimentation would be expected to be 

irregularly distributed throughout the year.

PHYSICOCHEMICAL COMPOSITIONS OF SELECTED 

CORE SAMPLES

The results of physical and chemical analyses of 23 

sediment samples from the two cores selected for detailed 

study are listed in table 5. In general, radioactive bottom 

sediment in the Clinch Kiver may be classed, according 

to particle size and mineralogical composition, as clayey 

silt (Shepard, 1954) composed of approximately 35 percent mica and clay minerals and 65 percent quartz. The 

mineralogical compositions and cation-exchange capacities of all 23 samples studied showed surprisingly little 

variation.

PHYSICAL CHARACTERISTICS 

PARTICLE-SIZE DISTRIBUTION

The results of particle-size analyses of the 23 samples 

studied are shown in tables 5 and 6 and figure 6. A 

diameter of 4 microns was used as the lower limit of siltsize particles (Lane, 1947, p. 937) in the two figures 

for the purpose of classification of the sediment according to particle size, which is normally based on hydraulic characteristics. A lower limit of 2 microns was used

for the summarized data presented in table 5 (cols. 2-7) 

and in constituent correlation studies, because it was 

believed that data on the finer size range would be more 

useful in relating particle-size distribution to the physical and chemical characteristics of the sediment. Lack 

of agreement between the two sets of particle-size data 

(cols. 2-4 and cols. 5-7, table 5) is the result of the use 

of two different methods of treatment and analysis.

The results of the particle-size analyses by wet sieving 

and bottom-withdrawal tube, plotted on triangular sandsilt-clay diagrams (Shepard, 1954), are shown in figure 

6. Most of the samples fall in the clayey silt part of the 

diagram.

Particle-size analyses were also made of composite 

samples of 45 Clinch Kiver bottom-sediment cores. Figure 7 is a plot of the results of these analyses. It is 

apparent that the particle-size distributions in the composite samples, which represent the radioactive parts of 

cores that were taken throughout a 21-mile-long reach of 

river, are more variable than those in the 2-inch-thick 

incremental samples of the two cores studied in detail. 

Greater variations occur in the contents of sand- and 

silt-size particles than in the content of clay-size particles. Nevertheless, more analyses fall in the clayey silt 

field of the diagram than in any of the other fields. The 

mean contents of particles in the three size groups for 

all composite samples are: sand, 23 percent; silt, 54 percent; clay (<4 microns), 23 percent. Because only composite samples with a relatively thick zone of radioactive 

sediment were chosen for particle-size analysis, the 

average particle-size distribution listed above, which 

would fall in the sand-silt-clay field of the diagram, is 

probably somewhat lower in sand content and higher in 

silt content than a true average of bottom sediment 

throughout the study reach would be. The greatest" thicknesses of radioactive sediment in the Clinch Kiver occur 

in the lower part of the river, where stream velocity 

is low and conditions are favorable for deposition of fine 

sediment. The two cores whose incremental compositions 

were studied in detail have average contents of sand-size 

particles that are still lower than the average of the 

composite samples (compare figs. 6, 7).

CATION-EXCHANGE CAPACITY

The cation-exchange capacities of the unsized samples 

from the two cores studied in detail do not vary greatly 

(see table 5). The cation-exchange capacities of the clayand silt-size fractions of the same samples do not vary 

greatly either (table 7), a fact suggesting that most of 

the variation in cation-exchange capacity of the unsized 

samples may be due to variations in content of clay-size
TABLE 5. Physical and chemical characteristics of selected samples of bottom sediment from the Clinch River

[Results are on a dry-weight basis, except for adsorbed water, and are in percent, except as indicated. Clay-size particles, <2 microns in diameter; silt-size particles, 2-62 microns 

microns in diameter. Analysts: USGS P. D. Blackmon, H. C. Starkey, H. E. Beeder, E. J. Fennelly, I. C. Frost; OBNL T. C. Bains, J. H. Mone

Depth interval 

(in.)

Particle-size 

distribution 1

Particle-size 

distribution 2

Cation- LeachableAd- exchange cation Carbon content 

sorbed capacity content 

water (meqper (meqperlOOg)

i nn ir\ 

Free oxide Minor element content 

content

Sand Silt Clay Sand Silt Clay Ca Mg Mineral Organic Total FejO3 A12O» K Bb Cs Sr 

GRM 7.5. hole 7-2

10-12 

14-16 

18-20 

22-24 

30-32 

34-36 

40-42 

44-46 _ ...

50-52 

52-54_. .......

56-58 

60-62 .

62-64. __ 

_ ... . 40

 ... 28

 18

.... ... 16

 13

 6

 8

 12

.... 17

18

.... _ 9

 ... . 4

.... ... 6

48

58

66

63

68

64

68

63

59

56

68

65

65

12

14

16

21

19

30

24

25

24

26

23

31

29

55

59

33

23

16

21

22

16

25

25

18

5

11

34

28

48

58

58

53

47

58

52

51

56

64

59

11

13

19

19

25

26

31

26

23

24

26

31

30

34.2

34.0

32.4

35.1

36.2

35.1

39.7

39.3

46.3

36.0

36.9

35.3

36.8

12.6

12.3

12.2

15.1

16.3

17.9

15.7

18.8

23.0

18.0

18.7

20.0

16.9

21.6

18.2

19.5

23.7

15.0

15.0

15.3

14.1

18.6

16.5

12.9

12.7

11.5

8.2

5.7

5.6

5.6

5.4

5.8

6.7

6.0

7.0

5.8

7.5

5.0

7.4

0.35

.28

.62

.15

.14

.21

.20

.21

.21

.22

.14

.08

.08

2.2

2.5

1.6

2.4

2.8

2.8

2.8

2.8

4.2

2.5

2.3

2.2

2.1

2.55

2.75

2.22

2.50

2.97

3.05

2.98

3.02

4.39

2.75

2.40

2.28

2.16

1.89

1.78

2.22

2.32

2.51

2.48

2.42

2.66

2.47

2.28

2.35

3.03

2.99

0.93

.92

1.28

1.41

1.52

1.53

1.54

1.63

1.33

1.37

1.37

1.87

1.86

1.67

1.47

1.98

1.96

2.02

1.91

1.85

1.82

1.75

1.74

1.85

2.01

1.90

0.0067

.0069

.0097

.0096

.0107

.0101

.0096

.0098

.0096

.0095

.0099

.0113

.0116

0.00044

.00031

.00047

.00038

.00047

.00048

.00040

.00047

.00046

.00038

.00039

.00065

.00046

0.0093

.0097

.0105

.0118

.0090

.0081

.0079

.0088

.0086

.0097

.0118

.0136

.0153

Mean value.. 15.0 62.4 22.6 25.3 51.3 23.4 36.7 16.7 16.5 6.3 0.22 2.6 2.77 2.42 1.43 1.84 0.0096 0.00044 0.0103 

GRM 14.0, hole 2

4-6.. ......

8-10.... __ .

