 

——.

‘ ‘ ' “\‘-" ‘ ‘ ' - ~ 1.1“..\‘.L'._1 4‘ ' vduﬁ ? o n 111', dean‘s ;.V~:oi.v(\-V\V~\\W. “ﬁx.— a 0*.“ '

A MEASUREMENT OF .ww LEVEL
CESIUM ssorop£ CONCENTRATIONS.
LN A FRESH WATER. LAKE . '

Thesis for the Degree of 2M . S.
MICHIGAN STATE UNIVERSITY
JAMES G. SEELYE
.1971

ABSTRACT

A MEASUREMENT OF LOW LEVEL CESIUM
ISOTOPE CONCENTRATIONS IN
A FRESH WATER LAKE

BY

James G. Seelye

Several methods of direct chemical analysis of
total cesium were examined for possible use on fresh water
samples. Special emphasis was placed on ion exchange
materials suited to use with alkali metals. The various
ion exchange materials were examined in terms of percent
uptake in relation to flow rate through the column,
chemical stability and mechanical stability. The direct
chemical methods of total cesium analysis proved to be too
insensitive for analysis of low level total cesium in fresh
water.

Radiocesium concentration was determined in fresh
water using ammonium hexacyanocobalt ferrate ion exchange
resin in a five-gram column. A field apparatus was built
to facilitate preconcentration of cesium from large volumes
of lake water at low flow rates. The cesium-137 concen-
tration in Wintergreen Lake during November 1970 was found

to be 0.0236 1 0.0024 pCi/liter.

James G. Seelye

With the failure of the direct chemical method of
total cesium analysis another method was incorporated.
Specific activities of some elements are assumed to be
equal in the water and the biological components of the
system being studied. Using this assumption and considering
equilibration times between water and fish flesh an
indirect method of obtaining total cesium in fresh water
was tested. Fish of two Species were taken and analyzed
for both cesium-137 and total cesium. Specific activities
were calculated for the two species of fish. Statistical
analysis of the mean values of specific activity of the
perch and bass indicated that there was no significant
difference between the two species of fish. Using this
result and the cesium-137 concentration in the lake water
the total cesium was calculated giving 21.16 ng/liter in

November 1970.

A MEASUREMENT OF LOW LEVEL CESIUM
ISOTOPE CONCENTRATIONS IN
A FRESH WATER LAKE

BY
I

_.4
‘1"

James G? Seelye

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Department of Fisheries and Wildlife

1971

u ‘ \
r - "
\

4‘7\:)

ACKNOWLEDGMENTS

To all the people that helped me complete my
research, I wish to express my thanks. Especially to
Dr. N. Kevern, Dr. F. D'Itri, and Dr. M. Zabik the members
of my graduate committee, for the invaluable help I
received from them.

For her tolerance and lasting support, I thank my
wife, Linda.

Lastly, I thank the U.S. (Atomic Energy Commission)
AT(ll-l)-l795 and the Michigan State University Agri-
cultural Experiment Station for financial support of my

research.

ii

 

TABLE OF CONTENTS

Chapter Page
INTRODUCTION . . . . . . . . . . . . . . 1
METHODS AND MATERIALS . . . . . . . . . . . 4
Ion Exchange Materials . . . . . . . . . 4
Ion Exchange Field Apparatus . . . . . . . 6
Cesium Determination in Water . . . . . . . 12
Cesium Determination in Fish . . . . . . . 13
RESULTS. . . . . . . . . . . . . . . . 15
Total Cesium Analysis in Water. . . . . . . l9
Cesium Isotope Analysis of Fish . . . . . . 24
DISCUSSION. . . . . . . . . . . . . . . 30
REFERENCES CITED. . . . . . . . . . . . . 36
APPENDICES
Appendix
A. Literature Review . . . . . . . . . . 39
B. Methods and Materials . . . . . . . . . 43
C. Data Tables . . . . . . . . . . . . 70

iii

LIST OF TABLES

Cesium Isotope Levels f l S.E. in Fish and

Water of Wintergreen Lake November 1970 .

Percent Recovery of Cesium-137 in Steps

of Analysis of Water . . . . . . .

Cesium Extractants Tested for Use on Acid

Digest of Ion Exchange Resin. . . . .

Specific Activities of Perch and Bass From

Wintergreen Lake November 1970 . . . .

Statistical Data for Pooled-t on Specific
ACtiVity O O I O O O O O O O 0

Statistical Data for Paired-t on Half-fish
Samples. . . . . . . . . . . .

Initial Extraction of Cesium with AMP From
Acid Fish Solution . . . . . . . .

Cesium-137 in Fish in Finish Lakes Compared
to Wintergreen Lake Fish . . . . . .

Cesium in Western American Rivers and Lakes
and Wintergreen Lake . . . . . . .

Digestion Procedure for Complex Cyanide
Resins . . . . . . . . . . . .

Procedure for AMP Extraction of Cs from Acid
Solution of Resin . . . . . . . .

Method for Cs Analysis of Sea Water Samples
(Folsom, 1970) . . . . . . . . .

Batch Absorption of Cesium from Water
Samples (Feldman and Rains, 1964) . .

iv

Page

20

22

23

25

26

26

28

33

34

44

45

46

48

Complex Cyanide Ion Exchange Resins . . .

Procedure for Elution of Cs from Zirconium
Phosphate Resin . . . . . . . .

Preparation of Complex Cyanides of Zn and
Cu (Kourim, et a1., 1964) . . . . .

Preparation of AMP (Folsom, 1970). . . .
Nitric Acid Digestion Procedure for Fish .

Cs Collection and Preparation for Flame
Emission Analysis. . . . . . . .

Flow Rate and Percent Recovery of Cesium-137

Percent Recovery of Cesium-137 on AMP from
Acid Digest of NCFC . . . . . . .

Cesium Recovered When AMP was Dissolved in
NaOH 0 I O O O O O O O O O O

Cesium Recovered from NaOH With TPB in
Hexone . . . . . . . . . . .

Page

49

50

60
61
65

68

7O

71

71

71

LIST OF FIGURES

Figure Page

1. Five gram NCFC Ion Exchange Columns Used for
Cesium-137 Determinations . . . . . . 8

2. Photograph of Ion Exchange Field Apparatus
Designed for Preconcentration of Cesium
From Fresh Water . . . . . . . . . ll

3. Percent Recovery for Ion Exchange Resins
Versus Flow Rate in Liters per Hour for
Cesium . . . . . . . . . . . . l7

B-l. Ion Exchange Apparatus Photographs
A. Micro-switch Apparatus
B. Battery and Flow Meter Box
C. Complete Apparatus Operating on
Wintergreen Lake November 1970 . . . 53

3-2. Photographs of Filters
A. Disassembled In-line Primary Filter
B. Assembled In-line Filter
C. Final Filter . . . . . . . . . 56

8-3. Photograph of Flow Rate Versus Uptake of Cs
Apparatus Used in Lab Studies. . . . . 58

B-4. Photograph of a Three Liter Digestion

Apparatus Used For Wet Oxidation of
WTlOle FiSh O O O O O O O O O O O 67

vi

NCFC
KCFC
AMP
TPB
hexone

ZrP

LIST OF ABBREVIATIONS AND NOMENCLATURES

ammonium hexacyanocobalt II ferrate II
potassium hexacyanocobalt II ferrate II
ammonium molybdophosphate

sodium tetraphenylboron

3/1 methylisobulylketone-cyclohexane

zirconium phosphate

vii

INTRODUCTION

Extensive measurements of radioactive cesium-137
concentrations in aqueous and various environmental samples
have been made. However, relatively little work has been
done on measuring total cesium in environmental samples,
and even less on measuring cesium in fresh water. Con-
siderable work has been done by Folsom (1970), on stable
cesium analysis in sea water, but generally these methods
do not apply to the low levels of cesium found in the
natural fresh water system. Methods for concentrating and
counting cesium-137 are relatively numerous (Finston and
Kinsley, 1961), when compared to methods of total cesium
analysis (Yamagata, 1965). Feldman and Rains (1964) offer
procedures for concentration and flame photometric
determination of cesium in water and biological samples.

