w

Relations Among 

Radionuclide Content and 

Physical, Chemical, and 

Mineral Characteristics of 

Columbia River Sediments

M

I GEOLOGICAL SURVEY PROFESSIONAL PAPER 433-M

2 Prepared in cooperation with the 

p U.S. Atomic Energy Commission
Relations Among 

Radionuclide Content and 

Physical, Chemical, and 

Mineral Characteristics of 

Columbia River Sediments

By J. L. GLENN

With a section on SAND AND GRAVEL MINERALOGY

By R. O. VAN ATTA

TRANSPORT OF R A D I O N U C L I D E S BY STREAMS 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 433-M

Prepared in cooperation with the 

U.S. Atomic Energy Commission

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1975
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY 

V. E. McKelvey, Director

Library of Congress catalog-card No. 72-600307

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

Washington, D.C. 20402 - Price 85c domestic postpaid or 60c GPO Bookstore

Stock Number 2401-00297
CONTENTS

Page Page

Abstract..................................................................................... Ml Presentation of data Continued

Introduction............................................................... ............. 2 Mineralogy Continued

Sample collection and preparation................................ 3 Silt (size classes 7, 8, and 9) ......... ..- M27

Analytical procedures..................................................... 6 Discussion: Quantitative X-ray mineralAcknowledgments.................. .. .... .............. .............. 7 ogy..... .... .. .............. . 31

Presentation of data................................... .......................... 8 Sand (size classes 2-6) and gravel (size class

Cation-exchange capacity........-.-....-.......-.--.-..-... 8 l),by R. 0. Van Atta............... . ........ 32

Nitrogen and carbon content... ............................... 12 Radionuclide content .................................... ...... 36

Mineralogy......... ................. ........................................ 14 Interpretation of radionuclide data.......... 45

Clay (size class 11)................................................. 14 Conclusions.......... ........ ............ ..................................... 49

Silt (size class 10) ...... .... . ......... 21 References cited........- ....... .................. ...., 51

ILLUSTRATIONS

Page

FIGURE 1. Map of the Columbia River study area......-........--....-.-..-----..-.-.---.-- . . - . M4

2-4. Graphs showing:

2. Longitudinal variation of cation-exchange capacity in size classes from the Columbia River and

tributaries.................. .. . ............................................. ................ . .... ... . 10

3. Relations among particle diameter, cation-exchange capacity, and calculated external specific

surface.................................................... .- . - -...--- .. ............ ......... 11

4. Relation of cation-exchange capacity and carbon content. - . .- ... 15

5. Representative X-ray patterns of undispersed sediments from size class 11...................................................... 16

6. Representative X-ray patterns of potassium-saturated sediments from size class 11....... .. ............. 17

7. Representative X-ray patterns of magnesium-saturated sediments from size class 11................. .................. 18

8. Graph showing summary of textural and compositional variations in size class 11............................ . .. 22

9. Representative X-ray patterns of size class 10 samples from Columbia River near Pasco and from Snake

River...........................................-...............-.......-....................................-........................-.............................. . 23

10. Representative X-ray patterns of size class 10 samples from Columbia River near St. Helens and from

Willamette River....-........................................---...............--..--............-..-..-.................-...-................. 24

11. Graph showing summary of compositional variations in size class 10.-.....--.- -. 26

12. Representative X-ray patterns of size class 7, 8, and 9 samples from Columbia River near Bonneville

Dam...----.........-...-.....-.-..-............-.-.--..--...-......................-.......-.------.-..........-.-...-..-.......................... 28

13-20. Graphs showing:

13. Variation in quartz and plagioclase-feldspar abundance with particle size and sample location 29

14. Relation between particle diameter and 1.82-A quartz-peak intensity.......................... -.. ... 31

15. Plot of 10-A peak intensity versus 3.34-A peak intensity------.---.-. - . 32

16. Relations between radionuclide concentration and particle diameter..................................... ....... 39

17. Change in average 65Zn concentration in size classes 4-11 along the Columbia River.. . 43

18. Variations in radionuclide ratios with particle diameter and sample location along the Columbia

River........-.... .... -.... -........................................_............... ..................... . ............... 44

19. Variation in radionuclide concentrations with "as received" cation-exchange capacities................ 45

20. Relation between 65Zn concentration and "as received" and "actual" cation-exchange capacity.... 46

TABLES

Page

TABLE 1. Cation-exchange capacities of sized sediments from Columbia River and tributary locations. . M8

2. Particle-size distributions of undispersed and dispersed sediments in size classes from Columbia River

locations............................................................................................................................................................ 12

3. Nitrogen data for. sediments in size classes from Columbia River and tributary locations 13

4. Carbon and nitrogen data for sediments from Columbia River and tributary locations . 13

III
IV CONTENTS

Page

TABLE 5. Carbon data for samples analyzed for cation-exchange capacity........................................................................ M14

6. Unweighted mean concentration and standard deviation of the most abundant constituents in 12 samples 

of Columbia River water collected near McNary Dam during the period October 1965 through September 1966............................................................................................................................................................... 15

7. Composition of size class 11 samples from Columbia River and tributary locations................--.-.-. .-... 19

8. Relative percentages of five clay minerals in size class 11 samples from Columbia River and tributary

locations-...-....----.-...............-...............-.-.................................................-................-....-.-.-........-..-. . . 20

9. Absolute percentages of clay and non-clay minerals in size class 11 samples from Columbia River and

tributary locations....-......---...-...-............-....-.........................-......-...--.......-..-....-..-........-........... 20

10. Average percentages of clay and non-clay minerals in size class 11 samples and in size class 10 samples

from Columbia River locations-...-.-..-..-....-.-...--..--....-....-..........-.........-..-.............-.. 21

11. Composition of size class 10 samples from Columbia River and tributary locations....................................... 25

12. Absolute percentages of clay and non-clay minerals in size class 10 samples from Columbia River and

tributary locations....-...-......................................................-....-...-...........-..-..........................-.....-....... 25

13. Composition of size class 7, 8, and 9 samples from Columbia River and tributary locations......................... 30

14. Types of analyses performed on size class 1-6 samples from Columbia River and tributary locations..... 33

15. Composition of size class 4, 5, and 6 samples from Columbia River and tributary locations 32

16. Average composition of size class 4, 5, and 6 samples from Columbia River locations 34

17. Sedimentary rock types in size class 4, 5, and 6 samples from Columbia River and tributary locations..... 34

18. Feldspar in size class 4, 5, and 6 samples from Columbia River and tributary locations.. . 34

19. Opaque and ferromagnesian constituents in size class 6 samples from Columbia River and tributary

locations..............................-.--.-......-................................-...................-...-..-.-...-.-..-.............-...--........... 35

20. Chemical and radiochemical analyses of water used to prepare size separates of Columbia River sediments................................................................................................................................................ 37

21. Radionuclide content in sized sediments from Columbia River locations....--....... . 37

22. Distribution of particle size and of 6sZn in a composite sample from each Columbia River location. 38

23. Relative order of radionuclide abundance in selected size classes from Columbia River locations 38

24. Regression equations for the relations between radionuclide concentration and particle size at Columbia

River locations.......................................................................................................................................................... 40

25. Percentage difference in radionuclide concentrations between Columbia River locations................................ 42
TRANSPORT OF RADIONUCLIDES BY STREAMS

RELATIONS AMONG RADIONUCLIDE CONTENT AND PHYSICAL, 

CHEMICAL, AND MINERAL CHARACTERISTICS OF COLUMBIA RIVER

SEDIMENTS

By J. L. GLENN

ABSTRACT

The radionuclides discussed in this report were produced 

by neutron activation of elements in Columbia River water 

that was used to cool the nuclear reactors in the Hanf ord area 

near Pasco, Wash., prior to their final shutdown early in 

1971. After return of the low-level radioactive cooling waters 

to the Columbia River, some radionuclides were attached to 

sediment particles, and some particles were incorporated in 

the streambed. This report presents data on radionuclides in 

size separates of streambed sediments and describes relations 

among radionuclide content, particle size, cation-exchange 

capacity, carbon and nitrogen content, and mineralogy. Differences in radionuclide concentrations with particle size and 

with sample location are evaluated in the framework of simple models for the origin or radionuclides in streambed sediments.

Cation-exchange capacity varies inversely with particle 

size. For medium sands to clays, the regression of the logarithm of cation-exchange capacity on the logarithm of geometric mean particle diameter is linear and has a regression 

coefficient of 0.6. Mean cation-exchange-capacity values for 

medium sands from seven Columbia River locations are 2.8 

(±1.7) milliequivalents per 100 grams; mean values for 

medium to fine clay are 40.8 (±5.1) milliequivalents per 100 

grams. Mean cation-exchange capacities are higher in coarse 

and very coarse sands than in medium sands. Very fine sands 

have cation-exchange capacities that are higher or nearly 

equal to those of medium and coarse silts. Anomalies in the 

relation of cation-exchange capacity to particle diameter are 

traced to the influences of organic matter and mineralogy and 

to the efficiency of the techniques that were used to prepare 

size separates.

No statistically significant difference in cation-exchange 

capacity was noted between locations at the upper and lower 

ends of the study reach. Cation-exchange capacities in Snake 

River and in Willamette River size separates generally are 

slightly higher than cation-exchange capacities in Columbia 

River size separates.

Nitrogen content also varies inversely with particle size. 

Mean values in medium to fine clay and in very fine sand are 

0.45 percent (about 6 percent organic matter) and 0.04 percent (less than 1 percent organic matter), respectively. High 

carbon contents in coarse and very coarse sands and high 

cation-exchange capacities frequently correlate. No longitudinal trends in carbon or nitrogen content are apparent.

Clay minerals make up 70-80 percent of all components in 

both the <2-micron and the 2- to 4-micron size separates. 

The dominant clay minerals are illite, montmorillonite, and 

mixed-layer clays in roughly equal proportions; chlorite and 

kaolinite in about 2 to 1 proportions compose 10 percent or 

less of the average clay-mineral suite. Rough calculations 

indicate that the mixed-layer clays have average cationexchange capacities of about 25 milliequivalents per 100 

grams. These cation-exchange capacities and the apparent 

thermal stability of some mixed-layer clays suggest that illite 

and chlorite layers are abundant in the mixed-layer fraction. 

Empirical observations and correlations between mineral and 

cation-exchange-capacity data suggest that the percentages of 

mineral types are fairly accurate.

'lie percentages of illite and non-clay components (except 

orfe^nic matter, computed from nitrogen or carbon content) 

increase and the percentages of montmorillonite, mixed-layer 

clays, and total clay minerals decrease as particle size 

increases from less than 2 microns to 2-4 microns. The dominant non-clay components are feldspars, which average 10-15 

percent of all components; quartz, which is about 6-12 percent of all components; and organic matter, which averages 

4-6 percent of all components.

The mineral suite in the <2-micron and the 2- to 4-micron 

separates from Snake River is not appreciably different from 

that in Columbia River. The Willamette River suite, however, 

contains more montmorillonite and less illite than does the 

Columbia River suite. Highly significant differences in mineral assemblage^ along the Columbia River are not evident, 

although montmorillonite may increase and quartz may decrease slightly between Pasco, Wash., and St. Helens, Oreg.

Amphibole-group minerals and other non-clay minerals 

occur in greater amounts as particle size increases from very 

fine to coarse silt. In the coarse silt separate, clay minerals 

average less than 15 percent of all components. Within the 

clay-mineral suite in silt separates, illite and kaolinite plus 

chlorite increase relative to montmorillonite as particle size 

increases. Although the two coarsest silt separates were ground 

prior to X-ray analyses, particle size may have affected estimates of mineral abundance.

Petrographic analyses of sand that was divided into five 

size separates and gravel that was unsized show that the 

dominant components are rock fragments, feldspars, and 

silica-group constituents. Rock fragments average one-third

Ml
M2 TRANSPORT OF RADIONUCLIDES BY STREAMS

to one-half of all components in the three finest sand separates and are even more abundant in coarse separates. Nearly 

two-thirds of all rock fragments are volcanic rocks or volcanic 

glass. Maturity indices, which are a measure of the susceptibility of sands to weathering, are correspondingly low. More 

than 25 percent of the feldspar grains and about 15 percent 

of the rock fragments in medium and fine sand are greater 

than one-third and one-half altered, respectively. Only the 

Willamette River, which has higher percentages of rock fragments and lower percentages of potash feldspar and silicagroup constituents, appears to have a mineral suite different 

from the Columbia River suite. No highly significant longitudinal changes in sand-separate mineralogy occur along the 

Columbia River.

Chromium-51, zinc-65, scandium-46, manganese-54, and 

cobalt-60, in decreasing order of concentration, are the 

gamma-emitting radionclides identified in Columbia River 

size separates. Fine- to medium-clay separates contain an 

average of 36 percent of the sum of the zinc-65 concentrations in all separates; fine- and medium-sand separates combined contain less than 2 percent of the sum of the zinc-65 

concentrations in all separates. Weighting radionuclide concentrations with results from particle-size analyses shows 

that the relatively more abundant fine- and medium-sand 

separates contain nearly 45 percent of the total amount of 

zinc-65; the relatively less abundant fine- to medium-clay 

separates contain only 16 percent.

Regression analyses show that the logarithms of radionuclide concentrations in size separates are related to the 

logarithms of geometric mean particle diameters in size separates. Correlation coefficients of greater than 0.9 indicate that 

the relations closely fit linear-regression lines. Consistent 

irregularities in the relation of radionuclide concentrations to 

geometric mean particle diameters correlate with cationexchange-capacity variations, organic-matter fluctuations, and 

(or) mineral changes. A strong tendency for the 2- to 

4-micron size separate to flocculate was observed, and flocculation has been suggested to explain relatively low radionuclide contents in the 2- to 4-micron size.

Covariance analyses indicate that regression coefficients 

for relations of the logarithms of radionuclide concentrations 

to the logarithms of particle diameters differ significantly at 

the Pasco location for different radionuclides. No significant 

difference exists when regression coefficients for the logarithms 

of zinc-65 concentrations versus the logarithms of particle 

diameters are compared among sample locations. The pooled 

regression coefficient for the relation of the logarithms of 

zinc-65 concentrations to the logarithms of particle diameters 

is 0.6 and is about equal to the regression coefficient for 

the relation of cation-exchange capacity to particle diameter. 

For silt and clay separates, radionuclide content and cationexchange capacity are related more directly to the total 

amount of clay minerals than to the particle size.

Between successive downstream locations, radionuclide concentrations in streambed sediments decrease, but not in proportion to distance. Greatest decreases occur between adjacent 

locations bracketing major tributaries. Zinc-65, manganese-54, 

cobalt-60, and scandium-46 concentrations at St. Helens, 

Oreg., are about 1 percent of their concentrations at Pasco, 

Wash.

Radionuclide-concentration ratios show varying relations to 

particle size and to sample location. The scandium-46/zinc-65 

ratio is an order of magnitude higher in clay than in fine 

sand, whereas the zinc-65/manganese-54 and zinc-65/cobalt-60

ratios appear to be independent of particle size. The zinc65/cobalt-60 ratio increases progressively at locations downstream from McNary Dam, but the scandium-46/zinc-65 ratio 

is nearly constant below McNary Dam.

Radionuclide content is related directly to cation-exchange 

capacity in medium-sand to clay separates but tends to be 

independent of cation-exchange capacity in coarse sands. 

Increases in cation-exchange capacity that are greater than 

increases in radionuclide content have been attributed to 

weathering rinds on coarse particles and to organic-matter 

content.

Two simplified qualitative models have been used to aid 

interpretation of streambed-sediment and radionuclide data. 

One model assumes a fixed streambed and reversible uptakerelease reactions that are dependent mostly on solute radionuclide concentrations. The second model involves sediment 

transport and considers irreversible uptake reactions that 

are dependent mostly on solute radionuclide concentrations. 

Most data presented in this report favor a model that combines features of the two simplified models and that includes 

at least partially reversible uptake-release reactions. The 

degree of reversibility and the rate of uptake determine the 

relative importance of sediment transport as a factor in interpreting radionuclide concentrations in Columbia River streambed sediments. Results from additional streambed-sediment 

and radionuclide studies and results from radionuclide-transport determinations can be used to further develop qualitative and quantitative models.

INTRODUCTION

From the early 1940's until early 1971,1 the Columbia River received radionuclides from water used to 

cool the nuclear reactors in the Hanford area near 

Richland, Wash. (fig. 1). Most radionuclides were 

produced by neutron activation of stable elements in 

or added to the cooling water. Radionuclide concentrations have been monitored almost continuously 

since operation of the Hanford reactors was begun, 

and results from the monitoring program and from 

related studies are contained in yearly reports (Nelson, 1961, 1962; Wilson, 1963, 1964) by the General 

Electric Co., one of the prime contractors responsible for operating the Hanford facilities.

With the advent of peaceful uses of atomic energy 

and with the prospect of increasing reliance on 

nuclear energy, detailed studies began on the disposition of radionuclides in the Columbia River. Initial 

studies indicated that nuclides separated naturally 

into particulate (associated with sediment, both inorganic and organic detritus) and solute phases. 

Those nuclides that became associated with particulates are incorporated in varying degrees in streambed sediments throughout the Columbia River below 

Richland, Wash.

J In early 1971, the last of eight reactors at Hanford that were cooled by 

once-through flow was shut down. A ninth reactor, which has a recirculating cooling system and, therefore, contributes very little radioactive material 

to the Columbia River, also was shut down in 1971 but may be started again.
COLUMBIA RIVER SEDIMENTS M3

In 1962, the U.S. Geological Survey and the General Electric Co. (later replaced by Battelle-Northwest, Pacific Northwest Laboratories) began studies 

in cooperation with the U.S. Atomic Energy Commission on the uptake, transport, and release of 

radionuclides in the reach of the Columbia River 

between Pasco and Longview, Wash. Results from 

transport studies through 1965 are included in reports by Perkins, Nelson, and Haushild (1966), 

Haushild, Perkins, Stevens, Dempster, and Glenn 

(1966), and Nelson, Perkins, Nielsen, and Haushild 

(1966).

Some of the first investigations of radionuclides 

in Columbia River streambed sediments were described by Nielsen (in Kornegay and others, 1963, 

p. 98-105), who reported on radionuclides in reservoir sediments behind McNary Dam (fig. 1). Additional results of studies of radionuclides in Columbia 

River streambed sediments between the Hanford 

reactors and McNary Dam are included in progress 

reports from the General Electric Co. (Gamertsfelder and Green, 1964; Nelson and others, 1964) 

and from Battelle-Northwest (Nelson, 1965; Pearce 

and Green, 1966; Pearce and Compton, 1967; Pearce, 

1968, 1969). Nelson, Perkins, Nielsen, and Haushild 

(1966, p. 148-155) described in some detail the kinds 

and quantities of radionuclides in streambed sediments above McNary Dam. Detailed surveys of the 

distribution of sediments and radionuclides in the 

streambed of the Columbia River from the head of 

the estuary near Longview, Wash. (fig. 1), to near 

Richland, Wash., were conducted by the Geological 

Survey in 1965 and 1966. Results from these surveys 

are planned to be included in a future report.

Streambed sediments and suspended sediments 

were collected in 1963 at Pasco, Wash., Hood River, 

Oreg., and Vancouver, Wash. (fig. 1), where routine 

sampling stations had been established to implement 

transport studies, and the sediments were analyzed 

for mineralogy, CEC (cation-exchange capacity), 

and carbon content. Results from these analyses, 

reported by Haushild, Perkins, Stevens, Dempster, 

and Glenn (1966, p. 43-79), indicated the possible 

significance of these important sediment characteristics on radionuclide uptake and transport, but the 

limited spatial distribution of data and the absence 

of direct measurement of radionuclide levels precluded many positive results.

The present report presents new data from a 

study of (1) kinds and amounts of radionuclides in 

streambed sediments and (2) CEC, mineralogy, and 

nitrogen and carbon contents of streambed sediments. The primary objective of the study was to 

establish relations among radionuclide content and

other more commonly measured physical, chemical, 

and mineral attributes of sediments. From this 

study, some conclusions also are possible relative to 

the causes of differences in radionuclide concentrations with particle size and with sample location.

SAMPLE COLLECTION AND PREPARATION

Sets of surficial streambed sediment samples were 

collected at seven locations along the Columbia River 

between Pasco, Wash., and St. Helens, Oreg. (fig. 1). 

Additional sets were collected from locations above 

the mouths of the two major Columbia River tributaries between Pasco and St. Helens the Snake 

River and the Willamette River (fig. 1). Throughout 

this report, sample sites are referred to as locations, 

and the Columbia River locations are called Pasco, 

McNary Dam, The Dalles, Hood River, Bonneville 

Dam, Vancouver, and St. Helens. "Snake River" and 

"Willamette River" are used to designate locations 

in tributary streams. Additional samples for only 

carbon or nitrogen analyses were collected from 

Columbia River locations near Ilwaco and near Harrington Point, Wash., and from Willow Creek, a 

small Columbia River tributary near Heppner Junction, Oreg. (fig. 1).

Samples were collected with a standard U.S. Geological Survey streambed sediment sampler that 

retrieves about a pint of surficial sediment (maximum depth below streambed surface about 1.5 in.) 

with each cast. Sampling was done between April 21 

and May 12, 1966, just prior to the annual spring 

rise of the Columbia River and its tributaries. The 

sample-collection procedure consisted of (1) selecting a location where local sediment inflow probably 

was minimal and where the channel cross section 

was fairly regular (no islands), (2) measuring the 

river depth to determine the cross-sectional profile, 

and (3) collecting 22-32 samples at about 50-yard 

intervals along a cross section.

In the laboratory, selected samples from each cross 

section were cored with a small (i/2-in.-diameter) 

tube to obtain a representative 10- to 20-gram split 

from each sample. The coring tube, rather than a 

standard sample splitter or a quartering technique, 

was used because of the wide range in particle size 

(coarse sand to clay) among samples and because 

of the need to avoid drying samples prior to some 

types of analyses. A minimum of 18 and a maximum 

of 24 of the available samples from each location 

were cored. Samples that were not cored generally 

were from nearshore or shallow zones where contamination by locally derived sediments was possible. 

The cored portions from a cross section were combined to form a composite sample that was analyzed
M4 TRANSPORT OF RADIONUCLIDES BY STREAMS

47°

45 -

43°-

INDEX MAP OF PART OF THE COLUMBIA RIVER BASIN

25

WILSONVILLE | 

WILLAMETTE RIVER -

THE DALLES

FIGURE 1. Columbia River study area. Sampling locations are designated by circled dots. (Modified from Haushild and others, 1966.)
COLUMBIA RIVER SEDIMENTS M5

EXPLANATION

© 

Sample locations

PRIEST RAPIDS 

DAM

BONNEVILLE DAM, « 

Mile\ =

' 5°«

BONNEVILLE DAM

McNARY Mile 

DAM 300

20 MILES
M6 TRANSPORT OF RADIONUCLIDES BY STREAMS

for particle size by pipette techniques for silt and 

clay sizes and by visual-accumulation tube for sand 

sizes. Results from these analyses were used to estimate the distribution of particle sizes in each cross 

section and to indicate the availability of material in 

selected size ranges.