12-14 

16-18 

20-22 

24-26 

28-30 

32-34 

36-38 

40-42 

 ... 11

 8

....... 6

.... 13

 28

. ... 13

 13

... 15

 13

 13

69

66

69

63

54

66

67

61

64

63

20

26

25

24

18

21

20

24

23

24

15

15

18

21

36

24

31

32

24

23

61

60

57

41

46

51

44

47

53

55

24

25

25

38

18

25

25

21

23

22

38.6

46.2

40.7

38.1

37.3

39.7

37.2

35.8

36.1

33.5

18.3

25.0

18.4

17.5

14.4

17.3

15.0

16.4

17.4

17.9

19.4

17.2

13.6

15.7

11.9

12.7

13.2

15.1

11.8

12.8

8.2

10.2

8.8

8.7

7.4

7.0

4.9

10.2

6.7

8.6

0.11

.15

.12

.13

.14

.25

.22

.36

.32

.33

2.2

2.4

2.5

2.7

3.2

2.3

2.3

2.4

2.2

2.1

2.35

2.59

2.63

2.80

3.29

2.59

2.49

2.73

2.53

2.40

2.68

2.85

2.56

2.65

2.22

2.31

2.22

2.30

2.20

2.23

1.50

1.51

1.41

1.68

1.17

1.51

1.40

1.38

1.38

1.28

1.89

2.01

1.95

1.87

1.64

1.84

1.82

1.87

1.74

1.77

0.0100

.0112

.0107

.0103

.0083

.0096

.0093

.0096

.0092

.0088

0.00039

.00039

.00038

.00045

.00052

.00041

.00040

.00037

.00035

nnnss

0.0059

.0066

.0061

.0063

.0059

.0060

.0055

.0070

.0054

.0058

Mean value..... 13.3 64.2 22.5 23.9 51.5 24.6 38.3 17.8 8.1 0.21 2.4 2.64 2.42 1.42 1.84 0.0097 0.00040 0.0061 

1 Separation of sand-size particles by wet sieving of wet sample. Separation of silt- and clay-size particles 

by bottom-withdrawal tube.

2 Separation of sand-size particles by wet sieving of previously dried sample. Separation of silt- and 

clay-size particles by centrifugation.

» Badionuclide contents are in picocuries per gram. Negative values 

of gamma-ray spectrum analysis used; true values are near zero.
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE

100 SAND

H15

Sandy silt / Sand-silt-clay \ Sandy clay 

75/ / \ \25

25 50 

PERCENTAGE CLAY

75 CLAY

100 SAND

100 

SILT 75

PERCENTAGE CLAY

100 

"CLAY

FIGURE 6. Results of particle-size analyses of selected samples. Upper: From hole 7-2, CRM 7.5. 

Lower : From hole 2, CRM 14.0. Nomenclature from Shepard (1954).
H16 TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 6. Particle-size analyses of selected samples of bottom 

sediment from the Clinch River

[Analysis by wet sieving and bottom-withdrawal tube; H. E. Reeder, analyst]

Depth Percent finer than size indicated, in millimeters

(in.) 0.002 0.004 0.008 0.016 0.031 0.062 0.125 0.250 0.500 1.000

CRM 7.5, hole 7-2

10-12. _ 12 14 18 25 37 60 93 96 98 100 

14-16__ 14 19 23 30 43 72 88 93 95 96 

18-20__ 16 19 26 39 55 82 91 97 100 _..- 

22-24__ 21 23 34 55 72 84 91 97 98 99 

30-32__ 19 24 36 54 72 87 92 97 100 .__. 

34-36__ 30 31 45 60 78 94 98 99 100 __ 

40-42. _ 24 28 38 50 68 91 98 99 100 __ 

44-46. _ 25 29 43 60 79 88 95 99 100 .._. 

50-52. _ 24 29 39 54 69 83 89 93 96 98 

52-54. _ 26 29 40 55 70 82 88 95 98 99 

56-58.. 23 29 42 60 76 91 96 98 99 100 

60-62. _ 31 38 52 68 86 96 97 98 99 100 

62-64. _ 29 36 51 70 84 94 97 98 99 100

CRM 14.0, hole 2

4-6.. __ 20 27 39 54 74 89 95 98 100 _ . 

8-10. __ 26 33 44 62 79 92 96 97 98 99 

12-14. _ 25 29 42 60 78 94 97 98 99 100 

16-18__ 24 30 43 60 75 87 93 97 99 100 

20-22. _ 18 23 33 47 60 72 84 95 100 __ 

24-26. _ 21 28 38 51 69 87 96 98 99 100 

28-30. _ 20 25 34 48 66 87 96 99 100 __ 

32-34. _ 24 27 37 51 66 85 95 97 98 100 

36-38__ 23 30 39 49 69 87 92 98 99 100 

40-42.. 24 27 40 52 64 87 97 98 99 100

material, the size fraction with the highest cation-exchange capacity. 

Size separations for cation-exchange capacity determinations were made by wet sieving and centrifugation 

after the samples had been initially dried (see "Methods 

and equipment") . This procedure can result in clay-size 

fragments becoming attached to sand grains and may 

fail to disperse all aggregates of smaller grains. As 

noted, it can result also in concentration of organic material in the sand- and clay-size fractions. The data reported in table 7 therefore do not represent the exchange 

capacities of the ultimate particle-size fractions of the 

sediment but do represent those of the size fractions approximately as they existed in the natural environment. 

The data in table 7 are based on the same size separation 

as the data in columns 5-7, table 5. 

The cation-exchange capacity of the clay-size sediment fraction was higher than that of the silt-size fraction in all samples, probably primarily due to the 

higher content of layered aluminosilicate minerals in 

the clay-size fraction of the sediment. Aluminosilicate 

minerals present in the other two size fractions, as well 

as their content of organic matter, probably account 

for most of the measured cation-exchange capacities of 

these two sediment fractions.

MINEBALOGICAL CHARACTERISTICS

Semiquantitative determinations of the mineralogical 

compositions of the clay- and sand-size fractions were 

made for all 23 sediment samples studied in detail 

(table 8). The size fractions studied were separated by 

wet sieving and centrifugation of previously dried 

samples, which might be expected to preserve some 

sand- and silt-size aggregates of smaller particles 

formed by drying. Careful redispersion of the sediment 

particles has minimized this effect, however, and the 

mineralogical compositions reported below are considered to be fairly representative of the three size fractions as they existed in the natural environment. 

Kesults of the mineralogical analyses showed that 

sand-size sediment fractions of all samples were composed of 70-80 percent quartz with lesser amounts of 

feldspar, dolomite, and mica. Kaolinite was detected 

in seven samples. 

The silt-size fraction of each sample contained 60-70 

percent quartz and lesser amounts of mica, mixedlayered mica-vermiculite, vermiculite (trioctahedral), 

aluminum-interlayered vermiculite (dioctahedral), kaolinite, feldspar, and dolomite (see Grim, 1953, p. 43- 

83, for discussion of the structures of the clay minerals) . 

Calcite was reported in three samples. 

The clay-size fractions (particles <2 microns in 

diameter) of each sample contained much less quartz 

10-20 percent than did the other two size fractions. 

