Concentration of natural radionuclides ( 40 K, Rashodhganga.inflibnet.ac.in/bitstream/10603/19465/16/16_publication.pdfBiographical notes: M. Feroz Khan is a Junior Research Fellow

Int. J. Low Radiation, Vol. 4, No. 3, 2007 217

Concentration of natural radionuclides (40K, 228Ra and 226Ra) in seafood and their dose to coastal adult inhabitants around Kudankulam, Gulf of Mannar, South India

M. Feroz Khan, Y. Lenin Raj, E. Mahiban Ross and S. Godwin Wesley*

Department of Zoology

Scott Christian College

Nagercoil, Tamil Nadu, 629003, India

E-mail: [email protected]




*Corresponding author

Abstract: The concentrations of naturally occurring radionuclides, such as 40K, 228Ra, and 226Ra, were determined in the edible fin fish and shellfish, consumed by most coastal inhabitants around Kudankulam. Fin fish and shellfish were collected from eight different sampling points within 30 km radius from the Kudankulam Nuclear Power Project site. The samples were processed and

counted using HPGe -ray spectrometry. In fin fish, 40K activity ranged from 34.16 to 360.7 Bq kg–1 fresh, 228Ra ranged from Below Detectable Limit (BDL) 0.12 to 1.9 Bq kg–1 fresh and 226Ra ranged from BDL 0.06 to 0.18 Bq kg–1 fresh. In shellfish, 40K, 228Ra and 226Ra activities ranged from 15.6

to 96.6 Bq kg–1 fresh; from 0.61 to 6.61 Bq kg 1 fresh and from BDL 0.06 to 1.15 Bq kg–1 fresh, respectively. The total daily intake resulting from consumption of fin fish and shellfish was 63.15 Bq kg–1 d–1 for 40K, 0.54 Bq kg–1 d–1 for 228Ra and 0.096 Bq kg–1 d–1 for 226Ra. The annual dosage resulting from ingestion of natural radionuclides was 1.76 × 10–4 Sv yr–1 for fishermen,

2.51 10–5 Sv yr–1 for farmers and 2.01 10–5 Sv yr–1 for labourers. In

general, 40K, 228Ra and 226Ra contribute a total dose of 1.43 10–4 Sv yr–1,

5.61 10–5 Sv yr–1 and 2.35 10–5 Sv yr–1, respectively.

Keywords: natural radioactivity; fin fish; shellfish; annual dose; India.

Reference to this paper should be made as follows: Khan, M.F., Raj, Y.L., Ross, E.M. and Wesley, S.G. (2007) ‘Concentration of natural radionuclides (40K, 228Ra and 226Ra) in seafood and their dose to coastal adult inhabitants around Kudankulam, Gulf of Mannar, South India’, Int. J. Low Radiation, Vol. 4, No. 3, pp.217–231.

Biographical notes: M. Feroz Khan is a Junior Research Fellow in the Department of Atomic Energy, Board of Research in Nuclear Sciences-sponsored project at the Scott Christian College, Nagercoil. He is currently doing his doctoral degree in the M.S. University, Tirunelveli. His research area includes radioactivity levels in biomatrices with special reference to marine radioactivity.

Copyright © 2007 Inderscience Enterprises Ltd.

218 M.F. Khan, Y.L. Raj, E.M. Ross and S.G. Wesley

Y. Lenin Raj is a Junior Research Fellow in the Department of Atomic Energy, Board of Research in Nuclear Sciences-sponsored project at the Scott Christian College, Nagercoil. He is currently doing his doctoral degree in the M.S. University, Tirunelveli. He is working on the major and trace metal concentration levels in flora and fauna around the Kudankulam coast.

E. Mahiban Ross holds an MSc in Zoology from the University of Madras (2002). After completing his degree he worked as a Research Assistant for IRNE, an environmental NGO, during 2003–2004. Currently, he is working as a Junior Research Fellow in the Department of Atomic Energy, Board of Research in Nuclear Sciences-sponsored project at the Scott Christian College, Nagercoil. He is currently doing his doctoral degree in the M.S. University, Tirunelveli. His research areas include trace elements and radioactivity in biological systems.

S. Godwin Wesley is a Professor in the Department of Zoology, Scott Christian College, Nagercoil. His principal research areas include marine biofouling and radiation biology.

1 Introduction

It is well known that marine organisms have concentrated natural and fallout

radionuclides like any other stable elements. As a result, we can obtain significant

information useful for radio-ecological and radiological studies (Narayana et al., 1995;

Aarkrog et al., 1997). There are many reports on the behaviour and distribution of natural

U series and Th series radionuclides in marine organisms. The concentration of the

immediate progeny of U and Th, such as 228Ra (T1/2, 5.8 y) and 226Ra (T1/2, 1600 y), in the

marine biota along the west and east coast of South India have been well documented.

Fin fish and shellfish represent an important source of food in many parts of the world

and have considerable potential as valuable sources of protein for many developing

countries (Young et al., 2002). The shellfish ingest detritus with a high degree of

radionuclide association and thus they have been recognised internationally as first-order

biological indicators of radioactive pollution (Phillips, 1980). The radionuclide transfer

into a particular fish depends on its intake and metabolism. Considerable literature is

available on naturally occurring radionuclides in foodstuff from normal background

areas, such as those for 238U (Fisenne et al., 1987). Moreover, the daily ingestion of

natural radionuclides has been evaluated ranging from 24 to 109 mBq of 226Ra and 36

to 180 mBq of 228Ra (UNSCEAR, 2000). However, most data concerning long-lived

naturally occurring radionuclides and dietary intake data from countries of tropical high

background areas are very few.