Following the particle-size analysis, about equal 

volumes of sediment were cored from each sample 

that had been cored previously for the initial composite sample, and this sediment was combined with 

supplemental amounts of sediment that came from 

samples appearing to contain certain desired sizes. 

By a combination of wet-sieve and settling-velocity 

techniques, the second composite sample from each 

location was separated into 11 size classes with the 

following particle-size boundaries (in microns, /*,) : 

Class 1, 4,000 to 2,000; class 2, 2,000 to 1,000; class 

3, 1,000 to 500; class 4, 500 to 250; class 5, 250 to 

125; class 6, 125 to 62; class 7, 62 to 31; class 8, 31 

to 16; class 9, 16 to 4; class 10, 4 to 2; and class 11, 

<2.

Distilled water (no dispersing agent) and mild 

physical agitation were employed in preparing the 

size classes. In an attempt to retain the sediment in 

as natural a condition as possible, more vigorous 

chemical and mechanical dispersion techniques, although perhaps better for some aspects of this study, 

were not employed. Native Columbia River water was 

not used for various reasons but chiefly because of the 

possibility that some undeterminable exchange might 

occur between radionuclides in the water and radionuclides in the sediments.

Particle-size analyses by the pipette method, both 

with and without vigorous dispersion, were run on a 

number of fine (<62Ju) size separates. When vigorous dispersion was desired, samples were suspended in a 5-percent sodium hexametaphosphate 

solution and were agitated mechanically in a maltedmilk cup for 10 minutes.

ANALYTICAL PROCEDURES

Each size class was divided into two to five splits, 

the number determined by the amount of sample 

available and by the amount of sample needed for 

each prospective type of analysis. A small Jones-type 

wet splitter was used for silts and clays (<62Ju), 

and a quartering technique was employed for sands 

(>62Ju). If sufficient sample was available, each size 

class from each Columbia River location was analyzed for (1) radionuclide content, (2) mineralogy, 

(3) CEC, and (4) nitrogen and carbon content. 

Samples from tributary streams were not analyzed 

for radionuclide content.

Advanced multidimensional and multichannel

gamma-ray spectrometry (Perkins, 1965) was used 

to identify five major gamma-emitting radionuclides 

in Columbia River sediments. These nuclides and 

their half lives (Leaderer and others, 1967) are: 

51 Cr (chromium-51), 27.8 days; 65Zn (zinc-65), 245 

days; 46Sc (scandium-46), 83.9 days; 54Mn (manganese-54), 303 days; and 60Co (cobalt-60), 5.26 years. 

An additional 60 nuclides (Wilson, 1964, p. 11), 

including some produced during nuclear bomb tests, 

have been measured in the Columbia River, but the 

five listed above generally are the most abundant 

activation products in sediments below Pasco. The 

major radionuclides, except 51Cr, originated chiefly 

from exposure to the neutron flux of natural elements in Columbia River water used to cool the 

reactors in the Hanford area (fig. 1). Chromium-51 

occurred chiefly because of the activation of chromium which was added as sodium dichromate to the 

reactor cooling water to inhibit corrosion. A small 

amount of some radionuclides probably came from 

activation of elements in metal pipes that carried 

water to or through the reactors.

Mineralogy of sand separates (>62Ju sizes) was 

determined by standard thin-section petrographic 

techniques supplemented by binocular and petrographic examinations of grains and grain mounts. 

Thin sections were prepared from approximately 

50-gram samples that were well mixed in vials and 

impregnated with plastic prior to cutting.

Mineralogy of silt and clay classes (<62Ju sizes) 

was determined by X-ray diffraction using the following instrument settings: Radiation, CuKa; slits, 

1-0.006-1; time constant, 1 second; scan rate, 2° per 

minute; chart speed, 30 inches per hour; power, 40 

kilovolts and 20 milliamperes. Pulse-height discrimination circuitry also was employed. To minimize preferred orientation and primary extinction (Klug and 

Alexander, 1954, p. 290-305), about 1 gram of size 

classes 7 and 8 material was ground mechanically in 

alcohol for 30 minutes, dried in a forced-air oven at 

60°C, and suspended in water; any remaining >16/x, 

material was allowed to settle, and the <16/x, material 

was decanted and used for X-ray analysis. The remaining size classes were analyzed without grinding.

A combination of cation saturations and heat 

treatments of oriented aggregates on porous tiles 

(Kinter and Diamond, 1956) was utilized to aid 

qualitative and quantitative evaluations of mineral 

composition. The saturations and treatments included (1) potassium saturation and (a) air drying, 

(b) heating for 1 hour at 110°C, (c) heating for 1 

hour at 300°C, and (d) heating for 1 hour at 550°C; 

(2) magnesium saturation and (a) air drying, (b) 

glycerol solvation; and (3) natural cation saturation
COLUMBIA RIVER SEDIMENTS M7

(no treatment) and (a) air drying, (b) vapor phase 

glycol solvation, (c) heating at 300°C for half an 

hour, and (d) heating at 550°C for half an hour. In 

addition to the analyses of oriented aggregates, a 

single trace was run on a random powder of each 

sample. Naturally saturated (dominantly calciumand magnesium-saturated) samples routinely were 

not treated prior to analysis; however, for a few 

samples, dispersion with 5 percent chlorox was necessary to insure a smooth mount.

Quantitative estimates of the mineral composition 

of silt and clay size classes were made utilizing the 

techniques developed by Schultz (1960, 1964). Basically, these techniques rely on relations among 

weighted sizes (height and (or) area) of reflections 

from certain basal planes of clay minerals after certain treatments in order to calculate relative amounts 

of five clay minerals. Because of differences between 

the Columbia River mineral suite and the suite in the 

rocks with which Schultz was concerned, two modifications of the relations were necessary. (1) Areato-height ratios of 7-A (Angstrom) peaks in samples 

that appeared to contain no contributing 14-A component indicated that a factor of 2.0-2.5 (corresponding to well-crystallized kaolinite, Schultz, 1960, 

p. 221), rather than 1.4, as used by Schultz, was 

appropriate for indicating the crystallinity of koalinite. The 7-A-peak area-to-height ratios for samples containing both 7-A and 14-A peaks also were 

about 2.0, which indicates that kaolinite and chlorite 

are of nearly the same crystallinity. (2) Mixed-layer 

clays in the Columbia River samples tended to be 

more heat stable than mixed-layer clays for which 

the Schultz relations were derived. In some cases, 

complete collapse of Columbia River mixed-layer 

clays apparently did not occur even after heating to 

550 °C. More to check the effect than to solve the 

problem, clay-mineral percentages were calculated 

using both 300°C-10-A heights and areas (standard 

Schultz technique) and 550°C-10-A heights and 

areas (modified Schultz technique).

Random-powder traces and intensity factors are 

used in the standard Schultz technique to estimate 

absolute amounts of total clay minerals and non-clay 

minerals. The only modification of intensity factors 

derived by Schultz (1964, p. C2) that appeared necessary resulted from differences between X-ray 

equipment used to analyze Columbia River sediment 

and X-ray equipment used by Schultz. Analysis of a 

standard slide on both X-ray units indicated that 

multiplication of Schultz' intensity factors by 1.3 

was necessary.

Cation-exchange capacity was determined by using 

the radioactive-cesium method (Beetem and others,

1962). Although CEC values are reported to the 

nearest 0.1 meq per 100 g (milliequivalents per 100 

grams), they are not better than 1-3 percent relative nor 1-10 percent absolute (W. A. Beetem, written commun., 1967). Reported results are averages 

of at least three CEC determinations each on duplicates or triplicates where sufficient sample was 

available. During processing of some coarse (>62/x) 

size classes it was noted that, according to fall velocity, not all material was in the indicated size class. 

Where this was noted, a fall-velocity separation was 

made, and CEC values are reported for both separates. These CEC values were combined algebraically 

to give an "as received" CEC of the sample. For a 

few coarse size classes, some additional dispersion 

was noted when the samples were treated with 0.5- 

normal cesium chloride. For these size classes, a second fall-velocity separation was made, and CEC 

values are reported for both separates.

The amount of organic matter was estimated indirectly by appropriate conversion of either nitrogen 

or carbon percentages. Nitrogen was determined by 

the Kjeldahl-Gunning-Arnold method for solid samples, and total carbon was measured either by a Leco 

carbon analyzer or by a modification of a wet-chemical method described by Van Hall, Safranko, and 

Stenger (1963).

ACKNOWLEDGMENTS

The investigation of radionuclides in the Columbia 

River was supported by the Division of Reactor 

Development and Technology, U.S. Atomic Energy 

Commission. Collection of samples and preparation 

of size separates were done by personnel of the 

Columbia River project under the supervision of 

W. L. Haushild, whom the authors acknowledge for 

many useful discussions and much supplemental information. Radionuclide analyses were performed at 

Battelle Memorial Institute, Pacific Northwest Laboratories, Richland, Wash. Jack L. Nelson ably 

supervised the analyses of samples and developed 

the necessary radionuclide calibrations for the small 

quantities of sample that were available. W. A. 

Beetem, U.S. Geological Survey, is especially 

acknowledged for noting the large amount of fines 

in some coarse size classes and for furnishing all 

CEC analyses. J. J. S. Yee and N. F. Leibbrand, Geological Survey, performed the carbon and nitrogen 

analyses. The writers extend their appreciation to 

E. A. Jenne and L. G. Schultz, Geological Survey, for 

allowing free access to their laboratories and for 

sharing their experiences in X-ray analysis. Discussions with Drs. Jenne and Vance Kennedy, Geological Survey, also were most beneficial.
M8 TRANSPORT OF RADIONUCLIDES BY STREAMS

PRESENTATION OF DATA 

CATION-EXCHANGE CAPACITY

Results from CEC determinations on sized sediments from the Columbia River and major tributaries are shown in table 1. A comparison of these 

data with data for streams throughout the continental United States (Kennedy, 1965) indicates that 

sediments from the Columbia River and major tributaries have CEC values that generally are comparable to CEC values for other stream sediments in 

western and midwestern areas. The fine- to mediumclay separate (size class 11) from Columbia River 

locations has CEC values (table 1) that range from 

33.4 to 47.8 meq per 100 g. Medium- and fine-sand

separates (size classes 4 and 5) have CEC values 

that average about 10 percent of average CEC values 

in fine- to medium-clay separates. In gravel and very 

coarse sand separates (size classes 1 and 2), however, CEC values increase to about 20 percent of 

average values in fine- to medium-clay separates. 

Size separates from tributary locations have slightly 

higher CEC values than comparable size separates 

from Columbia River locations.

For the fine- to medium-clay separates, average 

CEC values reported here of about 41 meq per 100 g 

(table 1) are lower than average values of about 

60 meq per 100 g reported in an earlier study (Haushild and others, 1966, p. 63-75). Although analytical

TABLE 1. Cation-exchange capacities (in milliequivalent per 100 grams) of sized sediments from Columbia River and

tributary locations

Type of sample (See "Analytical Procedures") :

1. Bulk sample as received for analysis. CEC computed algebraically by 

combining the results of CEC analyses on type 2 and 3 samples, where 

available, using the weight percent of material for each type as 

weighting factors.

2. Bulk sample after material finer than the lower limit of the size class 

had been removed by decantation.

3. Material finer than the lower limit of the size class.

4. Bulk sample after treatment with cesium chloride followed by decantation and removal of material finer than the lower limit of the size 

class.

5. Material from type 4 sample that is finer than lower limit of size class.

If type 4 or 5 samples are not listed for >62W size classes at a location, or if a dashed line is shown, no analyses were necessary; that is, no additional 

fines or floating organic matter were present. Size limits (in parentheses) are given in microns.

Location

Columbia River near :

Pasco................... ..................

McNary Dam......................

The Dalles............................

Hood River..........................

Bonneville Dam...................

Vancouver............................

St. Helens.............................

Mean..................................

Standard deviation.........

Mean................... .............

Standard deviation........

Snake River.................................

Willamette River........................

Type 

of 

sample

............. 1........

2........

3........

4........

5........

..............1........

2........

3........

4........

5........

..............1........

2........

3........

..............1........

2........

3........

4........

5. .......

... ..........1........

2........

3........

............. 1. .......

2........

3........

4........

5........

...... ........1.. ......

2........

3........

.............1. .......

............. 1. .......

..............(2)....

..............(2)....

.............1........

2........

3........

4........

5........

.............1. .......

2........

3........

4........

5........

1

(4000- 

2000)

3.0

3.0

6.7

2.9

10.2

12.6

8.4

28.3

8.3

14.0

(')

(!)

t 1 )

13.3

13.2

14.2

12.5

25.6

18.4

14.4

53.0

2.0

2.0

10.5

1.9

9.8

2.0

2.0

8.6

7.1

7.0

5.6

11.4

11.4

17.0

10.7

19.3

6.5

6.4

36.0

6.4

16.3

2 

(2000- 

1000)

3.2

3.2

6.7

2.9

10.2

8.5

5.9

53.5

5.8

12.3

(M(')

(!)

3.5

3.5

10.3

3.2

107.5

10.2

9.5

39.5

1.6

1.6

20.2

2.6

4.9

3.5

4.3

2.9

10.9

10.8

12.9

10.4

21.8

8.0

7.8

30.4

7.4

22.4

3 

(1000- 

500)

9.8

9.5

29.3

8.4

26.4

4.1

3.9

50.6

3.9

3.5

23.1

6.7

48.5

2.4

2.3

36.0

3.4

3.3

32.3

2.4

2.3

21.2

2.6

2.6

8.0

6.8

7.6

4.2

2.4

7.4

7.0

31.7

7.0

8.2

7.2

7.0

37.2

6.9

23.8

4 

(500- 

250)

2.9

2.8

18.0

2.7

18.8

2.6

2.2

37.5

4.3

3.8

25.9

2.3

2.1

29.5

2.1

2.1

10.4

3.0

2.9

32.0

2.2

2.2

19.0

2.8

1.7

2.6

.6

3.7

3.6

9.5

3.5

12.4

9.3

9.2

33.3

9.2

21.0

Size c

5 

(250- 

125)

2.8

2.7

18.1

2.6

19.6

5.0

4.2

32.3

5.3

4.8

34.3

3.1

2.8

39.6

4.2

3.7

22.3

4.1

3.8

17.0

3.0

2.8

29.2

3.9

1.0

3.5

.8

4.2

4.1

17.6

12.0

11.5

34.4

11.4

20.7

lass and limits

6 

(125- 

62)

3.3

2.8

14.9

2.7

5.9

9.5

6.3

30.0

9.9

8.2

40.9

10.4

8.1

42.3

9.1

7.5

25.8

8.1

6.4

36.2

12.6

8.8

38.7

9.0

2.9

6.8

2.0

7.0

5.7

32.5

15.9

14.4

35.9

14.4

25.6

7 

(62- 

31)

3.5

5.2

6.0

5.7

5.9

5.1

5.0

8.4

6.8

5.4

1.0

5.4

1.0

5.6

12.7

8 

(31- 

16)

9.2

8.7

9.3

8.0

9.5

9.3

10.2

9.2

.7

9.2

.7

8.7

18.0

9 

(16- 

4)

18.7

16.8

17.6

14.3

17.2

18.3

17.1

17.1

1.4

17.1

1.4

17.0

24.7

10 

(4- 

2)

22.3

22.6

20.0

31.7

32.1

28.7

34.4

34.7

32.5

32.8

31.6

32.1

22.8

29.6

30.0

25.3

26.3

27.1

22.0

29.8

4.2

30.2

4.1

30.0

30.1

26.8

34.3

34.8

29.2

11 

«2)

35.0

....

....

44.8

....

....

47.8

41.7

40.8

42.3

41.0

42.0

33.4

40.8

5.1

40.7

6.1

47.6

44.6

Total

113.7

149.5

157.7

137.7

152.6

125.5

118.8

153.5

193.2

1 Insufficient material for analysis.

Calculated using CEC data from sample types 4, 2, or 1, in that order of preference.
COLUMBIA RIVER SEDIMENTS M9

procedures were different (ammonium chloride 

method versus radioactive-cesium method) and although cesium is known (Tamura and Jacobs, 1960) 

to collapse some clay mineral structures (thus preventing free exchange of ions), published data 

(Beetem and others, 1962, p. B6) suggest that the 

observed average differences are so great that some 

other factor is responsible. Differences in mineralogy 

or carbon content do not appear to be sufficient to 

cause the difference in CEC.

Variations in CEC among sample locations are 

shown for selected size classes in figure 2. Data for 

tributary streams are plotted at the Columbia River 

mile where the tributary joins the Columbia River, 

even though the samples were collected some miles 

up the tributary stream. Statistical comparisons of 

data from the three uppermost locations (Pasco, McNary Dam, and The Dalles) with data from the 

three lowermost locations (St. Helens, Vancouver, 

and Bonneville Dam) indicate that no significant 

longitudinal trends are present. Although not consistent for all size classes, the available data suggest 

some reflection in Columbia River size classes of generally high CEC values in tributary-stream size 

classes. The fact that not all Columbia River size 

classes had higher values (fig. 2) below a tributary 

confluence simply may reflect the textural composition of sediments contributed by the tributary.

Relations among CEC, particle size, and an estimate of external specific surface (Sayre and others, 

1963; Baver, 1956) are shown in figure 3. CEC data 

are plotted at the theoretical geometric mean particle diameter (equal to the square root of the product of the upper and lower size class boundaries) 

of each size class unless otherwise indicated. Inspection of data in figure 3 indicates a regular decrease 

in CEC with increasing geometric mean particle size 

or decreasing external specific surface. The three 

coarsest size classes and size class 6, however, deviate rather greatly from the general trend of the 

relation. In part, this deviation is the result of 

incomplete dispersion and separation of silt and clay 

aggregates or of silt and clay present as semi-permanent coatings on sand particles. The presence of a 

small amount of fines in a size class that is mainly 

sand can greatly increase CEC, but their presence 

will not be reflected in the theoretical geometric 

mean, which is calculated on the assumption that all 

particles are distributed in a fixed manner within 

the boundaries of the size class. In some samples, 

carbon content (table 5) appears to be related to 

some deviations; for the coarser separates, however, 

the deviations also may be related to degree of 

weathering and to differences in mineralogy 

(p. M36).

The CEC-particle-diameter relation may be analyzed further by considering results from (1) particle-size distributions of size classes that contain 

<62^ sediment (table 2), and (2) type 3 CEC analyses of size classes that contain >62^, sediment 

(table 1). These results can be used to give an estimate of the "actual" geometric mean particle diameter in each size class.

Particle-size distributions were determined on 

both undispersed and dispersed samples. (See "Sample Collection and Preparation.") For size classes 

7 and 9, dispersion produced no apparently significant change (table 2) in the size distributions; for 

size class 10, dispersion resulted in appreciably more 

<2^ material and less 16^-4^ material, with little 

change in the amount in the 4^-2^ size range. Results for size class 11 were inconsistent but, in general, suggest that rigorous dispersion produced little 

change. For the analysis that follows, results for 

samples that were not dispersed are used mainly 

because more analyses were done in this fashion.

By assuming that all particles between size limits 

(table 2) have a size equal to the theoretical geometric mean of the size range and by weighting each 

such geometric mean by the percentage of particles 

in each size range, a size, called the "actual" geometric mean, can be computed. The average value 

of the "actual" geometric mean for each <62/x size 

class is plotted in figure 3 for comparison with the 

theoretical geometric mean for each size class.

CEC determinations of type 3 samples (table 1) 

can be used to estimate the "actual" geometric mean 

particle diameter of size classes that contain >62/xsize sediments. To do this, the regression equation 

for the relation between log CEC (logarithm of the 

"as received" CEC) and log D (logarithm of the 

theoretical geometric mean particle diameter) for 

size classes 7, 8, 9, and 10 was established. The particle diameter of type 3 material was then estimated 

by finding the diameter equivalent to the CEC of the 

material. Because organic material is a part of the 

type 3 material, this procedure results in the maximum deviation between the theoretical and an "actual" particle diameter. Calculations can be made 

to eliminate the contribution by organic material to 

the type 3 CEC, but the computations are limited by 

the necessity of assuming a CEC for the chips and 

splinters of wood that compose the organic component in >62^ size classes. The "actual" particle 

diameter in each >62^ size class may be calculated 

as the sum of the percentage of material in the size 

class times the appropriate theoretical geometric 

mean particle diameter of the size class plus the percentage of type 3 material times a particle diameter 

determined from the CEC of the material.
M10

to 

o o

50

40

30

X ^

lu > 20

O iu 

< J

1 10

V)

TRANSPORT OF RADIONUCLIDES BY STREAMS

I__________________I_________________I

A. Silt and clay separates

100 200 300 

DISTANCE FROM COLUMBIA RIVER MOUTH, IN MILES 

C. Sum of sand, silt, and clay exchange capacities

FIGURE 2. Longitudinal variation of cation-exchange capacity in size classes from the Columbia River and 

tributaries. Results from tributary streams are plotted as if the samples were obtained near the confluence 

of the tributary and the Columbia River. Location: SH, St. Helens ; WR, Willamette River; V, Vancouver ; 

BD, Bonneville Dam; HR, Hood River; TD, The Dalles; MD, McNary Dam; SR, Snake River; P, Pasco.
COLUMBIA RIVER SEDIMENTS Mil

Results from determining the average values of 

the "actual" geometric mean particle diameters of 

all size classes are plotted in figure 3. The correlation 

coefficient for the regression relation between log 

CEC and log "D," where "D" is the "actual" geometric mean particle diameter, is higher than the 

coefficient for the relation between log CEC and log 

D. Thus, the use of an "actual" rather than a theoretical geometric mean results in a more nearly 

linear relation between CEC and geometric mean

50,000

10,000

5000

1000

500

100

50

10

Specific surface (from Baver, 1956; Sayre end others, 1963)

7 

O O Mean "as received" cation-exchange capacity for Columbia River locations

- Mean "actual" cation-exchange capacity 

for Columbia River locations

Average "actual" geometric mean particle diameter

50,000

10,000

5000

1000

500

O

UJ

100

50

10

5000 1000 500 100 50

PARTICLE DIAMETER, IN MICRONS

10

FIGURE 3. Relations among pa.rticle diameter, cation-exchange capacity, and calculated external specific surface. Numbers by data points are 

size-class numbers.
M12 TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 2. Particle-size distributions (in percent) of undispersed and dispersed sediments in size

classes from Columbia River locations

[Type of analysis: A, not dispersed mechanically or chemically; B, dispersed mechanically and chemically. Size-distribution

limits given in microns]

Designated

size class Location Type of 

analysis

Particle size distribution

62-31 31-16 16-4 4-2 <2

7............Pasco.....................................A..................... 93.8 4.0 0.7 0.6 0.9

McNary Dam.......................A..................... 92.2 5.3 1.4 .1 1.0

The Dalles............................A..................... 89.0 8.9 1.3 .1 .7

Hood River...........................A..................... 90.8 7.3 .5 .5 .9

B...................... 86.4 9.5 1.4 1.1 1.6

Bonneville Dam...................A..................... 92.8 5.2 1.3 .0 .7

Vancouver............................A..................... 92.5 6.5 .6 .1 .3

St. Helens.............................A..................... 90.8 8.0 .8 .1 .3

8............McNaryDam.......................A..................... 10.8 83.7 3.7 1.8 .0

The Dalles............................A..................... 7.4 86.4 4.4 .5 1.3

Hood River...........................A..................... 9.8 84.1 5.5 .2 .4

Bonneville Dam...................A..................... 12.3 82.7 3.6 .1 1.3

Vancouver............................A..................... 8.7 85.4 5.2 .2 .5

St. Helens.............................A..................... 9.6 84.7 4.7 .3 .7

9............Pasco.....................................A..................... .0 22.9 68.1 5.1 3.9

McNary Dam.......................A..................... .0 11.0 84.6 1.1 3.5

B..................... .0 7.3 81.5 5.5 5.7

TheDalles............................A..................... .0 10.9 82.1 4.0 3.0

Hood River...........................A..................... .0 .0 90.5 7.6 1.9

Bonneville Dam...................A..................... .5 9.1 85.1 2.5 2.8

Vancouver............................ A..................... .0 8.8 83.7 3.9 3.6

St. Helens.............................A..................... .0 5.1 87.4 .0 7.5

10............McNary Dam.......................A..................... .0 3.7 40.5 46.7 9.1

B..................... .0 .0 11.6 52.2 36.2

The Dalles............................ A..................... .0 .0 24.3 60.4 15.3

B..................... 1.0 1.4 2.0 70.6 25.0

Vancouver............................ A..................... .0 .0 32.0 56.3 11.7

11............McNary Dam.......................A..................... .0 .0 .0 34.6 65.4

B..................... 1.1 .2 13.8 10.3 74.6

The Dalles............................A..................... .0 .0 .0 30.1 69.9

Hood River...........................A..................... .0 .0 .5 9.1 90.4

B..................... .0 .0 .7 10.1 89.2

Vancouver............................A..................... .0 .0 .5 19.7 79.8

St. Helens.............................A..................... .0 .0 .0 6.1 93.9

B..................... .0 .0 .1 7.9 92.0

particle diameter. Deviations from linearity are still 

evident, however, and suggest that factors other 

than particle diameter are affecting CEC. This conclusion is reinforced when mean "actual" CEC values 

for size classes 1-6 are substituted for mean "as received" CEC values (fig. 3). The mean "actual" CEC 

is the average of the best estimate (type 4, 2, or 1 

CEC values, in that order, table 1) of the CEC of 

material actually within the size-class boundaries.