Mica and kaolinite occurred in approximately the same 

abundance as quartz, along with slightly lesser amounts 

of vermiculite (trioctahedral), aluminum-interlayered

TABLE 7. Cation-exchange capacities of clay-, silt-, and sandsize fractions of selected samples of Clinch River bottom sediment

[Cation-exchange capacities determined by means of ammonium chloride leach and 

measurement of sorbed ammonium, by distillation; results are in milliequivalents 

per 100 grams, dry weight; Harry C. Star key, analyst. Maximum diameter of clay 

particles was 2 microns. Nd, not determined]

Depth 

interval Sand Silt Clay 

(in.)

CRM 7.5 hole 7-2

10-12_____ Nd 11.7 42.4

14-16 __ Nd 13. 8 33. 5

18-20 ___ Nd 9. 6 37. 1

22-24 _ _ Nd 10. 2 33. 2

30-32. __ Nd 10. 9 33. 5

34-36 __ _ 7.8 13.9 33.8

40-42. __ Nd 8.9 39.2

44-46... _. Nd 14. 1 33. 4

50-52 _ _ Nd 14. 9 39. 1

52-54... _. Nd 12.6 30.0

56-58 __ . Nd 11.6 33.4

60-62 ___ Nd 10.1 34.2

62-64 ___ Nd 11. 1 32. 2

Depth 

interval Sand Silt Clay 

(in.)

CRM 14.0, hole 2

4-6.... ._ Nd 12.0 34.8

8-10 ___ Nd 13.5 33.4

12-14 _ . Nd 13. 2 35. 6 

16-18___. Nd 15. 1 28. 1

20-22.. __ Nd 14.2 32.8

24-26 _ . 10. 5 12. 3 33. 2 

28-30 __ Nd 11. 0 30. 1

32-34 _ . Nd 11.5 35.6

36-38 _ . Nd 12. 2 38. 6

40-42. _ Nd 9. 3 30. 4
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H17

100 

SAND

100 

SILT 50 

PERCENTAGE CLAY

75

100 

CLAY

FIGURE 7. Results of particle-size analyses of composite samples of the radioactive parts of 45 cores of Clinch River bottom sediment.

Nomenclature from Shepard (1954).

vermiculite (dioctahedral), and mixed-layered micavermiculite. Traces of chlorite, montmorillonite, and 

feldspar were present in many of the samples.

Dolomite was present in the sand-size fraction of the 

sediment in some abundance, probably in the form of 

detrital grains, and was present in the silt-size fractions 

of all but four of the 23 samples (table 8). Calcite was 

detected in only a few of the samples; however, calcium 

carbonate can precipitate in river sediment in a poorly 

crystallized form which is not susceptible to detection 

by X-ray methods.

The presence of precipitated calcium carbonate in the 

bottom sediment was of interest because, in one place 

where calcite precipitated from Clinch Kiver water on 

a bimetallic object, the calcite contained an appreciable

content of radionuclides. A radiochemical analysis of 

the calcite showed it to contain 123.9 pc per g (picocuries 

per gram) ruthenium-103 to ruthenium-106 and 10.1 

pc per g strontium-90 (Parker and Blanco, 1963, p. 

105). This radionuclide content is within the range commonly found in suspended sediment in Clinch Kiver 

water downstream from the mouth of Whiteoak Creek. 

In the place cited, precipitation of the calcite may have 

been the result of local electrochemical action between 

the two metals and the river water.

In order to investigate the possible presence of poorly 

crystallized calcium carbonate in Clinch Kiver bottom 

sediment, the content of carbonate minerals (mineral 

carbon) in the raw sediment samples was determined 

by chemical analysis. In all samples, the content of min-
HIS TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 8. Mineralogical composition of selected samples of Clinch River bottom sediment

[Determined by X-ray diffraction method. Because of inherent inaccuracies of method, contents have been rounded to nearest 10 percent, ±5 percent, except where noted. 

Clay-size fraction, particles <2 microns in diameter; silt-size fraction, particles 2-62 microns in diameter; sand-size fraction, particles >62 microns in diameter. Tr, trace; 

 , mineral not detected. P. D. Blaekmon, analyst]

Mica- AluminumDepth interval Size fraction Mica Vermieulite vermieulite Mont- Chlorite interlayered 

(in.) (trioctahedral) (mixed- morillonite vermieulite 

layered) (dioctahedral)

Kaolinite Quartz Feldspar Dolomite Calcite

CRM 7.5, hole 7-2

10-12 __.

14-16. __.

18-20 __ .

22-24. __.

30-32___.

34-36 ....

40-42 __ .

44-46 __ .

50-52. __.

52-54.. _.

56-58___.

60-62 __ .

62-64. ...

Clay

Silt

Sand __ .

sat

Sand _ __

Silt

Sand __ .

... ClaySand. _ .

Silt

Sand

Silt

Sand__._.

Silt

Sand _ __

Silt

Sand__.__

Silt

Sand_____

Silt

Sand.. _.

sat ...

Sand.....

... Clay _

Silt......

Sand

... Clay.....

Silt......

Sand_____

20

<10

<10 .

20

10

<10 .

20

10

<10 _.

... 10-15

<10

<10 ..

20

10 _.

<10 .

20

... 10-15 -.

Tr _.

20

10 _.

Tr _.

20

10 ..

<10 .

... 10-15

10 _.

<10 .

20

10 _.

<10 _.

20

10

Tr

20

10 ..

Tr

20

10 _.

10 _.

10-15 

Tr

10-15 

Tr

10-15 

Tr

10-15

10-15

10-15

20

10-15

10-15

10-15

10-15

10

10

10 Tr 

Tr ____________

<10 Tr 

Tr

<"10

Tr ____________

10 __._._._

<io

<10

<"10

Tr ____________

10 Tr ____

10-15 ---_. ...

10-15 _-_..__.

<10

10 Tr __-.

10 Tr ___.

Tr ____________

10 ____-__._.__

Tr

Tr 

Tr ..

Tr

Tr

Tr

Tr

Tr

Tr 

10 ..

Tr

10-15 

Tr

20

20 

Tr

20

20 

Tr

10-15 

Tr

10

10

20

20 

10

10-15

20

20

20 

Tr

20 

Tr

20

20 <io

<10 

20 

Tr

20

20

20 

Tr 

Tr 

10-15 

Tr

20 

Tr

20

20 

Tr 

Tr 

20 

Tr 

Tr

10-15 .

70 

80 

10-15 .

70 

80 

10-15 

60-65 

70 

10-15 .

60-65 

70 

10-15 

60-65 

70-75 

20 

70 

70-75 

20 .

70 

70-75 

10-15 .

70 

80 

10-15 .

70-75 

70 

10-15 .

60-65 

70-75 

10-15 .

70 

80 

10-15 .

70 

70-75 

20 .

70 

70-75

<10 

<10

Tr 

10 

Tr .

10

Tr 

Tr .

10 .

10 

Tr .

10-15

10

<10 

<10

Tr 

10

10 

10

<10 

<10

10-15

10

<C10

10 ______

Tr Tr

Tr Tr 

10-15 __ ...

Tr _._.._

10 _.___-

10 __ ._

Tr __ ___

10 ___ .

Tr .. __ _

Tr ___._.

Tr __.__.

10-15 .._-__

Tr ______

10 ___-..

Tr .___..

Tr Tr 

Tr _...._

Tr

<10 . . .