The U and Th series radionuclides are of particular importance because they enter the

human body mainly through ingestion, and only to a considerably smaller degree through

inhalation (UNSCEAR, 1993). Hence, internal exposure for man can be evaluated from

the intake of these radionuclides in food and water. Apart from dose, the data obtained

can serve as a reference value for a given area for dose. 40K is important since it is a

long-lived natural radionuclide in the marine environment. Comparison of these various

radionuclide such as 40K, 228Ra and 226Ra having different origins and different chemical

properties may provide some important information on the enrichment mechanisms of the

Concentration of natural radionuclides (40

K, 228

Ra and 226

Ra) in seafood 219

nuclides in various marine organisms. 226Ra and 228Ra are of radiological importance

since radium closely follows the calcium metabolic process with eventual deposition in

bones, resulting in a build-up of radon and daughters, thereby causing significant

radiation exposure (Iyengar, 1990).

Kudankulam, the study area and the surrounding environment on the east coast

of India, is on the threshold of becoming a major nuclear power station (VVER,

1000 6 MWe). In view of this, a study on the distribution of natural radionuclides and

their dose to coastal adult inhabitants of this region was carried out and baseline data

have been evaluated to facilitate an ecofriendly operation of the nuclear power station.

2 Materials and methods

2.1 Sampling stations

Kudankulam (8° 13 N lat, 77° 47 lon) is situated 25 km from Cape Comorin. It lies in

the southern part of the Gulf of Mannar in the Tirunelveli district. The sampling stations

are shown in Figure 1. This marine province maintains a rich biological diversity of both

flora and fauna. For the study, fin fish and shellfish were collected from the fish landing

centres and also by trawling in the inshore waters up to 10 km off the coast.

Figure 1 Map showing the sampling locations

2.2 Collection and preparation of samples

A total of 14 species of fin fish and five species of shellfish were collected from the

sampling points from January 2006 to March 2007. The mussels were collected during

the low tide from the intertidal area. The collected samples were cleaned with deionised

water and weighed for fresh weight. From the fin fish and shellfish, the soft tissues were

isolated and dried in an oven at about 110°C and reduced to ashes in a muffle furnace at

450°C for about 24 h. The ashed samples were ground to a fine powder and transferred to


a vial. The activity was measured one month later to assure equilibrium between the 238U

and 232Th series and most of their daughter products (Alam et al., 1995). Assumption of

food consumption was done to obtain quantitative estimate of annual consumption by

household expenditure method (IAEA, 1999).

2.3 -ray activity measurement

A well-type HPGe coaxial detector (EGPC-390-P21-Canberra make, active volume

390 cc, well dimension of 65 mm depth by 21 mm diameter was used for counting. The

detector has a relative efficiency of 110% (w.r.t 3 3 NaI (Tl) crystal) with resolution

from 1.4 keV (FWHM at 122 keV) to 2.4 keV (at 1.33 MeV) and peak-to-Compton ratios

of 100 in this energy range. The samples are packed in a 19 ml cylindrical glass vial

(dia. 19 mm Ht. 100 mm), and counted for 50 000 s. The activity was measured by a

16 K EAGLE standalone multichannel analyser with digital spectrum stabiliser (Model

EC-5015). The background of the detector was reduced by 10 cm thick castle type,

cylindrical lead shield with a fixed bottom and swing top cover (Islam et al., 1990). The

energy calibration was carried out using 133Ba, 134Cs and 60Co sealed sources. The

background is acquired using empty vial for 50 000 s. The determination of the peak area

and the background subtraction was carried out using APTEC NRC software. 228Ra and 226Ra activity was determined from 228Ac (911 keV) and 214Bi (609.3 keV). The activity

of 40K was determined from 1460.8 keV (ICRP, 1983).

3 Results and discussion

The natural radionuclides considered in this study are 40K, 228Ra and 226Ra. The results of

the activity concentration are shown in Tables 1(a) and 1(b). The activities are reported in

Bq kg–1 fresh weight. The total 40K values in fin fish ranged from 34.16 to 360.7 Bq kg–1

fresh. The highest activity concentration was found in the oil sardine Sardinella longiceps

and the lowest in the catfish Arius sp. In the Bay of Bengal, the activity ranged from

4.93 to 77.09 Bq kg–1 fresh (Alam et al., 1995). In this study 40K activity in the brown

mussel Perna indica of Kudankulam coast ranged from 15.6 to 18.8 Bq kg–1 fresh in

the soft tissue and 50.8 ± 0.31 Bq kg–1 fresh in the shell. In the green mussel Perna

viridis of the Bangladesh coast the values ranged from 23.1 to 80 Bq kg–1 fresh in soft

tissue and 69.8 to 137 Bq kg–1 in shell (Alam et al., 1999). These values were higher

when compared to those in the Kudankulam coast. In the Bombay coast, the 40K activity

ranged from 76.2 to 129.2 Bq kg–1 fresh and in the Kerala coast, it ranged from 72.2

to 98.86 Bq kg–1 fresh (Mistry et al., 1970). Yu et al. (1997) reported the 40K content in

fish consumed in Hong Kong, which ranged from 56.46 to 108.2 Bq kg–1 fresh, which

is comparable with those in the Kudankulam coast. The patterns of accumulation of

radionuclide may vary from species to species and from region to region. According to

