MFCM093: Review of Human Health Studies in High Background Radiation Regions.pdf

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HBGR health-review

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Review of Human Health Studies in High Background Radiation
Regions

Padmanabhan VT *
There is a general agreement among the students of radiation
biology that the dose-effect curve is linear at higher doses.
The quarrel is about the increase per unit exposure and the
direction and magnitude of effects at lower dose ranges. There
are four hypotheses. The linear zero intercept hypothesis
suggests that the effects linear with zero effect at zero dose.
In other words, addition of any small dose will have its genetic
and somatic effects. According to the second hypothesis,
( U Intercept ) the curve would be supra-linear, ie. the effects
per rad of exposure would be higher ( and net proportionate) at
lower dose range. The third one-threshold hypothesis suggests
that-there is a threshold below which no effect will be observed.
According to Hormesis hypothesis , a recent entrant, a small
addition of radiation will have beneficial effects like a
reduction in the number' of cancers.
While the environmentalists argue that there is sufficient
evidence to accept the linear dose-response model/the atomic

energy research establishments insist that the tie can be resolved
only by an indepth studv of the health status of people living
in the monazite belts in Kerala and Tamilnadu. (2)
The beach sands in Ganjam in Orissa, Manavalankurichi in
Tamilnadu and Neendakara Chavara Ponmana Alappat Panchayats in
Quilon district of Kerala Contain Thorium-Uranium bearing
monazite. The background radiation in the Kerala'portion ranges
from 300 to 4000mr. yr. 'The strip, which is almost an island
with backwaters and canals in the east, has a population of
about 50,000, inhabiting there for several centuries. The HBGR
people are the only un ortunate humans who have been for genera
tions exposed to background radiation, some 5 to 50 times the
normal. They offer an excellent opportunity to make reasonably
'accurate risk estimate for radiation induced health damages over
generations and also to study the yet unknown mechanisms of
genetics.
The World Health Organisation ( WHO) in 1957 resolved to under
take a twenty year long continuous observation of the HBGR
people in India. A detailed plan of action ( which also involved
and efficient health care package' ) was drawn up on the basis of
preliminary investigation in the Kerala portion^ ,WHO1s funds
for health studies in HBGR go to BARC. The achievements during
the past three decades are reviewed here.

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AR Ayengar. et al. of BaRC

(1972J

HBGR health-review page 2
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' The first demographic study sought information on sex ratio at
bipth, fertility index, infant mortality, abortion, multiple ’
births and gross abnormalities from 2420 couples from Thekkumbhagom ( now Neendakara), Chavara, Panmana, Alappat,Aratupuzha,
Trikkunnapuzha and Purakkad Panchayats. Since the vital events
registers of the study area are of poor quality,Ayengar et al.
subjected their data to an internal comparison and ccncluded

that the difference between exposure groups is not significant.
The Biased Analysis : The northern half of the study areaArattupuzha and Purakkad panchayats are normal background radia
tion regions with an exposure range of 80 to 120 mr. yr. More

.

■ than half the people in the lowest exposure category-100 to 500 >

m r received less than 150 m/r a year. This resulted in the

dilution of the results. Secondly, the populations in other
exposure categories are extremely small - 17% in 600- 1000 mr,
4% in 1100- 2000 mr and 1% in 2000 mr and above as against 78% in
100 to 500 mr group.

Ayengars contention that vital registration system is non

existent in the study area is only partly true. While civil
registration system is what it is ( even today), there were two
sources of excellent data base which could have been used for
cross checking and comparison. The first one is the sample
registration system which provides rates for lowland Kerala.
The second one was the Indo-Norwegian Project (INP) Hospital
at Neendakara which provided an efficient preventive and curative
services. INP had even conducted periodic health surveys in the
Southern portion of Ayengar's field, which incidentally has the
highest radioactivity.

Since the population in the higher exposure categories are
extremely small, a comparison of the entire study population
with the published rates for Low Land Kerala is attempted in
table 1.
Table 1
Population SR in Live Births
Still Birth Rate
TP Strip
941
36
Low Land Kerala
1005
17 •
Source : For TP Strip, Ayengar above. For Low land Kerala Ref.8.

Kochopillai’s data ( being reviewed below ) also shows that the
sex ratio in HBGR is 955 against 971 in the control population.
In the lowest age group ( 0-5 ) the difference is even sharper
with 905 and 1050 respectively.
Ayengar's study population did experience a higher foetal
mortality and still birth rate.