Cesium has been shown to be concentrated con-
siderably with increasing trophic levels (Gustafson, 1966;
Pendleton, 1962). This biological amplification introduces
a possible hazard, not only to the higher trOphic level
organisms but also to man, using the organisms for food.

Stable cesium levels must be known to better understand the

dynamics of cesium in the ecosystem. Also stable cesium
has become of practical importance with its use as the
main constituent in the photoelectric cell.

This study was originally designed to develop a
method of total cesium analysis that was applicable to the
analysis of total cesium in fresh water. Numerous methods
using proconcentration and detection have been suggested
but few apply to the very low fresh water concentrations
encountered in most lakes and streams. Initially efforts
were directed toward a direct chemical method for total
cesium analysis. Pursuit of this type of method proved to
be quite futile considering available detection methods.
An alternative to the direct method of cesium analysis has
been hypothesized and was incorporated into the design.
This indirect method of obtaining total cesium concen-
tration consists of analysis of a biological factor or
factors of the fresh water system in question, for both
cesium-137 and total cesium. Yellow perch (P2522.
flavescens) and largemouth bass (Micropterus salmoides)
were chosen for this use. Using cesium concentrations in
the fish and the cesium-137 content of the water, the
total cesium could be calculated with more accuracy and
precision than the direct methods of cesium determination.
This method, based on the specific activities being equal
for the fish and the water, shows promise to be a good

method of isotope determination (Nelson, 1967).

Considerable methodology was developed for the
collection of cesium samples from fresh water lakes.
Methods for cesium analysis in whole fish also were

improved.

METHODS AND MATERIALS

Methods were developed for preconcentration of
cesium from lake water and analysis of cesium isotopes in

fish. Direct methods of cesium analysis also were explored.

Ion Exchange Materials

 

In the past decade a number of ion exchange
materials have been studied in terms of selectivity for
alkaline earth elements. The majority of the highly
specific exchangers fall in the class of inorganic anionic
exchangers. The group most suited to column operation is
the complex cyanides of heavy metals. These complex
cyanides have an affinity for the alkaline earths in the

following order:
C5 > Rb > K > Na > Li

The complex cyanides, using cobalt as the heavy metal, are
the strongest cesium sorbents (Kourim, et_al., 1964).

The alkali metals are bound with increasing
strength according to their increasing ionic radii, with
cesium having the largest ionic radius of the series

(Tananajev, et a1., 1957).

Some other ion exchange materials available for
use with cesium are ammonium molybdophosphate (AMP) used
as a batch absorber and quite specific for cesium (Feldman
and Rains, 1964), and zirconium phosphate. The zirconium
phosphate is suited to column operation but is much less
specific for cesium in the presence of potassium and sodium
(Macek, §t_al,, 1963). Dowex 50, a strongly acid cation-
exchanger also has been applied to cesium uptake, however,
it is not nearly specific enough for cesium uptake from
water containing relatively large concentrations of other
alkali metals.

The chemical stability of the complex cyanides in
general is as follows: Quite stable in mild alkaline
solutions and in neutral solutions, but soluble in concen-
trated H2804 and shows tendency to peptize in other
strongly acid solutions (Kourim, gt_al., 1964). The most
structurally stable of the complex cyanides are the copper
and zinc forms. Zirconium phosphate is stable in strong
acids and neutral solutions but breaks down somewhat in
strong alkaline solutions. It is structurally very stable
and excellent for use in columns. Ammonium molybdophosphate
(AMP) is a microcrystaline substance that is structurally
quite stable. It is chemically stable in strong acid to
neutral solutions but dissolves readily in alkaline
solutions. A number of the ion exchange materials suited
to column use were tested in the laboratory for cesium

uptake. Potassium hexacyanocobalt II ferrate II (KCFC),

ammonium hexacyanocobalt II ferrate II (NCFC) and
zirconium phosphate (ZrP) were studied in respect to uptake
of cesium at various flow rates through the column. The
columns were prepared using 1.0 inch by 2.67 inch poly-
styrene vials. The bottom of the vial was removed and a
polyethylene porous (120u) disk was placed in the bottom.
Five grams of the ion exchange material were slurried in
distilled water until saturated. This soaked resin was
poured into the vial and another polyethylene porous disk
(120u) was placed on top of the resin. The columns were
stored under distilled water until used. Figure 1 is a
photograph of columns prepared using NCFC. The NCFC,
KCFC, and ZrP were obtained commercially from Bio Rad
Laboratories. The AMP was prepared using a procedure
described by Folsom (1970). The copper and zinc ferro-
cyanides were prepared using a method described by Kourim,

et a1. (1964).

Ion Exchange Field Apparatus

 

In order to preconcentrate enough cesium-137 on a
five gram ion exchange column to facilitate a statistically
accurate count in a reasonable counting time, it was
estimated that at least four hundred liters of water must
be passed through the column. As it was not feasable to
transport this volume of water to the laboratory, a
constant flow apparatus was designed and built to operate

in the field. This system was built completely of

.mcoﬂumcHEumpop
smalasﬂmmo How poms chdHoo mmcmnoxm cod omuz Emumum>ﬂmll.a ousmﬂm

 

polyethylene to minimize the loss of cesium due to
adsorption on the container walls. A polyethylene (20
gal.) container fitted with a polyethylene valve at the
bottom and a micro-switch float assembly at the top served
as a constant head reservior. The float was set to
maintain a desired head in the container and thus to
produce a suitable flow rate through the column. The
micro-switch was connected to the lead of a submersible

12 volt water pump contained in a plexiglas frame surrounded
by plankton netting. The netting functioned as a primary
filter to keep large particles out of the system. The
pump outlet was connected through one half inch tygon
plastic tubing to a check-valve. The check-valve was
connected to a volume recording flow meter. From the flow
meter the water passed through two in-line filters and into
the 20 gallon container. When the water level reached the
preset level, the micro-switch breaks contact and the flow
of water into the container stOps. After approximately
ten liters of water had run out through the ion exchange
column the micro-switch is actuated and the container is
refilled to the preset level. Two 12 volt auto batteries
connected in parallel were used for electrical power to
run the pumps. Two identical systems were set up to
facilitate duplicate sampling of the lake simultaneously.
A photograph of the entire duplicated system is shown in

Figure 2.

10

Figure 2. --Photograph of ion exchange field apparatus _
designed for preconcentration of cesium from fresh water.

ll

 

 

“We. '_. _-_..-.._...
ti'ysk 3'.

:3-

 

12

Cesium Determination in Water

 

Radiocesium was determined by preconcentrating the
cesium on a five-gram column of NCFC and counting the
columns on a solid scintillation well type gamma counter.
Ion exchange columns were used with the continuous flow
field apparatus. Approximately 475.0 liters of lake water
per sample were passed through the column to concentrate
the cesium.

Methods of direct total cesium analysis were
attempted but none gave a satisfactory result. Several
methods were tested. A batch absorption of cesium was
attempted using the method proposed by Feldman and Rains
(1964). The greatest emphasis was on a method proposed by
Folsom (1970) and other similar methods. Generally they
consiSted of using a column preconcentration of cesium, an
acid digestion of the ion exchange resin, extraction with
AMP and a liquid-liquid extraction into an organic solution
suitable for flame emission analysis for cesium. A slight
variation of this method involved preconcentration of
cesium on an ion exchange column and an extraction directly
from the acid solution of the resin into an organic so-
lution. A number of different compounds were tested for
their cesium extracting abilities. One of these methods
was described by Flynn (1970) involving the use of a phenol
nitrobenzene mixture.

With the failure to find a suitable direct method

for total cesium analysis, an indirect method was devised.

13

Fish samples that consisted of yellow perch and largemouth
bass were taken by hook and line from the study lake.

These fish were analyzed for cesium-137 and total cesium.
With the specific activity of the cesium-137 in the fish
and the cesium-137 concentration of the water the total
cesium concentration was calculated for the water. This
was done assuming the specific activity of the cesium-137
was the same in the fish and the lake water (Nelson, 1967).

r137CS in PCi/g in fish = 137Cs in pCi/ml in water
TotaI Cs in ng7g*in fiEH' Total Cs in ng/ml in Water

 

 

Both perch and bass were used in this analysis to allow a
means of comparing specific activities. If the assumption
that there is no discrimination for either cesium-137 or
stable cesium in the aquatic system is true, the specific
activities should not vary significantly between the perch
and the bass. By measuring both the cesium-137 and the
total cesium in the perch and bass and then testing the
means of the specific activity of the fish statistically
and showing them to be equal would lend considerable
strength to the assumption.