CRM 14.0, hole 2

4-6

12-14. _.

20-22. _.

24-26

28-30. _ .

._. Clay____.

Sand_____

._. Clay .

Silt______

Sand.

Silt

Sand _ _

Silty_____

Sand _

... Clay.....

Sand

Silt

Sand..

Silt7.....

Sand__ _

20

10 _.

<10 ..

20

__ 10-15 _.

20

10 __

_. 20-25

10 _.

__ 10-15

Tr __

20

<10 _.

<10 __

__ 10-15

Tr __

10

10-15

10

10

10-15

10-15

10-15

10-15 ________

Tr ____________

10 ______-.

Tr ____________

10-15 ________

Tr ____________

10 Tr

10-15 Tr 

Tr _

10-15 ____________

Tr ____________

10-15 __ ____ _-.-

Tr ____________

Tr

Tr

Tr

Tr

Tr

10-15 

Tr

10-15 

Tr

10-15 

Tr

10

10-15 

Tr

10-15 

Tr

10-15 

Tr

20 

Tr

20 

<10 

<10 

20

10-15 

Tr

20

20 

Tr

10-15 

Tr

10-15 .

70-75 

80 

10-15 .

70 

70 

10-15 .

70 

80 

20-25 .

70 

80 

10-15 _

70

80-85 

10-15 _

70 

70 

20 .

70 

70

10 .

10

<cio

10

<io

<10

10-15 .

10

10 

10-15

10-15

Tr ____-.

<10 _ _ _

Tr _.--._

Tr .____.

Tr ______

Tr ______

10-15 ... .

Tr ___-_.

<10 ______
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H19 

TABLE 8. Mineralogical composition of selected samples of Clinch River bottom sediment Continued

Depth interval Size fraction 

(in.)

Mica- AluminumMica Vermiculite vermiculite Mont- Chlorite interlayered Kaolinite 

(trioctahedral) (mixed- morillonite vermiculite 

layered) (dioctahedral)

Quartz Feldspar Dolomite Calcite

32-34 __ .

36-38_...

40-42. __.

... ClaySat 

sat __

Sand _ _.

sat 

... 10-15

10 _.

Tr _.

__ 10-15

10

Tr _.

._ 10-15

10 ..

10 _.

10

10-15

Tr

10-15

CRM 14.0 hole 2 Continued 

10-15 ________________

Tr ______ _ __ _ __

10-15 Tr ________

Tr __ _ ___________

10-15 _-__-_---_---___

Tr __-_--_-____.___

10-15

Tr

10-15

Tr

20

Tr __

20

Tr

Tr

20

Tr

20

20

70

70-75

10-15 -.

70

70-75

10-15 __

70-75

70-75

<10

<10

10

10

10

10

10

<10

<10 _ -__

Tr ______

10-15 _-_-__

<10 _ _ _

<10 _____

eral carbon was very low compared to the content of 

organic carbon (table 5). The presence of dolomite as 

sand- and silt-size particles (table 8) suggests that 

much of the mineral carbon content was derived from 

the coarser sediment fractions. Thus, it appears that 

poorly crystallized calcium carbonate is not -abundant 

in the finer size fractions of Clinch River bottom 

sediment.

Tamura (1963) has described the strong affinity of 

strontium-90 for iron and aluminum oxides and hydroxides in basic solutions and has suggested that this 

affinity is related to the surface area of the sorbent. Results of determinations of free iron oxide and free 

alumium oxide in the sediment samples are listed in 

table 5. Constituent correlations indicate that most of 

the free iron and aluminum oxides occurred in association with clay-size particles.

Organic carbon contents of the samples are listed in 

table 5. The variation in content of organic carbon between samples is small.

CHEMICAL CHARACTERISTICS

Contents of one minor element and three trace elements in the sediment samples are shown in table 5. 

Contents of potassium and rubidium were measured as 

possible indcators of the amount of mica-type silicate 

minerals in the samples. The contents of cesium and 

strontium in the samples were of interest because, in 

chemical sorption and ionic substitution reactions, the 

amount of the radioactive form of an element that becomes associated with the sediment depends on the 

relative abundance of the stable form of the element; 

for example, stable cesium will compete with radiocesium (Cs137 ) for cation-exchange sites on clay-type 

minerals. Not only does stable strontium compete with 

radiostrontium (Sr90 ) for exchange sites, but both forms

compete with the much more abundant calcium. Nelson 

(1962) measured the ratio of radiostrontium to stable 

strontium in clamshells in the Clinch River and the 

Tennessee River and reported that the ratio decreased 

with distance downstream from the mouth of Whiteoak Creek in the same manner as that predicted on 

the basis of flow dilution. This relationship is apparently the result of the proportional substitution of radiostronium and stable strontium for some of the calcium 

ions in the calcium carbonate of the clamshell as the 

shell is formed.

In 22 of the 23 sediment samples, the contents of 

leachable calcium and magnesium total more than the 

cation-exchange capacity of the sediment (table 5). 

This observation suggests that in addition to sorbed ions 

displaced by ammonium ions from the leaching solution, minerals dissolved by the leaching solution and 

interstitial water contained in the sediment contributed 

to the cation content of the leachate. Dissolution of only 

a small fraction of the measured content of calcium 

carbonate (mineral carbon) in the sample could account 

for the excess calcium and magnesium in the leachates.

The only two major leachable cations found in the 

sediment were calcium and magnesium. No sodium or 

potassium was detected. This is to be expected in samples from a humid area in which the predominant rock 

types are limestone and dolomite and in which the predominant cations in river water are calcium and magnesium (Grim, 1953, p. 144-145).

Results of radiochemical analyses of the 23 sediment 

samples are shown in table 5.

CORRELATIONS OF PHYSICOCHEMICAL CHARACTERISTICS AND RADIONT7CLIDE CONTENT

In general, correlations of patterns of variation in 

constituent concentration with depth in each of the two 

sediment cores studied (tables 9 and 10) confirm the
H20 TRANSPORT OF RADIONUCLIDES BY STREAMS

interrelationships between cation-exchange capacity, 

particle size, and mineralogical composition that have 

been described previously. The correlations also emphasize the close association of potassium and rubidium 

in geochemical processes. The good correlation of free 

iron oxide with rubidium in hole 7-2, GEM 7.5, and 

with both potassium and rubidium in hole 2, GEM 14.0, 

may be due to a similarity in distribution of particle 

sizes of free iron oxide and the minerals in which the 

potassium and rubidium occur. Correlation of cationexchange capacity with particle-size distribution is better when the particle-size data used are those which 

were obtained by chemical dispersion and analysis by 

bottom-withdrawal tube. This method of separation 

should have resulted in the inclusion of nearly all clay 

minerals in the clay-size sediment fraction.