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Ayengar et al. did ol serve a few severe abnormalities like an
infant mortality rate of 250 in samples exposed to the highest
dose. IMR in lowland Kerala during the period 1965-71 was 34 as
per SRS. In /estern countries, congenital! anomalies account
lor a third of the infant mortality. The excess infant mortality
observed in a region of high radiation is, on the contrary
dismissed on the ground that villages in Uttarprade sh also
have similarly high rates.
(5)
NKochupillai, et al of AIIMS (1976)
N Kochupillai et. al surveyed 13000 people in Chavara- Neendakar
(HBGR) and 6000 people in Purakkadu Punnapra ( Control ) in
Alleppey district in 1975. The results are given below

1.
Cytogenetic abnormalities. Chromatid and chromosome
aberrations were scored in 1,705 metaphases from 46 subjects
and 1,547 metaphases from 39 individuals in the study and
control areas respectively. The mean frequency of chromosome
aberrations was higher in the study area, and the difference
was significant at the one percent level.
The observed freouency of Down's Syndrome in HBGR (Table2)
was higher than the values for other countries. Of the 12 cases
of Down's syndrome, one was born to a woman in age group 20-29,
nine to age group 30-39 and two to age 40-49.
Table 2 : Prevalence of Down's Syndrome and Severe mental
retardation.
2.

E ffects.

Study Population Control Population
Total per 1000 ...
Total per IPPS

Ge tie tics
12
Down's Syndrome
SNR with Physical
12
abnormalities
Idiopathic ( of urkn- 11
own causes )
Acquired
Perinatal and postnatal 6
41

Source : Ref. 5 Total

0.93
0.93

0
1

0

0.90

3

0.50

0.46

3

0.50

3.1

7

1.16

0

The authors observed that " the maternal age dependence
suggests’ that the damaging event accelerates oocyte aging
and causes primary trisomy rather than translocation trisomy
which is known to be independent of maternal age (....) The
higher prevalence of chromosome aberration in apparently norm
al subjects from the radiation area also supports the view
that environmental radiation may be the cause of the genetic
damage in the population. "
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In a rejoinder, K Sundaram of B.'iHC ^^raised the following

oMejctipns. ±
1) Comparison of the observed frequency at Neendakara with any
other published value would be valid only if the age str1.' t r >
of the population is similar. IMR in this region is 200
1,000 births and is independent of the background - id .
Furthermore, in most other surveys, only 4% of uhe bi; c. >

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been to females 40 years and older., The data of Koc:upil ’. :
et al. shows about 20% of the females in this age.group t 'o.;
incidentally carries the highest risk of bearing child-. IdDown's Syndrome. (....). The greater Frequency of Down's syndrom,

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in the study group (...) than in those reported from other
countries could be explained solely in the difference in
population structures. ".

*

Regarding the higher risk of Down's syndrome births in age

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group 30-39, Sundaram observes : " Kochupillai et al. have
demonstrated only that mothers in the age group 30-39 run a
risk 10 times greater than those in the younger age group
which agrees with other evidence of increasing risk with

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advancing maternal age,They made no comment as to why this
risk is about three times lower in authors in the age group
40-49 years. If higher background radiationia is involved, an

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even greater- risk would be expected in this group than in the

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comparable age group of the general population ''.
After the demolition, Sundaram reanalyses the data generated

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by the former- He estimated 11,500 births in the study popula
tion^ 12, 918 ), an infant mortality rate of 200 per 1,000
births and a mortality of 60 per 1,000 births in the age
group 1-20 years ", He further estimated a total of 20 cases
of Down's syndrome among 11,500 live births. The expected fre
quency, after Penrose and Smith ( 1.507 per 1,000 births) is
17 cases. The difference between expected and observed,
Sundaram rules,is not statistically significant.
(y'\
t»rt-- Authors Replyv 7

1.

Infant and Child mortality . In their rebuttal, IC Verma
et al. argued that even though " infant and childhood mortality
in India is about 6 times higher than in Western Countries •',
the-mortality of Down's syndrome should also be substantially
higher than the general population, and hence the difference
observed in the population frequency is not artifically caused
by lack of standardization for age structure.
2.

Fertility Rates. On the question of higher fertility rates

the authors replied 11 Sundram's comparison of 4% of all births
to females 40 and above in other surveys with 20% of females
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HBGR health-review p-^e 5
in this group is incorrect.The percentage of women 40-49 r ars
old in study area is 8.42% as against 23% apd above in Austria,
Denmark and the UK
the risk of Down's syndrome births in
the 40-49 yrs. age group is no less than in the 30-39 years
group " if the difference in age specific fertility ( about 56
and 186 per 1,000 females in the two groups respectively) is
remembered ".
3. Frequency of Down's Syndrome at birth. Verma et al. pointed
out that Sundaram erred in calculating the total Down's syndrome
births in the population " by incorrectly equating the
mortality of Down's syndrome with the usual childhood mortality
They estimated a total of 33 Down's syndrome births which works
out to 2.8 per 1,000 live births. The debate ended there.
The debating teams 1 total ignorance of the demographic situaztion of Low Land Kerala from where both the study and control
population of Kochu (, illai were drawn led to gross disfigure
ment of the data. Mortality and fertility rates here are
considerably lower than that of All Kerala and India ( See
Table 3 ).
Table 5 : Mortality rates : lowland Kerala,Kerala and Indif

Region.

0-1 yr.

2-4 yr.

5-9 yr.

10-14 yr.