The lake chosen for testing this assumption was
Wintergreen Lake. It is located in Kalamazoo County Tls,

R9W, Section 8, Lat. 42, Lon. 85 and elevation 890 Ft.

Cesium Determination in Fish

 

The analysis of cesium in whole fish is largely

involved with preconcentrating the cesium and getting it

14

into a matrix suitable for the detection equipment
available. Feldman and Rains (1964) proposed a method of
cesium analysis in tissue ash samples. This method was
used as a basis for the method used for fish analysis in
this study. Whole fish were frozen, cut into small pieces,
weighed and placed in the digestion flask. A wet nitric
acid digestion was used to dissolve the fish using about
3ml of concentrated nitric acid per gram wet weight of
fish. AMP was used as a scavenger in the fish solution to
collect the cesium isotopes; 4.0 mg per gram wet weight of
fish were used. The AMP was collected by centrifugation
and then dissolved in 1.0N sodium.hydroxide. This solution
was made acidic using powered tartaric acid and again
extracted with AMP using 0.4mg/g of fish. This AMP was
collected and counted to determine cesium-137 concen-
trations in a solid scintillation gamma counter. The AMP
was then dissolved in l.ON NaOH and extracted into a 3/1
methylisobutylketone-cyclohexane solution of sodium
tetraphenylboron (TPB) (0.1N). This organic solution of
TPB was retained for flame emission analysis for cesium at
8521K, A Jerrell-Ash model 82-800 atomic absorption
instrument was used. The instrument was equipped with an
infrared blazed grating and a red sensitive photomultiplier,

R446. A compressed air and hydrogen gas flame was used.

RESULTS

Flow rate versus percent recovery of cesium-137 was
studied for three of the ion exchange materials suited to
column use. NCFC, KCFC, and ZrP were the three resins
tested. Results of the tests are shown graphically in
Figure 3. These results were determined using five-gram
columns of each type of resin. Six liter distilled water
samples were spiked with a known cesium-137 activity. The
water was run through the column and the flow rate
determined using a timer. The columns were counted in a
3" NaI(Tl) crystal and percent recovery of cesium-137
calculated.

lOOX cpm on column
cmeIn spike

 

Percent recovery =

A linear relationship between flow rate in liters per hour
and percent recovery was found between five and thirty
liters per hour, varying among resins. From Figure 3 it
can be seen that the ammonium hexacyanocobalt II ferrate
II ion exchange resin has the least decrease in percent
recovery for increased flow rate of the three exchangers

examined. Because of this percent recovery and also

15

16

Figure 3. Percent recovery for ion exchange resins
versus flow rate in liters per hour for cesium.

IOO

90

I37

80

70

Percent recovery of CESIUM

60

 

17

_ NCFC rosin
---.. KCFC rosin

_ _ ZrP rosin

 

i l l 1 I A

4 8 l2 I6 20 24
Flow rate in liters per hour

18

because the NCFC resin offers a method of potassium

removal (Petrow and Lavine, 1967), the NCFC resin was used
for preconcentration of cesium isotopes. The ion exchange
columns were tested using cesium-137 spiked water samples
loaded with K+, NH+, and Na+ to test the effect of inter-
fering ions on the uptake of cesium. The K+ concentration
used was 2000 mg/liter, Na+ was 4000 mg/liter and the

NH: concentration was 500 mg/liter in the six liter
samples. These high concentrations were used to approxi-
mate the total amount of the ion that would be encountered
in 100 gallons of lake water. The spiked water samples
were run through the columns at approximately seven liters
per hour. The K+ and Na+ gave no decrease in percent re-
covery for the NCFC or the KCFC, however when 2000 mg/liter
K+ were run through the ZrP resin only 8 per cent recovery
of the cesium was obtained. The NH: samples, when run
through the NCFC and KCFC columns showed a slight depressing
effect on the percent recovery of Cs. The percent recovery

of Cs on the NCFC with 500 mg/liter NH+ was 91.0% while the

4
percent recovery on the KCFC was 93.0%. This depressing
effect was considered quite unimportant in this application
of the resin. The levels of NH: in fresh water are usually
very low, only 30-60 ug/liter as reported by Vetter (1938).
The determination of cesium-137 in Wintergreen Lake

was accomplished using NCFC resin in five gram columns and

the continuous flow ion exchange apparatus. These columns

19

of NCFC resin were tested at approximately 15 liters/hr.
and were counted at 0.662 Mev for cesium-137 long enough
to give 95% accuracy. The average concentration of
cesium-137 in Wintergreen Lake in November 1970 is given
in Table 1.

Elution of cesium from the NCFC columns was also
attempted. Thallium nitrate, sodium hydroxide, and nitric
acid were tried in varying concentrations and at various
temperatures, but no satisfactory results were obtained.
Results of elution attempts are given in Table B-5 in the

appendix.

Total Cesium Analysis of Water

 

The results of the various direct methods for
total cesium in fresh water are mainly negative. The one
procedure common to all of the methods examined, is the
final step; the quantative detection of the cesium. Flame
emission analysis is the most sensitive widely available
method of cesium detection. The Jarrell-Ash model 82-800
instrument used was one of the most sensitive available.
The detection limit of cesium in hexone TPB solution was
approximately 0.05 mg/liter. In order to obtain repro-
ducible readings at least 0.1 mg/liter of cesium should be
used. To preconcentrate cesium in fresh water so that
enough cesium is collected to give a detectable amount of
cesium on an ion exchange column is not difficult, however

the handling of the cesium once it has been collected is

20

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owma hmha umum3
oxma Ho>o Esﬂmmo

HMﬂOu. MO HOﬂOMM

coﬂumupcmocoo
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uwamz mxmq comma zoaamw mmmm QDSOEmmumq

 

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mxmq cmmumumucﬂz mo umumz pcm swam ca .m.m H + mam>ma omop0mﬁ Esﬂmmour.a mqmﬂa

21

quite difficult. For flame emission analysis the cesium
must be in a solution that is fairly low in total solids
and as low as possible in interfering ions.

The methods investigated were generally involved
with preconcentration of cesium on an ion exchange material
specific for cesium, a series of purification steps, and a
final extraction into an organic solution to be aspirated
into the flame emission instrument. The majority of the
methods were based on one method described by Folsom
(1970). This method uses a complex cyanide resin, AMP,
and the tetraphenylboron hexone solution to accomplish
analysis of Cs in sea water. Individual steps of the
procedure were examined using cesium-137 spikes to
determine percent recoveries. The average values of
percent recovery are given in Table 2. Another method
tested involved the extraction of the cesium directly from
a sulfuric acid digest solution of the ion exchange resin.
A number of extractants were examined for their ability to
absorb cesium. A list of these compounds and percent
recoveries of cesium-137 are given in Table 3. Batch
methods of cesium concentration using AMP as a scavenger
(Feldman and Rains, 1964), gave no detectable cesium-137.
AMP is not extremely specific for cesium uptake in the
presence of interfering ions, such as K+ and Na+. Because
of this and also because large volumes of water are

difficult for batch absorptions using a microcrystaline

22

TABLE 2.--Percent recovery of cesium-137 in steps of
analysis of water.

 

137

 

Step of Procedure Percent Recovery of Cs
Digestion of ion exchange
resin in H SO 100

2 4

Extraction of Cs from
digested resin using AMP 51.0:19
Solution of AMP in l.ON NaOH 50.0110
Extraction of Cs into 0.1N
Tetraphenylboron in hexone 30.719

Total %-recovery of Cs for entire method is 7.7%

 

23

 

 

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o.¢H wpﬂuoHnomuumu conumu ZH.o HocmgmﬁamusmnamnumﬁvImlamusnuommuv
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o.o mpﬂuoanomuumu conumu Zo.H Hosmnmaacmnmoguuo
o.o msmucmnouuﬂz .u3\.u3 wm.nm Hocmzm
m0 m0 usm>aom pcmuomnuxm

>Hm>oomm usmonmm

 

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own How Umummu mucMDomnuxm EsﬂmmOII.m mqm¢9

24

exchanger, this method was not considered a feasable

solution to the problem of cesium analysis in fresh water.

