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Plutonium was chemically separated and electrodeposited on a stainless steel disk, and the a-activity was measured by an a-spectro- meter with a Si (Au) ...
RADIOISOTOPES,

Plutonium and Uranium in Japanese Yasuhito

IGARASHI*,

Atsushi

36, 433-439 (1987)

Human Tissues

YAMAKAWA

and

Nagao

IKEDA

Department of Chemistry, University of Tsukuba Sakura-mura, Ibaraki-Pref. 305, Japan Received

Plutonium

and

determined of

each

element

concentrated whole of

uranium

in

human

by ƒ¿-spectrometry was

in

body. stable

and

special

This

on

the

of

states

of

track basis

while

from

of

in

body

of

the

respectively.

mean is is

to

Pu4+

area

be

due

pattern

Plutonium

generally

for

were

distribution

obtained. rather

considered

fluid;

Tokyo

The

concentration

distributed

tendency

elements

residents

method,

uranium

distribution

the

28, 1987

obtained

fission

organs,

difference

chemical

tissues

the

estimated

some

March

is

throughout

to

the

plutonium

the

characteristics and

UO22+

for

uranium.

Key Words:

plutonium, uranium, organ burden, total

human tissue, body burden

are 1.

Introduction

Several

compared

mentioned

transuranium

elements

have

to

tions

during

have

entered

time

and

will

elements.

human

level

From

exposure

this

of

artificial

of

in

the

behaviors

the

of

the

important,

these

amounts

long

years,

half

are

their

high

toxicity,

released

lives

of

nium

authors

reported

on

determination

the

and uranium Japanese.

uranium additional * Present tional Isozaki,

In

this

samples

human

Division

Nakaminato,

Ibaraki-Pref.

Sciences,

at

smaller

in

determination

same

(about of

a

uranium,

and

sam-

sufficiently. into

mg)

lyosamdish

the

mortar

10

bone quartz

ashing,

divided

The first

or on

agate

was

uranium

samples.

sample

an

sub-

death

were

After

of during

the

of

samples

was

part

died

and

470-500•Ž

sample

from

residents

who

cause

the

oven.

mixed each

of

plutonium

for

electric

was

Then a

asked an

ple

two

parts;

was

for

the

the

rest

for

plutonium.

Plutonium

of and

in the

of Radioecology,

was

using

pluto-

and the analytical

determined

ple

kCi1))

plutonium

work,

lyophilized

in

tissues

this

Each

6.6•~103

are determined

of Radiological

above-

concerning and

philized.

rela-

fallout

In

sex

of

previous pa-pers2)-4)

of

paper,

tissues

address : Institute

the

in several

in human tissue

in

information

age,

bone

future.

330 and

No

except

respectively.

The

the

obtained

study area

samples

give

were

medical

metropolitan

except

were

especially

(about

2.4•~104

a

the

nuclides

240Pu

analyzed

in

available.

prediction

and

Tokyo

these

could

the

the

1980-82.

those

in

autopsy

ject

of

the

tissues

the

these

future.

with

elements

239Pu

large

and

distant

transuranium

considering

tively

the

comparison

facilitate

man-made

environment,

that

environment

to

of

hazardous

actinides

information

Among

most

seems

in

view,

natural

ones

some

of

of

naturally

potentially

even

point

behaviors

it

beings

lapse

to

Since

from

view.

Methods

Human

nuclides

the

similarly

discussed

of

detona-

These with

a-emitters,

bring

nuclear

decades.

biosphere behave

long-lived

low

by

four

the

actinide

might

the

environment

these

occurring are

the

and

point

been

2. released

individual

data Na-

was

chemically

separated

and

electrodeposited on a stainless steel disk, and the a-activity was measured by an a-spectrometer with a Si (Au) surface barrier type semiconductor detector. Uranium was determined by the fission track method with calibration curves. Details for the analytical procedures are described in the previous papers2)-4). 3.

Results

and

Discussion

3609, 3.1

311-12, Japan.

(3)

Concentration

distribution

of plutonium

434

RADIOISOTOPES

Table

1

Concentrations

* The

number

of arithmetic parentheses ** Bone samples Table

2

of plutonium

of samples

available

and geometric were

Concentrations

taken

Vol.36,

in human

for calculation

means

is shown

in

from rib and femur

of uranium

in human Fig. l

Cumulative trations

* Bone

samples

were

No.9

taken

from

skull

frequency

in human

curves

lung

of Pu concen-

and liver samples.