Alam et al. (1999) the activities of radionuclides in mussels depend greatly on body size

of individuals and the concentration decreases with increase in body size. In fin fish of

the Batinah coast, Northern Oman, the value ranged from 38 to 570 Bq kg–1 (Goddard

et al., 2003) and the highest concentration was found in Saurida undosquamis, whereas in

the Kudankulam coast it was only 115 ± 0.58 Bq kg–1 for Saurida tumbil (Figure 2a). In

this study, 40K activity followed lognormal distribution (0.5 < p < 0.95, n = 57), which is

tested using chi-square test of goodness of fit (Figure 3a).


K, 228

Ra and 226

Ra) in seafood 221

Table 1(a) Species description, ecology, feeding habit and concentration of 40K, 228Ra and 226Ra

in fin fish around Kudankulam

22

6R

a (

range)

0.0

6–

0.1

8

0.0

6

0.0

6–

0.0

8

0.0

6–

0.2

0.0

6–

0.1

2

0.0

6–

0.1

5

0.0

6

0.0

6–

0.1

4

22

8R

a (

range)

0.1

2–

1.2

7

0.1

2–

0.4

6

0.1

2–

0.2

5

0.2

1–

0.3

1

0.1

4–

0.4

1

0.1

2–

0.3

4

0.1

2

0.1

7–

0.4

0

Act

ivit

y co

nce

ntr

ati

on i

n B

q k

g–

1 f

resh

40K

(ra

nge)

72

.9–

36

0.7

10

6.3

5–

11

3.6

2

10

8.9

2–

12

9.7

10

3.6

–1

21

.5

87

.09

–1

25

.5

87

.4–

12

0.8

53

.24

99

.2–

10

2.1

4

Fee

din

g h

abit

s

Pla

nkto

n

An

imal

s an

d

mac

rofa

una

An

imal

s an

d

mac

rofa

una

An

imal

s an

d

mac

rofa

una

An

imal

s an

d

mac

rofa

una

An

imal

s an

d

mac

rofa

una

Pla

nts

and

det

ritu

s

An

imal

s an

d

mac

rofa

una

Habit

at

Pel

agic

Pel

agic

Pel

agic

Pel

agic

Pel

agic

Pel

agic

Ben

thopel

agic

Ben

thopel

agic

Ord

er a

nd F

am

ily

Clu

pid

ea

(Clu

pei

form

es)

Per

cifo

rmes

Ch

iroce

ntr

idae

(Clu

pei

form

es)

Sco

mbri

dae

(Per

cifo

rmes

)

Sco

mbri

dae

(Per

cifo

rmes

)

Car

angid

ae

(Per

cifo

rmes

)

Chan

idae

(Gonory

nch

iform

es)

Sci

aenid

ae

(Per

cifo

rmes

)

Co

mm

on

na

me

Oil

sar

din

e

Bar

racu

da

Do

rab

India

n m

acker

el

Indo-P

acif

ic

kin

g m

acker

el

Bla

ck-t

aile

d t

reval

ly

Mil

k f

ish

Tig

er-t

ooth

ed c

roak

er

Spec

ies

Sard

inel

la l

ongic

eps

Sp

hyr

aen

a b

arr

acu

da

Chir

oce

ntr

us

dora

b

Rast

rell

iger

kanagurt

a

Sco

mb

ero

mo

na

s

gutt

atu

s

Ale

ctis

sp

Ch

an

os

cha

no

s

Oto

lith

es s

p


Table 1(a) Species description, ecology, feeding habit and concentration of 40K, 228Ra and 226Ra in fin fish around Kudankulam (continued)

22

6R

a (

range)

0.0

6–

0.1

3

0.0

6–

0.0

7

0.0

6

0.0

6

0.0

6–

0.1

2

0.0

6–

0.1

1

0.0

6

0.0

8

22

8R

a (

range)

0.1

2–

0.8

0

0.1

2–

0.2

6

0.1

4–

0.3

3

0.1

2

0.1

4–

0.3

9

0.1

2–

1.9

0.1

2

0.2

4

Act

ivit

y co

nce

ntr

ati

on i

n B

q k

g–

1 f

resh

40K

(ra

nge)

75

.76

–1

05

.4

34

.16

–1

02

.89

49

.93

–1

03

.42

11

5

58

.2–

89

.4

87

.8–

13

5.9

0.6

7

99

.87

Fee

din

g h

abit

s

An

imal

s an

d

var

iable

fee

d

An

imal

s an

d

mac

rofa

una

Mai

nly

anim

als

An

imal

s an

d

mac

rofa

una

Var

iable

fee

d

An

imal

s an

d

mac

rofa

una

Habit

at

Ben

thopel

agic

Dem

ersa

l

Dem

ersa

l

Dem

ersa

l

Dem

ersa

l

Ree

f as

soci

ated

Ord

er a

nd F

am

ily

Lei

ognat

hid

ae

(Per

cifo

rmes

)