Cesium Isotopes Analysis of Fish

 

Nine largemouth bass and ten yellow perch samples
were digested in nitric acid and analyzed for cesium-137
and total cesium. The average values of the concentrations
obtained are given in Table 1. Concentration factors of
cesium in the fish over the cesium concentration in the
lake water also are given in Table 1. Individual values
of specific activity in the perch and bass are given in
Table 4. Average specific activites of the yellow perch
and largemouth bass were calculated and a pooled-t sta-
tistical comparison of means was performed. The evidence
indicated that there was no significant difference between
the specific activities of the bass and perch with P < 0.5.
The data for the pooled-t test are given in Table 5. Six
largemouth bass were cut in half (dorsal-ventral longi-
tudinally) and each half was treated as a separate sample.
The specific activities were calculated for each half and
a paired-t comparison of means was run on the results. The
evidence indicated that the subsample means were equal with
P < 0.1. This indicates that there is no great variation
in the procedure used for fish analysis. The data for the
paired-t test performed are given in Table 6.

The method used for determination of cesium in fish

was examined in terms of total percent recovery of cesium.

25

TABLE 4.--Specific activites of perch and bass from Winter-
green Lake November 1970.

 

Specific Activity

 

Sample Code in pCi/ng
Largemouth Bass
Wi-l 0.010
Wi-2 0.008
Wi-5 0.012
Wi-7 0.011
Wi-8 0.015
Wi-13 0.015
Wi-16 0.009
Wi-21 0.012
Wi-22 0.014
Yellow Perch
Wi-3 0.010
Wi—4 0.010
Wi-lO 0.017
Wi-ll 0.015
Wi-l4 0.008
Wi-15 0.008
Wi-17 0.009
Wi-18 0.009
Wi-l9 0.008
Wi-20 0.009

 

26

TABLE 5.—-Statistical data for pooled-t on specific

 

 

activity.
Largemouth Bass Yellow Perch
n = 9 n = 10

2 x1 = 0.105 V 2 X2 = 0.103

X1 = 0.0117 X2 = 0.0103

2 2-
S1 = 0.000054 81— 0.000058
Calculated t = 0.408 Critical value t = 0.689
(.5,17)

 

TABLE 6.--Statistical data for paired-t on half-fish
samples.

 

Sample 1 Sample 2

 

n = 6 pairs

2 x1 = 0.078 2 x2 = 0.033
x1 = 0.013 x2 = 0.0138
s: = 0.0000065

Calculated t = 1.73 Critical value t( 1 5): 2.015
- I

 

27

The critical step was found to be the first batch ion
exchange using AMP to remove the cesium from the digested
fish solution. A sample of four fish was used. Multiple
extractions using AMP were performed on the acid fish
solutions until no more cesium-137 activity was removed.
Two extractions proved to be sufficient for this purpose.
Using the total cesium—137 activity obtained from both
extractions, a percent uptake of cesium was calculated for
each of the fish. The average value was 82.8:2.3% for the
multiple extractions. The same acid solutions with cesium
removed by multiple extractions were then spiked with a
known activity of cesium-137. The spiked solution was
again extracted with AMP and percent recovery calculated,
the average value being 71.2 1 1.67%. For an estimate of
the actual percent uptake using one AMP extraction, an
average was taken of the two methods, giving a value of
77.0%. This value was used in calculating cesium concen-
trations in the fish. The data used for this calculation
are given in Table 7.

Fish samples were taken two weeks after the lake
had overturned and within one week of the cesium-137
determination on the lake water. The date of water
sampling was November 23, 1970. Water samples were taken
from surface to bottom for analysis of K+ and Na+ by flame
emission. The K+ and Na+ concentrations demonstrated that

the lake was in a state of thorough mixing. The values of

28

TABLE 7.--Initial extraction of cesium with AMP from acid
fish solution.

 

 

Spiked Samples Multiple Extractions
72.0% 86.0%
70.5% 83.6%
73.3% 82.6%
69.0% 79.0%
X = 71.2:1.67% X = 82.8:2.3%

Average of Two Methods:

77.0:3.79%

 

29

K+ and Na+ concentration were 5 mg/Liter and 6.4 mg/Liter

respectively for all five depths tested demonstrating that
the lake water was a homogenous mixture during the sampling

period.

DISCUSSION

NCFC ion exchange columns were used for cesium
isotope preconcentration for a number of reasons. The
NCFC columns showed the best percent recovery for in-
creasing flow rates of the three resins tested. This
NCFC resin also has a low level of potassium in its
structure and offers a method of potassium removal by
passing ammonium nitrate through the column, to elute the
potassium and leave the Cs (Petrow, §E_al., 1967). This
resin also exhibits great selectivity for cesium over
potassium and sodium. This factor is very important when
working with lake water that contains considerable concen-
trations of these elements. The NCFC resin also exhibits
good structural stability when used in columns for pre-
concentration of cesium.

The methods of direct determination of total cesium
that were tested showed little promise for use in fresh
water of low cesium content. Most methods that are now
being used for total cesium analysis were designed for
water of a significantly higher cesium concentration than

exists in the lake that was examined. These methods were

30

31

designed for use in salt water and contaminated water such
as reactor effluents and are simply not sensitive enough

to give precise results in low cesium waters. Methods of
direct total cesium determination proved to be quite unreli—
able when used with low cesium concentrations. values

of percent recovery for individual steps of procedures and
total percent recovery for the steps tested showed that the
methods are not suitable for the low total cesium concen-
tration in most fresh water lakes and streams.

The limiting step in the use of direct methods of
total cesium analysis is the last, the quantative de-
tection of the cesium. Flame emission is the most widely
used and is currently the best method. Neutron activation
analysis could prove to be a more sensitive method of
detection, allowing that a procedure would be available to
preconcentrate the cesium in a matrix that is suitable for
this method.

Nelson (1967) used specific activity of cesium for
calculation of concentration of cesium isotope in fish.
Using this method for calculating concentrations seemed to
be an analytically reliable procedure. Comparing the
specific activity in two species of fish and supporting
the evidence that these values are equal does strengthen
the argument that the specific activity is constant.
Assuming that the specific activity is the same in the

water, one needs only cesium-137 activity of the water to

32

calculate the total cesium concentration of the water. The
level of cesium-137 in age 3 perch was substantially lower
in Wintergreen Lake in 1970 than in Finnish lakes in 1963
(Kolehmainen, et_al., 1966). Values of cesium-137 found by
Kolehmainen are given in Table 8. Some of this difference
could be explained by the level of fallout receding greatly
since then. The Clinch River Study (1967), established that
69 to 92 percent of the cesium-137 was associated with
suspended particles. With the input of cesium-137 being
reduced and because the cesium-137 is largely associated
with particulates (Nelson, D. M., et_§13, 1970) which settle
to the bottom making the cesium-137 unavailable the levels
of cesium-137 in the fish would decrease. In addition

there may be minor losses of soluble and suspended cesium—
137 from the lake resulting from terrestrial and semi-
aquatic organisms using the lake. In this sense the lake
becomes a source rather than a sink for cesium-137

according to Gustafson (1966).

In calculating the total cesium concentration in
Wintergreen Lake, a weighted average of the mean values of
Specific activity for the perch and bass was used. The
calculated value seems quite reasonable considering Winter-
green Lake. The lake has a large input of foreign material
from the water fowl that use the lake. This would tend to
increase the amount of trace elements found in the water
and fish. Sreekumaran, gt_§l. (1968) gives values of

cesium in western American rivers and lakes which agree

33

TABLE 8.--Cesium-137 in fish in Finnish lakes compared to
Wintergreen Lake fish.

 

Cesium-137 in
Lake and Fish Age nCi/kg Fresh Wt.