Mutual correlations of the contents of strontium-90, 

cesium-137, and cobalt-60, which occur in both cores, are 

best in hole 2. For hole 7-2, a correlation of cesium-137 

and cobalt-60 contents with those of particles less than 2 

microns in diameter was detected after application of 

a correction for variations in annual releases of cesium137 to the river (see "Eelationship of vertical distribution to annual releases"). The correction was possible 

for only the upper five samples out of the 13 samples 

analyzed in hole 7-2. Application of a similar correction 

to data for all samples from hole 2 did not materially 

improve the correlations. The corrected contents of 

cesium-137 and cobalt-60 correlate with cation-exchange 

capacity and the contents of free iron oxide, free aluminum oxide, adsorbed water, and organic matter in hole 

7-2, and with free iron oxide content and free aluminum 

oxide content in hole 2. The content of ruthenium-106 

correlates with leachable calcium in both cores.

In the 45 composite samples of bottom-sediment cores 

that were analyzed for both particle-size distribution 

and radionuclide content, the content of sand-size particles shows a strong negative correlation with the content of silt-size particles. This negative correlation emphasizes the previously noted small variation in content 

of clay-size particles in the composite samples. In the 

case of a relatively unvarying content of clay-size particles, any major variation in content of silt-size particles will be accompanied by an opposite variation in the 

content of sand-size particles hence the reported negative correlation. No correlation of particle-size distribution with the content of individual radionuclides in the 

samples was noted. A strong correlation of cesium-137 

content with cobalt-60 content observed in the composite 

samples is consistent with the correlation of those two 

radionuclides observed in other samples of Clinch 

Eiver bottom sediment.

DISCUSSION

The quantity of a radionuclide sorbed on river sediment might be expected to increase with decreasing particle size of the sediment for two reasons: (1) The relative content of layered aluminosilicate minerals, the 

mineral group with the highest sorption capacities for 

many cations (Grim, 1953, p. 131-132), generally increases as the mean particle size of the sediment decreases, and (2) in some reactive materials, including 

several of the layered aluminosilicate minerals and organic matter, sorption capacity varies directly with surface area, which increases as particle size decreases 

(Grim, 1953, p. 132; Sayre and others, 1963, p. 15).

The study of the relationship between particle-size 

distribution and radionuclide content of Clinch Eiver 

bottom sediment is complicated by the effect of variations in the amounts of each of the radionuclides released annually. Both cores that were studied in detail 

exhibited patterns of variation in gross gamma radioactivity with depth which were similar to the pattern 

of annual releases of cesium-137 to the Clinch Eiver 

from OENL. Variations in annual releases of cesium-137 

are strongly reflected in the contents of cesium-137 and 

cobalt-60 in the bottom sediment, as has been shown in a 

preceding section of the report. Because these two radionuclides account for most of the radioactivity in the 

sediment, corrections must be made for the effect of 

annual releases in order to investigate the effect of particle-size distribution on the content of the two radionuclides in Clinch Eiver bottom sediment. Attempts at 

such a correction were made in two ways: (1) In the 

incremental samples of the two sediment cores, by decreasing the measured radiochemical contents of the individual slices by an amount proportional to the amount 

of cesium-137 released during the years which the sample is believed to represent, and (2) in the composite 

samples of the sediment cores, by using cores from parts 

of the river in which there has been a great preponderance of sediment deposition over sediment erosion, an 

integrated sample representing sediment deposited during the entire period since 1943 thus being obtained.

Another complicating factor in a study of the relationship of sediment composition to radionuclide content is the effect of dilution of radioactive sediment 

by nonradioactive sediment. If incorporation of 

cesium-137 and cobalt-60 in Clinch Eiver bottom sediment is by deposition of suspended radioactive solids, 

as has been suggested in this report, the concentration 

of the two radionuclides at a given sample site, and at 

a given depth, will be greatly affected by the amount of 

nonradioactive sediment deposited with the radioactive 

sediment. Because the proportions of the two kinds of
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H21

TABLE 9. Coefficients of correlation for constituent pairs, hole 7-2, CRM 7.5 

[Clay-size particles, <2 microns in diameter; silt-size particles, 2-62 microns in diameter; sand-size particles, <62 microns in diameter]

Particle-size distribution «

Sand».._. __ . ___ ...... __ .

Silt > .. . ...... ...........

Clay» _ .........................

Sand 2.................. ..........

Silt 2-.. ................... ......

Clay*.... .___ __. _.._._.._..._.

Mineral carbon _________ .

Organic carbon _________ .

Total carbon ____ . _____ .

Fe2Oj ...........................

AlsOi.. ..........................

Cs1"

Co^

RulOO

Sand

...... -0.84 .

...... -.85

...... .91

...... -.81

...... -.93

...... -.23

...... -.57

71

...... .33

...... .52

...... -.07

...... .05

...... -.83

...... -.89

...... -.67

...... -.90

...... -.44

...... -.31

...... -.15

...... -.15

...... -.01

...... .61

...... -.62

...... -.60

Silt

-0.84

.43 .

-.70

.62 

.71 

.06 

.21 

-.53 

-.36 

-.25 

-.09 

-.16 

.56 

.64 

.69 

.74 

.23 

.21 

.28 

.36 

.13 

-.37 

.55 

.49

Free oxide 

content

Sand' _ . __ ...... __ .........

Silt i... ..........................

Clay i...... ......................

Sand 2........ ....................

Silt 2................. ............

Clay 2...... ......................

FesO,.. ........................ ..

A120.__ ..........................

Qgl37

Co««..............................

Fe.O,

...... -0.83

...... .56

...... .84

...... -.92

...... .87

...... .87

...... .29

...... .64

...... -.69

...... -.18

...... -.58

...... .06

...... -.07

...... .97 .

...... .68

...... .92

...... .72

...... .51

...... .04

...... .03

...... -.14

...... -.58

...... .79

...... .76

A1203

-0.89 

.64 

.86 

-.94 

.88 

.91 

.20 

.55 

-.69 

-.26 

-.58 

-.01 

-.14 

.97

.72 .

.94 

.64 

.46 

.12 

.10 

-.08 

-.57 

.77 

.75

Clay

-0.85 

.43

-.83 .

.75 

.87 

.32 

.74 

-.67 

-.20 

-.63 

.20 

.07 

.84 

.86 

.45 

.79 

.50 

.31 

-.01 

-.10 

-.10 

-.66 

.68 

.74

Particle-size distribution *

Sand

0.91 

-.70 -.83

 97

-.91 

-.29 

-.67 

.64 

.25 

.58 

-.09 

.04 

-.92 

-.94 

-.78 

-.96 

-.58 

-.37 

-.17 

-.18 

-.002 

.59 

-.77 -.76

Silt

-0.81 

.71 

.87 -.97

.77 ..

.23 

.64 

-.48 

-.28 

-.53 

.06 

-.07 

.87 

.88 

.83 

.92 

.59 

.42 

.27 

.25 

.08 

-.42 

.71 

.73

Minor element content

K

-0.67 

.69 

.45 

-.78 

.83 

.59 

-.09 

.23 

-.25 

-.35 

-.17 

-.22 

-.26 

.68 

.72

.82 .

.62 

.32 

.40 

.46 

.30 

-.19 

.56 

.58

Rb

-0.90

.74 

.79 

-.96 

.92 

.87 

.19 

.56 

-.64 

-.29 

-.47 

-.006 

-.11 

.92 

.94 

.82

.59 .. 