Calculation of the regression relation between log 

CEC and log D also allows estimation of a particle 

diameter for particles in size class 11. Entering the 

relation at a CEC value of 40.8, which is the average 

(table 1) for size class 11, indicates that the material in this class behaves as if it had a particle diameter of about 1.75^. All data for size class 11 are 

plotted as if the particle diameter in this class were 

1.75/i.

NITROGEN AND CARBON CONTENT

Results from nitrogen and carbon analyses of size 

separates from the Columbia River and tributaries 

are shown in tables 3, 4, and 5. The techniques used

for carbon and nitrogen analyses all determine total 

carbon or total nitrogen (both inorganic and organic) . In using factors to convert data on total carbon and total nitrogen to estimates of organic-matter 

content, it was assumed that all the carbon and (or) 

nitrogen came from organic matter. Data in Haushild, Perkins, Stevens, Dempster, and Glenn (1966, 

p. 75-79) suggest that this assumption results in 

little error for silt and clay size classes. For sand 

size classes, however, the error could be large; thus 

no conversion of total carbon to organic matter was 

attempted for size classes 1-6.

The use of factors to convert data on carbon and 

nitrogen content to estimates of organic-matter content has been discussed by Bader (1954, p. 709-710), 

who concluded that elemental concentrations should 

be reported. In this report, where a conversion was 

necessary, 8.1 was used to determine the percentage 

of carbon from the percentage of nitrogen, and 1.7 

(Buckman and Brady, 1960) was used to obtain the 

percentage of organic matter from the percentage 

of carbon. Use of 8.1 as the nitrogen-to-carbon factor
COLUMBIA RIVER SEDIMENTS M13

for relatively fine grained sediments appears reasonable from the available data (table 4). Visual inspection of organic material in these sediments indicates 

that it is chiefly brown and flakey or filamentous in 

appearance. In coarse-grained sediments, where 

much of the organic material is chips and splinters 

of wood, a factor of 8.1 may be unrealistic, but it is 

used in the absence of better information. The factor of 1.7, commonly used by soil scientists, is used 

here without experimental verification.

Nitrogen data (table 3) indicate increasing

amounts of nitrogen as particle size decreases. An 

increase on the order of three times occurs between 

size classes 8 and 9 and between 9 and 10. Comparison of data from size class 6 with data from size 

class 8 indicates relatively little change in nitrogen 

content in spite of the difference in particle sizes. For 

some samples, size class 6 appears to contain more 

nitrogen than does size class 8. No significant trends 

with sample location are apparent.

The distribution of nitrogen, hence organic material, in sized sediments may be a function not only

TABLE 3. Nitrogen data (in percent) for sediments in size classes from Columbia River and tributary

locations

[Nitrogen determined by the Kjeldahl-Gunning-Arnold method for solid samples. Size limits (in parentheses) given in microns]

Size class and limits

Location j> 

125)

Columbia River near : 

Pasco...........................................................

McNary Dam.. ...........................................

The Dalles.................................................. 0.04

Hood River.................................................

Bonneville Dam.........................................

St. Helens...................................................

Mean...................................................

Standard deviation............. ..............

Ilwaco1 ........................................................

Snake River near Pasco.. ............................

Willow Creek near Heppner Junction2..... 

Willamette River near Wilsonville............

6 (125- 

62)

0.03 

.04 

.05 

.06 

.04 

.04 

.04

.04 

.000

.04 

.04

7 8 

(62- (SI31) 16)

'.'.'.'. 0.04 

.04

'.'.'.'. .03

.04 

.001

.03'

9 

(16-4)

0.34 

.10 

.11 

.08 

.12 

.12 

.08

.14 

.008

.35 

.34

.10 

.14 

.14 

.14 

.08

10 

(4-2)

0.33 

.32

.44 

.35

.36 

.003

.45 

.41

11

0.67 

.41 

.41 

.42 

.51 

.45 

.28

.45 

.014

.38 

.33

'Results from analyses of two splits from a bed-sediment sample with a median diameter in the indicated size class. 

2Results from analyses of three splits from a suspended-sediment sample with a median diameter in the indicated size class.

of particle size but also of the methods of sample 

preparation. During the wet-sieving process by which 

coarse size classes were prepared, chips and splinters 

of wood accumulated in the coarsest (normally size 

class 1, 2, or 3) and finest (size class 6) sieve-size 

classes. Similarly, organic material, because of its 

low density, was concentrated in fine size classes 

during the decantation process by which the classes 

were separated.

Carbon and nitrogen data on splits from the same 

samples are shown in table 4. These data indicate a 

fairly high degree of analytical precision for both 

the Leco carbon analyzer (LEGO) and the wet-chemical method, but the wet-chemical method consistently gives higher carbon contents than the Leco 

analyzer. The lower values generally compare more 

favorably with values reported for size separates 

from other streams (Malcolm and Kennedy, 1970) 

and for sediments from oceanic environments adjacent to the Columbia River (Gross, 1969).

Results of carbon determinations on splits that

previously had been analyzed for CEC are shown in 

table 5. For many samples, an insufficient quantity 

of material was available (about 1 gram is desired), 

and the results are only approximate. In addition,

TABLE 4. Carbon and nitrogen data for sediments from 

Columbia River and tributary locations

[Carbon determined by LECO (Leco carbon analyzer) and by WCM (wetchemical method ; Van Hall and others, 1963) ]

Location

Columbia River near :

St. Helens.............................

Mean..................................

Size

11

11

19

....... 110

Percent 

carbon

(LECO)

2.7 

2.3 

3.2

3.3

(WCM)

3.33 

3.21 

3.54

4.41

CarbonPercent nitrogen 

nitrogen ratio 

(LECO)

0.41 

.28 

2.35 

2.34 2.45

2.41

6.6 

8.2 

9.1 

9.4 

7.3 

8.0

......8.1

Standard deviation..

Willow Creek near 

Heppner Junction.......

1.1

Willamette River near 

Wilsonville................... 11

21.2

21.3

3.1

3 1.35

31.35

3 1.39

4.73

3.14

3.14

3.14

8.6 

9.3

9.4

J See table 3.

2Results from analyses on two splits from the original sample.

"Results from analyses on three splits from the original sample.
M14 TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 5. Carbon data for samples analyzed for cation-exchange capacity

Location

Columbia River near : 

Pasco

McNary Dam............

The Dalles.................

Hood River..... ...........

Vancouver.. ...............

St. Helens....... ...........

Snake River near 

Pasco... ................. ........

Willamette River 

near Wilsonville... ......

Type of 

sample1

1

1

3 

3 

3 

3

5

1

3 

3 

3

3

1

1 

1 

3

1

1 

3

3

3

1

1 

3 

3 

3 

3 

3

1

3 

. 3

3 

5 

5

Size 

class

10 

2 

3 

5 

6 

3

11

4 

5 

6

6

9

10 

11 

6

10

11 

6

5

6

10

11 

3 

4 

5 

6 

10

10

6 

3

6 

3 

6

Weight 

(grams)

fi 7007

.2589 

.0548 

.0582 

.0542 

.2345 

.2118

.3703

.0213

.5668 

.1289 

.2908

.3578

.9573

.9583 

.9697 

.2316

.2431

.2087 

.2798

.1529

.2992 

.3252

.8686 

.0322 

.0086 

.0364 

.3620 

.0590

.4262

.2847 

.0533

.3242 

.0508 

.0229

Percent 

carbon

29 Q

.0 

2.8

13.2 

3.9 

1.9 

2.2

2,33.6

38.5.........

1.5

7.5 

5.1

3.8

21.0

1.6

22.8 

9.4

25.1

24.5 

7.9

7.3

6.7 

4.5 2,33.6 

5.4 

19.2 

13.2 

9.6 

.0

4.0

6.4 

17.2

4.1 

3.4 

5.4

Remarks

...... Complete

combustion 

questionable.

...... Woodchips.

J See table 1 for explanation of sample type.

2For comparison with nitrogen content in table 3, divide by 8.1.

3For comparison with carbon content of samples not analyzed for CEC, see table 4.

comparison of results from some of these splits with 

results from splits that had not been used for other 

analyses (table 3) suggests rather large differences; 

in general, splits analyzed after determination of 

CEC contain more carbon than splits that were not 

analyzed for CEC. The cause of the difference is 

unknown, but obvious possibilities include nonrepresentative splits and differential losses. A rather 

large carbon loss (18 percent) with time has 

been noted by N. F. Leibbrand (written commun., 

1967), who made carbon analyses of splits from 

streambed-sediment samples that were stored wet 

for a period of up to 1 year after collection. Similar 

losses were not noted when samples were dried and 

stored.

Carbon determinations (table 5) on splits that 

were first analyzed for CEC indicate that many type 

3 and 5 samples (table 1) contain large amounts of 

carbon. Visual inspection of these samples and petrographic analysis (see p. M34) of type 1 samples indicate that most of the carbon is associated with 

organic rather than inorganic material. The relation 

between carbon content and CEC of these samples, 

shown in figure 4, indicates that CEC increases as 

carbon content increases. There is a suggestion 

(fig. 4) that the CEC-carbon relation varies with 

particle size class.

MINERALOGY

CLAY (SIZE CLASS 11)

X-ray-diffraction patterns for clay (size class 11) 

from the Columbia River and major tributaries are 

shown in figures 5-7. For the Columbia River, patterns from only the uppermost (Pasco) and lowermost (St. Helens) sampling locations are shown; 

for intervening locations, the patterns are very similar.

Qualitative aspects of the mineralogy of clays are
COLUMBIA RIVER SEDIMENTS M15

50

g

oc ui ui °- 

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O ui

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o

Size 

class

a 3

06

I l i i I I

5 1O 20 

TOTAL CARBON, IN PERCENT

50

FIGURE 4. Relation of cation-exchange capacity and carbon content of 

type 3 samples.

evaluated by analysis of X-ray patterns from random powders and from oriented aggregates. Inspection of powder patterns (fig. 5E) indicates that 

quartz and feldspar are common constituents. The 

strongest feldspar peak occurs between 3.21 A and 

3.18 A, which indicates that plagioclase is more 

abundant than alkali feldspar. In silt size classes, 

where feldspar is relatively more abundant and 

peaks are better defined, peak positions indicate that 

plagioclase composition is variable but tends to be 

in the oligoclase to labradorite range. The alkalifeldspar peak, centered around 3.24 A, often appears 

as a shoulder or a short, sharp spike on the plagioclase peak in clay-size material; in silt size classes, 

the alkali-feldspar peak often is masked completely 

by the plagioclase peak. Although some microcline 

can be identified in some clay and silt samples, orthoclase appears to be the dominant alkali feldspar.

Clay minerals that are identified from X-ray patterns include montmorillonite, illite, chlorite, 

kaolinite, mixed-layer clays, and vermiculite. Clay 

minerals in powder patterns are indicated by peaks 

(fig. 5E) centered around 14 A or 12 A, 10 A, 7 A, 

4.44 A, 2.57 A, and 1.49 A. The position and characteristics of the initial peak (14 A or 12 A) depend 

on the type of clay and on how well the samples could 

be dispersed mechanically; for samples that did not 

disperse, such as the Snake and Willamette River 

samples (fig. 5E), the addition of a dispersant 

(5-percent chlorox) produced an initial powder-pattern peak at about 12 A, or a broad shoulder with 

many small peaks between 17 A and 10 A, if complete dispersion and sodium saturation were not 

attained.

The powder patterns (060 peaks at about 1.5 A) 

indicate that most clay minerals are dioctahedral 

aluminous varieties. The 14-A peaks in powder patterns and in traces from oriented aggregates (fig. 

5A-D) that consist of natural clay (untreated=undispersed) indicate that most montmorillonitic clays 

in Columbia River and tributary sediments are calcium-magnesium saturated. Chemical analyses (U.S. 

Geol. Survey, 1967, p. 25) show that about 75 percent of the common cations in Columbia River water 

(table 6) are calcium and magnesium.

TABLE 6. Unweighted mean concentration (in milligrams per liter) and standard deviation of the 

most abundant constituents in 12 samples of Columbia River water collected near McNary Dam 

during the period October 1965 through September 

1966

[From data in U.S. Geol. Survey, 1967, p. 25]

Chemical constituent

Silica (SiO2 ). .......................

Calcium (Ca) .......................

Magnesium (Mg) ................

Sodium (Na)

Bicarbonate (HCO3 ). .........

Carbonate (CO3 )..... ............

Sulfate (SO4 ) .......................

Chloride (Cl) .......................

Concentrs

Mean

........ 8.1

00

........ 5.9

........ 7.5

1 4

........ 89

........ 0

......... 19

......... 3.6

ition

Standard 

deviation

3.0

3 1

1.4

3.8

.58

16

0

5

2.1

Montmorillonite in well-dispersed samples of 

"natural" Columbia River clay shows a relatively 

sharp, slightly asymmetrical peak centered around 

14 A. Upon sodium saturation, the peak shifts to 

12 A where, in most samples, its appearance is much 

like that of the 14-A peak. A few samples, notably 

those from the tributary streams (fig. 5B and C), 

show broad and asymmetric 12-A peaks that appear 

to result, in part, from incomplete sodium saturation. When saturated with potassium (fig. 6), the 

14-A and (or) 12-A peak shifts toward 10 A, often 

with a considerable loss of intensity and symmetry.

Solvation with glycol (fig. 5A-D) and glycerol 

(fig. 7A-D) results in a montmorillonite peak shift 

to 17 A and 18 A, respectively. Although 8.5-A or 

9.0-A second-order montmorillonite peaks are present in most solvated samples, other higher-order 

peaks are rare or shifted from expected positions. 

The second-order peaks are not defined sharply regardless of the characteristics of the expanded 17-A 

or 18-A peaks. These attributes suggest that "montmorillonite," as identified both qualitatively and 

quantitatively in Columbia River and tributarystream sediments, may include some nonexpanding 

interlayer material.

Heat treatments for 1 hour at 300°C and 1 hour 

at 550 °C cause progressive collapse of the 17-A peak 

(fig. 5A-D) and concomitant increase in the 10-A
§' "a- 

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COLUMBIA RIVER SEDIMENTS M19

indicated by separation of the 002 kaolinite from the 

004chlorite (Biscaye, 1964).

Mixed-layer clays are indicated by broad low reflections between 10 A and 14 A in most samples and 

by incomplete collapse to 10 A in heated samples. 

Although it is difficult to be specific about mixedlayer clays, most patterns suggest that illite and 

chlorite, as well as montmorillonite, layers are present.

Although magnesium-saturated and glycerol-solvated samples (fig. 7) were prepared and analyzed 

specifically to aid in identification of vermiculite, 

positive identification of this mineral was limited to 

two samples that appeared to lack chlorite but still 

had a peak at about 14 A. This peak appears as a 

slight bump on the shoulder of the 18-A solvation 

peak; where chlorite is present, the 14-A peak is 

more sharply defined (fig. 7).

Estimates of the mineral composition of size class 

11 samples from Columbia River and tributary locations are shown in table 7, and the calculation procedure is illustrated in figure 5 for the Columbia 

River sample from the St. Helens location. In the 

absence of data on accuracy and precision, numbers 

have not been rounded. Schultz (1964, p. C14-C20) 

indicated that accuracy and reproducibility were 

±10 percent for components present in amounts 

greater than 15 percent; somewhat larger variations 

are very probable for the Columbia River samples.

Six estimates of the amount of total clay minerals 

in size class 11 samples are shown in table 7. The 

first three estimates (cols. 5-7) and their average 

(col. 8) depend on heights of nonbasal clay peaks 

at about 4.44 A, 2.57 A, and 1.49 A (fig. 5#) and on 

intensity factors. The estimate in column 9 is derived 

by recomputing (normalizing) the average (col. 8) 

of the percentages of clay minerals determined from

intensity factors so that the total of components in 

each sample is 100 percent rather than the values 

shown in column 11. The last estimate (col. 10) is 

derived by subtracting from 100 the percentages of 

identified non-clay-mineral components determined 

from intensity factors (quartz and feldspar) or from 

independent analyses (organic material). For the 

Columbia River samples, analyses of variance indicate that (1) the mean total clay-mineral content 

determined by averaging percentages estimated 

from intensity factors is significantly less than 

the mean total clay-mineral content determined 

by the difference method, and (2) the mean 

of the normalized total clay-mineral content is not 

significantly different from the mean of the total 

clay-mineral content determined by the difference 

method. These observations suggest that either the 

intensity factors used to determine total clay-mineral 

content are high or the sum of non-clay components 

is low. The presence of amorphous material, which 

has been noted (Kennedy, 1965, p. D14-D15) in 

sediments from a Columbia River tributary, or of 

other unidentified non-clay-mineral components 

could cause the latter effect.

If it is assumed that the intensity factors for nonclay minerals are correct and that the difference 

method gives the best answer for the percentage of 

total clay minerals, new intensity factors for Columbia River clays can be calculated by dividing the 

observed intensities at 4.44 A, 2.57 A, and 1.49 A by 

the percentage of total clay minerals that was determined by difference. These calculations suggest that, 

on the average, the intensity factors derived by 

Schultz for 4.44-A and 2.57-A clay peaks are about 

5 percent too high for Columbia River samples; the 

factor for the 1.49-A peak is about the correct magnitude.

TABLE 7. Composition (in percent) of size class 11 samples from Columbia River and tributary locations

Feldspar

Location Organic 

material 1

(1)

Columbia River near : 

Pasco........................

McNary Dam...... .

The Dalles...............

Hood River..............

Bonneville Dam...... 

Vancouver...............

St. Helens................

Snake River near

Willamette River 

near Wilsonville.. ........

9.2 

. 5.6 

5.6 

5.8 

. 7.0 

6.2 

3.9

5.2

. 4.5

Quartz

(2)

9.6 

5.8 

5.4 

5.2 

6.2 

5.5 

7.8

5.9 

4.7

Plagioclase

(3)

6.4 

5.6 

6.1 

5.8 

5.8 

6.7 

6.1

7.4 

5.8

Alkali 

(4)

4.6 

5.1 

5.5 

4.4 

4.3 

5.2 

4.4

4.6 

4.3

4.44-A 

peak

(5)

71.4 

66.9 

79.7 

72.9 

78.2 

72.0 

66.2

72.2 

69.9

2.57-A 

peak

(6)

68.7 

70.0 

66.2 

80.0 

78.8 

75.0 

73.8

65.0 

63.8

Total clay minerals

1.49-A 

peak

(7)

75.0 

62.5 

592.5 

77.5 

82.5 

5 62.5 

70.0

72.5

77.5

Average 

of 

columns 

5-7 

(8)

71.7

66.5 

72.9 

76.8 

79.8 

73.5 

70.0

69.9 

70.4

Normalized2 

(9)

70.6

75.1 

76.3 

78.4 

77.4 

75.7 

75.9

75.2

78.5

By 

difference3

(10)

70.2

77.9 

77.4 

78.8 

76.7 

76.4 

77.8

76.9 

80.7

TotaH 

(11)

101.5 

88.6 

95.5 

98.0 

103.1 

97.1 

92.2

93.0 

89.7

JBy conversion of data in table 3.

2Average value in column 8 adjusted so that the total of all components in each sample is 100.

3Difference between 100 and the sum of columns 1-4.

4Sum of columns 1-4 and 8.

Questionable value. Not used in average.
M20 TRANSPORT OF RADIONUCLIDES BY STREAMS

The total of components (clay minerals, non-clay 

minerals, and organic material) in the clay size class 

is shown in column 11, table 7. The average percentage of total clay minerals (col. 8) obtained from 

Schultz' intensity factors was used to compute the 

total of all components. A total computed by use of 

intensity factors has certain advantages (Schultz, 

1964, p. C5) in that high or low totals can indicate 

the presence of undetected components or inaccurate 

intensity factors. How close these totals are to 100 

is an indication of the reliability of the method. 

When the totals are much less than 100 (Schultz, 

1964, p. C5, considers the normal range to be 90 to 

105), the presence of amorphous material may be 

indicated.

Measurements and equations used to calculate relative amounts of five clay minerals in the Pierre 

Shale were discussed in detail by Schultz (1960, 

1964), and results of similar calculations for Columbia River and tributary sediments are shown in

table 8. The absolute mineralogy of clay-size materials is shown in table 9; the percentage of total 

clay minerals determined by the difference method 

(col. 10, table 7) was used rather than the percentage determined from intensity factors. Using the 

difference method makes the total of all components 

100 percent and facilitates comparisons among samples.