 

Finnish 1akes*

 

 

 

 

Perch
(Perca fluviatilis) 3 16.1
5 25.1
Pike
(Esox lucius) 3 15.8
4 16.2
Burbot
(Lota vulgavis) . . 1.53
3.28
Wintergreen Lake
Perch
(Perca flauescens) 3 0.343
Bass
(Micropterns salmoides) 3 0.438

 

 

*Kolehmainen, et a1., 1966.

34

TABLE 9.--Cesium in western American rivers and lakes and
Wintergreen Lake

 

Locality ' Date Cesium in ug/liter

 

Lake Mead* 28-1-67 0.057

Colorado River, end of
Iceberg Canyon* 29-1-67 0.022

Colorado River at
Moreles Dam* 21-2-67 0.023

Wintergreen Lake
(This Study) 0.021

 

*Sreekumaran, et a1., 1968.

35

favorably with the values obtained (Table 9). Assuming

that there is no preferential uptake of either of the

cesium isotopes, this method should be a sound determination
of total cesium. Further work should be done to test the
soundness of the specific activity assumption. More

diverse biological components of the aquatic system could

be tested and variations due to changing food habits might

be explored.

REFERENCES CITED

REFERENCES CITED

Amphlett, C. B., L. A. McDonald, J. S. Burgess and J. C.
Manard. 1959. Synthetic inorganic ion-exchange
materials—III. The separation of Rubidium and
Cesium on zirconium phosphate. J. Inorg. Nucl.
Chem. 10:69.

Boni, A. L. 1966. Rapid ionexchange analysis of radio-
cesium in milk, urine, seawater, and environmental
samples. Anal. Chem. 38 (l):89-92.

Clinch River Study. 1967. Comprehensive report of the
Clinch River study. ORNL-4035.

Crowther, P. and F. L. Moore. 1963. Liquid-liquid
extraction of cesium with 2-thenoyltrifluoroacetone.
Anal. Chem. 35:2081.

Edgington, D. N., M. M. Thommes and C. I. Harrison. 1968.
Separation of cesium and rubidium by the ferro-
cyanide of copper, zinc and zirconium. Argon
National Lab Radiological Physics Division Annual
Report ANL-7615.

Egan, B. Z., R. A. Zingare, and B. M. Benjamin. 1965.
Extraction with 4-sec-buty1-2(a-methylbenzyl)
phenol (BAMBP). Inorg. Chem. 4:1055.

Feldman, C. and T. C. Rains. 1964. The collection and
flame photometric determination of cesium. Anal.
Chem. 36:405.

Finston and Kinsley. 1961. The Radiochemistry of cesium.
National Academy of Science, National Research
Council Nuclear Science Series.

Flynn, W. W. 1970. A rapid solvent extraction method for

the determination of cesium-137 in environmental
materials. Anal. Chem. Acta 50:365.

36

37

Folsom, T. R. 1970. Some reference methods for determining
radioactive and natural cesium for marine studies.
Reference methods for Marine Radioactive Studies,
Annex IV, I.A.E.A. Vienna.

Folsom, T. R. 1970. Personal communications.

Gustafson, P. F. 1966. Comments on radionuclides in .
aquatic ecosystems. Radioecological Concentration
Processes Pergamon Press, London 1040.

Gustafson, P. F. 1967. Cesium-137 in fresh water fish
during 1954-1965. Symposium on Radioecology 249.

Horner, Crouse, Brown, and Weaver. 1963. Cesium recovery.
Nucl. Sci. Eng. 17:240.

Kahn, B., D. K. Smith and C. P. Straub. 1957. Determi-
nation of low concentrations of radioactive cesium
in water. Anal. Chem. 29:1210.

Kolehmainen, S., Hasanen and J. K. Miettinen. 1966.
37Cs levels in fish of different limnological
types of lakes in Finland during 1963. Health
Physics 12:917-922.

Kourim, V., J. Rais and B. Million. 1964. Exchange
properties of complex cyanides-I. J. Inorg. Nucl.
Chem. 26:1111-1115.

Maeck, W. J., M. E. Kussy and J. E. Rein. 1963. Ad-
sorption of elements on inorganic ion exchangers
from nitrate media. Anal. Chem. 35:2086.

Mohanrao, G. J. and T. R. Folsom. 1963. Gamma-ray
spectrometric determination of low concentrations
of radioactive cesium in sea water by a nickel
ferrocyanide method. Analyst 88:105.

Nelson, D. J. 1967. The prediction of 908r uptake in
fish using data on specific activities and bio-
logical half lives. Radiological Concentration
Processes Pergamon Press, London 843.

Nelson, Donald M., G. P. Romberg and W. Prepejchal. 1970.
Radionuclide concentrations near the big rock
point nuclear power station. Argonne National
Laboratory.

38

Palmer, H. E. and T. M. Beasley. 1967. Fe-SS in the
marine environment and in people who consume
ocean fish. Radioecological Concentration
Processes. Pergamon Press, London 1040.

Pendleton, R. C. and W. C. Hanson. 1958. Absorption of
cesium-137 by components of an aquatic community.
2nd UN Geneva Conference. Pergamon Press, London.

Pendleton, R. C. 1962. Accumulation of cesium-137 through
the aquatic ecosystems. Radioecological Concen-
tration Processes. Pergamon Press, London.

Petrow, H. G. and H. Lavine. 1967. Ammonium hexacyanoco-
balt ferrate as an improved inorganic exchange
material for determination of cesium-137. Anal.
Chem. 39:360.

Prout, W. E., E. R. Russell and H. J. Groh. 1965. Ion
exchange absorption of cesium by potassium
hexacyanocobalt II ferrate II. J. Inorg. Nucl.
Chem. 27:473-479.

Ross, W. J. and J. C. White. 1964. Determination of cesium
and rubidium after extraction with 4-sec-butyl-2-
(a-methylbenzyl) phenol. Anal. Chem. 36:1998.

Sekine, T. and D. Dyrssen. 1969. The solvent extraction
of alkali metal tetraphenylborates. Anal. Chem.
Acta. 45:433-446.

Smit, J. vanR., W. Robb, and J. J. Jacobs. 1959. Cation
exchange on ammonium molybdophosphate-I. The
Alkali Metals. J. Inorg. Nucl. Chem. 12:104-112.

Sreekumaran, C., K. C. Pillai and T. R. Folsom. 1968.
The concentration of lithium, potassium, rubidium,
and cesium in some western American rivers and
marine sediments. Geochimica et. Cosmochimica
Acta. 32:1229-1234.

Tananejev, I. V. and Gluskova. Zh. Neorg. Khim. 2:281.

Vetter, H. 1937. Limnologische Untersuchungen ﬁber das
Phytoplankton und seine Bezihungen zur Erﬁahung
des Zooplanktons in Schleinese bei Langenangen am
Bodensee. Int. Rev. Hydrobiol. 34:499-561.

Yamagata, N. 1965. Review on the analytical methods for
the stable and radioactive cesium. Dept. of
Radiological health. The Institute of Public
Health, Tokyo UDC. 543.036:546.36.

APPENDICES

APPENDIX A

LITERATURE REVIEW

APPENDIX A

LITERATURE REVIEW

RadioisotOpe accumulation in our environment was
not considered extremely important until the advent of the
atomic and hydrogen bombs and more recently the thermal
nuclear power plant. Considerable effort is now being
asserted to understand the cycling of the biologically
active isotopes in our ecosystems. One of the most
important parameters controlling the radioisotope dynamics
is the stable isotope of the element.

Cesium, at. wt. 132.905; at. no. 55; m. p. 28.5 C;
B. P. 690 C; sp. gr. 1.873 (20 C) valence 1, was spectro-
graphically discovered in 1860. Cesium occurs in
lepidolite, polucite (hydrated silicate of aluminum and
cesium) and is the most electropositive and most alkaline
element. Cesium has recently become one of the chief
components in the photoelectric cell. It also has been
found that it may have application in ion propulsion
systems. Trace amounts of cesium-137 from fallout and

thermal nuclear plants are present throughout the world.

39

40

Cesium-137 is found as a result of the following decay

scheme:

137 19 137 3.4 137 30.5 137
1W xeﬁ‘fﬁ‘) CSW Ba (stable)

A 30.5 year half life allows sufficient time for consider-
able biological accumulation. Cesium has been compared to

potassium in biological reactivity.