Ari

idae

(Sil

uri

form

es)

Let

hri

nid

ae

(Per

cifo

rmes

)

Synodonti

dae

(Aulo

pif

orm

es)

Pota

motr

ygonid

ae

(Raj

iifo

rmes

)

Lutj

anid

ae

(Per

cifo

rmes

)

Co

mm

on

na

me

Pony f

ish

Gia

nt

cat

fish

Pin

k e

ar e

mper

or

Gre

at l

izar

d f

ish

Ray

fis

h

Red

bas

s

Spec

ies

Lei

ognath

us

sp

Ari

us

sp

Let

hri

nus

lentj

an

Sauri

da t

um

bil

Try

gon s

p

Lutj

anus

bohar

MD

L

Geo

mea

n

No

tes:

M

DL

– M

inim

um

Det

ecta

ble

Lim

it.

Val

ues

sh

ow

n

are

at

Bel

ow

Det

ecta

ble

Lim

it.


K, 228

Ra and 226

Ra) in seafood 223

Table 1(b) Species description, ecology, feeding habit and concentration of 40K, 228Ra and 226Ra

in shellfish around Kudankulam

226R

a (

ran

ge)

0.0

6

0.0

6

0.7

5

0.7

1

0.1

6

0.0

8

0.0

9–

0.4

2

0.1

6

0.0

6

0.1

4

228R

a (

ran

ge)

0.6

1

0.9

1

6.5

2

6.0

7

0.6

8

0.3

1

1.9

5–

6.4

2

6.6

1

0.1

2

1.0

3

Act

ivit

y co

nce

ntr

ati

on

in

Bq

kg

–1 f

resh

40K

(ra

ng

e)

53

.8

54

.4

83

.48

48

.45

87

.39

64

.87

15

.6–

18

.8

50

.8

0.6

7

43

.82

Fee

din

g h

ab

its

Det

ritu

s

Det

ritu

s

Det

ritu

s

Det

ritu

s

Fil

ter

feed

er

(Mic

roal

gae

)

Ha

bit

at

Su

bli

tto

ral

ben

thic

Dee

p m

ud

dy

bo

tto

m

Mu

dd

y b

ott

om

Sh

allo

w c

ora

l

reef

s

Su

bti

dal

har

d

bo

tto

m

Fa

mil

y

Po

rtu

nid

ae

Maj

idae

Pen

aeid

ae

Pal

inu

rid

ae

My

tili

dae

Com

mon n

am

e

Blo

od

-sp

ott

ed

swim

min

g c

rab

Spid

er c

rab

Wh

ite

shri

mp

Sp

iny

ro

ck l

ob

ster

Bro

wn

mu

ssel

Sp

ecie

s

Po

rtu

nu

s sa

ng

uin

ole

nte

s

S

oft

tis

sue

S

hel

l

Do

clea

gra

cili

pes

S

oft

tis

sue

S

hel

l

Fen

ner

op

ena

eus

ind

icu

s

Pa

nu

liru

s o

rna

tus

Per

na

in

dic

a

S

oft

tis

sue

S

hel

l

MD

L

Geo

mea

n


Figure 2 (a) Comparison of geomean 40K concentration in fin fish. (b) Comparison of geomean 228Ra and 226Ra concentration in fin fish

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Sardine

lla lo

ngicep

s

Sphyr

aena

bar

racu

da

Chiro

cent

rus do

rab

Ras

trellig

er kan

agur

ta

Scom

bero

mon

as g

utta

tus

Alectis s

p

Cha

nos ch

anos

Oto

lithe

s sp

Leiogn

athu

s sp

Arius sp

Leth

rinus

lent

jan

Saurid

a tu

mbil

Trygo

n sp

Lutja

nus bo

har

Species

Acti

vit

y in

Bq

kg

–1 f

res

h 228Ra

226Ra

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

Sardine

lla lo

ngicep

s

Sphyr

aena

bar

racu

da

Chiro

cent

rus

dora

b

Ras

trellig

er k

anag

urta

Scom

bero

mon

as g

utta

tus

Alectis sp

Cha

nos

chan

os

Oto

lithe

s sp

Leiogn

athu

s sp

Arius sp

Leth

rinus

lent

jan

Saurid

a tu

mbil

Trygo

n sp

Lutja

nus

boha

r

Species

Ac

tiv

ity

in

Bq

kg

–1 f

res

h

(a)

(b)


K, 228

Ra and 226

Ra) in seafood 225

Figure 3 (a) Lognormal distribution of 40K in fish (n = 57, 0.5 < p < 0.95). (b) Normal

distribution of 228Ra in fish (n = 55, 0.5 < p < 0.95)

R2 = 0.8

0

2

4

6

8

10

12

14

16

18

4.3–4.4 4.4–4.5 4.5–4.6 4.6–4.7 4.7–4.8 4.8–4.9 4.9–5.0

Class interval

Ln

acti

vit

y

R2 = 0.96

0

2

4

6

8

10

12

0.10–0.20 0.20–0.30 0.30–0.40 0.40–0.50 0.50–0.60

Class interval

Acti

vit

y

(a)

(b)


The total 228Ra in fish ranged from BDL 0.12 to 1.9 Bq kg–1 fresh and from 0.31 to

6.61 Bq kg–1 fresh in shellfish. In fin fish, the highest activity was observed in Lutjanus

bohar and Sardinella longiceps (Figure 2b). In the brown mussel Perna indica, the

activity ranged from 1.95 to 6.42 Bq kg–1 fresh. In the crab Portunus sanguinolentes it

was 0.61 ± 0.13 Bq kg–1 fresh in soft tissue and 0.91 ± 0.39 Bq kg–1 fresh in exoskeleton.