Results of calculations of the relative and absolute 

compositions of Columbia River samples are summarized in table 10. These data indicate that the 

clay-mineral suite consists of about equal amounts 

of illite, montmorillonite, and mixed-layer clays followed in average abundance by chlorite, plagioclase 

feldspar, and quartz, with small amounts of alkali 

feldspar and kaolinite. The Snake River clay-mineral suite does not appear to be greatly different 

from the Columbia River suite; the Willamette 

River suite, however, may contain more kaolinite 

and montmorillonite and less illite than the Columbia River suite.

TABLE 8. Relative percentages of five clay minerals in size class 11 samples from Columbia River and tributary locations

[a, standard Schultz ; b, modified Schultz]

Location

Columbia River near : 

Pasco... .............................

McNary Dam.. ......... .......

The Dalles.......................

Hood River......................

Bonneville Dam.. ........... .

Vancouver............... ........

St. Helens........................

Snake River near Pasco........

Willamette River near 

Wilsonville...........................

Chlorite

a

.... 16.4

.... 4.0

Q 1

Q n

.... 8.3

.... 4.4

.... 16.5

..... 1.6

.... 6.5

b

12.4 

3.6 

5.2 

6.7 

5.9 

4.2 

9.7 

1.9

7.2

Kaolinite

a

4.0 

9.0 -.2 

1.6 

2.3 

8.2 

1.8 

13.8

22.6

b

3.0 

9.4 

-.1 

1.2 

1.6 

7.6 

1.1 

16.3

25.4

Illite

a

44.4 

51.3 

32.2 

25.7 

32.7 

44.8 

26.0 

35.1

8.7

b

28.9 

48.4 

18.5 

18.8 

23.3 

42.1 

15.3 

51.1

9.8

Montmorillonite

a

27.4 

19.1 

37.2 

27.4 

27.8 

29.1 

54.2 

17.2

42.4

b

20.8 

17.5 

28.7 

26.4 

22.7 

26.8 

59.1 

27.6

45.6

Mixed layer

a

7.8 

15.7 

21.7 

36.3 

28.9 

13.5 

1.5 

32.3

19.8

b

34.9 

21.1 

47.7 

46.9 

46.5 

19.3 

14.8 

3.1

12.0

A comparison of the data from modifying the 

Schultz calculations to account for the stability of 

mixed-layer clays in Columbia River sediments indicates (table 10) that the effect of the modification 

is to increase the amount of mixed-layer clays, 

chiefly at the expense of illite and chlorite.

A summary of textural and compositional variations in clay-size materials from Columbia River 

and tributary sediments is shown in figure 8. These 

data demonstrate the complex interrelations that 

exist among mineralogy, CEC, organic matter, and 

particle size. The stronger relative relations are

TABLE 9. Absolute percentages of clay and non-clay minerals in size class 11 samples from Columbia River and tributary

locations

[a, standard Schultz ; b, modified Schultz]

Location

Columbia River near :

The Dalles.......................

St. Helens........................

Snake River near

Willamette River near 

Wilsonville.. ....................

Organic 

material 1

Q 9

5.6

5.6

5.8

7.0

fi 9

3.9

5.2 

4.5

Quartz

9.6 

5.8 

5.4 

5.2 

6.2 

5.5 

7.8

5.9

4.7

Feldspar

P1ca,!ir Alkali

6.4 

5.6 

6.1 

5.8 

5.8 

6.7 

6.1

7.4 

5.8

4.6 

5.1 

5.5 

4.4 

4.3 

5.2 

4.4

4.6 

4.3

Chlorite2

a

11.5 

3.3 

7.0 

7.1 

6.4 

3.4 

12.8

1.2 

5.2

b

8.7 

2.8 

4.0 

5.3 

4.5 

3.2 

7.5

1.5

5.8

Kaolinite2

a

2.8 

7.0 

 .1 

1.3 

1.8 

6.3 

1.4

10.6 

18.2

b

2.1 

7.3

__ 1

.9

1.2 

5.8 

.9

12.5 

20.5

Illite2

a

31.2 

40.2 

24.9 

20.2 

25.1 

34.2 

20.2

27.0 

7.0

b

20.3 

37.7 

14.3 

14.8 

17.9 

32.2 

11.9

39.3 

7.9

Montmorillonite2

a

19.2 

14.9 

28.8 

21.6 

21.3 

22.2 

42.2

13.2 

34.2

b

14.6 

13.6 

22.3 

20.8 

17.4 

20.5 

46.0

21.2 

36.8

Mixed layer2

a

5.5 

12.3 

16.8 

28.6 

22.1 

10.3 

1.2

24.9 

16.1

b

24.5 

16.3 

36.9 

37.0 

35.7 

14.7 

11.5

2.4 

9.7

TotaP

100 

100 

100 

100 

100 

100 

100

100 

100

ifiy conversion of data in table 3.

2 Relative percentages from table 8 multiplied by percent total clay from column 10 of table 7.

3Sum of the non-clay minerals plus the percentages of clay minerals from either "a" or "b."
COLUMBIA RIVER SEDIMENTS M21

TABLE 10. Average percentages of clay and non-clay minerals in size class 11 samples and in size class

10 samples from Columbia River locations

[Type of calculation: a, standard Schultz; b, modified Schultz]

Component

Illite...................................

Montmorillonite...............

Mixed layer... .................. .

Chlorite.............................

Kaolinite........ ...................

Plagioclase feldspar........

Quartz...............................

Alkali feldspar.................

Organic material.. ...........

Type of 

calculation

.............. .a.............

b.............

..............a

b.............

Q

b.............

.............. a

b.............

b.............

Range

Size 

class 11

... 20.2-40.2

... 11.9-37.7

.... 14.9-42.2

... 13.6-46.0

... 1.2-28.6

... 11.5-37.0

... 3.3-12.8

... 2.8-8.7

.... -.1-7.0

... -.1-7.3

... 5.6-6.7

.... 5.2-9.6

... 4.3-5.5

... 3.9-9.2

Size 

class 10

23.0-40.4 

17.7-35.0

12.1-24.4 

10.4-16.3

-5.5-22.6 

8.6-32.0

3.3-18.4 

3.0-10.4

.8-5.7 

.5-4.8

8.3-11.4 

9.9-18.9 

4.5-6.7 

.0-7.6

Mean

Size 

class 11

28.0 

21.3

24.3 

22.2

13.8 

25.2

7.4 

5.1

2.9 

2.6

6.1 

6.5

4.8 

6.2

Size 

class 10

30.5 

23.5

17.6 

13.6

8.3 

22.5

8.1 

5.7

3.6

2.8

10.0 

12.4 

5.0 

4.5

Standard deviation

Size 

class 11

7.4 

9.8

9.5 

11.7

9.5 

11.2

3.8 

2.3

2.6

2.8

.4 

1.6 

.5 

1.6

Size 

class 10

7.5 

6.1

4.0 

1.8

9.8 

9.1

4.9 

2.5

1.8 

1.5

1.3 

3.3 

.8 

2.6

those between total clay-mineral content and CEC, 

and between CEC and the percentage of montmorillonite. These relations appear to be improved somewhat when the percentage of total clay minerals is 

derived by the difference method and the percentage 

of montmorillonite is calculated by the modified 

Schultz method, which suggests that these methods 

give the best results. Organic material, which is calculated from nitrogen content in table 3, is relatively uniform among samples and does not appear 

to be related to differences in mineralogy or CEC. 

A relation between percentage less than 2/x and percentage of montmorillonite is suggested by the data.

Highly significant longitudinal trends in mineral 

abundance are not evident, although montmorillonite 

appears to increase (fig. 8) and quartz to decrease 

(table 9) downstream from the Pasco location. Differences in the abundance of some constituents between the Vancouver and St. Helens locations (fig. 

8 and table 9) may reflect contributions from the 

Willamette River. No significant mineralogic differences appear to be related to the Snake River.

The clay mineralogy of <2/* Columbia River sediments recently was discussed by Knebel, Kelley, and 

Whetten (1968). These authors, using a "construct" 

similar to that described on page M30, determined 

the relative amounts of montmorillonite, illite, and 

chlorite plus kaolinite. Their data are comparable to 

data presented here if the mixed-layer clay is considered as "montmorillonite." As is noted in a subsequent section, however, if mixed-layer clay is not 

identified, then mineralogy and CEC data tend to 

conflict. Knebel, Kelley, and Whetten (1968), along 

with Russell (1967), and Russell and Duncan (1968), 

indicated that very little kaolinite occurs in sediments of Columbia River origin. Knebel, Kelley, and 

Whetten (1968, p. 603-604) noted little difference 

in montmorillonite content between Pasco and Bonneville Dam, although samples from this reach contained more montmorillonite than samples from 

above Pasco.

SILT (SIZE CLASS 10)

Representative X-ray-diffraction patterns for size 

class 10 are shown in figures 9 and 10. Comparison 

of these patterns with those for the clay size class 

(figs. 5-7) indicates very little qualitative difference 

in mineralogy. Quantitatively, however, non-clay 

peaks are more intense and clay peaks are less intense in size class 10.

The Schultz method was used to obtain quantitative data (table 11) for size class 10. Comparison 

of the average total clay-mineral percentage obtained 

by intensity factors (col. 8, table 11) with the total 

clay-mineral percentage obtained by the difference 

method (col. 9, table 11) suggests that the two techniques give similar average results. The similar results between these techniques in class 10 contrast 

with the different results in class 11 (p. M19). One 

explanation for the difference might be more amorphous material in the finer size class.

Kennedy (1965, p. D16-D19) suggested a technique whereby data on CEC and quantitative X-ray 

mineralogy of clay-size material can be combined 

with data on CEC of silt-size material to yield an 

additional estimate of the total clay-mineral content 

of silt-size material. Estimates for Columbia River 

and tributary samples are shown in column 10, table 

11. These estimates are about 12 percent less than 

either the average intensity-factor values (col. 8, 

table 11) or the difference values (col. 9, table 11).
M22 TRANSPORT OF RADIONUCLIDES BY STREAMS

As particle size increases, quantitative differences 

in clay and non-clay minerals are expected. These 

differences between class 11 and class 10 affect one 

of the assumptions in the technique used to estimate

100

| 90

cc

C3 

§80

CC 

UJ

0.

70

Ul

5 60

o

Ul

5 50

Z

t ^

o *°

a.

U 

uj 30

X

X 20

ui

I

Z 

O

10

T

total clay minerals in the silt fraction from CEC 

data (Kennedy, 1965); namely, that the CEC of clay 

minerals in the clay fraction (class 11) is the same 

per unit weight as that of the clay minerals in the

____________I_________

Less than 2/x

Total clay by difference

Average total clay from

intensity factors 

"As received" cationexchange capacity

Arrows pointing to 

correct marginal scale

Relative montmorillonite 

(modified Schultz technique)

Montmorillonite (standard 

Schultz technique)

Montmorillonite (modified 

Schultz technique)

Organic matter

LOCATIONS

WR

BD 

I

HR 

I

TD

I

MD 

I

SR

100

90 -

_j

80 Z "j 

Ice

70 o -

Og 

60 ft

ii

50 H £

O in

40

30

20 =

< 

O 

CC

10 °

100

I I 

200 300 

DISTANCE FROM COLUMBIA RIVER MOUTH, IN MILES

FIGURE 8. Summary of textural and compositional variations in size class 11. Locations: P, Pasco; MD, McNary Dam; TD, The Dalles; HR, Hood 

River; BD, Bonneville Dam; V, Vancouver; SH, St. Helens; SR, Snake River; WR, Willamette River,
S.3 

Ig"

n n 

?»

i

« « S.Pa. <i 

l!

cj « 

II

g 5' 

IN INTENSITY, 

SECOND PER COUNTS 

,MM|IIM| II 

zero and Treatments 

levels intensity 

IN INTENSITY, 

SECOND PER COUNTS 

a

o

 o 

o

a

zero and Treatments 

levels intensity 

viawmoo
, S.3 P 

S « & <T» ^ _ 

3 H* cr 

I 85 

°

Q

W (0 11 S' 3 "' 

ra a <-j 

w re III

8 \- I 

si I 

ft) n 

fl

IN INTENSITY, 

SECOND PER COUNTS 

^d-g 

I ? 

ci i? 

'§ o. 

x- 7 

1C C C! 

'Ul

zero and Treatments 

levels intensity 

IN INTENSITY, 

SECOND PER COUNTS 

iiliiiiiiiii

Q. 

0

3

 o

zero and Treatments 

levels intensity 

IHOJSNVHI, saanonNOiavH AS swvaHis 
COLUMBIA RIVER SEDIMENTS M25

TABLE 11. Composition (in percent) of size class 10 samples from Columbia River and tributary locations

Feldspar

Location

Columbia River near :

THua l~)a)10Q

St. Helens......................

Willamette River near 

Wilsonville.........................

Organic 

material1

(1)

...... 4Q.O

...... 4.5

4 4

...... 2.7

7 1

....... 4.8

...... 7.6

...... 6.8

...... (6)

Quartz 

(2)

14.7 

11.6 

9.9 

10.7 

10.8 

10.1 

18.9 

10.9

10.4

Plagioclase

(3)

8.3 

9.2 

10.0 

10.8 

8.6 

11.4 

11.4 

8.8

9.9

Alkali 

(4)

4.6 

5.0 

4.8 

4.5 

4.9 

6.7 

4.6 

5.2

4.1

4.44-A 

peak

(5)

60.2 

77.4 

69.2 

66.9 

69.9 

66.9 

53.4 

57.9

58.6

2.57-A 

peak

(6)

67.5 

82.5 

71.2 

70.0 

86.2 

68.8 

72.5 

65.0

62.5

Total clay minerals

1.49- A 

peak

(7)

452.5 

460.0 

467.5 

"80.0 

92.5 

75.0 

65.0 

57.5

62.5

Average 

of 

columns

5-7 

(8)

63.8 

80.0 

70.2 

68.4 

82.9 

70.2 

63.6 

60.1

61.2

By 

difference2

(9)

72.4 

69.7 

70.9 

71.3 

68.4 

67.0 

57.5 

68.3

675.6

From 

CEC

(10)

44.7 

55.1 

55.7 

62.0 

59.1 

53.8 

63.8 

48.4

62.1

Total3 

(11)

91.4 

110.3 

99.3 

97.1 

114.5 

103.2 

106.1 

91.8

685.6

JBy conversion of data in table 3 or 5.

2Difference between 100 and the sum of columns 1 4.

3Sum of columns 1-4 and 8.

Questionable value. Not used in average.

5Insufficient sample to fill regular sample holder. Values for non-clay minerals are probably about 10 percent low; values for clay minerals appear high.

6No organic-material data available.

silt fraction (Kennedy, 1965, p. D16). The differences in clay-mineral composition in class 10 are 

such that an approximation of the magnitude of the 

difference, using the average amounts of clay minerals (table 10) and an assumed CEC (see fourth 

paragraph below) for the clay minerals, indicates 

about a 20-percent decrease in CEC per unit weight 

between class 11 and class 10. The 12-percent discrepancy between total clay-mineral estimates from 

intensity factors and estimates from CEC data is 

lessened appreciably if the CEC of class 10 material 

is increased by 20 percent.

Except for two samples, the total of all known or 

estimated components (col. 11, table 11) is within

the range (90-105 percent) found by Schultz, which 

suggests that the intensity-factor method is satisfactory. The high calculated totals for the samples 

from McNary Dam and Bonneville Dam locations 

may have resulted from having insufficient sample 

for the standard sample holder; as a result, a smaller 

holder was used. Results from analyses of two samples using the small as well as the large holder 

indicated that nonclay minerals consistently are 

underestimated and clay minerals generally are overestimated when the sample is mounted in the small 

holder.

The absolute mineralogy of size class 10 samples 

's shown in table 12 and is summarized in table 10.

TABLE 12. Absolute percentages of clay and non-clay minerals in size class 10 samples from Columbia River and tributary

loc -'.tions

[a, standard Schultz ; b, modified Schultz]

Location

Columbia River near :

The Dalles........................

Snake River near Pasco....... 

Willamette River near 

Wilsonville........ ....................

££&

0.0 

4.5 

4.4 

2.7 

7.3 

4.8 

7.6 

6.8

Quartz

14.7 

11.6 

9.9 

10.7 

10.8 

10.1 

18.9 

10.9

10.4

Feldspar

Plagioclase

8.3 

9.2 

10.0 

10.8 

8.6 

11.4 

11.4 

8.8

9.9

Alkali

4.6 

5.0 

4.8 

4.5 

4.9 

6.7 

4.6 

5.2

4.1

Chlorite2

a

18.4 

7.6 

5.0 

6.6 

6.3 

3.3 

9.4 

4.8

8.2

b

10.4 

5.3 

3.8 

4.3 

5.8 

3.0 

7.5 

4.0

6.6

Kaolinite2

a

5.7 

2.4 

2.4 

.8 

5.2 

4.2 

4.7 

6.5

6.9

b

3.2 

1.7 

1.9 

.5 

4.8 

3.8 

3.7 

5.5

5.5

Illite2

a

26.1 

37.4 

23.0 

40.4 

37.5 

24.8 

24.5 

39.0

b

17.7 

26.1 

18.0 

25.8 

35.0 

22.6 

19.4 

33.2

9.1

Montmorillonite2

a

16.6 

14.6 

20.2 

16.7 

18.0 

12.1 

24.4 

10.4

44.1

b

14.0 

12.8 

14.3 

13.3 

14.2 

10.4 

16.3 

8.4

39.6

Mixed layer2

a

5.6 

7.7 

19.4 

6.8 

1.4 

22.6 

 5.5 

7.6

5.1

b

27.1 

23.8 

32.0 

27.4 

8.6 

27.2 

10.6 

17.2

14.8

TotaP

100 

100 

100 

100 

100 

100 

100 

100

100

JBy conversion of data in table 3 or 5.

2Relative amounts determined as for size class 11 multiplied by percent total clay from column 9 of table 11.

3Sum of the non-clay minerals plus the percentages of clay minerals from either "a" or "b."

4Insufficient sample to fill regular sample holder. Values for non-clay minerals are probably about 10 percent low; values for clay minerals appear high.

5 No organic-material data available.

Comparing these data with data for size class 11 

(tables 9 and 10) shows that quartz, feldspar, illite, 

chlorite, and kaolinite are more abundant and montmorillonite and mixed-layer clays are less abundant 

in the fine-silt size. As in size class 11, the modified 

Schultz as compared with the standard Schultz calculations result in higher mixed-layer-clay percentages and in lower percentages of other minerals, 

chiefly illite. Also, as in size class 11, the Snake 

River mineral suite appears to be nearly the same

as that in the Columbia River, whereas the Willamette River mineral suite appears to contain less 

illite and more montmorillonite than does the Columbia River suite.

Relations among CEC, mineralogy, and organic 

content in size class 10 are indicated in figure 11. 

In general, the same relations that were noted for 

size class 11 can be seen for size class 10.

If certain assumptions are made, CEC and mineralogy data can be combined to test their mutual
M26 TRANSPORT OF RADIONUCLIDES BY STREAMS

compatibility. The necessary assumptions are: 

(1) CEC values of quartz and feldspar are insignificant relative to those of organic material and clay 

minerals; and (2) CEC values of kaolinite, illite, 

chlorite, montmorillonite, and organic material are 

8, 30, 30, 100, and 100 meq per 100 g, respectively. 

Because quartz and feldspar are present in relatively small amounts in clay and fine-silt separates, 

the first assumption probably introduces no serious 

error. Although the CEC values of clay minerals

vary (Grim, 1953, p. 129), the assumed values probably are of the correct relative magnitude (Buckman 

and Brady, 1960, p. 93). The CEC value of 100 for 

organic material is based on the observation that the 

organic matter is not strongly altered to humuslike 

material. Malcolm and Kennedy (1970, p. 158) reported a CEC of 94 meq per 100 g for somewhat 

similar organic materials that also were obtained 

from sized river sediments. However, the extremely 

variable nature of organic material (Buckman and

100

g so

o 

o

1

UJ

< 60

50

40

30

20

10

Total clay by difference 

Average total clay from intensity factors 

O O Total clay from cation-exchange capacity 

"As received" cation exchange capacity 

Montmorillonite (standard Schultz technique) 

Organic matter 

Arrows pointing to appropriate marginal scale

WR

SH | V 

I I

LOCATIONS

BD

1

HR

I

TD

I

MD 

I

SR

100

UJ

80 CC

UJ 

Q.

70 jj

CJ

60

50

40

30

20

10

I 

100 200 

DISTANCE FROM COLUMBIA RIVER MOUTH, IN MILES

300

FIGURE 11. Summary of compositional variations in size class 10. Locations: P, Pasco; Md, McNary Dam; TD, The Dalles; HR, Hood River; BD, 

Bonneville Dam; V, Vancouver; SH, St. Helens; SR, Snake River; WR, Willamette River.
COLUMBIA RIVER SEDIMENTS M27

Brady, 1960, p. 143), the resulting large differences 

in CEC, and the indirect method of determining the 

organic-matter content indicate that considerable 

error may arise from assumptions involving organic 

material.

The test procedure involves determining the difference between the "as received" CEC (table 1) 

and a CEC calculated by summing the products of

(1) the percentages of the individual clay minerals 

times the assumed CEC values of the minerals, and

(2) the percentage of organic material (tables 9 

and 12) times the assumed CEC value of organic 

material. Dividing the difference by the percentage 

of mixed-layer clays (tables 9 and 12) in a sample 

yields an estimate of the CEC of the mixed-layer 

clays. Because the mixed-layer clay appears to be 

mostly illite and chlorite with some montmorillonite 

(p. M19), this estimate should range around 30 meq 

per 100 g. If much higher or much lower values are 

calculated, either (1) mineralogy and CEC data are 

incompatible or (2) a basic assumption is incorrect. 

Mixed-layer-clay CEC values that are reasonable 

can be computed for most size class 10 and 11 samples. In general, the mineral abundance estimates 

from the modified Schultz calculations give higher 

and perhaps more reasonable estimates of mixedlayer-clay CEC. At Pasco and St. Helens locations, 

computed mixed-layer-clay CEC values are low, and 

at McNary Dam location, the computed CEC values 

seem to be high. Although there is no way to determine exactly where the error(s) lie, at both Pasco 

and St. Helens, CEC values (table 1) are below average; at St. Helens and McNary Dam locations, the 

percentage of montmorillonite (tables 9 and 12) 

also may be in error. Visual inspection of the oriented aggregate for St. Helens location suggests that 

the aggregate is especially thin, a condition which 

Schultz (1964, p. C12) indicated can result in overestimation of montmorillonite abundance. A particularly thick oriented aggregate from McNary Dam 

location could cause the computed low percentage of 

montmorillonite (table 9), which, in turn, could result in computed CEC values for mixed-layer clays 

that appear high. For those samples that appeared 

to give reasonable CEC values for mixed-layer clays, 

the values ranged from 14 to 40 meq per 100 g and 

averaged about 25 meq per 100 g. These CEC values 

suggest that illite and chlorite layers are abundant 

in the mixed-layer component.