, rib and

femur and uranium

in human

tissues

The results obtained for plutonium are summarized in Table 1. In the table geometric mean values with geometric standard deviations are given in addition to arithmetic mean values, because plutonium concentrations in tissues indicate a log-normal distribution as shown in Fig. 1, as other authors have pointed out5)-8). The results for uranium are given in Table 2. Uranium concentrations in individual tissue also reveal a log-normal distribution as shown in Fig. 2, which is of the same tendency as most of other trace elements in human tissues. It should be noted that plutonium and uranium concentrations in bones, regardless of the kind of bone, may compose a single population (Fig. 3). Generally speaking, the concentrations of essen(4)

Fig. 2

Cumulative centrations

tial

elements

in

if they

are

even

tain nearly Their

tion tions

the

constant

increase

amounts,

curves human

tissues

trace

concentrations,

by the

frequency in several

values

and

their

living

beings,

tend

to main-

by the homeokinesis.

therefore,

or decrease

in the tissues

of

elements,

of U consoft tissues.

are

in intake

not

affected or excre-

concentration

of living

beings

distribuare

normal

Y. Igarashi

Sep. 1987

Table

et al.:

3

Plutonium

Weights

and uranium

and compositions

in Japanese

human

of the composite

Table

4

Errors

435

tissues

samples

Concentrations of composite samples

represent

counting

plutonium

statistics

in

of

the

1ƒÐ

adding new data. As plutonium activities in muscle, kidney and spleen are rather low and the corresponding counting statistics are not so good, the analytical values previously obtained for these tissues were not sufficiently accurate. Therefore, in order to obtain more reliable data for the plutonium levels in the tissues, a com-

Fig. 3

Cumulative

frequency

concentrations distributions. tration by

of

their

ment,

thus

or

their

other

elements in

concentration

of Pu and U

bones.

hand,

decrease

distributions9).

uranium,

essential

the

non-essential increase

log-normal facts,

On

curve

in human

Table

4

shows

concen-

found

are

affected

contents

were

the

environ-

kidney,

while

the

distributions Considering

as well as plutonium,

element

posite sample for each tissue was analyzed. Each composite sample was prepared by mixing each corresponding tissue from six or seven subjects, the weights and compositions of which are shown with age and sex in Table 3. in these

Okabayashi11

are

concentrated

these is a non-

for man.

plutonium

composite rather

significant

unexpectedly pointed

out

in spleen.

with

about

0.4 kg

high

concentration

concentrations

samples.

of

In

in low

that our

spleen,

as in liver

Plutonium spleen

and

in

muscle . plutonium is

result

obtained

however,

not

nor

in lung

so was

observed. 3.2

Distribution uranium

patterns among

of plutonium

human

The individual organ burden total body burden (TBB) of the ICRP Reference Man10), which in the previous papers2),9), were

Based on the results,

and

a new TBB value of

plutonium was estimated as shown in Table 5. The TBB value is smaller than the previously reported one by about 40 mBq (1 pCi). It. should be noted that this estimation was made on the basis of mean concentration. The IOB .

tissues

(IOB) and the elements for the were estimated re-estimated by

(5)

436

RADIOISOTOPES

Table

5

* An assumed

Table

Estimated

organs

and total

body

burdens

Vol.36,

of 239,240Pu for the ICRP

Reference

No.9

Man

value

6

Estimated

* See Ref . 2 ** A value estimated

uranium

organs

from the average

and total body

of liver,

kidney,

burdens

spleen,

for the ICRP

muscle , heart

Reference

Man

and brain

Using the data, the distribuiton patterns of these elements among human tissues and organs were illustrated as shown in Fig. 4, comparing with the weight distribution of tissues for the ICRP Reference Man10). It is evident that uranium is distributed rather uniformly all over the body, while plutonium is concentrated in skele-

Fig. 4

Distribution patterns human tissues with for the ICRP

and

of Pu and U among weight distribution

Reference

TBB

values

of

uranium

using

the

mean

concentrations

Table

6.

ton (60%) and liver (30%), reconfirming that these two organs are important for systemic distribution of plutonium. ICRP Publication 48 reviewed and summarized the distribution of fallout plutonium in members of the general

Man.

also are

obtained shown

population from various geographical regions, suggesting the deposition percentage of 45% for liver and 35% for skeleton as weighted mean of the data12). It also shows, however, the

by in

( 6)

Sep.