In the white prawn Fenneropenaeus indicus it was 1.95 ± 0.12 Bq kg–1 fresh in soft tissue

and 6.61 ± 0.24 Bq kg–1 fresh in exoskeleton. The vast variations in a single species may

be due to age, sex, reproductive stage and other environmental factors. In the edible

fish of the Kerala coast, the activity was 44.3 Bq kg–1 fresh (Mistry et al., 1970). In the

fin fish of the Kalpakkam coast, it was found to vary between 0.3 and 0.7 Bq kg–1 fresh

(Rajan et al., 1980). In the fin fish of the Mangalore environment, the activity of 228Ra

ranged from BDL to 0.62 Bq kg–1 fresh (Radhakrishna et al., 1996). The wide difference

in 228Ra activities in fishes may be due to the more efficient capture of the element by

different fishes. 228Ra followed a normal distribution in this study (0.5 < p < 0.95, n = 55)

(Figure 3b).

The total 226Ra in the seafood around Kudankulam ranged from BDL 0.06 to

0.18 Bq kg–1 fresh. The highest activity was observed in Sardinella longiceps followed

by Scomberomonas guttatus, Leiognathus sp, Trygon sp and Alectis sp (Table 1a).

In most of the samples the activity was BDL. In Perna indica, it was found to be

0.09 ± 0.01 Bq kg–1 fresh in soft tissue and 1.15 ± 0.14 Bq kg–1 in shell. In the fin fish of

the Mangalore environment, it ranged from 0.08 to 0.27 Bq kg–1 fresh, which is higher

than that in the Kudankulam coast. In the Bombay coast, activity ranged from 0.32 to

0.62 Bq kg–1 fresh (Ramachandran and Mishra, 1989) and in the Kalpakkam coast it

ranged from BDL to 0.2 Bq kg–1 fresh. In fish consumed in Hong Kong, all the values are

below the MDL. In Perna viridis of the Bangladesh coast the activity ranged from 2.3 to

4.8 Bq kg–1 fresh in soft tissue and 9.8 to 14.4 Bq kg–1 in shell, which is higher than that

in the Kudankulam coast. The activity of 226Ra was comparable with the world range,

which ranged from 0.007 to 0.2 Bq kg–1 (Maul and O’Hara, 1989). Higher concentration

of 226Ra in shell is due to its similarity in the behaviour, both environmentally and

physiologically to Ca2+ (Pyle and Clulow, 1998). In Poland, 226Ra activity in herring and

cod are 0.04 Bq kg–1 fresh and 0.02 Bq kg–1 fresh, respectively (Pietrzak-Flis et al.,

1997), whereas in the Kudankulam coast it ranged from BDL 0.06 to 0.18 Bq kg–1

fresh for clupeids (herrings) such as Chirocentrus dorab and Sardinella longiceps. 226Ra

did not follow any distribution since the activity was BDL in most of the samples.

The measurement of radium in fish species assumes importance for two reasons.

First, fish occupy a higher tropic level in an aquatic ecosystem and therefore their tissue

radium concentration may be expected to reflect a cumulative series of events in the

movement of Ra through the aquatic chain leading to either its gradual accumulation or

discrimination, at the higher tropic level. Secondly, fish constitute one of the very

important components of human diet and therefore this study on Ra distribution in

fish muscle, would be of vital significance in evaluating the radiological exposure of

the population.

A similar trend of concentration range was obtained in pelagic fish and this may

be due to their varied feeding habits. Feeding habits of fish are found to influence

radionuclide accumulation rate. Higher concentrations of radionuclides are observed in

the muscle of pelagic planktivores followed by benthopelagic and demersal fishes. The

intimacy between the animal and the sediment coupled with the carnivore feeding could


K, 228

Ra and 226

Ra) in seafood 227

have probably resulted in a higher rate of accumulation of radionuclides in these fishes.

Further, direct absorption through the gill surfaces and through the membranous pores

also facilitates entry of radium into the animal. The 228Ra/226Ra activity ratio for fishes is

shown in Table 4.