SILT (SIZE CLASSES 7, 8, AND 9)

Representative X-ray-diffraction patterns for size 

classes 7, 8, and 9 are shown in figure 12. Inspection 

of the powder patterns and comparison of the powder patterns with those for size classes 10 and 11 

indicate both qualitative and quantitative mineralogic differences. Probably the most conspicuous 

additional peak that is not a quartz or feldspar peak 

is centered around 8.4 A. This peak and a peak at 

2.82 A indicate the presence of amphibole-group mineral (s) (Biscaye, 1965, p. 807). Hornblende and 

pyroxene-group minerals have been identified (Whetten and others, 1969, p. 1160; Kulm and others, 

1968; Glenn, 1965; also table 19 of this report) as 

abundant constituents in Columbia River sands, and 

their presence in silt size classes is to be expected.

Quantitative estimates of the composition of size 

classes 7, 8 and 9 are shown in table 13. These estimates were derived from intensity factors that had 

been used previously for non-clay minerals and from 

an intensity factor (127) slightly lower than had 

been employed previously for total clay minerals. 

The factor of 127 was used because data presented 

for size class 11 samples (p. M19 of this report) indicate that Schultz' factors for total clay minerals 

were about 5 percent too high for these samples. 

Small peaks, and in some cases, interfering peaks 

from non-clay minerals, prevented determination of 

an average total clay content from peaks at 4.44 A, 

2.57 A, and 1.49 A; thus, total clay was estimated 

from the intensity of only the 4.44-A peak. A total 

clay content determined by the difference method is 

not valid for size classes 7, 8, and 9 for two reasons: 

(1) Strong plagioclase-feldspar peaks generally tend 

to mask the desired alkali-feldspar peak, and no consistent quantitative relation could be established 

with any other feldspar peak; and (2) other nonclay minerals, such as amphibole-group minerals, 

cannot be evaluated quantitatively.

If the total of known components (quartz, plagioclase, total clay, and organic materials) is subtracted 

from 100, the result is an estimate of the percentage 

of unidentified minerals; the result also is an indicator of the reliability of the analyses. If the difference is negative and if peaks for alkali feldspar and 

(or) amphibole are present, then the abundance of 

some component (s) is overestimated. Although some 

low differences and a negative value (table 13) were 

calculated for some samples that contained amphibole and alkali feldspar, most samples gave apparently realistic differences.

A second and perhaps better indication of the 

relative reliability of quantitative data for quartz 

and plagioclase is gained by plotting the abundances 

of these minerals for each size class at each location 

(fig. 13). These plots indicate, in general, that the 

same relative differences between locations frequently occur in all size classes. The same relative
A. Oriented aggregates, size class 7

tpS tzo WDO

111 ~« ^ «

r 100

1. Potassium saturated

7 A 1QA 17 A 

14 A = 0-5

H ~ 

\500°

v \soq°

\ 110°

20, IN DEGREES 

14 10 6

\550°

\3oq°

\ Gly

B. Oriented aggregates, size class 8

Oco° inn 1. Potassium saturated

>{2z ~ 100

tzO : 7,A 10.A 14,A

Z3Z--50 17 A

isSsE .1 , A i !

ZZuj^o 

 o. - 

C. Oriented aggreg

14

2(9, IN DEGREES 

10 6

1200 cps

D. Powder patterns, size classes 7, 8, and 9

10 

26. IN DEGREES

62 _58_ 54

i

_50_ 46 42

i

38 34 30

i

26

i

22 18

i

14

i

10

_i_

FIGURE 12. Representative X-ray patterns of size class 7, 8, and 9 samples from Columbia River near Bonneville Dam. Treatments : AD, air dried; Gly, s

at 110° C for 1 hour; 300°, heated at 300° C for 1 hour; 550°, heated at 550° C for 1 hour.
ABUNDANCE, IN PERCENT ABUNDANCE, IN PERCENT

O 2.

SI

W 3 g- 51- a "

 «. »

3 t-1 ^

M

O .
M30 TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 13. Composition (in percent) of size class 7, 8, and 9 samples from Columbia River and tributary locations

[Leaders (....) indicate no data]

Clay minerals

Location

Columbia River near: 

Pasco..............................

McNary Dam................

The Dalles...... ...............

Hood River....................

Bonneville Dam............

Vancouver......................

St. Helens......................

Snake River near Pasco......

Willamette River near 

Wilsonville................. ........

Size

class

... 7.....

8....

9....

.. 7....

8....

9....

... 7....

8....

9....

... 7....

8....

q

... 7.....

8....

9....

7

8....

9.....

... 7.....

8....

9....

.. 7.....

8.....

9....

7

8....

9....

Organic 

material 1

(1)

/4\

.... 5

.... (4)

.... 0

.... 1

.... 0

.... 2

/4\

.... 1

.-. ( 4 )

.... 2

... 0

... 2

( 4 )

.... 1

/4\

... 1

-- ( 4 )

1

Quartz 

(2)

43 

41 

21

47 

43

27

34 

26 

23

39 

30 

20

45 

45 

19

30 

35 

19

44 

41 

32

41 

35 

21

23

26 

17

Plagioclase 

(3)

27 

22 

12

34 

33 

19

36 

28 

22

38 

36 

21

33

29 

16

36 

35 

21

30 

28 

21

25 

23 

18

29 

33 

18

Total clay2 

(4)

12 

20 

55

16 

26 

43

16 

20 

43

12 

28 

41

13 

21 

41

9 

21 

43

21 

17 

37

16 

20 

41

21 

37

45

Other 

minerals 1 

(5)

18 

17

7

3

-2 

10

14 

26 

10

11 

6 

17

9 

5 

22

25 

9 

15

5 

14 

9

18 

22 

19

27 

4 

19

Montmorillonite

3 Relative 

(6)

10 

16 

19

20 

21 

32

12

20

15 

21 

30

27 

29 

30

28 

37 

49

22 

28 

29

58 

73

Absolute 

(7)

2

4 

8

3

4 

14

1 

6

2 

4 

12

2 

6 

13

6 

6 

18

3

6 

12

21 

33

Illite Kaolinite + Chlorite

Relative 

(8)

64 

70

68

67 

66 

54

72 

65

71 

67 

59

55

58 

61

55 

44 

37

67 

62 

58

40

27

Absolute 

(9)

10 

18

29

11 

13 

23

9 

18

9 

14 

24

5 

12 

26

12 

8 

14

11 

12 

24

15 

12

Relative 

(10)

26 

14

13

13 

13 

14

16 

15

14 

12 

11

18 

13 

9

17 

19 

14

11 

10 

13

2 

0

Absolute 

(11)

4 

4 

6

2 

3 

6

2 

-4

2 

3 

5

2 

3 

4

3 

3

5

2 

2 

5

1

0

a By conversion of data in table 5. Rounded to nearest percent.

2Calculated by using only the 4.44-A peak height and an intensity factor equal to 127.

3Calculated from 100 minus the sum of columns 1-4.

4Not analyzed. Organic content probably very low.

differences should occur if quartz and feldspar at 

all locations were derived from the same primary 

source or from primary sources in which quartz and 

feldspar have similar particle-size distributions. For 

quartz, in particular, the primary source or sources 

seem to be mostly in the upper Columbia River basin 

or in deposits originally derived from the upper 

Columbia River basin (Haushild and others, 1966, 

p. 60-61). Hence, quantitative data for quartz in all 

size classes would be expected to show the same 

relative differences between locations.

Clay minerals (fig. 12) in size classes 7, 8, and 9 

consist chiefly of an expandable 14-A component 

(montmorillonite), a 10-A component (illite), and 

a 7-A component (kaolinite and chlorite). Mixedlayer clays, such as were identified in size classes 10 

and 11, are not as common in 7, 8, and 9 sizes; and 

where present, the clays do not have the thermal 

stability that was noted in 10 and 11 sizes. Montmorillonite, which collapses in potassium-saturated 

samples only after heat treatments in size classes 10 

and 11, collapses more readily in size classes 7, 8,

and 9. However, its collapsed spacing is slightly 

greater than 10 A, and the peak height is not greatly 

different from the 10-A peak height due to illite 

alone. The occurrence of a 7-A peak in some samples 

that lack any 14-A peak after heating to 550°C indicates that kaolinite is present. In a few other samples, 7-A peaks remained and the 14-A peaks were 

accentuated after heating to 550°C; this suggests 

that chlorite composition may be slightly different 

in coarse-silt sizes than in clay sizes.

Calculations of relative amounts of clay minerals 

in 7, 8, and 9 sizes by the Schultz technique give 

results that indicate that peak areas and heights cannot be measured accurately or with sufficient precision to permit use of the Schultz relations. In 

general, and particularly for size classes 7 and 8, 

in which all peaks are very small, the relative 

amount of illite is overestimated, and in many cases 

illite is computed to represent more than 100 percent of a sample.

Because the Schultz technique gave unreasonable 

results, relative amounts of illite, montmorillonite,
COLUMBIA RIVER SEDIMENTS M31

kaolinite plus chlorite the most abundant clay minerals in size classes 7, 8, and 9 were estimated by 

means of a "construct" described by Biscaye (1965, 

p. 808-809) and similar to that of Johns, Grim, and 

Brindley (1954). The procedure consists of weighting and summing peak areas as follows: For montmorillonite, one times the 17-A glycol peak area; for 

illite, four times the 10-A glycol; and for chlorite 

plus kaolinite, two times the 7-A glycol. The weighting factors (Johns and others, 1954; Weaver, 1961, 

p. 149) permit a direct comparison between relative 

amounts of these clay minerals. To obtain the relative amount of each mineral, the weighted peak area 

of each mineral is divided by the sum of the weighted 

peak areas.

For some samples, the relative amounts of each 

mineral determined by both the "construct" and 

the Schultz method were compared. This comparison 

indicated that both methods give nearly the same 

ratio of kaolinite-plus-chlorite: illite: montmorillonite, even though the Schultz relations often indicated that more than 100 percent of a sample was 

ilh'te. For size classes 10 and 11, however, the "construct" results in percentages of montmorillonite 

that are incompatible with other data, notably CEC 

data. This incompatibility results from the substantial amount of mixed-layer clay in these classes.

An estimate of the absolute amount of each clay 

mineral in size classes 7, 8, and 9 is obtained by 

multiplying the percentage of total clay minerals 

(column 4, table 13) by the relative amount. Both 

the relative and absolute amounts indicate that illite 

is the dominant clay mineral. There is some indication that the relative amounts of illite and of kaolinite plus chlorite are higher in coarser silt as 

compared with finer silt and clay, whereas the relative amount of montmorillonite is lower. Muscovite 

occurs in substantial amounts in Columbia River 

sands; therefore, a relatively large 10-A component 

is expected in coarser silt as compared with finer 

sizes. In terms of absolute amounts, however, all 

clay minerals decrease with increasing particle size 

because the total clay-mineral content decreases 

markedly.

DISCUSSION: QUANTITATIVE X-RAY MINERALOGY

As has been indicated previously, the peak intensity, and hence the computed relative abundance, of 

a mineral is not solely dependent on the amount of 

a mineral that is present in a sample. The available 

data can be used to examine two possible effects 

particle-size differences and mineral interferences 

on intensity determinations and abundance estimates.

The average 1.82-A quartz-peak intensities for size 

classes 9-11 from Columbia River locations are 

plotted against the geometric mean particle diameter 

of each class in figure 14 along with similar data 

from Gordon and Harris (1955, 1956) as cited in 

Brown (1961, p. 506-507). Gordon and Harris' data 

show the effect on the 1.82-A quartz-peak intensity 

when only particle size is changed. A comparison of 

their data with data for Columbia River size classes 

suggests that the increase in 1.82-A intensity between size class 11 and size class 9 may not reflect 

solely increasing amounts of quartz. In fact, because 

the slope of the Columbia River data is not greatly 

different from the slope of Gordon and Harris' data, 

the reported increase in quartz could be due to a 

change in particle size alone. For size classes 7 and 

8, the relation of intensity to particle diameter cannot be established directly because the sediments were 

ground (see "Analytical Procedures") prior to X-ray 

analyses. If the diameters of the mechanically

140 i i i i i i i i r 11 i i i r ] r

O From Brown (1961, p. 507)

 Average for Colurribia River sediments in 

indicated size class

100 10 5 

PARTICLE DIAMETER, IN MICRONS

FIGURE 14. Relation between particle diameter and 1.82-A quartz-peak 

intensity. Numbers adjacent to Columbia River data points are size-class 

numbers.
M32 TRANSPORT OF RADIONUCLIDES BY STREAMS

ground 7 and 8 sizes are not significantly different 

from the geometric mean particle diameter of size 

class 9, which is reasonable when grinding times and 

conditions are considered, then the increase in intensity in classes 7 and 8 probably reflects increasing 

amounts of quartz.

The second effect, that of mineral interferences, 

relates to the use of the 3.34-A quartz-peak intensity 

as an indication of quartz abundance. Because of the 

large amount of 10-A clay minerals in Columbia 

River sediments, a strong 003 reflection from these 

clay minerals could contribute significantly to a

(GROUND,

_* _

§

NC

<z

(DO 80 

mU

irill

I*

iuO 

1-040

Sz

Ul

a- 20

r*

n

i i i i i i i i i i i i 

Locations 

° Pasco 

 McNary Dam 

A The Dalles g 

* Hood River 

a Bonneville Dam 

 Vancouver 

v St. Helens D 

*8 08 -

ft *" - .11 -8

.11 og g

11° v £*io Oio «9

A 1l" °10 10v°| »7 va? -

v9 o ? 7

i i i i i i i i i i i i

0 200 400 600 800 1000 1200

3.34-A PEAK INTENSITY ABOVE BACKGROUND, 

IN COUNTS PER SECOND

FIGURE 15. Plot of 10-A peak intensity versus 3.34-A peak intensity for 

random powders of samples from Columbia River locations. Numbers 

adjacent to data points are size-class numbers.

3.34-A peak, particularly if a completely random 

orientation was not attained in powder mounts. Because these clay minerals have only weak or very 

weak (Brown, 1961, p. 238-239) reflections in the 

1.82-A region, the 1.82-A peak and the 4.26-A peak 

have been used (Biscaye, 1965, p. 807) to estimate 

the abundance of quartz.

A plot of 3.34-A peak intensity versus 10-A peak 

intensity in powder patterns from Columbia River 

locations is shown in figure 15. These data indicate 

that no highly significant relation exists between 

these intensities either among particle size classes 

from a single location or among particle size classes 

regardless of location. The absence of a significant 

correlation suggests that the intensity of the 003 

reflection from 10-A components does not affect significantly the 3.34-A intensity from quartz.

SAND (SIZE CLASSES 2-6) AND GRAVEL (SIZE CLASS 1) 

By R. 0. VAN ATTA

The availability of sand and gravel size classes 

and the type of analysis on each class are indicated 

in table 14. Generally, precise quantitative and qualitative examinations were limited to the three finest 

sand size classes; however, thin sections and loose 

grains from all available size classes were examined 

with binocular and petrographic microscopes, and 

some estimates of the identity and abundance of 

constituents were made.

Determination of relative abundance of components in the three finest sand classes was made by 

point counting the constituents in thin sections. The 

method of preparing thin sections of these size 

classes generally left so little void space that point 

counting was acceptable. An automatic point counter

TABLE 15. Composition (in percent) of size class 4, 5, and

[Numbers under locations are size classes. Type of percent:

Component

Rock fragments... .....................................

Volcanic.............................................

Sedimentary......................................

Metamorphic................. ............. .......

Felsic....... ............................... ............

Glassy.. ....... .............................. .........

Altered1 ............................... ............ ..

Feldspars..................................................

Plagioclase. .......................................

Potash................................................

Altered1 ..... ........................................

Silica group...............................................

Glass...... .....................................................

Heavy minerals........................................

Maturity index3 .......................................

Type of 

percent

A

................................. B

................................. B

................................. B

........... .. .... .. B

................................. B

A

................................. A

................................. A

................................. B

................................. A

................................. A

................................. A

................................. C

4

39 

49 

29 

15 

6 

1 

11

27 

67 

33 

48

30 

3 

1

...0.45

Pasco

5

37

~~6

34 

62 

38 

39

22 

6 

1

0.31

Snake River

6

25 

26

73

27

27 

21 

1 

25

0.53

4

46 

48 

31 

6 

3 

12 

13

20 

40 

60 

40

26 

3 

5

0.39

5

43

is"

23 

65 

35

28

26 

5 

3

0.39

6

34

23 

70 

30

23 

16 

4 

12

0.40

McNary Dam

4

49 

59 

21 

6

13 

2 

8

15 

73

27 

40

27 

4 

5

0.42

5

31

15

31 

58 

42 

31

27 

9 

2

0.44

6

28

33 

73

27

20 

17 

2 

11

0.33

1 Percentage of altered grains within the component.

2Glass included as part of the rock-fragment component for this sample only.

3Ratio of silica group (stable components) to rock fragments, feldspar, and glass (unstable components).
COLUMBIA RIVER SEDIMENTS M33

TABLE 14. Types of analyses performed on size class 1-6 samples from Columbia River and tributary

locations

[Types of analyses: A, point count; B, altered feldspar; C, altered rock fragments; D, heavy minerals; E, qualitative]

Size 

class

1............

2............

3............

4............

5............

6............

Types of 

analyses

E..............

E..............

E..............

A..............

B..............

C..............

A..............

B..............

C..............

A..............

B..............

D..............

Pasco

X

. C 1 )

X

X

X

X

X

X

. X

X

. X

X

Snake 

River

C 1 )

7

X

X

X

X

X

X

X

(2 )

X

McNary 

Dam

C 1 )

C 1 )

X

X

X

X

X

X

X

X

( 2 )

X

The 

Dalles

C 1 )

C 1 )

C 1 )

X

( 2 )

X

X

X

X

X

( 2 )

X

Hood 

River

X

X

X

X

<!>X

X

X

X

X

( 2 )

X

Bonneville 

Dam

X

X

X

X

( 2 )

X

X

X

X

X

( 2 )

X

Vancouver

X

X

X

X

( 2 )

X

X

X

X

X

( 2 )

X

Willamette 

River

X

X

X

X

( 2 )

X

X

X

X

X

( 2 )

X

St. 

Helens

X

X

X

X

X

X

X

X

X

X

X

( 2 )

>No sample available from this location. 

2Sample available but not analyzed.

was utilized, and traverses were spaced to provide 

complete coverage of the thin section when 500 

points were counted. In four thin sections, counts of 

500 points were compared with counts of 1,000 

points; percentages varied no more than a few tenths 

of a percent, so counting 500 points each for all thin 

sections appeared reasonable. Percentages determined from point counts are volume percentages, 

and no effort was made to convert them to weight 

percentages.

The degree to which grains are altered is one of 

the mineralogic aspects that undoubtedly affects the 

quantity of radionuclides sorbed by sand and gravel. 

Special grain counts were made of altered and unaltered feldspars and of altered and unaltered rock 

fragments in some size classes (table 14). Feldspar 

and rock-fragment grains were counted as unaltered 

if less than one-third and one-half, respectively, of 

a grain were clouded or obscured with alteration 

products. The use of one-third and one-half, rather

6 samples from Columbia River and tributary locations

A, by volume; B, by number; C, by weight. Tr.( trace]

than some other proportions, represents an arbitrary 

decision that significant differences in radionuclide 

content might exist if the degree of alteration were 

greater than these proportions. Only grains in size 

classes 4 and 5, where both feldspars and rock fragments are abundant, were inspected for degree of 

alteration.

Staining techniques (Gabriel and Cox, 1929; 

Rosenblum, 1956) were used to determine plagioclase and potash feldspar in size classes 4, 5, and 6. 

Heavy-mineral separations, using tetrabromoethane 

(specific gravity 2.95 at 20°C), were made on size 

class 6 sediment, and the relative abundance of heavy 

minerals was determined by grain counts or was 

estimated by inspection of grain mounts.

Qualitative and quantitative mineralogic data for 

the three finest sand size classes are shown in table 

15. Six major components were identified, and their 

volumetric abundance was determined. The component "rock fragments" includes all polymineralic

The Dalles

4

46

59

13

6

9

13

11

24

75

25

20

10 ( 2 )

0.29

5

37

20

29

72

28

16

17

9

8

0.26

6

36

20

80

20

15

24

5

20

0.27

Hood River

4

47

78

8

3

6

5

16

23

43

57

24

4

2

0.34

5

36

17

26

77

23

16

28

8

2

0.45

6

44

20

80

20

12

22

2

23

0.19

Bonneville Dam

4

46

63

7

22

6

2

12

24

46

54

27

2

1

0.39

5

42

14

21

62

38

21

24

12

1

0.38

6

30

20

65

35

18

24

8

17

0.36

Vancouver

4

58

20

17

65

35

17

7

1

0.23

5

37

72

11

4

0

13

17

33

61

39

21

17

11

2

0.24

6

36

22

68

32

18

15

9

10

0.31

Willamette River

4

75

85

11

2

2

Tr.

22

9

89

11

11

4

1

0.13

5

60

20

18

94

6

17

13

7

2

0.17

6

48

17

94

6

18

16

1

14

0.28

St. Helens

4

60

13

24

75

25

26

10

4

2

0.12

5

31

58

19

15

3

23

32

72

28

30

18

16

3

0.29

6

32

25

76

24

19

18

6

0.33
M34 TRANSPORT OF RADIONUCLIDES BY STREAMS

grains; the "silica group" includes not only quartz 

but also quartzite, chert, and other dominantly 

siliceous materials, including chalcedony. "Opaques 

and femags" are essentially the abundant heavy minerals ; the opaques are magnetite, ilmenite, hematite, 

and pyrite; the femags (ferromagnesian minerals) 

are chiefly amphibole- and pyroxene-group minerals.

Rock fragments are the most abundant component (table 15) in size classes 4, 5, and 6 from 

Columbia River and tributary locations. For Columbia River locations, the percentage of rock fragments 

(table 16) ranges from an average of 33 percent in 

class 6 to 49 percent in class 4. Grain counts of class 

4 and 5 samples (table 16) indicate that volcanic 

rocks are by far the most abundant constituent of 

the rock-fragment component; on the average, volcanic rocks (table 16) are about four times as abundant as the next most common constituent. The 

groundmass of most volcanic rocks is vitrophyric 

and contains abundant phenocrysts of plagioclase 

feldspar. The phenocryst composition indicates an 

intermediate-to-basic (andesitic-to-basaltic) composition for most volcanic rocks.

Sedimentary, metamorphic, and felsic rocks, in 

that order, are the most abundant rock types after 

volcanic rocks (table 16). Chert and various types 

of sandstone (table 17) are relatively widespread 

sedimentary rock types, claystone is not infrequent, 

and carbonate or other chemical or organic rock 

types are rare. Metamorphic rocks are dominantly 

quartzite and some schist and are rarely gneiss, phyllite, or hornfels. The felsic rocks include those with 

quartz, potash, and (or) plagioclase feldspar and 

with more or less equigranular texture. Most felsic 

rocks would probably be called microgranites or 

granodiorites.