Y. Igarashi

1987

variations in relative in these organs, which 55% for liver and 25 Major uncertainty may how the total skeletal mated from fragmentary the scope of the present 6, the skeletal contents

et al. ; Plutonium

and uranium

partition of plutonium ranged between 23 and and 56% for skeleton. be due to the difficulty content should be estidata, which is beyond work. In Tables 5 and of plutonium and ura-

first

to

at

not

exist

fluid,

naturally

supposed

higher

charge

by

itself

there

proteins,

amino

etc.

act

that

in

are

The

complex

ions

decreases

be

acids

>Pu(VI)>Pu(V)13),14) by

Taylor14),

as

rather

plasma etc.

major

stable

human

other

organic

ligands

for

ability order

of

of

Pu

part

complexes globulin beings

and

to

of

the

plutonium of

such several

as

transf

the

would

be

of

5•~10-14

of of

was

and

ion

all 150

that

it

its

concentra-

were

is attributed

and

the

followed on

also

in

pH

body,

in the liver the

polymer

system

the

found

that

human

blood10),

hydroxide,

Spleen

step In

M.

of

the

system16).

4, to

between

the

deposition

formation

(OH)

second

Pu(IV)

239Pu

ml

hydrolysis

Pu

Provided in

5200

Plutonium

thelial

of

calculated

irreversible13).

that

were

in

hydroproceed

as •gpseudocolloid•h

pCi),

position

mostly

was

be

present

(4

ions

6.8•~10-8M14).

plutonium

to the

to

at

Therefore,

addition,

described

at

dissolved

the

de-

reticuloendothelial

contains

its

polymer

by

reticuloendo-

tissuel7),

relatively

high

plutonium concentration in spleen might to the deposition of plutonium polymer

be due on this

cell system. As

for

form

uranium,

stable

it

14.6

-15.6

at

acids, ions.

is

bound

U(VI)

60%

of

with

bicarbonate

the

20%

errin,

and

with

bound

tein

cytic

lipoprotein.

and the tendency towards hydrolysis decreases in the order of Pu(IV)>Pu(VI)>Pu(III)> Pu(V)13>,14). The equilibrium constant for the

plex

ions

of

were

physiological body.

are

the

most

the

review,

number for and

of U(VI)

lipopro-

n=1.7

for

bi-

n=0.6 n=0.46

behaviors

of the

protein

given

albumin

albumin; ƒÀ=8.90, Thus,

47%

with

the

uranyl important, of

uranium

is

blood

with

In and

it

that

32%

plasma

around

the

associated

also

high,

R3

in

complex; ƒÀ=10.48,

plasma

(7)

(VI)

erythrocyte; ƒÀ=18.04,

carbonate

man

for

and is

(ƒÀ)

bicarbonate,

On the other hand, hydrolysis is closely related to the complex formation of an ion. It is said that the Pu(IV) ion undergoes the most extensive hydrolysis of all the plutonium ions,

U

of

are

Gindlerl8),

erythrocytes.

(n)

with

constants

by

plasma,

constants

ligand

mammals.

blood of

ions

ions

literature

18.3-23

that

part

stability

and

review

in

and

with

the

the

inorganic

review

N2 In

uranyl

[UO2(CO3)2]2-or

stability

in

for

25•Ž14).

described

(III)

as

The

carbonate

that

complex

such

[UO2(CO3)3]4-.

as

seems

soluble ions,

uranyl

exists

Pu(IV)

is

-1.06

hydrolysis,

which

said

present

mBq

plutonium

(IV)>Pu

be

of

body

metal

it

carbonate

such

In is

reported

and

polymers

of

10-5013).

2.8-7.5

does In

matters

According a

proteins, ƒÀ1 in

and

formation the

fluid.