The 228Ra concentration in soft parts of molluscs in the near shore marine

environment of Kalpakkam ranged from 0.88 to 2.2 Bq kg–1 and from 0.08 to

0.23 Bq kg–1 for 226Ra (Iyengar, 1983). Slightly enhanced levels are found in the shells,

with values between 12.0 Bq kg–1 for 228Ra and 0.45 to 0.89 Bq kg–1 for 226Ra. Cherry and

Shannon (1974) reported 226Ra concentration range 0.07–2.11 Bq kg–1, with a mean value

of 0.74 Bq kg–1 for molluscan soft parts, and for shells, values ranging from 0.11 to

7.8 Bq kg–1,with a mean value of 1.85 Bq kg–1.This value is less when compared to

the present study. The activity ratio of 228Ra/226Ra for fin fishes ranged from 1.5 to 10.7

and for shell fishes it varied from 3.87 to 21.6 for soft tissue and from 5.74 to 15.1

for shell (Table 4). Among shellfish, bivalves and benthic crabs accumulate more, that is,

they ingest detritus materials with a high degree of radionuclide accumulation, and

are capable of accumulating contaminants in their body organs to a concentration

significantly higher than in the ambient water, thereby facilitating analysis of impact of

these contaminants in biological systems (Forester, 1980; Farrington et al., 1983). The

crustacean exoskeleton, however, showed appreciable Ra concentration than the muscle.

Similar results have been reported from Kalpakkam coastal crustaceans (Iyengar, 1983).

During metabolism, radium is expected to take the calcium pathway and accumulate in

calcium-rich tissue. However, considerable variability in the enrichment of radium

relative to calcium among different biological species has been reported (Iyengar, 1990).

The observed 228Ra/226Ra ratio in the biota strongly suggests higher intake of 228Ra

than 226Ra, because of the higher bioavailability of 228Ra. The analysis of the three

radionuclides indicated that the accumulation was found in almost all groups of

organisms, but in varying degrees.

4 Dose estimation

Baseline radiation exposure evaluation of the local population is an essential prerequisite

for assessment of the external and internal radiation dose. 226Ra contributes about 10% to

20% of the internal radiation dose because of its skeleton and its decay products. But not

much is known about 228Ra. Natural radioactivity affects most kinds of living organisms

to a different degree. In fact, the growing rate of human activities in nuclear and

non-nuclear fields calls for the data to evaluate the exposure of man at natural levels.

These data provide information on human exposure to low levels of radiation and on

possible dose effect relationships, which is essential for radiation protection in nuclear

installations (ICRP, 1959). In the present investigation, the adult inhabitants considered

were greater than 17 years (ICRP, 1998). The individual and total activity intake are

given in Tables 2(a) and 2(b). The dose conversion factor used was 6.2 10–9 for 40K

(IAEA, 1996); 2.8 10–7 for 228Ra and 6.7 10–7 for 226Ra (ICRP, 1994). Non-detectable

levels are handled by taking the MDL values itself for calculating the Geomean

concentration. It was observed that the average daily activity intake and ingestion dose of 40K was maximum (Table 2). However, it causes no concern because it is essential for

metabolic activity and homeostatically controlled by the body (Holtzman, 1980). The


total annual ingestion dose owing to the ingestion of fin fish were 9.91 10–5 Sv y–1 for 40K, 1.01 10–5 for 228Ra and 8.55 10–6 for 226Ra. For shellfish, it was 4.36 10–5 Sv y–1

for 40K, 4.59 10–5 for 228Ra and 1.49 10–5 for 226Ra respectively (Table 3a). Because

fishermen consume more fish than farmers and labourers, the total radionuclide doses

were high (1.76 10–4 Sv y–1). For farmers and labourers it was 2.51 10–5 Sv y–1 and

2.01 10–5 Sv y–1, respectively. The total dose to the entire inhabitants was found to be

2.21 10–4 Sv y–1 (Table 3b). In the Kerala state, 226Ra was higher than in other states

of India owing to higher levels of uranium and thorium in monazite sands (Chhabra,

1966). In the Mangalore environment, it was found to be 1.22 10–5 for 40K, 7 10–7

for 226Ra and 2.9 10–6 for 228Ra (Radhakrishna et al., 1996). Rajan et al. (1980)

determined natural radioactivity levels owing to 226Ra and 228Ra in seafood items of

the Kalpakkam environment and estimated a dose of 3.7 10–7 for 226Ra and 3.92 10–6

for 228Ra. In the monazite beds of Brazil, the intake of 228Ra ranged from 135 to

3241.2 Bq–1y–1 (Penna Franca, 1968; Penna Franca et al., 1970; 1972) and in India, it was

2160.8 Bq–1y–1 (Mistry et al., 1970). The mean intake from the standard US diet as

estimated from total food consumption was about 18.9 Bq–1y–1 from 226Ra. The intakes

reported from other countries also range from 8.1 to 40.5 Bq–1y–1 (NCRP, 1975).

However, the doses for 226Ra and 228Ra seem to be well within the maximum permissible

dose (0.005 Sv yr–1).

Table 2 Per capita activity intake (Bq kg–1 d–1) of fin fish and shellfish for coastal adult inhabitants around Kudankulam

A. Fin fish

Activity intake Bq kg–1

d –1

Radionuclides Fishermen Farmers Labourers Total

40K 34.9 4.99 3.99 43.88 228Ra 0.08 0.01 0.009 0.099 226Ra 0.028 0.004 0.003 0.035

B. Shellfish

Activity intake Bq kg–1

d –1


40K 15.33 2.19 1.75 19.27 228Ra 0.36 0.051 0.041 0.45 226Ra 0.049 0.007 0.0056 0.061

Table 3 Total annual ingestion dose (Sv y–1)