Feldspar is the second most abundant component 

in most samples of the three finest sand classes 

(table 15) ; soda-lime varieties generally tend to be 

about twice as abundant as potash varieties (table 

16). A rough idea of the proportion of various feldspars can be seen from the data in table 18. Orthoclase is the dominant potash feldspar, although 

microcline is widespread. The soda-lime species are 

prevailingly intermediate to basic (closer to An50 

than to An10 or An100 ) in composition.

Silica-group constituents are the third most abundant component in size classes 4, 5, and 6. Although 

quartz is the dominant constituent in this group, it 

is nearly always subordinate to feldspar. In many 

samples, chert and quartzite make up 20-25 percent 

of the silica group; chalcedony is a very minor but 

widespread constituent. Relative to other components, silica-group constituents exhibit a higher deTABLE 16. Average composition (in percent) of size class 

4, 5, and 6 samples from, Columbia River locations

[Unless otherwise indicated, averages include data for all Columbia River 

locations. Type of percent: A, by volume; B, by number]

Potash...........................

Glass.......... ........................

Type 

of

percent

A

.. B ... ..

.. B..................

.. B..................

. B..................

. B..................

. A..................

. A..................

. A..................

. A..................

. A..................

. A..................

M

49

61

16

10

8

5

22

64

36

22

5

2

Size

25

36

65

15

10

29

66

34

22

10

3

class

6

DO

24

71

29

18

20

5

4, 5, and 6

1Q

25

68

19

21

12

3

1 Averages for types of rock fragments are for data from Columbia River 

locations near Pasco, Me Nary Dam, The Dalles, Hood River, and Bonneville 

Dam.

2Averages for types of rock fragments are for data from Columbia River 

locations near Vancouver and St. Helens.

TABLE 17. Sedimentary rock types in size class 4, 5, and 6 

samples from Columbia River and tributary locations

[Types identified are designated by the letter "I"]

Rock type

Chert...........................

Wacke.........................

Diatomite..... ...............

a

PH

. I

. I

I

I

. I

fl

CO

I

I

I

I

I

s i

s

I

I

I

I

I

& 5 4, 0

H M

I I

Bonnev Dam

I

I

I

I

o E «

fi !"*1 *-^ rt ^" 

> fc

I I

I I

Hel« St. 

I

I

1 Could be metaquartz.

2Could be vein calcite or from amygdules.

TABLE 18. Feldspar in size class 4, 5, and 6 samples from 

Columbia River and tributary locations

[Relative abundance: (X), present; X, abundant; [XL dominant; Tr., 

trace; (?), probably present]

Potash varieties Soda-lime varieties

Location

The Dalles..................

Hood River................

Willamette River......

St. Helens...................

Orthoclase

v

( V*

... Tr.

X

Sanidine

( VI

( VI

( V)

Microcline

< V)

v

( \()

1 y *

( y ^

1 -y\

Tr.

(X)

AnoAnio

( v)

( V}

( vS

(?)

AnioAn50

rvi

fvl

X

X

X

AnsoAniQO

( V>

rvi

( V)

< vt

( V)

( V)

[XI

(X)

gree of rounding, although they seldom are better 

than subrounded. Some quartzite and chert fragments are well rounded, a condition which suggests 

that they represent at least second-cycle weathering 

products.

Opaque and ferromagnesian minerals are generally relatively minor components in the three finest 

sand classes (tables 15 and 16). Although ore minerals (magnetite and ilmenite) and ferromagnesian 

minerals are by far the most abundant constituents, 

less than an estimated 2 percent of accessory minerals also are found. Preliminary estimates of the composition of the opaque-ferromagnesian component in 

size class 6 are shown in table 19. These data, al-
COLUMBIA RIVER SEDIMENTS M35

TABLE 19. Opaque and ferromagnesian constituents in size class 6 samples from Columbia

River and tributary locations

[Relative abundance: VC, very common; C, common; S, scarce; VS, very scarce; R, rare; VR, very rare; (X), 

present; [X], dominant; (?), probably present. Abundance estimates for Pasco, Snake River, and Willamette 

River are based on the system of Milner (1962) and are not comparable with estimates from other locations]

Constituent

Opaques :

Hematite................

Pyrite......................

Pyroxene group :

Amphibole group :

Biotite».......................

Zoisite.........................

Kyanite.......................

Andalusite.................

Pasco

C

.. VC

R

C

.. VC

.. VC

S

C

R

S

VR

.. VR

S

Snake 

River

VC

C

VS

VR

VC

VC

VC

S

VS

C

S

VS

C

(?)

VR

8

VS

McNary 

Dam

( X)

( X)

( X) (?)

(X)

(X)

( X)

/y I

(?)

< X)

/y )

1 y )

(?)

f y \

(V)

( v)

(X)

The 

Dalles

(y\

/y )

/y\

/y \

/y \

(X)

(X)

(y)

(X) /y\

(?)

(V)

(X)

/y)

( V>

Hood 

River

/y )

I y \

/y )

(X)

(X) (?)

(X)

(y)

(X)

(X)

(X)

I y \

(?)

(?)

{ X)

/y \

( X)

Bonneville 

Dam

f y\

fy)

(y \

[X]

(X)

(X) (?)

(X)

(X)

(X)

(X)

( X)

/y )

{ X)

Vancouver

/y I

/y l

( VI

/y )

( y I

(X)

(X)

(X)

[X]

(X)

(X)

(X)

(X)

(X)

(X)

( XI

/y V

( XV

( X)

Willamette 

River

VC

VC

VR

VS

C

S

VS

R

R

(?)

VR

VR

1 Specific gravity less than 2.96. Probably present due to entrapment.

though not complete, suggest that the opaques (magnetite and ilmenite), the pyroxenes (augite and 

hypersthene), and the amphiboles (hornblende) are 

the abundant major constituents; garnet, epidote, 

apatite, and sphene are widespread accessory minerals.

Volcanic glass (table 15) is a conspicuous and 

ubiquitous minor component in the three finest sand 

classes from Columbia River and tributary streams. 

When compared with other types of rock fragments 

(table 15), volcanic glass is almost as abundant as 

felsic rocks and may represent as much as 13 percent of all rocks. In addition to individual glass fragments, whose abundance is indicated in table 15, 

many mineral grains exhibit a fringe of volcanic 

glass; thus, available data probably indicate the 

minimum amount of glass in a sample.

Several distinct forms of volcanic glass are found: 

brown, clear; colorless, clear; colorless, with many 

microlites; opaque, choked with magnetite; microvesicular, with aligned tubules; microvesicular, with 

"swiss-cheese" texture; sideromelane; palagonitic 

glass; and clear, with a dust of magnetite(?). The 

opaque glass compares almost identically with 

tholeiite glass taken from the eruption products of 

Kileauea Iki, Hawaii.

Data in tables 15 and 16 indicate some fairly consistent differences in the rock and mineral suite as 

particle size varies. The most evident difference is 

the increase in rock fragments as particle size increases (table 16). This trend continues in size

classes 3 and 2, where nearly all samples are dominantly rock fragments. In class 1, which contains 

gravel-size material, available samples contain exclusively rock fragments.

Other major components decrease as particle size 

increases. Opaque and ferromagnesian minerals, 

which average 20 percent of all components in class 

6, average only 5 percent (table 16) in class 4. Volcanic glass also appears to be more abundant in fine 

size classes. Feldspar and silica-group constituents, 

however, do not vary significantly in abundance as 

particle size differs.

Available data (table 15) indicate that a fairly 

large percentage of feldspar is more than one-third 

altered. An average of about 25 percent of feldspar 

grains in class 5 at Columbia River locations show 

greater than one-third alteration, and perhaps 

slightly higher percentages in class 4 are altered. 

Feldspar-alteration products consist mainly of sericite, chlorite, and undetermined "clay," some of 

which may be montmorillonite. In many samples, 

almost totally unaltered feldspar was commonly 

found along with some grains so badly altered that 

they were difficult to recognize. Feldspar phenocrysts 

in rock fragments often are surprisingly fresh, although in numerous samples the enclosing matrix 

is badly altered.

A significant percentage of the rock fragments 

(table 15) is more than one-half altered; the average 

percentage in size classes 4 and 5 is about 15 percent. The dominant alteration product (s) is a red-
M36 TRANSPORT OF RADIONUCLIDES BY STREAMS

dish to yellowish material that is apparently some 

form of iron oxide. Volcanic rock and glass, the relatively unstable components of the rock-fragment 

suite, tend to be more severely altered than do other 

rock types.

Although the above data represent at least one 

measure of the significance of alteration, many rock 

fragments as well as mineral grains that are less 

than one-half or one-third altered exhibit wellformed peripheral alteration bands or weathering 

rinds. These rinds are often very sharply defined in 

coarse and medium sand grains, and even though 

they may be thin, their position around the exterior 

of a grain indicates that they could affect significantly CEC values and radionuclide concentrations. 

Inspection of the thin section for size class 3 from 

the Pasco location indicates that the anomalously 

high CEC (table 1) and radionuclide values (table 

21; fig. 16) are related to well-developed weathering rinds. Although much of the weathering product 

in this thin section is red or yellow, its other optical 

characteristics suggest that it is an iron-stained clay.

The maturity index represents a ratio of the chemically and mechanically stable component (silica 

group) to the chemically and mechanically unstable 

components (rock fragments, feldspar, and glass). 

The lower the value of this ratio, the more susceptible are the sands to weathering processes; hence, the 

more likely the sands are to contribute to anomalous 

CEC values and (or) high radionuclide concentrations.

The maturity index for Columbia River and tributary sands (table 15) is very low and averages about 

0.33 for the three finest sand size classes. This value 

is about one-third as high as the average value of a 

similar ratio (PettiJohn, 1957, p. 508) computed for 

major types of sandstone. The relatively large percentage of unstable volcanic detritus is the main 

factor in the low ratio for Columbia River and tributary-stream sands. The maturity index does not appear to reflect differences in the mineral and rock 

suite that have been related to particle size.

No highly significant differences (table 15) in the 

rock and mineral suite apparently occur in the part 

of the Columbia River between Pasco and St. Helens. 

Of the two major tributaries along this part of the 

river, only Willamette River sediments have an apparently different rock and mineral suite. The major 

differences between the Columbia River suite and 

the Willamette River suite (table 15) are higher 

percentages of rock fragments and lower percentages of potash feldspar and possibly silica-group 

constituents in the tributary stream sediments. The

percentage of rock fragments of volcanic origin 

increases slightly between Pasco and St. Helens, and 

the percentage of the silica-group constituents decreases. A slight decrease in the maturity index 

between the two locations may be a response to the 

apparent changes in these two components.

The mineralogy of bulk samples (sand-, silt-, and 

clay-size material) from the Columbia River has 

been described by Whetten (1966), Whetten, Kelley, 

and Hanson (1969), and Kelley and Whetten (1969). 

Whetten (1966, p. 1057), from bulk-sample mineral 

and chemical analyses, concluded that Columbia 

River sediments were comparable to graywacke 

sandstone in that the sediments contained a large 

percentage of unstable constituents. Whetten, Kelley, 

and Hanson (1969, p. 1161) reported an increase in 

the abundance of rock fragments (particularly volcanic rock fragments) and a decrease in the abundance of quartz and potash feldspar between McNary 

and Bonneville Dams. Similar longitudinal trends 

were suggested by Haushild, Perkins, Stevens, Dempster, and Glenn (1966, p. 47-58) and are supported 

partly by data in this report. Kelley and Whetten 

(1969, p. 1169), using discriminate-function analysis, 

noted no statistically significant change in bulk-sample mineralogy in the reach of the Columbia River 

between McNary and Bonneville Dams; heavy minerals, however, did allow a distinction between reservoirs along the reach.

Data reported by Haushild, Perkins, Stevens, 

Dempster, and Glenn (1966) for >62/*-size material 

cannot be compared directly with data presented 

here for sand size classes with relatively narrow 

class limits. Despite some apparent differences that 

probably reflect mostly particle-size effects, their 

data are generally compatible with data presented 

here.

RADIONUCLIDE CONTENT

Radionuclides associate with sediments by numerous mechanisms, including some that are reversible 

(Kelley, 1948) and some that are irreversible (Morton, ed., 1965). Because an average of about 15 gallons of distilled water was used to separate the 

particle size classes at each location, chemical and 

radiochemical analyses were made of filtered (using 

cellulose acetate filters with a 0.45/x pore size) distilled water that had been used to process samples 

from Pasco and McNary Dam locations. Because of 

decay and of low concentrations of other radionuclides, only 65Zn could be determined accurately 

in the distilled water. Laboratory tap water also was 

analyzed chemically for comparative purposes, and 

the results from all analyses are shown in table 20.

If all the 65Zn in the distilled water came from
COLUMBIA RIVER SEDIMENTS M37

TABLE 20. Chemical and radiochemical analyses of water used to prepare size 

separates of Columbia River sediments

[Abundance of all constituents except 65Zn is in milligrams per liter; 65Zn has units of picocuries]

Distilled water

Constituent

Silica (SiO2 ) ...............

Iron (Fe) .....................

Manganese (Mn). .......

Calcium (Ca) ..............

Magnesium (Mg) .......

Sodium (Na) ...............

Potassium (K) ............

Zinc-65 («5Zn) .............

Laboratory 

tap water

......... 9.3

......... .39

.......... .09

......... 2.8

......... 1.5

.......... 2.2

......... .4

.......... (2)

before 

preparing 

separates

0.1 

t 1 ) 

t 1 ) 

.0 

.0

.4 

.0 ( 2 )

after 

preparing 

Pasco 

separates

C 1 ) 

C 1 ) 

t 1 ) 

t 1 ) 

G) 

t 1 ) 

0)

311,224

after 

preparing 

McNary Dam 

separates

2.5 

.1 

.0 

1.1 

.4 

.4 

.4 3703

Pasco 

size 

separates

4143,858

McNary Dam 

size 

separates

467,436

1 Not determined.

2Not determined but probably very low.

3Represents the 65Zn content leached from the total weight of the sediment.

4Calculated as the sum of the products of the weight of sediment processed in each size class times the 

65Zn concentration of the sediment in each size class. Represents the 65Zn content in the total weight of 

the sediment that was exposed to distilled water.

constituents (inorganic and organic) in the sediments, then about 7 percent of the available 65Zn 

was released from sediments obtained at the Pasco 

location, and about 1 percent, from sediments obtained at the McNary Dam location (table 20). 

Small amounts of some stable constituents (table 20) 

also were removed.

Nishita and Essington (1966) reported that only 

insignificant amounts of 65Zn are released when calcareous sediments are leached with distilled water 

or with artificially prepared irrigation water. Johnson, Cutshall, and Osterberg (1967, p. 99-102) 

found that only small amounts (less than 3 percent) 

of 65Zn were removed from Columbia River sediments by leaching with sea water. They also noted 

that essentially no 51Cr or 46Sc was released, although 

some 54Mn was removed. These observations indicate 

that the use of distilled water to prepare size separates should have resulted in little loss of radionuclides from Columbia River sediments.

Results from radionuclide analyses of size classes 

from seven Columbia River locations are shown in 

table 21. Because of insufficient amounts of material 

and because of some delay prior to analysis, radionuclide data were not obtained for all size classes 

(indicated by dashed leader lines in table 21), and 

some values are questionable. Data for 51Cr (table 

21), the radionuclide with the shortest half life and 

lowest gamma energy of the five nuclides determined, 

were affected most. For this reason, 51Cr data mostly 

are ignored. In general, however, most relations discussed in subsequent pages for other radionuclides 

also are valid for 51Cr. (See fig. 16.)

Inspection of the data in table 21 indicates that 

the highest radionuclide concentrations are found in 

fine size classes; for all locations, the 65Zn concentration in size class 11 averages about 36 percent of the

TABLE 21. Radionuclide content (in picocuries per gram) in 

sized sediments from Columbia River locations

[Leaders (....) indicate no data are available]

Size

class Pasco McNary The Dam Dalles

Hood 

River

BvillT Vancou- St. 

Dam ver Helens

Chromium-51

1...............

2........ ......

3...............

4...............

5...............

6...............

7...............

8................

9...............

10...............

11...............

............ 50

............ 156

............ 81

............ 116

............ 248

............ 1,070

10 13 

21 8 

50 40 

29 25 

............ 26

239 ............

261 ............ .

............ 559

28 

17 

15 

17 

20 

54 

44 

35 

73

42 

12 

10 

22 

35 

24 

27

27 

83

22 

<2 

<2 

12 

30 

91 

73 

136

609

485

14 

6 

12 

21 

29

84 

5 

128 

310 

415

Zinc-65

1...............

2...............

3...............

4...............

5...............

6...............

7................

8................

9................

10................

11................

............ 63.7

............ 528

............ 241

............ 303

............ 440

............ 860

............ 1,650

........... 5,540

............ 3,305

........... 7,210

22.2 ............

53.3 32.1 

134 47.5 

270 108 

205 74 

307 122 

381 338 

982 746 

1,670 862

56.6

19.7 

31.7 

30.6 

44.3 

121 

112 

168 

310 

173 

778

35.1 

23.6 

20.8 

41.4 

69.8 

61.4 

91.0 

147 

432 

429

4.7 

8.7 

17.7 

12.7 

25.8 

68.4 

58.3 

98.8 

191 

428 

450

4.1 

5.0 

6.8 

9.4 

11.5

20.8 

29.0 

42.1 

80.0 

91.6

Manganese-54

1...............

2...............

3...............

4...............

5...............

6...............

7...............

8...............

9...............

10...............

11...............

............ 28.1

............ 68.3

............ 21.4

............ 19.8

............ 19.5

............ 58.0

............ 63.6

............ 316

............ 254

............ 342

1.4 ............

2.6 2.5 

5.1 4.0 

9.5 7.6 

4.1 2.3 

6.9 6.6 

21.1 19.7 

90.6 84.8 

62.9 54.6

3.9

1.2 

1.3 

1.4 

2.2 

6.8 

3.3 

5.9 

14.7 

9.2 

185.2

5.4 

2.2 

1.3 

1.8 

3.4 

1.7 

2.8 

8.6 

35.2 

29.1

0.3 

.4 

.9 

.6 

1.0 

1.9 

1.1 

2.0 

5.0 

26.7 

17.6

<0.2 

<-2 

.3 

.5 

.4

.4 

.7 

2.4 

8.5 

4.8

Cobalt-60

1...............

2...............

3...............

4...............

5...............

6...............

7...............

8...............

9...............

10................

11................

............ 20.1

............ 57.6

............ 21.8

............ 27.6

............ 24.5

............ 20.6

............ 52.6

............ 191

............ 136

............ 216

2.5 ............

5.2 2.0 

10.5 2.2 

16.4 4.2 

8.0 1.8 

10.8 3.5 

8.5 7.4 

44.5 29.1 

50.5 19.7

1.2

.4 

.5 

.6 

1.3 

2.8 

2.1 

3.2 

4.7 

3.5 

17.3

1.7 

.8 

.8 

1.5 

2.8 

1.5 

2.2 

3.6 

16.0 

13.4

<0.2 

.7 

1.3 

.5 

.8 

1.5 

.9 

1.7 

1.3 

11.1 

8.2

<0.2 

.3 

<-2 

.4 

<-2

.3 

<.2

.7 

2.6 

1.4

Scandium-46

1...............

2...............

3...............

4...............

5................

6...............

7................

8................

9................

10................

11..... .. .........

............ 3.2

............ 18.2

............ 9.0

............ 11.5

............ 23.6

............ 227

............ 253

........... 1,160

............ 810

........... 2,070

<.2 ............

<.2 .5 

1.0 .4 

5.7 3.0 

4.4 1.1 

5.7 5.2 

22.6 4.2 

127 86.7 

231 145

0.7

<-2 

<-2 

.5 

<.2 

2.3 

1.1 

3.2 

16.9 

6.8 

143

<-2 

<-2 

.4 

<-2 

.9 

.4 

1.6 

6.0 

55.3 

77.3

0.3 

<-2 

<.2

.'4 

1.0 

.6 

1.5 

<-2 

42.2 

69.4

<0.2 

<-2 

<-2 

<.2 

<-2

<-2 

<.2 

2.3 

8.6 

17.0
MBS TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 22. Distribution of particle size and of fi5Zn in a composite sample from each Columbia River location

[Distribution: A, particle size, percent by weight in each size class; B, 65Zn, percent in each size class of the total amount in the composite sample.

Size class limits (in parentheses) given in microns]

T .. Distri- 123 

1X)Catl0n button (4000- (2000- (1000- 

2000) 1000) 500)

Columbia River near : 

Pasco.................................... A 4.9 0.0 0.1

B 1.0 .0 .2 

McNary Dam...................... A .0 .0 1

B .0 .0 .0 

The Dalles........................... A .1 .0 .0

B .0 .0 .0 

Hood River.......................... A .2 .8 9

B .2 .4 5.1 

Bonneville Dam.................. A .3 .0 3.7

B .0 .0 2.1 

Vancouver............................ A 2.8 3.2 27

B .6 1.7 27.3 

St. Helens............................ A 6.3 2.7 27

B 3.5 1.2 20.6

Average........................ B .8 .5 7.9

sum of the 65Zn concentrations in all size classes ; the 

65Zn concentration in size classes 4 and 5 averages 

less than 2 percent of the sum of the 65Zn concentrations in all size classes. 

A significantly different perspective of the distribution of radionuclides is gained, however, when results 

of particle-size analyses (table 22) of composite crosssection samples are combined with results of radionuclide analyses of size separates. If the particle-size 

analyses fairly represent the actual distributions of 

particle sizes in the cross sections, then their combination with radionuclide concentrations reveals 

that, at five of the seven locations, more of the 65Zn 

is associated with sand size classes than with silt or 

clay size classes. On the average, size class 11 contains only about 16 percent (table 22) of the total 

amount of 65Zn, whereas size classes 4 and 5 contain 

about 22 and 23 percent, respectively. This results 

principally from the relative abundance of 125- to 

500-micron sizes in Columbia River sediments. 