.47 

.17 

.24 

.06 

-.56 

.69 

.65

Cs

-0.44 

.23 

.50 

-.58 

.59 

.49 

.04 

.43 

-.39 

-.26 

-.17 

-.06 

-.08 

.72 

.64 

.62 

.59

.06 

.02 

-.04 

-.36 

.30 

.20

Clay

-0.93 

.60 

.90 -.91

.77

.36 ..

.63

-.79 

-.16 

-.58 

.14 

.01 

.87 

.91 

.59 

.87 

.49 

.26 

-.04 

.003 

-.16 

-.76 

.81 

.75

Adsorbed 

water

-0.23 

.06 

.32 

-.29 

.23 

.36

.74 .

-.16 

.29 

-.35 

.88 

.83 

.29 

.20 

-.09 

.19 

.04 

-.27 

-.27 

-.25 

-.20 

-.45 

.89 

.93

Cationexchange 

capacity

-0.57 

.21 

.74 

-.67 

.64 

.63 

.74

-.47 

-.001 

-.59 

.66 

.55 

.64 

.55 

.23 

.56 

.43 

.05 

-.13 

-.14 

-.12 

-.66 

.97 

.99

Leachable- Carbon content 

cation content

Ca

0.71 

-.53 

-.67 

.64 

-.48 

-.79 

-.16 -.47

.01 ..

.51 

.02 

.13 

fit)

-.69 

-.25 

-.64 

-.39 

-.30 

.11 

.05 

.26 

.86 

-.49 -.34

Mg Mineral

0. 33 0. 52 

-. 36 -. 25 

-.20 -.63 

.25 .58 

-.28 -.53 

-.16 -.58 

-.29 -.35

-.001 -.59 

.01 .51 

........ -.01

-.01 ..........

-.09 -.32 

.08 -.09 

-. 18 -. 58 

-. 26 -. 58 

-.35 -.17 

-.29 -.47 

-.26 -.17 

.04 -.34 

-. 53 . 12 

-.38 -.19 

-.41 -.04 

-.02 .42 

-.40 -.71 

-.38 -.81

Organic Total

-0. 07 0. 05 

-.09 -.16 

.20 .07 

-.09 .04 

.06 -.07 

.14 .01 

.88 .83 

.66 .55 

.02 .13 

.09 .08 

-.32 -.09 

.-... .- .97

97

.06 -.07 

-. 01 -. 14 

-.22 -.26 

-.006 -.11 

-.06 -.08 

-. 52 -. 65

-. 05 -. 004 

.01 -.02 

.18 .19 

- .35 -.29 

.74 .71 

.77 .69

Radionuclide content

Sr

-0.31 

.21 

.31 

-.37 

.42 

.26 

-.27 

.05 

-.30 

.04 

-.34 

-.52 

-.65 

.51 

.46 

.32 

.47 

.30

-.30 ..

-.13 

-.35 

.07 

-.19 -.07

Sr»°

-0.15 

.28 

-.01 

-.17 

.27 

-.04 

-.27 

-.13 

.11 

-.53 

.12 

-.05 

-.004 

.04 

.12 

.40 

.17 

.06 -.30

.69 .

.72 

.11 

.78 

.76

Cs'«

-0.15 

.36 

-.10 

-.18 

.25 

.003 

-.25 

-.14 

.05 

-.38 

-.19 

.01 

-.02 

.03 

.10 

.46 

.24 

.02 

-.13 

.69

.90 

.03 

.99 

.96

COM

-0.01 

.13

-.10 

-.002 

.08 

-.16 

-.20 

-.42 

.26 

-.41 

-.04 

.18 

.19 

-.14 

-.08 

.30 

.06 

-.04 

-.35 

.72 

.90

.12 

.99 

.98

Ru106 Csl3? Co80 

(corrected) (corrected)

0.61 

-.37 

-.66 

.59 

-.42 

-.76 

-.45 

-.66 

.86 

-.02 

.42 

-.35 

-.29 

-.58 

-.57 

-.19 

-.56 

-.36 

.07 

.11 

.03 

.12

-.54 ...... -.39

-0. 62 -0. 60 

.55 .49 

.68 .74 

-.77 -.76 

.71 .73 

.81 .75 

.89 .93 

.97 .99 

-.49 -.34 

-.40 -.38 

-.71 -.81 

.74 .77 

.71 .69 

.79 .76 

.77 .75 

.56 .53 

.69 .65 

.30 .20 

-.19 -.07 

.78 .76 

.99 .96 

.99 .98 

-.54 -.39 

........ .98

.98 ............

1 Separation of sand-size particles by wet sieving of wet sample. Separation of 

silt- and clay-size particles by bottom-withdrawal tube. 

* Separation of sand-size particles by wet sieving of previously dried sample. Separation of silt- and clay-size particles by centrifugation. 

* Five values only.

sediment can be expected to vary considerably from 

place to place, and from time to time at the same place, 

only a rather imperfect correlation of radionuclide content and sediment composition can be expected at best. 

The lack of consistent correlations with particle size 

of the corrected cesium-137 and cobalt-60 contents of 

the incremental samples from the two cores is probably 

the result of the complicating factors just described. 

Corrections for the effects of annual radionuclide releases were applied to the analyses for the two radionuclides but may not have been adequate. Effects of

dilution of radioactive sediment by nonradioactive sediment may have been considerable. Particle-size ranges 

(sand, silt, clay) used in the comparisons may not have 

been detailed enough to demonstrate relationships between particle size and radionuclide content. The latter 

two statements might be used also to explain the poor 

correlations between particle-size and radionuclide 

content exhibited by the 45 composite samples analyzed. 

This conclusion is supported by the results of R. W. 

Andrew's work, which has been described in a preceding section of this report.
H22 TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 10. Coefficients of correlation for constituent pairs, hole 2, CRM 14-0 

[Clay-size particles, <2 microns in diameter; silt-size particles, 2-62 microns in diameter; sand-size particles, >62 microns in diameter]

Particle-size distribution '

Sand

Sand >...... ........ 

Silt i __ .......... .......... 0-.91 . Clay ^........ ......................... -.69

Sand '_... . _ .80

Silt 2... . __ -.52

Clay 2 .....................-..........- -.40

Adsorbed water ___________ . _ .43

Cation-exchange capacity....... . ... .63

Calcium __ . ___ ________ . _ .42

Magnesium.... _ .. __ ___ ... _ .. .26

Mineral carbon _ . _ .... __ ... ... .07

Organic carbon __ . _ . ___ .. ..... .69

FejOj...... ........................... -.55

AlsOs -.60

Potassium ___________ . ___ . .84

Rubidium.. _______________ .79

Cesium ___ ... _ _ . _ ..... . .76

Strontium __ ......... _ -.--... .. .12

SrW....... ..... ............ ...... -.12

Cs»7 ... .............. . . . -.28

COM. . . _ -.08

Euw« ........... __ . _ ........... -.27

OS"' (corrected) _ .... ___ ... .... -.23

Co60 (corrected). ____________ .08

Silt

-0.91

.33 .

-.74

.51

.32

.37

.43

.43 -.06

-.20

-.71

-.83

.46

.56

.22

.65 -.67

-.13

-.03

.12

.02

.44

.09

.02

Free oxide

Clay

-0.69

.33

-.53 .