Ion Exchange Materials

 

Several papers have been published on the complex
cyanides and their use as sorbers of the alkali metals.
Petrow, et_al. (1967) describes NCFC as an improved resin
for use with cesium; Prout, et_al, (1964) discusses KCFC
as a cesium sorber; Mohanrao, gt_al, (1963) used nickel
ferrocyanide for cesium-137 determinations. Kourim, et_al,
(1964) and Edgington, et_al. (1969) review and compare
many of the forms of complex cyanides.

Yamagata (1965) reviews many of the ion exchangers
used in cesium work while Maeck, e£_§1. (1963) compares
zirconium exchangers at different pH values and Amphlett,
eE_al. (1958) discusses separation of rubidium and cesium
on zirconium phosphate resin. Feldman and Rains (1964)
used AMP as a cesium scavenger in water and biological
samples while Kahn, gt_al. (1957) used a precipitation
method of cesium determination with AMP being formed and

Van, et a1. (1959) described AMP as an exchanger for

41

alkali metals using an asbestos mixture to facilitate its

use in column form.

Cesium Analysis in Water

 

Methods of cesium analysis have been largely
involved with areas of relatively high cesium concen-
tration. Much of the preconcentration processes were
involved strictly with cesium-137 in reactor effluents.
Methods of total cesium analysis are offered by Feldman and
Rains (1964), but results of tests on this method showed it
to be not nearly sensitive enough for low levels of cesium
found in water of this southern Michigan area. Folsom
(1970) gives many methods, but all are designed for sea
water. Yamagata (1965) gives a summary of methods of
cesium analysis but most apply to higher levels than are
present here. He also covers methods of cesium analysis in
biological materials and gives a fairly complete reference.
Feldman and Rains (1964) offer a method of cesium analysis
in biological samples that was used with some alterations
in this study and gave favorable results. Methods were
also examined using a liquid-liquid extraction of cesium
from the acid solution of the ion exchange resin used for
preconcentration. Flynn (1970) reports a rapid solvent
extraction using a phenol nitrobenzene solution. Sekine
and Dyrssen (1969) discuss the use of tetraphenylborates
for use with alkali metals; Horner, et_al. (1963) used

substituted phenols in a suitable diluent for recovery

42

of cesium. The use of 4-sec-butyl—2-(-methylbenzyl)
phenol (BAMBP) as a cesium extractant is discussed by
Egan, et_al, (1964) and Ross and White (1964) also report
the use of BAMBP. Crowther and Moore (1963) used 2—

thenoyltrifluoroacetone for liquid-liquid extraction of

 

cesium.
Specific Activity
Specific activity has been used by Nelson (1967)
to predict 90$r uptake in fish. Nelson (1967) also used

specific activity data to calculate cesium-137 levels in
white crappies. He showed the specific activity of
strontium in the water to be very close to that in the fish
samples. Using results from Pendleton, et_al. (1958) on
equilibration time between cesium in fish flesh and water
the fish were sampled at a time that would reflect the
concentration of cesium in the water. Pendleton reported
about 10-12 days for equilibration between the cesium in
fish flesh and in the water. Other investigators have
indicated the equality of specific activity of cesium in
fish and their surroundings (Folsom, et_al., 1967 and

Palmer and Beasley, 1967).

APPENDIX B

METHODS AND MATERIALS

APPENDIX B

METHODS AND MATERIALS

The methods of direct total cesium analysis are of
three major types: The first and most common involves
preconcentration of cesium on ion exchange columns,
digestion of ion exchange resin, extraction with AMP,
solution of the AMP, and finally liquid-liquid extraction
into an organic phase suited to flame emission photometery.
The method of NCFC digestion is given in Table B-1. The
procedure for preparation of cesium analysis from digested
resin is given in Table B-2. A method prOposed by Folsom
(1970) is given in Table B—3. The second type of method
uses the same preconcentration method employing an ion
exchange column. The resin is digested in acid and a
liquid-liquid extraction is performed directly on the acid
solution. Various extractants were examined for their
extraction power of cesium. A list of extractants and
percent recovery of cesium-137 is given in Table B-3.

The third method involves a batch absorption of cesium.
AMP was added directly to a volume of water, slurried and

collected. This AMP was dissolved and the cesium was

43

44

TABLE B-l.--Digestion procedure for complex cyanide resins.

 

Dry a 5g resin sample for 8 hrs. at 70 C.

Place dry resin in 500ml boiling flask; add 10ml conc.

Boil gently with reflux condenser for 1-4 hours, until
residue is pink-purple color.

Allow to cool.

Add 50ml of distilled water slowly; bring to a gentle
boil.

Continue refluxing 1—3 hours, until resin is completely
in solution.

Cool solution.

 

45

TABLE B-2.--Procedure for AMP extraction of Cs form acid

solution of resin.

 

10.

11.

Place resin solution in a 200ml Pyrex beaker.
Put solution on a magnetic stirrer.

Adjust pH to approximately 2.5 with 5N NaCH and remove
pH electrodes.

Add AMP (2.59) and stir for 30-60 min.
Remove stirring bar and allow AMP to settle.
Decant the clear liquid from the top.

Place the slurried AMP in a 50ml centrifuge tube and
centrifuge.

Decant the supernatant and discard.
Dissolve AMP in about 20Ml l.ON NaOH.

Place solution in a sepratory funnel and add 20ml
0.1N tetraphenylboron in hexone and shake.

Separate upper organic layer and retain for flame
emission analysis.

 

46

TABLE B-3.--Method for CS analysis of sea water samples

(Folsom, 1969).

 

1.

lo.
11.

12.

l3.

14.

15.
16.

17.

Dried ion exchange granules are covered with 5 times
their weight in conc. H2804, heated slowly for about
20 minutes.

More H2804 is added to rinse the walls of the
container, and heating is increased until white fumes
appear. Heating is continued to dryness.

The dish is cooled and .05 N nitric acid is added and
heat applied to dissolve most of the residue.

Small amounts of residue are removed by filtering
through Whatman no. 41 paper and collecting in a
plastic beaker.

5 grams of AMP is stirred into the cold solution for
10 minutes with a magnetic stirrer.

AMP is settled over night and supernatant then is
decanted off.

The beaker is refilled with 0.05 NHNO3 and allowed to
settle again over night and decanted.

AMP is washed into centrifuge tube and centrifuged.

The supernatant is decanted off and AMP is hardened
in oven for 10 minutes at 60°.

Sample is counted on NaF crystal for Cs concentration.

AMP is transferred to a 250 ml centrifuge tube and
40ml 2 M NaOH is added to dissolve the AMP.

After centrifuging the iron hydroxide residue is
packed down and the supernatant is transferred into a
plastic beaker containing 20ml of glacial acetic acid
and the residue is washed with 10ml of 0.5 N NaOH.

Powdered AMP is stirred into the solution that now
has a pH = 4. Stir for 15 minutes and then centrifuge.
Add 50mg more AMP and stir and again centrifuge.

This ppt. is dissolved in 5ml 1 M NaOH and washed
with deionized water into a separatory funnel.

10ml of 0.025 N TPB solution is added.

Shake vigorously for 1 minute and allow to stand over
night.

Separate organic layer and retain for flame emission
analysis.

 

47

extracted into an organic solution. This method was
described by Feldman and Rains (1964) and is given in
Table B-4.

Elution techniques were also attempted to remove the
cesium from the ion exchange columns. Table B-5 gives the
results of these elution tests. These attempts were not
successful as can be seen by the results for all but one
ion exchange resins. The one exception, ZrP gave very good
elution values at 77 C. ZrP was not specific enough to use
for cesium concentration in the presence of K+ and Na+, so
this elution capability was of little use in this study.

It does offer an excellent method of laboratory separation
of alkali metals in "clean" solutions (Amphlett, 1958).
The procedure used for elution of cesium from ZrP is given
in Table B-6.

Resins used in column form were prepared using 5 grams
dry weight of 20-50 mesh material. This 5 grams of resin
was slurried in 50ml of distilled water and allowed to soak
for at least 24 hours. The resin was then placed in poly-
styrene vials (obtained from Dynalab Corp.) 30mm x 70mm with
the bottoms removed and fitted with polyethylene porous
disks. A column similar to this was described by Boni
(1966). This size and shape of column and amount of resin
proved to be a good compromise between percent uptake of
cesium and flow rate necessary for large quantities of
water to be preconcentrated. A photograph of the column

is shown in Figure 1.