A. Due to consumption of fin fish and shellfish

Radionuclides Fin fish Shellfish Total

40K 9.91 × 10–5 4.36 × 10–5 1.43 × 10–4

228Ra 1.01 × 10–5 4.59 × 10–5 5.6 × 10–5

226Ra 8.55 × 10–6 1.49 × 10–5 2.35 × 10–5


K, 228

Ra and 226

Ra) in seafood 229

Table 3 Total annual ingestion dose (Sv y–1) (continued)

B. For coastal adult inhabitants around Kudankulam

Annual ingestion dose (Sv y–1

)


40K 1.13 × 10–4 1.62 × 10–5 1.29 × 10–5 1.43 × 10–4

228Ra 4.49 × 10–5 6.23 × 10–6 5.11 × 10–6 5.61 × 10–5

226Ra 1.88 × 10–5 2.69 × 10–6 2.1 × 10–6 2.35 × 10–5

Total 1.76 × 10–4 2.51 × 10–5 2.01 × 10–5 2.21 × 10–4

Table 4 Comparison of 228Ra/226Ra ratio in fin fish and shellfish

Species 228Ra/226

Ra ratio (range)

Sardinella longiceps 1.9–10.7

Sphyraena barracuda 1.7–7.6

Chirocentrus dorab 1.5–4.16

Rastrelliger kanagurta 1.8–4.5

Scomberomonas guttatus 2.3–2.6

Alectis sp 1.5–5.2

Chanos chanos 2

Otolithes sp 2.8

Leiognathus sp 1.8–6.15

Arius sp 1.8–3.5

Lethrinus lentjan 2.3–5.5

Saurida tumbil 2

Trygon sp 1.16–6.83

Lutjanus bohar 1.36–9.3

228Ra/226

Ra ratio

Soft tissue Shell

Portunus sanguinolentes 10.16 15.1

Doclea gracilipes 8.69 8.54

Fenneropenaeus indicus 4.25 –

Panulirus ornatus 3.87 –

Perna indica 15.2–21.6 5.74

Acknowledgements

The authors would like to thank the Department of Atomic Energy, Board of Research in

Nuclear Sciences, and the Government of India for its financial support during this

project (No. 2004/36/16 – BRNS).


References

Aarkrog, A., Baxter, M.S., Bettencourt, A.O., Bojanowski, R., Bologa, A., Charmasson, S., Cunha, I., et al. (1997) ‘A comparison of doses from 137Cs and 210Po in marine food: a major international study’, J. Environ. Radioact., Vol. 34, No. 1, pp.69–90.

Alam, M.N., Chowdhury, M.I., Kamal, M. and Ghose, S. (1995) ‘Radioactivity in Marine fish of Bay of Bengal’, J. Applied Radiat. Isotope, Vol. 46, pp.363–364.

Alam, M.N., Chowdhury, M.I., Kamal, M., Ghose, S., Matin, A.K.M.A. and Ferdousi, G.S.M. (1999) ‘Radionuclide concentration in mussels collected from the southern coast of Bangladesh’, J. Environ. Radioact., Vol. 47, pp.201–212.

Cherry, R.D. and Shannon, L.V. (1974) ‘The alpha radioactivity of marine organisms’, Atom.

Energy Rev., Vol. 12, pp.1–45.

Chhabra, A.S. (1966) ‘226Ra in food and man in Bombay and Kerala State (India)’, Br. J. Radiolo., Vol. 39, pp.141–146.

Farrington, A.W., Goldberg, E.D., Risebrough, R.W., Martin, J.H. and Brown, V.T. (1983) ‘US “Mussel Watch” 1976–1978; an overview of the tracemetals, DDE, PCB, hydrocarbons and artificial radionuclide data’, Environ. Sc. Technol., Vol. 17, pp.490–496.

Fisenne, I.M., Perry, P.M., Docher, K.M. and Keller, H.W. (1987) ‘The daily intake of 234,235, 238U, 228,230,232Th, 226,228Ra, by New York City residents’, Health Phys., Vol. 53, pp.357–363.

Forester, A.J. (1980) ‘Monitoring the bioavailability of toxic metals in acid stressed shield lakes using pelecypod mollusc (clams and mussels)’, University of Montana Annual Conference on Trace Substances and Environmental Health, Vol. 14, pp.142–147.

Goddard, C.C., Mathews, C.P. and Al Mamry, Y. (2003) ‘Baseline Radionuclide concentrations in Omani fish’, Mar. Pollu. Bullet., Vol. 46, pp.913–917.

Holtzman, R.B. (1980) ‘Normal dietary levels of 226Ra, 228Ra, 210Pb and 210Po for man’, in T.F. Gessel and W.M. Lowder (Eds.) Natural Radiation Environment III, Proceedings of International Conference, CONF – 780422, Vol. 2, pp.755–781.

International Atomic Energy Agency (IAEA) (1996) ‘International basic safety standards for protection against ionizing radiations and for the safety of radiation sources’, Safety Report Series No. 115, Vienna.

International Atomic Energy Agency (IAEA) (1999) ‘Assessment of doses to the public from ingested radionuclides’, Safety Report Series No. 14, Vienna.

International Commission on Radiological Protection (ICRP) (1959) ‘Permissible dose for internal radiation’, Publication 2, Oxford: Pergamon Press, Ltd.