The relative order of radionuclide abundance in 

Columbia River sediments varies among particle size 

classes and among sample locations (table 23) . Chromium-51 and 65Zn, not necessarily in that order,

TABLE 23. Relative order of radionuclide abundance in 

selected size classes from Columbia River locations

Size class Location Relative order

I........ ..............Pasco................. 65zn > 51 Cr > 54Mn > 6°Co > 46gc 

Hood River.. ............. 65Zn > 51Cr > 54Mn > 6°Co > 46gc

St. Helens.......... .......51 Cr > 65Zn > 54Mn = 6°Co ~ 46gc

5... .......... ......Pasco......... . 65Zn > 51 Cr > 60Co > 54Mn > 46gc

Hood River...... .. 65Zn > 51 Cr > 5 4Mn > 6°Co > 46gc

St. Helens....... ...........51Cr > 65Zn > 5 4Mn > 6°Co = 46gc

8.. .................... Pasco.............. ............65zn > siCr > 4egc > 54Mn > 60Co 

Hood River...... 65Zn > 51 Cr > 54Mn > 6°Co 46gc

St. Helens........ . 65Zn > 51 Cr > 54Mn > 60Co = 4egc

Hood River...... . ...... ..65zn >(!) > 54Mn > 46gc > eoco

St. Helens......... . 51 Cr > & 5 Zn > 46Sc > 54Mn > 60Co

Size class and limits

4 5678 9 10 11 

2650)~ lit" (6$)~ (62~31) (31-16) (16-4) (4"2) (<2)

24 58 12 0.5 0.2 0.2 0.0 0.1

18.3 55.6 16.7 1.4 1.0 3.5 .0 2.3 

5 11 13 13.9 17.2 26.2 1.9 10.8

.6 3.4 8.1 6.6 12.2 23.1 4.3 41.7 

2.9 25 18 17.9 15.0 13.8 1.3 6.0

.5 6.9 11.3 7.7 10.6 27.3 5.6 30.1 

46 34 1 2.4 2.7 2.5 .4 1.0

24.7 26.4 2.1 4.7 7.9 13.7 1.2 13.6 

54 29 2 2.7 3.0 3.2 .2 1.9

26.1 28.0 3.2 2.3 6.3 10.9 2.1 19.0 

48 18 0 0 .5 .4 .0 .1

34.7 26.1 .0 .0 2.8 4.5 .0 2.3 

47 13 2 1 .5 .3 .1 .1

50.3 17.2 .0 2.4 1.2 1.2 1.2 1.2

22.3 23.4 5.9 3.6 5.9 12.0 2.0 15.7

are the most abundant radionuclides in all classes 

and at all locations. The general order of the remaining radionuclides, however, depends somewhat on 

particle size with 46Sc tending to become relatively 

more abundant than °°Co as particle size decreases. 

Overall, available data indicate that the decreasing 

order of radionuclide abundance is 51Cr, 65Zn, 46Sc, 

54Mn, and 60Co. 

Relations between radionuclide concentrations and 

geometric mean particle size at three locations are 

shown in figure 16. As expected, radionuclide concentrations increase as particle diameters decrease, 

although the increase is not always regular. Part of 

the irregularity is undoubtedly statistical; however, 

for many locations and radionuclides, consistent 

irregularities exist and suggest causes in addition to 

usual statistical variations. 

Three typical irregularities in the relations of 

radionuclide concentrations to particle diameters are 

illustrated by data in figure 16J5. For convenience, 

the irregularities are called ( 1 ) coarse separates deviation, (2) size class 6 deviation, and (3) size class 

10 deviation. The coarse separates deviation normally shows disproportionately high radionuclide 

concentrations in one or more coarse separates (size 

classes 1, 2, or 3) ; in some cases, minimum radionuclide concentrations occur in size class 4 rather

than in size class 1 where concentrations might be

expected to be lowest. The size class 6 deviation at

five of six possible sample locations indicates more

radionuclides in this class than in size class 7 and

usually more radionuclides than in size class 8. The 

size class 10 deviation is somewhat variable (compare fig. 16A and B with fig. 16C), but, in general,

radionuclide concentrations are low in size class 10
COLUMBIA RIVER SEDIMENTS M39

10000

5000

2000

1000

500

- 200

50

ff 100

o 

oc

UJ

o.

V)

UJ 20

CC 10

5

Q.

. 1000 

r 500

Z 200

ui

O 100

O 

0 

ui 

O

- A. Pasco location 

65 Zn

/

^60Co 

regression

/ I I I I I I

50 -

20

10

0.5

0.2 

0.1

:in i i r r run M i i M 111 i i i i HUM i i 

: B. Hood River location

«Co 

46 Sc

0<0.2 picocuries per gram

i i

345678

SIZE CLASS NUMBER

11 I I I I I III 11 i I i i

10 11

46sc 

i60 Co

0<0.2 picocuries 

per gram

l I I I I

345678 

SIZE CLASS NUMBER

II I I I I I INN I I I I

10 11

J_L

o o ooo ooo §

o ooo o o in

o o o in (N *-

«- in <N «-

o o

<N «- § § § § § 

o o o o in § §

(N rO O 

(N «-

PARTICLE DIAMETER, IN MICRONS

FIGURE 16. Relations between radionuclide concentration and particle diameter.

Explanations for the most commonly observed 

irregularities are available from particle-size, CEC, 

carbon-nitrogen, and mineralogy data. The coarse 

separates deviation is closely allied with anomalies 

in CEC and particle-size data (table 1; fig. 3) that 

show that average CEC increases rather than decreases between size class 3 and size class 1. These 

anomalies have been related to fines (p. M9), to carbon content (p. M13), and (or) to mineralogy 

(p. M36). The size class 6 deviation also corresponds 

with an anomaly in the CEC-particle-diameter relation that is attributed to fines (p. M9) and to nitrogen (organic-matter) content (p. M13). However, 

even after organic material and fines apparently 

were removed more completely, CEC data (table 1) 

show that size class 6 has higher CEC values than 

size class 7. These higher CEC values suggest a possible mineralogic difference between classes. Although such a difference could not be evaluated 

directly because the methods of determining mineralogy (X-ray versus optical) varied between class 

6 and class 7, more rock fragments and weathered
M40 TRANSPORT OF RADIONUCLIDES BY STREAMS

particles capable of sorbing radionuclides might be 

expected in size class 6 than in size class 7.

No completely satisfactory explanation has been 

found for the size class 10 deviation. Particle-size 

analyses (table 2) suggest that this size class may 

contain a high percentage of particles that tend to 

naturally occur as floes. If this is true, the opportunity for particles on the inside of a floe to attract a 

radionuclide would be limited, and radionuclide concentrations would be lower than expected. CEC data 

(table 1) for size class 10 show an anomaly that may 

or may not be compatible with the floe explanation; 

namely, particles that were finer than those in the 

indicated size class (sample type 3, table 1) had 

lower CEC values than did particles in the indicated 

size (sample type 2, table 1). An explanation of this 

phenomenon, other than sample number error, which 

is considered unlikely, remains to be determined.

Regression, variance, and covariance analyses are 

useful tools for quantifying the relations between 

radionuclide concentrations and particle diameters, 

as well as for indicating the significance of differences in relations among radionuclides and among 

locations. Because of lack of data for coarse grain 

sizes at some locations (table 21), the only radionuclide data that were considered in establishing 

regression relations were data from size classes 4-11. 

It should be noted, however, that in many cases, 

using data from the coarse separates results in little 

difference in the correlation coefficients of the relations.

Linear-regression techniques were used to define 

relations between the logarithms of radionuclide concentrations of each size class and the logarithms of 

the geometric mean particle diameters of each size 

class. Because multiple observations of radionuclide 

concentration in each size class from each location 

are not available, the linearity of the relations at a 

location cannot be established directly by statistical 

techniques. However, if a "location" is defined as 

the Columbia River, the available radionuclide concentrations can be grouped by size classes and the 

linearity of the relation between radionuclide concentration and particle size can be established (Li, 

1964, p. 336-339). Indirectly, this analysis suggests 

that a linear relation could exist at each location 

between the logarithms of the radionuclide concentrations and the logarithms of the geometric mean 

particle diameters.

Regression equations that describe the relations 

between the logarithms of 65Zn, 4r> Sc, ")4Mn, and 60Co 

concentrations of each size class and the logarithms 

of the geometric mean particle diameters of each 

size class at the Pasco location are shown in table 24.

TABLE 24. Regression equations for the relations between 

radionuclide concentration and particle size at Columbia 

River locations

[65Zn, concentration of 65Zn, in picocuries per gram of sediment; D, geometric mean particle diameter of the sediments in each size class, in 

microns; r, correlation coefficient; SE, standard error of estimate, in log 

units]

Location Regression equation SE

Pasco.. .Log 65Zn=4.03739 0.66379(log D) 0.91 0.16492

Log 54Mn =2.74559 0.62150 (log D) .95 .18788

Log 6°Co=2.42137 0.47956(log D} .91 .19799

Log 46Sc=3.69i46-1.06759(log D) .96 .29698

The Dalles.................

St. Helens..................

....... Log 65Zn 3.24811 0.53877 (log D)

....... Log 65Zn -3.07603 -0.62683 (log D)

....... Log 65Zn -2.82532-0.48456(log D)

....... Log sszn 2.76724 0.54510 (log D)

....... Log 65Zn 2.87776 0.64838 (log D)

....... Log 65Zn 2.06311 0.44155 (log D)

.96

.98

.91

.98

.96

.99

.14797

.12288

.20100

.10392

.15811

.02881

In addition, equations are given for the relation between log 65Zn and log D at all Columbia River locations. The high correlation coefficients and the low 

standard errors of estimate for these equations indicate a close relation between radionuclide concentration and particle diameter.

Inspection of the regression equations (table 24), 

as well as of the data in figure 16A, suggests that 

not all radionuclide concentrations are related similarly to particle diameters; that is, the slopes (regression coefficients) of the regression lines are 

not all equal. A covariance analysis (Li, 1964, 

p. 393-399) applied to data from the Pasco location 

indicates that relations between radionuclide concentrations and particle diameters at that location 

have statistically different regression coefficients at 

the 5-percent significance level (probability of rejecting a true hypothesis).

Regression relations and covariance analyses are 

useful also in establishing the significance of amonglocation differences in the slopes of regression lines 

for the same radionuclide. Inspection of the data 

in figure 16 suggests, for example, that the slope of 

the regression of log 63Zn versus log D decreases 

between Pasco and St. Helens. Covariance analyses 

show, however, that statistically no differences 

(5-percent significance level) in slope exist when 

the data from all locations are considered. When 

data from the upper three locations are pooled and 

are compared with pooled data from the lower three 

locations, covariance indicates no statistically significant (5-percent significance level) difference in 

the slope of the relation of log 65Zn to log D.

With a theoretical, simplified model that assumes 

that sediment particles are spherical, the relation of 

the logarithm of specific surface to the logarithm 

of particle diameter has a slope of 1.0 (Sayre and 

others, 1963, p. 16). Because the sorption capacity 

of sediments is roughly proportional to specific surface (Sayre and others, 1963, p. 15), the slope of a 

regression line for the relation of the logarithm of
COLUMBIA RIVER SEDIMENTS M41

radionuclide concentration to the logarithm of particle diameter also is expected to be about 1.0 if 

particle diameter is the only or dominant variable 

controlling both specific surface and radionuclide 

concentration.

Statistical tests (Li, 1964, p. 317-322) show that 

the observed slopes of the regression lines for log 

65Zn versus log D are generally significantly less 

than 1.0; at all locations, the pooled slope estimate is about 0.6. A very similar slope was determined for the regression of log CEC versus log D. 

(See p. M9 and fig. 2.) Thus, the explanation that is 

suggested for differences between observed and expected relations must accommodate the relations of 

both CEC and radionuclide concentration to geometric mean particle diameter. The applicability of 

the theoretical specific-surface model is open to question ; however, refining the model by considering different shapes for fine particles could result only in 

a steeper theoretical slope if a linear relation were 

assumed.

Three possibilities are suggested as causes of the 

deviations between expected and observed relations. 

The possibilities are the effects of (1) flocculation, 

(2) inclusion of fines, and (3) variations in mineral 

composition. If sediments in fine size classes were 

naturally present as floes, the concentration of a 

radionuclide in these classes could be low because 

of a possible shielding effect. This explanation, however, does not appear reasonable for the log CEClog D relation because equilibration times were long 

and samples were mechanically agitated during 

equilibration. The inclusion of small amounts of fines 

in coarse and medium size classes could greatly 

increase CEC or radionuclide concentrations without 

changing appreciably a weighted geometric mean 

particle diameter. This explanation is reasonable for 

both the CEC and the radionuclide-concentration 

versus particle-diameter relations; however, it does 

not explain all deviations in the CEC versus geometric-mean-particle-diameter relation. Hence, it 

seems unlikely that inclusion of fines can explain all 

deviations in the relation between radionuclide concentration and geometric mean particle diameter.

It has been shown previously (p. M21 and M31) 

that differences in particle size are accompanied by 

differences in mineralogy. One of the more obvious 

mineralogic differences is the decrease in the amount 

of total clay minerals as particle size increases. When 

the regression equation for the relation of the logarithms of the amounts of the total clay minerals (as 

indicated by the average intensity of the 4.44-A peak 

at all locations) to the logarithms of geometric mean 

particle diameters for classes 7-10 is determined,

the regression coefficient, or slope of the relation, 

also is about 0.6. This suggests that both CEC and 

radionuclide content may be related intimately to 

mineralogic content that is related in turn to particle 

size.

Differences in radionuclide concentration along the 

Columbia River can be evaluated with data from 

particle size classes. The percentage difference between adjacent locations and between Pasco location 

and each location downriver are shown in table 25. 

For 65Zn, the differences in clay (size class 11) and 

in medium sand (size class 4) are shown as well as 

the difference in the average amount of 65Zn in the 

eight finest size classes (size classes 4-11). Zinc-65 

concentrations in the clay size class were determined 

both from actual analyses (type A radionuclide concentration, table 25) shown in table 21 and from 

regression equations (type B radionuclide concentration, table 25) presented in table 24. Some available 

radionuclide concentrations and some computed percentage differences are not shown in table 25 because 

they provide little additional information.

Inspection of the data in table 25 indicates that 

radionuclide concentrations in the clay size class at 

St. Helens are about 1 percent of comparable concentrations at Pasco. The decrease is only slightly 

different if regression-determined values are substituted for actual measured values. Cobalt-60, 46Sc, 

and 54Mn in the clay size class appear to decrease 

somewhat differently than 65Zn in the same size 

class, but the difference is probably not statistically 

significant. A slight increase in 65Zn concentration 

between Bonneville Dam and Vancouver (table 25) 

probably reflects usual statistical variations rather 

than any real change.

From Pasco to St. Helens, 65Zn in the mediumsand size class decreases less than 65Zn in the clay 

size class decreases. The average concentration of 

65Zn in the eight finest size classes, as might be expected, decreases between Pasco and downstream 

locations in a manner intermediate between decreases in the clay and the medium-sand sizes.

Data in table 25 and figure 17 very convincingly 

demonstrate where largest decreases in radionuclide 

concentrations occur and, indirectly, suggest reasons 

for varying rates of decrease. Per mile of river, the 

largest decreases are between Pasco and McNary 

Dam locations and between Vancouver and St. 

Helens locations. Pasco and McNary Dam locations 

bracket a major water- and sediment-contributing 

stream, the Snake River; Vancouver and St. Helens 

locations also are separated by a major water- and 

sediment-contributing stream, the Willamette River.
M42 TRANSPORT OF RADIONUCLIDES BY STREAMS

TABLE 25. Percentage difference in radionuclide concentrations between Columbia River locations

[Type of radionuclide concentration: A, from radionuclide analysis of size class 11; B, from regression equation at geometric mean for size class 11; 

C, from radionuclide analysis of size class 4; D, average of concentrations for size classes 4-11 from radionuclide analyses]

Location

The Dalles...........

Hood River.........

Bonneville Dam.

Vancouver...........

St. Helens............

Type of

radionuclide

concentration

..A ........................

B.........................

C.........................

D.........................

..A.........................

B.........................

C.........................

D.........................

B.........................

C.........................

D.........................

..A.........................

B.........................

C.........................

D.........................

...A.........................

B.........................

C.........................

D.........................

...A.........................

B........................

C.........................

D.........................

.A.........................

B.........................

C.........................

D.........................

Radionuclide concentration,

in picocuries per gram

eszn eoco 46Sc 54Mn

791 fl 91 fi 9A7rt 5A9

7520 ................ ................ ................

241 ................ ................ ................

2443 ................ ................ ................

1670 50.5 231 62.9

1310 ................ ................ ................

53.3 ................ ................ ................

500 ................ ................ ................

862 19.7 145 54.6

839 ................ ................ ................

32.1 ................ ................ ................

291 ................ ................ ................

17170 1T9. 14Q. / 1 \

510 ................ ................ ................

30.6 ................ ................ ................

217 ................ ................ ................

431 ................ ................ ................

20.8 ................ ................ ...............

162 ................ ................ ................

450 8.2 69.4 17.6

525 ................ ................ ................

12.7 ................ ................ ................

167 ................ ................ ................

91.6 1.4 17.0 4.8

90.3 ................ ................ ................

9.4 ................ ................ ................

37.4 ................ ................ ................

esZn

 77

__ 00

_ on

do

 36

 40

JO

10

_ 39

 5

 25

-45

__ AQ

, _ qo

 26

+5

+22

-39

1 9

. _ CA

.fl^

-26

 82

Percent difference in radionuclide concentration

Between adjacent locations Between Pasco and indicated location

L eoco 4«Sc s4Mn eszn 6°Co 46Sc S4Mn

-77 89 -82 77 77 -89 82

. . ....... ................ 83 ........ ....... .......... ..... ................

................ ................ ................ -78 ................ ................ ................

.... ................ ................ 80 ................ ................ ................

fit «*7 _m.1 9 __ QQ __ Q-l ftO QJ

................ ................ ................ 89 ................ ................ ...............

................ ................ ................ 87 ................ ................ ................

................ ................ ................ -88 ................ ................ ................

1» 1 /i\ _ on _ qo no /M

................ ................ ................ -93 ................ ................ ................

................ ................ ................ -87 ................ ................ ................

................ ................ ................ 91 ................ ................ ................

 23 46 (») 94 94 96 92

................ ................ ................ -94 ................ ................ ................

................ ................ ................ 91 ................ ................ ................

................ ................ ................ -93 ................ ................ ................

-39 -10 -40 -94 -96 -97 -95

 93

................ ................ ................ 95 ................ ................ ................

................ ................ ................ 93 ................ ................ ................

83 76 73 99 99 99 99

 99

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

................ ................ ................ -98 ................ ................ ................

1 Questionable value.

Radionuclide ratios provide an insight into the 

relative differences in ratio components among particle sizes and among locations. Plots in figure 18 

show that some ratios behave differently among locations, as well as among particle sizes. The 46Sc/65Zn 

ratio increases greatly as particle size decreases; 

other ratios increase only slightly or change erratically as particle size decreases. The 65Zn/60Co ratio 

shows no statistically significant difference between 

Pasco and McNary Dam locations. When 65Zn/60Co 

ratios at upstream locations are compared with 

ratios at downstream locations, ratios at downstream 

locations usually are highest. This indicates that 65Zn 

associated with sediment increases relative to 60Co 

along the river. The 46Sc/65Zn ratio, unlike the 

65Zn/60Co ratio, is statistically significantly higher at 

Pasco than at McNary Dam; below McNary Dam 

the ratio appears to be more or less constant. When 

compared with the 46Sc/65Zn and 65Zn/60Co ratios, 

the 65Zn/54Mn ratio is intermediate; that is, it generally increases downstream from Pasco, as does the 

65Zn/c °Co ratio, and tends to change little below 

McNary Dam, as does the 46Sc/65Zn ratio.

The 34Mn/c°Co ratio has been plotted in figure ISO 

to illustrate differences in a ratio that does not have 

65Zn as one of the ratio components. In general, this 

ratio may increase slightly with decreasing particle 

size, but it shows no consistent difference with sample location.

The relation between CEC and radionuclide concentration is illustrated in figures 19 and 20. With 

noticeable deviations, direct relations are evident for 

most radionuclide concentrations and CEC values of 

clay, silt, and some fine to very fine sand size 

classes. For medium- to coarse-sand classes, however, radionuclide concentrations frequently are 

more or less independent of CEC. Although the 

exact reasons for the independence are unknown, it 

probably reflects differences in the location and (or) 

mechanism of ion sorption on coarse particles as 

compared with silt or clay particles. In this connection, Malcolm and Kennedy (1970, p. 156) noted that 

ion exchange rates for coarse particles are much 

slower than for fine particles.

Data indicate that some radionuclides respond differently, if erratically, to changes in CEC. For example, 60Co and 54Mn are frequently more abundant 

in size class 10 than in size class 11 (fig. 19) even 

though the CEC in size 10 is much less than that in 

size 11. At most locations, 65Zn and 46Sc also tend 

to be higher in size 10 than might be expected from 

the difference in CEC although their concentrations 

in size class 11 generally are greater than in size 10. 

Again, no good explanation can be given for these 

observations.

As indicated previously (p. M9 and M39), size 

class 6 has higher than expected CEC and radionuclide concentrations. The CEC-65Zn relation (fig. 20, 

McNary Dam and Vancouver locations) and other 

CEC-radionuclide relations (tables 1 and 21) indi-
COLUMBIA RIVER SEDIMENTS M43

2600

§ 2400

<r

UI

a.

w 2200

g 2000

O 

CL

1 1800

5 1600

UJ

Location

Pasco

McNary Dam 

The Dalles 

Hood River 

Bonneville Dam 

Vancouver 

St. Helens

Rate of change in ^Zn 

between locations, 

in picocuries per gram 

per mile

-52.5

-2.0

-2.7

-3.7 

+0.1

-8.6

Pasco/

1400

1200

Z

1000

O

800

600

400

[McNary Dam

CC

ui 200 Vancouver

St. Helens

Hood River ^^^ The Dalles

 v^

Bonneville Dam

50 100 150 200 250 

DISTANCE FROM COLUMBIA RIVER MOUTH, IN MILES

300 350

FIGURE 17. Change in average 65Zn concentration in size classes 4-11 along the Columbia River.

cated that the high CEC is not accompanied by a proportionately high radionuclide concentration. Quite 

commonly, the CEC in some coarse separates (for 

example, fig. 20, Pasco location, size class 3) also 

is disproportionately higher than the radionuclide 

concentration.

When "actual" CEC values (p. M12) are plotted 

against radionuclide concentrations, many size class 

6 (for example, fig. 20, McNary Dam location) and 

some coarse separates discrepancies are eliminated, 

although CEC values and radionuclide concentrations in size class 6 are still higher than in size class 

7. The elimination indicates that the high CEC but 

low radionuclide content in the "as received" size 

class 6 sediment is due principally to the inclusion 

of materials that contribute unequally to CEC and 

radionuclide content.

Both organic matter and fines could contribute 

unequally by virtue of having different CEC:radionuclide-content ratios than other materials indigenous to a size class. Because of differences in the 

nature of exchange sites and exchange mechanisms 

between organic and inorganic materials, it is possible that organic material would tend to take up 

less nuclides than inorganic material even though 

both had the same exchange capacity. Thus, where 

both are present in a sample, as they are in the "as 

received" Columbia River samples, radionuclide concentrations might tend to be lower than expected. 

More likely, however, the discrepancies arise from the 

nature of fines associated with coarse particles. If 

the fines are principally weathering rinds or compacted clays that were removed or dispersed during 

sample preparation for CEC analyses, then the discrepancies would be explained because radionuclides 

would probably only be associated with the surface 

layers of such materials. Regardless of its origin, 

any type of weathering product or clay layer could 

result in less increase in measured radionuclide concentrations than in measured exchange capacity.
M44 TRANSPORT OF RADIONUCLIDES BY STREAMS

0.3 

0.2

0.1 

0.05

c 

N

in <o

O

u. 