48

TABLE B-4.--Batch absorption of Cesium from water samples

(Feldman and Rains, 1964).

 

Transfer 8 liters of water to a wide-mouthed battery
jar which can be drained through a stop cock in the
bottom.

Adjust the pH to 6-7 if necessary. Add 800mg of AMP
and stir for 10 minutes.

Add 25 mg of Al+3

stirring.

solution and heat to 40 C while

Allow solution to cool and AMP to settle out.

Siphon off as much of the supernatant liquid as can be
removed without disturbing the residue.

Stir the remaining liquid vigorously and drain the
resulting slurry through the stop cock. Transfer the
slurry to the required number of 50ml centrifuge
tubes. Centrifuge and combine.

Count AMP for 137
NaOH (10-15m1).

Cs level. Dissolve AMP in 1.0 N

Adjust pH to 3.5 with tartaric acid and extract with
50mg of AMP.

Dissolve this AMP in 1.0 N NaOH and extract into 10ml
of 0.1 N TPB hexone solution and retain for flame
emission analysis.

 

49

I if
'1‘

 

 

 

6 pkg m.mm moZamz 2m.o o.mm .Ag\qo.oH mo.m omuom mumgmmogm
EDHCOUH HN

o.o momz 20.H 0.0m .naxqo.mH mo.m omuom _mxzoemmooeemz

0.0 mozHe 2H.o o.mm .H:\qo.mﬂ o.m omLON Hmlzoemmooemx

o.m~ mozm zmﬂ o.kw .03\5o.m mm.m carom Hmlzovmmceemx

o.mm mozm zmH 4.>m .ug\gm.0H mo.m carom ”mlzovmmsoamx
coausam w aoHusHom mcﬂusam muhm mo oumm 30Hm cﬂmmm m0 muﬂm Euom Gamma

oxmnma w ugmﬂoz 5mm:

 

.maﬂmmn mmcmnoxo :OH opasmmo xmameourn.mnm mqmde

50

TABLE B-6.--Procedure for elution of Cs from zirconium
phosphate resin.

 

1. 5 gm columns of zirconium phosphate spiked with 137Cs

and counted to determine exact 137Cs content were used.

2. The column was suspended above a 300ml beaker on a
plexiglas sheet fitted with a hole to set the column
in. This apparatus was placed in a Sargent drying oven
at 77 C.

3. A 100ml capacity addition buret was placed on top of
the drying oven with the stem extending down to the
top of the ion exchange column.

4. The ion exchange column was allowed to equilibrate with
the oven temp.

5. 100ml of 0.5 N NH NO3 hot water soln. is then added to
the addition buret.

6. The stop cock is then adjusted to give an approximate
flow rate of 40ml per hour.

7. The column was then dried and counted to determine
% elution of the 137Cs spike.

 

 

51

The ion exchange columns were operated on the
continuous flow constant head ion exchange apparatus I
designed and built for field use. The unit was built in
duplicate so two samples could be taken simultaneously or
so two types of ion exchange materials could be compared.
Detailed photographs are-given in Figure B-l to supplement
the earlier description.

The filtration system designed to clean the lake
water of particulate matter before it was passed through
the ion exchange column was an essential part of the
system. Two in-line filters were used to remove the bulk
of the material before the water entered the reservoir and
a final filter removed traces of matter just before the
water passed through the column. All three of the filters
were built completely of inert plastic material to minimize
absorption of cesium. Soft polyethylene funnels, ll.0cm in
diameter, were fitted with plexiglas rings. These rings
had four holes drilled through them for brass nuts and
bolts. A piece of rubber gasket material was used between
the funnels for the in-line filters. The actual filtering
material consisted of a porous polyethylene disk (90p pore
size). This disk was 9.0cm in diameter so it would fit
down inside one of the funnels. Polyethylene filter
floss, purchased at an aquarium supply house, was used as
the filtering material. Filter floss was used in varying

amounts depending on the size of the particulate matter

52

Figure B-l.--Ion exchange apparatus photographs.
A. Micro-switch apparatus
B. Battery and flow meter box

C. Complete apparatus operating on Wintergreen
Lake November 1970

53

 

54

to be filtered. The final filter was built using the same
materials. The difference was that only one funnel was
used and the polyethylene porous disk was cut 11.5cm in
diameter and was clamped to the rim of the funnel with the
plexiglas rings. Photographs are shown of the two types

of filters in Figure B-2.

Flow Rate and Percent Uptake of Cesium

 

The flow rate and percent recovery data for the
ion exchangers were determined using six-liter distilled
water samples. Five-gram columns were prepared as
described earlier. These columns were counted for
background radiation and placed on the outlet of a ten-
liter glass battery jar. The cesium-137 spike was counted
and placed in-six liters of water in the battery jar. The
stop cock was then adjusted to the required flow rate and
a timer started. The time of flow was recorded for the six
liters of water and an average flow rate calculated. The
column was counted at 0.662 Mev for cesium-137 and percent
recovery determined and all the samples were run at room
temperature. Using this apparatus, flow rates up to 30
liters/hr. were obtained. A photograph of the apparatus
used is shown in Figure B-3.

The NCFC, KCFC and ZrP ion exchange resins were
purchased from Bio Rad Laboratories. The other two forms
of complex cyanide resins, Zn and Cu, were prepared by a

method described by Kourim, et a1. (1964). Methods of

 

55

Figure B-2.--Photographs of filters.
A. Disassembled in-line primary filter
B. Assembled in-line filter

C. Final filter

56

 

57

Figure B-3.--Photograph of flow rate versus uptake
apparatus used in lab studies.

 

 

 

 

59

preparation are given in Table B-7. The AMP was first
purchased from Bio Rad Laboratories but Folsom (1970)
reported considerable contamination of cesium in this
product. He gives a method which was used for preparation
of AMP and is given in Table B-8. Chemicals used for
preparation of ion exchange materials were obtained from

Mallinckrodt and were all reagent ACS grade.

CountingﬁRadiocesium

 

Cesium-137 counting was done by means of a single
channel solid scintillation counter. A three inch NaI(Tl)
crystal with a 1.25 inch by 2 inch well was used (Harshaw).
This crystal was connected to a Tracerlab single channel
spectrometer and a NMC scaler.

A 0.05 Mev window was used to give a good signal
to background ratio. Columns and counting vials were
1.0 inch diameter to insure consistent counting geometry.
The counting efficiency averaged about 17.0% for cesium-137
standard. The efficiency was determined daily.

Counting times were determined using the following

formula: (Overman and Clark, 1960)

 

Rs+B + /(Rb)(Rs+b)

(02) (R32)

T =
S

 

where:

*3
ll

sample time (min)

w
ll

sample rate (min)

60

'TABLE B-7.--Preparation of complex cyanides of Zn and Cu

(Kourim, et a1., 1964).

 

0.1 M solution of potassium ferrocyanide (167ml) was
added slowly to 0.1 M zinc nitrate (500ml) while
stirring.

The mixture was heated on a hot plate magnetic stirrer
for 1-2 hours.

After cooling the mixture was filtered through no. 1
Whatman paper in a Buchner funnel.

The precipitate was washed twice with 9.3 M NaNO3 and
then with water.

The material was then placed in a drying oven and dried
at 70 C overnight and ground to mesh size 20-50. The
Cu form of the resin was prepared exactly the same
substituting 0.1 M copper nitrate for zinc nitrate.

 

61

TABLE B-8.--Preparation of AMP (Folsom, 1969).

 

Sol. 1.—-81g NH4NO3 + 81g citric acid + 102g
+ 2140ml H 0

(NH4)6MO7024 2

801. 2.--39lm1 70% HNO3 + 455ml H20

Sol. 3.--Pour Sol. 1 slowly into Sol. 2 stirring
without heat

Sol. 4.--100g (NH4)2HPO + 2000ml H O

4 2

1. To Sol. 3 in a 4 liter pyrex beaker add 2ml of Sol. 4
and heat to a boil while stirring.

2. After cooling solution allow AMP formed to settle to
bottom of beaker.

3. Decant the supernatant into another 4 liter beaker and
discard AMP that was made in step 1.

4. To supernatant in 4 liter beaker add 100ml of Sol. 4
and bring to boil while stirring.

5. Allow to cool and filter solution through Whatman no. 4
filter paper.

6. Wash the AMP with two 1 liter solutions of .1 N
NH NO .
4 3
7. Place the AMP in drying oven at 70 C overnight and
store in dry place.