.28

.34

.32

.68

.20

.68

.17 -.34

__ 09

.45

.38

.66

.67 -.56

.50

.33

.43

.15 -.16

.36

.14

Particle-size distribution 8 

Adsorbed

Sand

0.80 -.74

-.53

-.72 .

-.42

-.55

-.77

-.63

-.38

.41

.46

60 -.79

-.62

-.73

-.77

.44 -.08

-.33

-.45

-.20

-.58

-.41

-.19

Silt

-0.52

.51

.28 -.72

-.32 ..

.41

.67

.43

.34 -.14

-.49

_ F.A

.45 -.02

.44

.39 -.49

-.01

-.29

-.22

-.50

.66 -.27

-.50

Clay

 0.40

.32

.34 -.42

-.32

.20 ..

.19

.31

.07 -.36

-.005 -.13

.50

.87

.41

.52

.05

.12

.82

.90

.91 -.05

.91

.91

-0.43

.37

.32

-.55

.41

.20

.77 ..

.45

.32

-.60

.12

009

.77

.44

.71

.80

.002

.35

.47

.30

.20

.37

.27

.20

Cationexchange

-0.63

.43

.68

-.77

.67

.19

.77

.54 .

.59 -.23

-.30

-.35

.77

.42

.74

.78 -.36

.39

.33

.29

.05

.41

.24

.05

Minor element content

o-jin /i n iiT

Sand i _ . _____ ... ___ . 0.55

Silt ».. .............. . 46

Clay 1... ............... ........... ... .45

Sand 2.. _ ... ___ __ . __ .79

Silt 2................ . .45

Clay a....... .................... . . .50

Adsorbed water....... .... .77

Cation-exchange capacity. .... . .77

Calcium ___ ... . .82

Magnesium ___ .... ... .58

Mineral carbon...... _ . ... .68

Organic carbon _ _ _ . _ ....... .003

Total carbon...... . . .17

FeaOa..

AljOs ... ___ . . .67 .

Potassium __ . ______ ... _ . .81

Rubidium ____ ..... .88

Cesium ____ . ___ ... . .05

Strontium.. _ _ ___ . _ . _ . .46

Si'90 g4

Cs»«__... ... ........................ .65

Co60.... . __ . .48

Ruw«......... ..................... . . .60

C«i" (corrected) ______ .. . .61

COM (corrected)................ . 48

A1203

-0.60

.56

.38 -.62

-.02

.87

.44

.42

.57

.19 -.33

-.24

-.35

.67

.67 ..

.73 -.19

.28

.68

.72

.70

.27

.72

.70

K

-0.84

.22

.66 -.73

.44

.41

.71

.74

.67

.54 -.31

-.35

-.46

.81

.67

.95 .

-.46

.55

.36

.40

.25

.40

.34

.24

Rb

-0.79

.65

.67 -.77

.39

.52

.80

.78

.64

.52 -.46

-.19

-.31

.88

.73

.95

-.34 .

.49

.55

.57

.39

.36

.52

.39

Cs

0.76 -.67

-.56

.44 -.49

.05

.002 -.36

-.16

-.14

-.50

.89

.83 .05

-.19

-.46

-.34

-.009 -

.40

.20

.40 -.14

.25

.41

Sr

-0.12 -.13

.50 -.08

-.01

.12

.35

.39

.46

.85

-.004

.18

.22

.46

.28

.55

.49

-.009

.35 ..

.27

.20

.05

.22

.20

-0.12 -.03

.33 -.33

-.29

.82

.47

.33

.31

.31 -.59

.45

.33

.64

.68

.36

.55

.40

.35

.94 ..

.92 -.05

.94

.92

-0.28

.12

.43 -.45

-.22

.90

.30

.29

.38

.33 -.53

.27

.12

.65

.72

.40

.57

.20

.27

.94

.92 ,

-.009

.99

.92

Leachablecation content

Ca

-0.42

.43

.20 -.63

.43

.31

.45

.54

.50 ... -.45

-.19

-.34

.82

.57

.67

.64 -.16

.46

.31

.38

.30

.84

.35

.30

Carbon content

Mg Mineral

-0.26 0.07

-.06 -

.68 -.38

.34 -

.07 -

.32 -

.59 -

.50 -,

-.04

.05 -,

.07 -.

.58 -

.19 -,

.54

.52

-. 14 -,

.85 -.

.31 -,

.33

.10 -

.18 -

.27 -.

.09 -,

.20

.17

.41

.14

.36

.60

.23

.45

.04

.48

V4

.68

.33

.31

.46

.50

.004

.59

.53

.52

.45

.53

.52

Organic Total

0. 69 0. 78

-.71 -.83

.34 -7.32

.46 .60

-. 49 -. 54

-.005 -.13

. 12 . 009

-.30 -.35

-.19 -.34

.05 .07

-.41 -.24

...... .96

.96 ..........

.003 -.17

-.24 -.35

-.35 -.46

-.19 -.31

.89 .83

.18 .22

.45 .33

.27 .12

.37 .23

-.26 -.40

.29 .15

.37 .23

Radionuclide content

Co«o

-0.08

.02

.15 -.20

-.50

.91

.20

.05

.30

.10 -.52

.37

.23

.48

.70

.25

.39

.40

.20

.92

.92

-.08 .

.94

=1.00

Ru«>e

-0.27

.44 -.16

-.58

.66 -.05

.37

.41

.84

.18 -.45

-.26

-.40

.60

.27

.40

.36 -.14

.05 -.05

-.009 -.08

-.02 .. -.08

Q

!c!37 r~!n60

(corrected) (corrected)

-0.23 -0.08

.09 .02

.36 .14

-.41 -.19

-.27 -.50

.91 .91

.27 .20

.24 .05

.35 -.30

.27 .09

-. 53 -. 52

.29 .37

.15 .23

.61 .48

.73 .70

.34 .24

.52 .39

.25 .41

.22 .20

.94 .92

.99 .92

.94 =1.00

-.02 -.08

 .94

.94 ............

1 Separation of sand-size particles by wet sieving of wet sample. Separation of siltand clay-size particles by bottom-withdrawal tube. 2 Separation of sand size particles by wet sieving of previously dried sample. Separation of silt and clay-size particles by centrifugation.

Contents of radionuclides which have been incorporated in bottom sediment as a result of simple cationexchange reactions might be expected to correlate with 

the total cation-exchange capacity of the sediment. 

Desorption experiments performed on sediment collected near the mouth of Whiteoak Creek have indicated that, of the four most important radionuclides in 

Clinch River bottom sediment (strontium-90, cesium137, cobalt-60, and ruthenium-106), only strontium-90 

was held primarily by simple ion exchange (Morton, 

1965, p. 53). Even in the case of strontium-90, there is 

evidence that some of the radionuclide is associated

with calcium carbonate as the result of a process other 

than simple ion exchange.