O

pO.02

< 

CC

0.01

0.007

100

Z 50

I I TI TH 

Location 

A Pasco 

 McNary Dam 

n Hood River 

o St. Helens

in 

O

20

10

2

100

O 50

Location 

A Pasco 

 McNary Dam 

D Hood River 

o St. Helens

fl. 65 Znto 54 Mn

O 

N 20

10

5

3

20

10

65

Location 

A Pasco

 McNary Dam 

D Hood River 

o St. Helens

C DO Zntoou60Co

Location 

A Pasco

 McNary Dam 

D Hood River 

o St. Helens

0.5

- D. 54 Mnto 60Co

I I I I I I I I I

10 20 50 100 200 500 1000 2000 

PARTICLE DIAMETER, IN MICRONS

5000

FIGURE 18. Variations in radionuclide ratios with particle diameter and sample location along the

Columbia River.
COLUMBIA RIVER SEDIMENTS M45

100

50

\ I I I I I I I I

11 11.-

< tt

I Qj 

O &

u £

z z 10 

2S 

^ <

o g

ui iif

uj d

co ""

I I I I I

5 10 50 100 

RAOIONUCLIOE CONCENTRATION, IN PICOCURIESPER GRAM

500 1000

FIGURE 19. Variation in radionuclide concentrations with "as received" cation-exchange capacities. Data are for size classes from The Dalles location.

The number beside each data point is the size-class number.

However, the fact that size class 6 sediments have 

higher CEC and radionuclide contents than size class 

7 sediments, even after removal of organic matter 

and fines, indicates that a fundamental compositional 

difference must exist between these two classes.

INTERPRETATION OF RADIONUCLIDE DATA

The presentation of radionuclide data has been 

limited purposefully to detailing observations in 

various forms. In order to interpret these observations, a model that describes at least qualitatively 

the origin of radionuclides in streambed sediments 

must be developed. Some necessary elements for a 

model are available, and some elements can be inferred from data presented here; but detailed studies 

on radionuclide transport phenomena are needed.

The discussion which follows considers very briefly 

(1) the composition and release of radionuclides to 

the Columbia River, (2) the uptake of ions by sediments, (3) two simplified models for the origin of 

radionuclides in streambed sediments, and (4) the 

compatibility of these models with data presented 

here. An anticipated future reoort, which would include results from additional studies of radionuclides 

in bottom sediments and results from radionuclidetransport determinations, also will include a more 

detailed evaluation of the origin of radionuclides in 

streambed sediments.

Radionuclides in the Columbia River resulted principally from neutron activation of stable elements 

(Zn, Co, Sc, and Mn) that occur naturally in Columbia River water or of elements (Cr) that were added 

to inhibit corrosion. With the exception of 51Cr, 

therefore, radionuclide concentrations in reactor 

effluents should be less than stable-element concentrations in ambient waters. National security 

requires that the absolute concentrations of radionuclides in plutonium-production reactors be classified; relatively, however, 51Cr is probably initially 

about 17 times as abundant as 65Zn, which, in turn, 

is probably much more abundant than 54Mn, 60Co, 

or 4GSc (Nelson, 1961, p. 9-11). From data on stableelement concentrations in the Columbia River above 

the reactor-effluent outfalls (Silker, 1964, p. 541), 

Zn is about 12, 800, and 10,000 times as abundant as 

Mn, Co, and Sc, respectively.
100

oc

0 50

o 

o

oc 

111

Q. 

V)

z

111

10

Tl I I I I T

Location

- Pasco

- McNary Dam

- McNary Dam ("actual" cation exchange capacity)

- Vancouver

- St. Helens 10,

"1 T

.11

I I I I I I I I I I I I I I I I I I I I

10 50 100 500 

65Zn CONCENTRATION, IN PICOCURIESPER GRAM

1000

FIGURE 20. Relation between 65Zn concentration and "as received" and "actual" cation-exchange capacity in size classes from four Columbia River loca

each data point is the size-class number.
COLUMBIA RIVER SEDIMENTS M47

The reactor-effluent radionuclides are initially 

mostly in the solute phase (Nelson, in Pearce and 

Green, 1966, p. 89-90). Scandium-46, however, does 

have a high initial particulate component (68 percent), and about 16 percent of the 65Zn is initially 

in a particulate phase. The solute-phase radionuclides 

are not all in a form amenable to immediate uptake 

by sediment. Chromium-51 and 46Sc both have large 

percentages (Nelson, in Pearce and Green, 1966, 

p. 89; Nelson and others, 1966, p. 157-158) of 

anionic forms that probably are not sorbed readily. 

Zinc-65, 60Co, and 54Mn in the solute phase are chiefly 

cationic forms initially, and hence probably are 

sorbed readily. The percentage of the solute-phase 

radionuclides that is cationic decreases irregularly 

downstream from the reactor outfalls.

During the period of reactor operations, radionuclides were released to the Columbia River at midchannel point sources along about a 12-mile-long 

reach (Nielsen, in Kornegay and others, 1963, p. 91) 

adjacent to the Hanford area (fig. 1). The rate of 

release (Perkins and others, 1966, p. 243-247) had 

been fairly constant for several years preceding the 

collection of samples for this study. Annual variations in solute radionuclide concentrations that were 

related to Columbia River discharge variations 

(Haushild and others, 1966; Perkins and others, 

1966) were large, and low concentrations that accompanied high Columbia River discharges may 

have been experienced for as long as 2 months during a year. Mean or near-mean solute concentrations 

should have prevailed at most sampling locations for 

several months prior to the time samples were collected for this study.

In the Columbia River, periods of relatively 

greater sediment transport alternate with periods of 

lesser movement. During the low-flow period that 

preceded collection of samples for this study, only 

suspended sediments <62/t in size were in transport 

at Pasco, Wash., Umatilla, Oreg., and Vancouver, 

Wash. (fig. 1). At Vancouver, a very small amount 

of >62/t bedload also was being moved during the 

low-flow period. During the high-flow period that 

followed sample collection, sediment particles as 

large as 500/x were transported at most Columbia 

River locations.

Data on the composition of radionuclides in the 

Columbia River indicate that, as a result of some 

type of sorption mechanism (s), sediments remove 

trace levels of radionuclides from essentially continuous releases of radionuclides that are initially 

mostly in a solute phase. For stable elements present 

in high concentrations and for some stable elements 

present in low concentrations, soil scientists have

investigated sorption-desorption reactions. Concentration gradients, characteristics of stable elements 

and of sediments, and many other perhaps less important factors have been indicated as controlling 

the reactions. Both reversible and irreversible reactions have been observed. The amount of sorption 

has been observed in laboratory experiments to 

reach limiting values that presumably reflect the 

combination of all controlling influences.

Investigations with stable elements and with 

radionuclides (Tamura and Jacobs, 1960; Rowe and 

Gloyna, 1964; Yousef and Gloyna, 1964; Jenne and 

Wahlberg, 1968) have indicated the importance of 

selective and often irreversible sorption by some 

sediment components when ions are present in tracelevel concentrations. Stable elements and radionuclides of the same species generally are regarded as 

having similar sorption-desorption reactions.

The preceding discussion provides background information that must be considered in any model that 

attempts to portray qualitatively or quantitatively 

the origin of radionuclides in Columbia River streambed sediments. A relatively simple model might consider these sediments as being noncumulative and 

immobile (no deposition or erosion and transport) 

and as having the same characteristics (CEC and 

mineralogy) at any location. Under these conditions 

and after any extended period of continuous and 

constant radionuclide release, the concentration of 

radionuclides associated with surficial sediments 

presumably would attain a steady-state value that is 

determined mostly by the concentrations of radionuclides, of their stable elements, and of other competing ions in the ambient-water column. This 

simple solute-concentration-dependent model has 

built-in implications relative to the nature of sorption-desorption reactions. If radionuclide sorption in 

this model were not reversible, the radionuclide concentrations in streambed sediments would decrease 

owing to decay after steady-state concentrations 

were reached. Decay might be compensated partly by 

additional uptake of radionuclides while stable ions 

or decay products from previously sorbed radionuclides are released.

Before discussing a model that considers sediment 

transport, it is interesting to evaluate data presented here in terms of the simple solute-concentration-dependent model described above. First, the 

longitudinal attenuation of radionuclide concentrations in streambed sediments should be a function of 

the decrease in solute radionuclide concentrations 

that occurs along the river owing to dilution and 

dispersion; according to data shown in figure 17, the 

attenuation approximates a relation that might be
M48 TRANSPORT OF RADIONUCLIDES BY STREAMS

predicted from dilution-dispersion data. The magnitude of the total attenuation and of the attenuation 

between locations bracketing major sources of dilution (tributary streams), however, is much greater 

than the decrease that can be calculated from waterand sediment-discharge data in Haushild, Perkins, 

Stevens, Dempster, and Glenn (1966) and in Roden 

(1967). Because radionuclide content is not a conservative property, the overall magnitude of the 

longitudinal attenuation would be greater than predicted from dilution-dispersion considerations alone, 

but decay during transport between closely spaced 

locations should be relatively unimportant. The decrease along the river in the percentage of the solutephase radionuclides that is cationic (Nelson, in 

Pearce and Green, 1966; Nelson and others, 1966) 

also could result in greater total attenuation, but 

this decrease is apparently unrelated to tributary 

inflow.

Some streambed sediments obviously are not immobile, and sediment transport must be considered 

in any model that describes the origin of radionuclides in Columbia River streambed sediments. Many 

observations that are presented in the preceding section of this report can be interpreted as solely transport related, particularly if sorption is considered 

to occur rapidly (Kennedy and Brown, 1966; Malcolm and Kennedy, 1970) and irreversibly. Under 

these conditions, the concentration of radionuclides 

in streambed sediments at any location downstream 

from the point below the effluent outfalls where 

sorption attains steady-state values is no longer only 

a function of radionuclide and competing ion concentrations in the ambient-water column. Rather, 

after an extended period of exposure, the radionuclide concentration is a function of particle traveltime and of dilution due to incorporation of tributary 

sediments that have radionuclide concentrations that 

are commensurate with lower radionuclide levels in 

the ambient waters below a tributary confluence.

Radionuclide content has been related to particle 

size and to mineral and chemical characteristics of 

sediments. However, even if these characteristics 

were invariant, or varied in such a manner that all 

sizes initially had the same radionuclide concentration, decay during transport of fine and coarse particles might produce some observed relations. Decay 

during transport, rather than changes in composition, could result in the observed decrease in radionuclide concentration with increasing particle size, 

and differential decay during transport also could 

account for the particle-size dependency of the 

4fiSc/fir>Zn ratio. Decay plus dilution by tributary 

sediments could produce a downstream attenuation

in radionuclide concentration. From data in Haushild, Perkins, Stevens, Dempster, and Glenn (1966) 

for the 1963 water year, Snake River sediments 

alone could effect a maximum dilution of about 60 

percent.

Several lines of evidence indicate that the transport model as described above is inadequate even if 

uptake reactions could be shown to be irreversible. 

First, the transport rate would have the same functional relation to particle diameter as radionuclide 

concentrations have to particle diameter. Because 

clay and silt sizes probably are transported at nearly 

the same rate, differences in radionuclide concentration between fine-sediment size classes are not solely 

a function of traveltime. If traveltime were significant in determining radionuclide concentrations, 

nuclides with varying decay coefficients also would 

exhibit different relations to particle diameter; observed relations, however, are generally similar. 

Because of varying decay coefficients, radionuclide 

ratios and percentage changes between locations also 

would be functions of particle diameter and distance 

in a model based on sediment transport alone. Only 

the 4GSc/65Zn ratio, which is discussed later, is a 

function of particle size, and the percentage change 

with distance bears little apparent relation to radionuclide decay. Finally, because of several intervening dams, it is unlikely that sediment particles in 

coarse size classes ever travel from Pasco to St. 

Helens; thus, the radionuclide content of these 

classes obviously is not related in any simple way 

to sediment transport.

Much of the discussion of models and radionuclide content has stated or implied connotations 

relative to radionuclide sorption and (or) desorption. Radionuclide ratios can provide information on 

changes in radionuclide concentrations that imply 

sorption, desorption, or radionuclide decay. Unfortunately, how the ratios are interpreted often depends on how the radionuclides are assumed to 

originate in sediments. The 46Sc/65Zn ratio presents 

some interesting contrasts in this respect. The ratio 

is higher at Pasco than at downstream locations, 

where it has nearly constant values, and it is greater 

in fine than in coarse particles. The difference in 

ratio between Pasco and McNary Dam locations 

could be due to differential decay during transport 

or to greater 65Zn uptake relative to 46Sc uptake 

between locations. Because the 46Sc/65Zn ratio remains constant below McNary Dam, decay effects 

must be offset by sorption of additional 46Sc or by 

desorption of C5Zn.

The particle-size dependency of the 46Sc/65Zn ratio 

could be due to differential transport rates of fine
COLUMBIA RIVER SEDIMENTS M49

and coarse particles, or it could indicate selective 

sorption of 46Sc over 65Zn by components in fine sizes 

(or the reverse in coarse sizes). Another possibility 

is indicated by data (Nelson, in Pearce and Green, 

1966, p. 89-90) that show a large percentage of particulate 46Sc in reactor effluent. If this particulate 

46Sc is chiefly in fine particles, which seems likely, 

then the observed particle-size-dependent 46Sc/65Zn 

ratio could be produced.

The general increase in 65Zn/60Co ratio at successive locations downstream from the Pasco location 

also indicates continued sorption of 65Zn and (or) 

desorption of 60Co. Neither relative decay during 

transport nor dilution could cause this increase; 

thus, at least partly reversible sorption and (or) 

desorption reactions apparently occur to some extent 

throughout the Columbia River.

It is not possible with data presented here, or 

presently available, to combine the two simplified 

models and to obtain a general qualitative model that 

fits all observations. Most data presented in this report favor at least partially reversible sorption 

reactions dependent mostly on solute radionuclide 

concentrations and on physical, chemical, and mineral characteristics of sediments. Under these conditions, transport of sediments would be of secondary 

importance as a control of streambed-sediment 

radionuclide concentrations. During the annual highflow period, however, and for a time thereafter until 

a steady state between solute and streambed-sediment radionuclide concentrations is reestablished, 

sediment transport may be very important. Sediment 

movement also would be important in those instances 

where high sediment concentrations or rapid deposition produce a shielding effect that prevents interchange between radionuclides in solute and sediment 

phases.

The magnitude of the radionuclide attenuation between locations bracketing tributaries remains a 

problem regardless of the origin of radionuclides in 

streambed sediments no explanation satisfactorily 

accounts for as much decrease as the data indicate. 

Resident sediments in the streambed below a tributary confluence and sediments entering from a tributary presumably attain a radionuclide concentration 

commensurate with that in the mixed waters from 

the tributary and from the mainstream. Sediments 

in a mainstream above a tributary confluence presumably have radionuclide concentrations that are 

commensurate with concentrations in the mainstream only. When the sediments are mixed, the resulting unit-weight radionuclide concentrations will 

decrease. To the extent that uptake is reversible, the 

mainstream sediments may tend to lose some radionuclides, and they may attain a concentration that is 

about equal to that attained by resident or tributary 

sediments. It is not readily apparent, however, how 

the overall decrease can exceed the decrease in solute 

radionuclide concentrations unless there is a shielding effect or the radionuclides are no longer amenable to sorption by sediments.

CONCLUSIONS

On the basis of information in this report, the 

following conclusions can be drawn:

1. Cation-exchange capacity (CEC). CEC increased 

irregularly as particle size decreased. Mean 

values for medium sands from Columbia River 

locations were 2.8 (±1.7) meq per 100 g; mean 

values for medium to fine clay were 40.8 (±5.1) 

meq per 100 g. For medium sands to clays, the 

regression of the logarithm of CEC on the logarithm of particle diameter was linear and had 

a regression coefficient of 0.6.

Mean CEC values are higher in coarse and 

very coarse sands than in medium sands; very 

fine sands have CEC values that are higher or 

nearly equal to those of medium and coarse silts. 

Irregularities in the relation of CEC to particle 

diameter were traced to the influences of occluded fines in coarse separates, to organic matter, and to mineralogy.

No statistically significant difference in CEC 

values of the various size separates was noted 

between locations at the upper and lower ends 

of the study reach. CEC values in Snake and 

Willamette Rivers size separates generally are 

slightly higher than CEC values in comparable 

Columbia River size separates, although the influence of higher CEC in tributary-sediment 

size separates was not reflected similarly in all 

Columbia River size separates.

2. Nitrogen and carbon content. Nitrogen content increases as particle size decreases. Mean values 

in medium to fine clay and in very fine sand 

are 0.45 percent (about 6 percent organic matter) and 0.04 percent (less than 1 percent organic matter), respectively. No longitudinal 

trends in nitrogen content are apparent. High 

carbon contents in coarse separates and high 

CEC values frequently correlate.

3. Mineralogy. Clay minerals make up 70-80 percent 

of all components in both the <2^ and the 2^-4^ 

size separates. The dominant clay minerals are 

illite, montmorillonite, and mixed-layer clays in 

roughly equal proportions; chlorite and kaolinite in about 2 to 1 proportions compose 10 

percent or less of the average clay-mineral
M50 TRANSPORT OF RADIONUCLIDES BY STREAMS

suite. The percentages of illite and non-clay 

components (except organic matter) increase 

and the percentages of montmorillonite, mixedlayer clays, and total clay minerals decrease as 

particle size increases from <2/x to 2/x-4/x. The 

dominant non-clay components are feldspars, 

which average 10-15 per cent of all components; quartz, which is about 6-12 percent of 

all components; and organic matter, which averages 4-6 percent of all components.

Mixed-layer clays have average CEC values 

of about 25 meq per 100 g. These CEC values 

and the apparent thermal stability of the mixedlayer clays suggest that illite and chlorite layers are abundant in the mixed-layer fraction.

The mineral suite in <2/x and 2/x-4/x separates 

from the Snake River is not appreciably different from that in the Columbia River. The Willamette River suite, however, contains more 

montmorillonite and less illite than does the 

Columbia River suite. Highly significant differences in mineral abundance along the Columbia 

River are not evident, although montmorillonite 

may increase and quartz may decrease slightly 

between Pasco and St. Helens.

Amphibole-group minerals and other non-clay 

minerals occur in increasing amounts as particle 

size increases from very fine to coarse silt. In 

the coarse silt separate, clay minerals average 

less than 15 percent of all components. Within 

the clay-mineral suite in silt separates, illite 

and kaolinite plus chlorite increase relative to 

montmorillonite as particle size increases. Although the two coarsest silt separates were 

ground prior to X-ray analyses, particle size 

may have affected estimates of mineral abundance.

Petrographic analyses of sand that was divided into five size separates and gravel that 

was unsized show that the dominant components are rock fragments, feldspars, and silicagroup constituents. Rock fragments average 

one-third to one-half of all components in the 

three finest sand separates and are even more 

abundant in coarser separates. Nearly twothirds of all rock fragments are volcanic rocks 

or volcanic glass. Maturity indices are correspondingly low. More than 25 percent of the 

feldspar grains and about 15 percent of the 

rock fragments in medium and fine sand are 

greater than one-third and one-half altered, 

respectively. Only the Willamette River, which 

has higher percentages of rock fragments and 

lower percentages of potash feldspar and silicagroup constituents, appears to have a mineral 

suite different from the Columbia River suite. 

No highly significant differences in sand-separate mineralogy occur along the Columbia 

River.

4. Radionuclide content. Chromium-51, 65Zn, 46Sc, 

54Mn, and 60Co, in generally that order of decreasing concentration, are the gamma-emitting 

radionuclides identified in Columbia River size 

separates. Zinc-65 concentrations in clay separates average 36 percent of the sum of the 65Zn 

concentrations in all size separates; fine and 

medium sands combined contain less than 2 percent. Weighting radionuclide concentrations 

with results from particle-size analyses shows 

that the relatively more abundant fine and medium sands contain nearly 45 percent of the 

total amount of 65Zn; the relatively less abundant clay separate contains only 16 percent.

Consistent irregularities in the relation of 

radionuclide concentrations to particle diameter 

correlate with variations in CEC, nitrogen-carbon content, and (or) mineralogy. Flocculation 

has been suggested to explain relatively low 

radionuclide contents in the 2/x-4ju. size.

Regression analyses show that the logarithms 

of radionuclide concentrations of size separates 

are related to the logarithms of geometric mean 

particle diameters of the separates. High correlation coefficients and low standard errors of 

estimate indicate that the relations closely fit 

linear regression lines.

Covariance analyses indicate that regression 

coefficients for relations of the logarithms of 

radionuclide concentrations to the logarithms of 

particle diameters differ significantly at the 

Pasco location for different radionuclides. No 

significant difference exists in regression coefficients for the relations of the logarithms of 

65Zn concentrations to the logarithms of particle diameters at different sample locations. 

The pooled regression coefficient for the relation 

of the logarithms of 65Zn concentrations to the 

logarithms of particle diameters is 0.6 and is 

about equal to the regression coefficient for the 

relation of the logarithms of CEC to the logarithms of particle diameter. For silt and clay 

separates, radionuclide content and CEC are 

related more directly to the difference in the 

total amount of clay minerals than to the difference in particle size.

Between successive downstream locations, 

radionuclide concentrations decrease, but not in 

proportion to distance or to half life. Greatest
COLUMBIA RIVER SEDIMENTS M51

decreases occur between adjacent locations 

bracketing major tributaries. Zinc-65, 54Mn, 

60Co, and 46Sc concentrations at St. Helens, 

Oreg., are about 1 percent of their concentrations at Pasco, Wash.

Radionuclide ratios show varying relations to 

particle size and to sample location. The 46Sc/65Zn 

ratio is an order of magnitude higher in clay 

than in fine sand, whereas the 65Zn/54Mn and 

65Zn/60Co ratios appear to be independent of 

particle size. The 65Zn/60Co ratio increases progressively at locations downstream from McNary Dam, but the 46Sc/65Zn ratio is nearly constant below McNary Dam.

Radionuclide content is directly related to 

CEC in medium-sand to clay size separates but 

tends to be independent of CEC in coarse sands. 

Increases in CEC that are greater than increases in radionuclide content have been attributed to weathering rinds on coarse particles and 

to organic-matter content.

Two simplified qualitative models have been 

used to aid interpretation of radionuclide data 

for streambed sediments. One model assumes a 

fixed streambed and reversible sorption-desorption reactions that are dependent mostly on 

concentrations of radionuclides, of their stable 

elements, and of other competing ions in ambient water. The second model involves sediment 

transport and considers irreversible rapid sorption reactions that are dependent mostly on 

solute concentrations in water that is not necessarily ambient. Most data presented in this 

report favor a model that combines features of 

the two simplified models and that includes at 

least partly reversible uptake-release reactions. 

The degree of reversibility and the rate of uptake determine the relative importance of sediment transport as a factor in interpreting 

radionuclide concentrations in Columbia River 

streambed sediments. Results from additional 

streambed-sediment and radionuclide studies 

and results from radionuclide-transport determinations can be used to further develop qualitative and quantitative models.

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U.S. GOVERNMENT PRINTING OFFICE: 1973 SIS 658/19