7 x

(IV)

insoluble

hydrolysis

to

Pu

product

was

25•Ž

successive

proton

nomenclature

temperature14).

pH,

highly

review,

plutonium radius

body

organic

complex

in

the

smaller

human

many

as

that

and

form

the

Martell15), at

body

through

solubility

tion

is

and

to

radius and electric charge (the so-called charge density of the ion). The different trend of distribution of the two elements in human body can be interpreted by the difference of stable species present in body fluid. Both plutonium and uranium similarly have four oxidation states from III to VI and they take normally either IV or VI (Pu4+, U4+ or PuO22+, UO22+)13). It seems, however, that plutonium is most stable in the tetravalent state in body fluid, while uranium is most stable in the hexavalent state.

and

to

with

to

-1.26

physiological

lyse,

of

of

Sillen

close

437

hydrolysis

according

-1.94-

34•Ž,

tissues

Pu(IV) *K1,

by

be

human

of

defined

therefore, provides preliminary estimates of skeletal burdens of both plutonium and uranium. Behaviors of these elements in human body should be associated with hydrolysis and the complex formation of the ions in body fluid. Generally speaking, the activity of an ion species in a solution is affected by its ionic

It

step

eliminaiton,

nium calculated from small number of different bone samples are shown. The present work,

ion

in Japanese

for

for erythro-

carbonate

com-

considering in

the

hu-

438

RADIOISOTOPES

On

the

hydrolysis

of

uranium

ions,

the

Vol.36,

No.9

same

References observation

can

ions.

The

the

order

in

-4-

of

the

U(IV)

mers

in

of

curring

to

in

ions

In

plexes

in

a

state

insoluble

is polymers

liver,

while

with

deposited

in

un

sible

to

of

conclude

extremely

low

naturally

occurring

level

the

at

the

results

plutonium

10)

poseven

the

and

Dentistry, discussion. This

Kazunari

Nihon

work

was

Inter-University of

the

Japan part

Atomic of

from Culture are

the

the

supported

Program

Reactors

at

expenses

of Japan,

the

by

Maruzen,

Tokyo

International

part

by

by

authors'

of

Man•h,

ICRP

Press,

Ed.)•h,

Chemical.

(1975)

Commission

Oxford

Society,

(in

Japanese)

on

Radiological

the

Task

Group

on

Publication

23,

(1974)

(in Japanese) Commission

on

Protection, •gThe

Metabolism

nium

Elements•h,

and

Related

licaiton

the

48,

Pergamon

Radiological of

Pluto-

ICRP Press,

PubOxford

(1986) 13)

at

Katz,

J.J.

istry

A

by

a grant

Science

Japan

in

(3rd

International

Use

and

Elements

Nutrition

12)

kind

Institute.

covered

translated

(1984)

of

the Common

Education,

to which

their

University

Research was

of

in

for

Rikkyo

Energy

Ministry

for

School

Animal

Okabayashi, H.: Project Report for a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan, (A) 57380017, 15-19

to Professor

Moriwaki,

University

E.J.: •gTrace and

11)

Tokuzo Kojima, School of Medicine, Nihon University, Professors Tadashi Kitagawa, Eiko Sairenji

Underwood,

Pergamon

uranium.

greatly appreciate

(1980) Popplewell, D.S., Ham, G.J., Johnson, T.E. and Barry, S.F.: Health Phys., 49, 304-309 (1985) Takizawa, Y., Hisamatsu, S. and Abe, T.: Radiat. Res., 109, 245-255 (1987)

Reference

Acknowledgement

The authors

(1985) Igarashi, Y., Seki, R. and Ikeda, N.: J. Radiat. Res., 27, 213-218 (1986) Campbell, E.E., Mulligan, M.F. and Moss, W.D. et al.: LA-4875, Los Alamos Scientific Laboratory of the University of California, New Mexico (1973) Fisenne, I.M., Cohen, N., Neton, J.W. and Perry, P.: Radiat. Res., 83, 162-168

Protection, •gReport

at

and

Hardy, E.P., Krey, P.W. and Volchok, H.L.: Nature, 241, 444-445 (1973) Igarashi, Y., Seki, R. and Ikeda, N.: Radioisotopes, 33, 55-59 (1984) (in Japanese) Igarashi, Y., Yamakawa, A., Seki, R. and Ikeda, N.: Health Phys., 49, 707-712

Human

The

seems

holds

9)

and

body.