The content of strontium-90 in the samples from the 

two sediment cores does not show a good correlation 

with either the total cation-exchange capacity or the 

mineral carbon (calcium carbonate) content of the samples. This lack of good correlation may be due to the 

effect of annual releases of strontium-90. Measured contents of strontium-90 could not be corrected for variations in annual releases as were contents of cesium-137 

and cobalt-60. Also, if detrital calcium carbonate predominates over precipitated calcium carbonate in the
RADIONUCLIDES IN BOTTOM SEDIMENT, CLINCH RIVER, EASTERN TENNESSEE H23

sediment, the content of strontium-90 cannot be expected to correlate with the mineral carbon content of 

the samples.

In the two samples for which the cation-exchange 

capacity of the sand-size sediment fraction was determined, the cation-exchange capacity of the silt-size 

sediment fraction exceeds that of the sand-size fraction. 

In all samples the cation-exchange capacity of the claysize fraction exceeds that of the silt-size fraction by 

a ratio of nearly 3:1 (see table 7). These relationships 

between the various size fractions of the sediment can 

be largely explained by the relative content of layered 

aluminosilicate minerals in each size fraction. The ratio 

of the content of these aluminosilicate minerals in the 

clay-size fracton to that in the silt-size fraction is also 

almost 3:1. The higher specific surface area of the 

clay-size fraction no doubt has modified the effect of 

mineralogy on the cation-exchange capacity of the 

sediment.

The role which calcium carbonate has played in the 

incorporation of radionuclides in Clinch River bottom 

sediment requires further clarification. Evidence for the 

precipitation of calcium carbonate in the Clinch River 

has been obtained, yet the carbonate content of the 

sediment appears to be minor, and much of that which 

is present appears to be in the form of detrital carbonate grains associated with the larger particles of sediment. It has been observed (Morton, 1965, p. 58) that 

the content of calcium carbonate is higher in bottom 

sediment from Whiteoak Lake than in bottom sediment 

from near the mouth of Whiteoak Creek, 0.6 mile downstream, and that the fraction of the total content of 

strontium-90 desorbed from Whiteoak Lake sediment 

through ion-exchange mechanisms is less than in sediment from near the mouth of the creek. The tendency 

of strontium to substitute for calcium in the lattices of 

calcium carbonate minerals (Nelson, 1962), the observed inverse relationships between the calcium carbonate content of Whiteoak Creek bottom sediment and 

the amount of strontium-90 held through ion exchange, 

the incorporation of both strontium-90 and ruthenium106 in calcium carbonate that precipitated in the Clinch 

River, and the correlation of ruthenium-106 with leachable calcium in Clinch River bottom sediment, all illustrate the need for further study of the role which 

calcium carbonate plays in incorporation of radionuclides in Clinch River bottom sediment.

The significance of the content of free oxides in the 

samples of bottom sediment requires further investigation. The correlation of free iron oxide with the claysize sediment fraction suggests that iron oxide coatings 

on sand grains are not a major source of the iron. Iron

and aluminum oxides should be investigated further 

because of their high specific sorption capacities for 

strontium. Sorption of cobalt by iron and manganese 

oxides also should be investigated.

Organic matter (organic carbon) appears to add to 

the cation-exchange capacity of the sediment in hole 

7-2 (see table 9). The reported high cation-exchange 

capacities of a number of organic materials (Faust, 

1963, p. 28) support this observation. Both vegetal 

material, consisting of individual leaves and leaf mats, 

twigs, and other woody material, and metabolic products and remains of aquatic animals are present in the 

river. Coal is an obvious constituent of the coarser sediment fractions in many places throughout the study 

reach.

The use of minor and trace elements to indicate the 

relative abundance of certain layered aluminosilicate 

minerals in samples of Clinch River bottom sediment 

appears to be complicated by the presence of other 

minerals, such as feldspar, which contain the same constituents. The content of adsorbed water in the sediment seems to be a better indication of its cationexchange capacity and possibly, therefore, of its content 

of layered aluminosilicate minerals.

The mutual correlations between the contents of 

strontium-90, cesium-137, and cobalt-60 in the two cores 

(quite strong correlation in hole 2) suggest that the 

strontium-90 content of Clinch River bottom sediment 

may be related in some way to the process of sedimentation of suspended matter in the river, which is believed 

to be the process by which cesium-137 and cobalt-60 are 

incorporated in the bottom sediment, as has been noted 

in a preceding section of this report. This relationship 

could result from sedimentation either of clay minerals 

on which strontium-90 has been sorbed or of precipitated 

calcium carbonate containing strontium-90 in its crystal 

structure.

CONCLUSIONS

On the basis of the information reported in this paper, 

the following conclusions can be drawn:

1. Variations in gross gamma radioactivity with depth 

in Clinch River bottom sediment largely reflect 

variations in the content of cesium-137 in the 

sediment.

2. A similar pattern of variations in the content of 

cesium-137 in the sediment at several coring sites 

in the reach of river downstream from CRM 18 

indicates fairly regular, persistent deposition of 

sediment at those particular sites, and thus longterm net accumulation of sediment at those sampling sections.
H24 TRANSPORT OF RADIONUCLIDES BY STREAMS

3. Incorporation of cesium-137 in Clinch Kiver bottom 

sediment by sedimentation of cesium-bearing aluminosilicate minerals entering the Clinch River 

from the Oak Ridge National Laboratory is indicated by: (1) the similarity of the patterns of 

variations with depth in cesium-137 content of bottom-sediment cores to the pattern of annual releases of cesium-137 from the laboratory to the 

Clinch River, (2) the knowledge that at least 70 

percent of the cesium-137 released from the laboratory to the Clinch River was associated with 

suspended solids, and (3) the known preferential 

sorption of cesium by certain layered aluminosilicate minerals.

4. The similarity of the distribution pattern of cobalt60 to that of cesium-137 in Clinch River bottom 

sediment suggests that cobalt-60 may be incorporated in the sediment by deposition of suspended 

solids entering the Clinch River from Whiteoak 

Creek. The two radionuclides are not necessarily 

associated with the same solids, however. The fact 

that the distribution pattern of cobalt-60 does not 

reflect the pattern of annual releases of cobalt-60 

from Whiteoak Creek implies that most of the 

cobalt-60 released to the Clinch River is not associated with suspended sediment large enough to 

be deposited in the Clinch River, and that a rather 

small fraction of the total cobalt-60 released to the 

river becomes incorporated in Clinch River bottom 

sediment.

5. The relatively small contribution of ruthenium-106 

to the gross gamma radioactivity of the upper part 

of Clinch River bottom sediment indicates that 

only a small fraction of the total amount of ruthenium-106 released to the river is incorporated in 

the bottom sediment. The manner of incorporation 

of ruthenium-106 in the sediment is not known.

6. Cation-exchange properties of Clinch River bottom 

sediment are largely controlled by its content of 

mica and clay minerals. These minerals are found 

primarily in the finest sediment fraction, but occur 

also in the coarser fractions in the form of mineral 

aggregates and shale particles. Calcium and magnesium are the major leachable cations in the sediment; potassium and sodium are not present in 

measurable quantities.

7. The effects of chemical and physical properties of 

Clinch River bottom sediment on its radionuclide 

content are obscured as a result of variations in 

annual releases of the radionuclides and as a result of dilution of radioactive sediment by nonradioactive sediment in the river. Corrections for 

these two factors should be applied if an assessment of the effect of sediment composition on 

radionuclide content is sought.

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