International Commission on Radiological Protection (ICRP) (1983) ‘Radionuclide transformations’, Publication 38, Oxford: Pergamon Press, Ltd.

International Commission on Radiological Protection (ICRP) (1994) ‘Age dependent doses to members of the public from the intake of radionuclides’, Part II: Ingestion Dose Co-efficient, Publication 67, Oxford: Pergamon Press, Ltd.

International Commission on Radiological Protection (ICRP) (1998) ‘Age dependent doses to members of the public from the intake of radionuclides’, Publication 71, Oxford: Pergamon Press, Ltd.

Islam, M.N., Alam, M.N., Mustafa, M.N., Siddique, N., Miah, M.M.H., Shah, S.L., Chowdhury, M.I., Masud, K., Liakot, A. and Prabir, K.R. (1990) ‘Characteristics of a shielding arrangement for a HPGe detector designed and fabricated locally. Chittagong University Studies, Part II’, Science, Vol. 14, No. 2.

Iyengar, M.A.R. (1983) ‘Studies on the distribution of natural radioactivity in marine organisms’, PhD thesis, University of Bombay, Bombay.

Iyengar, M.A.R. (1990) ‘The environmental behaviour of radium’, Technical Report Series, 310, International Atomic Energy Agency, Vienna, Vol. II, pp.59–128.


K, 228

Ra and 226

Ra) in seafood 231

Maul, P.R. and O’Hara, J.P. (1989) ‘Background radioactivity in environmental materials’,

J. Environ. Radioactivity, Vol. 9, pp.265–280.

Mistry, K.B., Bharatan, K.G. and Iyengar, G.A.R. (1970) ‘Radioactivity in the diet of populations of the Kerala coast including monazite bearing high radiation areas’, Health Phys, Vol. 19, pp.535–542.

Narayana, Y., Radhakrishna, A.P., Somashekarappa, H.M., Karunakara, N., Balakrishna, K.M. and Sidappa, K. (1995) ‘Distribution of some natural and artificial radionuclides in the environment of Coastal Karnataka of South India’, J. Environ. Radioact., Vol. 28, pp.113–139.

National Council of Radiation Protection and Measurements (1975) ‘Exposure of the population in the United States and Canada from natural background radiation’, Report No. 94.

Penna Franca, E. (1968) ‘Radiochemical and radiological studies on Brazilian areas of high natural radiation’, USAEC Report, NYO-3273-11 (Pt-1) New York Operations Office, NTIS, p.10.

Penna Franca, E., Costa-Ribeiro, C., Cullen, T.L., Barciniski, M. and Gonzalez, D.E. (1972) ‘Natural radioactivity in Brazil; a comprehensive review with a model for dose-effect studies’, Natural Radiation Environment II, Proceedings of an International Symposium held at

Houston, Texas, USA, CONF – 720805 – P2, pp.929–940.

Penna Franca, E., Fiszman, M., Lobao, N., Trinidade, H., Costa-Ribeiro, C. and Santos, P.L. (1970) ‘Radioactivity in the diet in high background areas of Brazil’, Health Phys., Vol. 19, pp.652–657.

Phillips, D.J.H. (1980) ‘Quantitative aquatic biological indicators’, London: Applied Science Publishers.

Pietrzak-Flis, Z., Chrzanowski, E. and Dembinska, S. (1997) ‘Intake of 226Ra, 210Pb and 210Po with food in Poland’, Sci. of Tot. Environ., Vol. 203, pp.157–165.

Pyle, G.G. and Clulow, F.V. (1998) ‘Radionuclide equilibria between the aquatic environment and the fish tissues’, J. of Environ. Radioactivity, Vol. 40, pp.363–364.

Radhakrishna, A.P., Somashekarappa, H.M., Narayana, Y. and Sidappa, K. (1996) ‘Distribution of some natural and artificial radionuclides in Mangalore environment of South India’, J. of Environ. Radioactivity, Vol. 30, pp.31–54.

Rajan, M.P., Kannan, V., Ganapathy, S. and Iyengar, M.A.R. (1980) ‘Natural radioactivity intake through dietary sources at Kalpakkam’, Bull. Radiat. Prot., Vol. 3, pp.69–74.

Ramachandran, T.V. and Mishra, U.C. (1989) ‘Measurement of natural radioactivity level in Indian food stuffs by gamma spectrometry’, Bull. Radiat. Prot., Vol. 12, pp.51–55.

United Nations Scientific Committee on the Effects of Atomic Radiation (1993) Dose Assessment Methodologies, United Nations, New York.

United Nations Scientific Committee on the Effects of Atomic Radiation (2000) Dose Assessment

Methodologies, United Nations, New York.

Young, A.K., Mc Cubbin, D. and Camplin, W.C. (2002) ‘Natural radionuclides in seafood’, Food Standard Agency Report, CEFAS, FSA Project, R 03010.

Yu, K.N., Mao, S.Y., Young, E.C.M. and Stokes, M.J. (1997) ‘A study of radionuclides in six types of fish consumed in Hong Kong’, Appl. Radiat. Isot., Vol. 48, pp.515–519.

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Concentration of natural radionuclides ( 40 K, Rashodhganga.inflibnet.ac.in/bitstream/10603/19465/16/16_publication.pdfBiographical notes: M. Feroz Khan is a Junior Research Fellow