 

62

I!
ll

bkgd rate (min)

 

b
s+B = total rate (min)
G = percent error (0.05)
R
_ s+b
Tb _ Ts / Rb
where:
Tb = bkgd time (min)

Thus, the determination of cesium-137 activity was signifi-

cant at the 95% level.

Fish Collection

 

The majority of the fish taken for analysis
including perch and bass were age three and of fairly
uniform weights. Some larger bass were taken for sub-
sampling procedures in the lab to test the variation of
the method. Fish samples were taken at least two weeks
after fall overturn and within one week of the water
samples of cesium-137 concentration. The perch and bass

were all taken by hook and line.

Study Site

 

Wintergreen Lake was chosen as the study site due
to its high cesium levels in fish and water compared with
other lakes in the area. This lake in Kalamazoo County
has been managed as a waterfowl refuge for many years.

It is a part of the W. K. Kellogg Biological Station,

63

Michigan State University. It may be speculated that the
relatively high concentrations of alkali metals Na, K,
and Cs is in part due to the large number of waterfowl
that regularly occupy the lake. The lake can be termed
eutrophic and typically dimictic. The presence of large

numbers of waterfowl and some agricultural drainage has

1.
Al
I
In

contributed to its natural tendency toward enrichment.

The availability of fish in the lake also make it ideal

 

 

for this type of study as adequate samples are easily 1
obtained.

At present, another study is being performed on
the lake. The concentrations of cesium through the trophic

levels are being examined by D. Eyman.

Fish Digestion

 

All perch were treated individually except two
samples where two fish were combined. Bass were either
digested individually or halved for subsamples. Prior to
digestion the fish were cut into pieces small enough to
fit through the neck of the digestion flask.

A wet oxidation method of digestion was employed.
This allowed a low temperature (130 C) digestion to
minimize cesium loss due to volitilization. Digestions
were executed in 3 and 5 liter round bottom two-necked
boiling flasks. These flasks were fitted with reflux
condensers and electrical heating mantles. The method

of nitric acid digestion of whole fish is given in

64

Table B-9. A photograph of the digestion apparatus is

shown in Figure B-4.

Cesium in Whole Fish

 

The concentration of the cesium from the acid
solution of the fish was accomplished using AMP. The batch
absorption of cesium using AMP and successive clean-up

steps were described by Feldmand and Rains (1964). Some

 

changes have been made in the procedure to accommodate

whole fish analysis. The procedure is given in Table B-10.
The final sodium hydroxide solution of the AMP is

extracted into organic solution and retained for flame

emission analysis of cesium.

Flame Emission Analysis

 

Basically, it involves the aspiration of a solution
containing the element to be analyzed into the flame, the
element is first atomized and is said to be in the ground
state. This means that the electrons are at their normal
energy level. The thermal energy in the flame excites
some of the electrons to a higher energy level. This
excited state is not a stable state for the electrons, so
they keep losing energy and falling back into the ground
state. In this process, the atom emits energy at a
wavelength characteristic to the element. Flame emission

measures this energy and from the amount of energy emitted

65

TABLE B-9.--Nitric acid digestion procedure for fish.

 

10.

Cut fish into pieces to fit boiling flask neck.
Determine wet weight of sample.
Place fish pieces in boiling flask.

Add approximately 3.0ml of conc. HNO3 per gram of
fish.

Allow oxidation to proceed 3-4 hours with no heat
applied.

Reflux the solution approximately 8 hours allowing
excess water and acid to be distilled off until about
2ml of acid are left per gram of fish.

Add sufficient conc. HNO3 to bring back to original
volume.

Reflux with stop cock closed for approximately 4-6
hours until no oil can be seen floating on the surface.
Additional acid should be added if oil is not digested.

Allow to cool and remove from flask rinsing with
distilled water into a plastic beaker at least twice
the volume of the digest.

Allow to cool to room temp. and proceed with AMP
collection of Cs.

 

66

Figure B-4.--A photograph of a three liter di-
gestion apparatus, used for wet oxidation of whole fish.

 

 

68

TABLE B-10.--Cs collection and preparation for flame
emission analysis.

 

1. To the acid solution of fish tissue add 4mg AMP/gm
wet wt.

2. Stir solution 15-30 minutes and allow to settle
overnight.

3. Pour off supernatant and collect AMP in 50ml centri—
fuge tubes.

 

4. Collect AMP in one tube and count 137Cs.

5. Dissolve AMP in 1.0 N NaOH (approximately 15ml per
gram).

6. Adjust pH of solution to 3.5 using powdered tartaric
acid.

7. Add 0.4mg AMP/gm wet wt. and stir for 15 minutes.
8. Collect AMP in centrifuge tube and again count 137Cs.
9. Dissolve AMP in 1.0 M NaOH (about 10ml).

10. Place 10ml NaOH Cs soln. in separatory funnel with
10ml 0.1 N TPB and shake vigorously for 1-2 minutes.

11. Allow layers to separate overnight.

12. Retain organic layer for flame emission analysis.

 

69

a quantitative estimation of the amount of the element in
the sample can be calculated.

Cesium is best suited to flame emission due to its
ratio of ground state to excited state atoms (7 x 102 at
3000 K). Atomic absorption depends on having many atoms
in the ground state to be excited.

The instrument used in this study was a model
82-800 Jerrell-Ash equipped with an infrared grating and
a red sensitive photomultiplier (R446). The detection
limit for cesium in hexone TPB solution was approximately
0.05mg/1iter. An air-H2 flame was used for cesium.
Standards were prepared using CsCl. One hundred mililiters

of NaOH solution standard was extracted with 0.1N TPB in

3/1 hexone solution.

APPENDIX C

DATA TABLES

70

TABLE C-1.--Flow rate and percent recovery of cesium-137.

 

 

Flow Rate Percent
Resin Type Liters/hr. CPM in Spike Recovery

NCFC 7.0 270.0 270.0 100.0
- 7.7 87.2 86.1 99.0
(NH4)2[CoFe(CN)6] 12.5 187.0 178.0 95.2
15.7 111.4 100.3 90.0
15.79 107.0 96.1 89.0
20.9 306.0 248.0 81.0
24.8 262.0 219.0 83.6
28.8 354.0 290.0 81.9

KCFC
5.26 126.6 126.0 99.5
K2[CoFe(CN)6] 7.72 136.0 129.0 94.8
9.0 136.6 119.9 87.7
12.56 141.0 116.0 82.2
14.4 114.0 80.9 71.0
15.0 128.0 89.6 70.0

ZrP
8.65 147.3 143.0 97.3
ZrO p 0 13.32 150.0 135.0 90.0
2 13.5 173.5 155.5 90.0
15.6 177.0 163.0 92.0
16.98 158.0 137.0 86.0
18.0 139.0 108.0 77.0

 

71

TABLE C-2.--Percent recovery of cesium-137 on AMP from acid
digest of NCFC.

 

 

Sample No. mg AMP Used Percent Recovery
1 200 37.0
2 300 69.0.
3 500 68.7
4 100 41.0
5 100 40.0

x = 51.0119.0%

 

TABLE C-3.-—Cesium recovered when AMP was dissolved in

 

 

NaOH.
mg AMP Vol. NaOH Percent Recovery
200 10ml 40.0
300 10ml 65.0
500 10ml 51.0
100 10ml 45.0

2': 50.0:10.0%

 

TABLE C-4.--Cesium recovered from NaOH with TPB in hexone.

 

 

30.7:9.0%

Vol. NaOH Vol. TPB Percent Recovery
10ml 10ml 36.4
10ml 10ml 23.6
10ml 10ml 34.2
10ml 10ml 28.7

 

"TIE unnmwmmnmmwiu A 11111111158

 

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