it

8)

the

reasonable

fact

of

in in soluble

From

of level

tetra-

stable

human

this

7)

distributed

work,

that

com-

resulting

is

present

6)

taken as

deposits

levels.

the

tissues

expected.

respectively.

is

part

concentration

obtained

the

in

finally

discussion

5)

If

uranium

forming

every

not18).

tetravalent

be

hydrolysed,

carbonate,

above-mentioned higher

U(VI), plutonium

4)

citrate

oc-

mainly

of

uranium,

complexes

in

and

that

that

hydrolysis.

fluid

readily

as

among

and part

3)

addition

is

would

body

Pu(IV)

Consequently, valent

the were

plutonium

exist of

in

plutonium

conclusion, man

said

phenomenon

pattern

of

is the

hydroxide

man

distribution

and

poly-

such

similar

into

that

It by

U (IV) a

2)

al-

25•Ž15),18).

hydroxide

agents

Pu(IV)

to

into

form

be

U(IV)

at

process.

be

taken a

1)

in

to

for

dissolved

while

uranium

similar

-2

complexing

seems

decreases

around

is

bicarbonate,

state,

-1-

hydrolysis

strongly

plutonium

reported

U(VI)

hydroxide

There

was

U(VI) and

the

U(VI)

for

hydrolysis

*K1

for

Both

as

U(IV)>U(VI)>U(III)13),18).

range

-6

or

of

constant

most

made

tendency

Stability

of

be

of

thanks

(1962)

due.

14)

Taylor, Properties

(8)

Seaborg,

Actinide

Miyake,

mura,

and

and the

Y.,

Y.

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G.T.: •gThe Elements•h,

Tominaga, al.,

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Asakurashoten,

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Japanese)

D.M.: •gChemical of

Plutonium•h

and

Physical

in •gUranium,

Y.Igarashi et al.: Plutonium and uranium in Japanese human tissues

Sep. 1987

Plutonium, (Ed.

Transplutonium

by

Hodge,

Hursh,

J.B.),

lag, 15)

and

Constants

Suzuki,

of

and

XVII-2,



and

17)

Ver-

Complexes•h,

by

The

Yamada, F.

T.,

et

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T.,

(1967)

Gindler,

(Ed.

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and

J.B.

Berlin

(1973)

),

To-

H.C., pp.69-164,

Chemical

in •gUranium,

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Elements•h Stannard, Springer

J.N.

旨 日本 人 臓 器 中 の プ ル トニ ウ ム と ウ ラ ン 五 十 嵐 康 人,山 川 敦 志,池

田長 生

城県 新 治郡 桜村 天 王 台1-1-1

東 京 近 郊 居 住 者 の 臓 器 中 の プ ル トニ ウ ム と ウ ラ ン を 定 量 し,そ ウ ム は α 線 ス ペ ク ト ロ メ ト リで,ウ

れ ら の 分 布 を 比 較 し た 。 プ ル トニ ラ ン は フ ィ ッ シ ョ ン トラ ッ ク 法 で 定 量 し た 。 プ ル トニ ウ ム と ウ

ラ ン の 体 内 分 布 の パ タ ー ン を 平 均 濃 度 値 を も と に 見 積 っ た 。 プ ル トニ ウ ム は 特 定 の 臓 器 に 集 積 す る の に 対 し,ウ

ラ ン は 比 較 的 体 全 体 に 分 布 す る 傾 向 が 認 め られ る 。 両 元 素 の 分 布 の 違 い は,体 液 中 で ル トニ ウ ムPu4+,ウ ラ ンUO22+)や 化学的性質の差 による

安 定 に 存 在 す る 両 元 素 の 化 学 状 態(プ と こ ろ が 大 き い と考 え られ る 。

(9)

and

Verlag,

Japa-

筑 波 大 学 化 学 系,305茨

and

Biology

Iwanamishoten,

of

Hursh,

F. in

Japanese)

J.E.: •gPhysical

by

Maekawa,

al.: •gDictionary

(in

Plutonium, in

Mukikagaku-zensho

Tokyo

(1983)

Properties

yoboutaisaku)•h Nakai,

T.),

kyo

(1964) and

to

(Ed.

Maruzen,

by

Egami,

A.E.: •gStability

London

(Shougai

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