Lowland Kerala(1971)
Kerala (1971)
India (1965-70)

34.39
60.89
139.00

11.47
13.08

2.39
2.39
15.50

0.86
1.13
4.60

19.90

Source : For Ke rale. Re f.9. Jor India, UN Demographic Year
Book 197.1 2_._6.70j_
The infant mortality rate in Low Land Kerala in the seventies
was 34 and not over 200 as quoted by Sundaram and Verma. If
the rate in the study area is so high ( and this has not been
proven ), it may be attributed to a higher incidence of congeni
tal malformations .

Age Specific Fertility Rates ( ASFR ) quoted by Verma et al.
(186 & 56 among age groups 30-39 and 40-49 respectively) are
for All India Rates for Lowland Kerala are 141 and 25. ASFR
among the latter is not just three times but six times lower
than the former
There were 2,983 women in the child
bearing age group in the study population. Sundaram quoted
too low a number - 2213 - without revealing the source. (This
escaped the notice of Verma et al. )His estimate of births
in the study area based on fictitious data has no use value.

A more accurate method would be to work out the female popula
tion of the study region and estimate the total births using
the fertility rates of the past. The study population was drawl
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HBGR health-review paged 6
from Chavara and Neendakars segments (locally known as Kara)
of two revenue villages Chavara and Thekkumbhagam. The total
population and the number of women aged 15-49 years in the
region in 1975 is 12,918 and f. 2,983 respectively. From the
census growth rate, total population and fertile women in the
study region in the previous years are 12,330 and 2,840 in 1971,
943<yin 1961, and 6,530 and 1,510 in 1951 respectively. Using
180
fertility rates for Lowland Kerala, 6440 births has
(9)
been estimated in the study population
.
Verma et al. estimated 33 Down's Syndrome births, of whom twelve
were alive at the time of survey. Incidence of Down's Syndrome
at birth at Chavara- Neendakara is 5.1 per 100G which is eight
times higher than Trivandrum and all India (excluding Madras)

and 20 times higher than Madras.
Age Specific Down's Syndrome risk- Down's syndrome birth risk in
different age groups has been worked out in Ref. 9, The risk

among mothers aged 30 - 39 years and 40-49 years is 18 and 33
times higher respectively than that of mothers in the lower
year age group. 'The mothers aged 40-49 years haye almost a two
times greater chance of giving births to Down's syndrome babies
than women in age group 30-39 years.
Cytogenetic Studies :

Ever since the inception of the genetic studies of BARC at
Neendakara, cytogentic studies on humans, animals and plants
are being conducted. The few reports published just state that
no statistically significant difference has been found.
Kochupillai was the first to report an increased chromosal
aberration in the HBGR people. Yet, Soundaram totally ignored
this finding.
A report presented at the II Special Symposium of Natural
Radiation Environment Studies by KP George shows that the
aberration rate in the HBGR human samples was 12 per thousand
as against 7 per 10,000 in the unexposed.

Sample.
Twelve invited lectures and 80 contributed papers were
presented at the above symposium. Of these, 91 has been
published in the proceedings published by BARC in 1982. Gorge's

paper is not found. This inspite of the fact that his was the
only paper quoted by CM Sunta in her summing up of studies on

biological effects.
Natural Rad.-atipn Environment Studies :
The Atomic Research Establishment organised five international
symposia on Natural Radiation Environment Studies (NRES).

Summing up the conclusions derived from the 1975 conference,
Merril’Eisenbug stated : " The epidemiological work in Kerala

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and Brazil should be continued. CM Sunta sums up the discussions
at the second conference held after 6 years : i!" rtn ambitious
epidemiological study coupled with a comprehensive health survey
is now proposed for Kerala. A happy fallout of the programme
will be the availability of a good medical care to the concerned
population, i! rhe big study and the good medical care have not
arrived so far.
Rather than picking up the thread from the AIIMS team and condu
cting a detailed investigation, BARC scientists busied themselves
in demolishing the study by using fictitious data. In fact, Alll'iS
did suggest a collaborative study with BARC, which would have
cost less than Rs. 3 Grores. This is not so big a bill for the
premier research centre in the country which receives a lion's
share of our Science R and D resources.

Why the study, when Dr. KG Vohra, the co-ordinator of .
the symposium had foreclosed the chances of any abnormal finding?
From his keynote address : 11 The population receiving high doses
have not shown any abnormal health situations. In fact, one
would not expect to see any effects, because the number of
exposed persons in each study is small when considered in the
range of natural background. Thus NRES do show that the
presently estimated low risk factors are valid and N power
production with good engineering practices would not pose
radiation health problems of any significance.'1 (11)
While the middle level DAE scientists resolve, plan and •
resolve about the impending big study of Chavara Neendakara
people, Chariman AEC affdjrtas that the people at ChavaraNeendakara exposed to 5000 millirems and above a year have
no health problems and they are thriving. (12)
The attitude of BARG to the proposed health studies in HBGR
is both unscientific and unethical. The truth is that a more
tight and detailed study would reveal the magnitude of damages
caused by " small additions " of dose. And the tall claim that
the normal functioning of the nuclear power stations will not
pose any threat to people will stand exposed.

REFERENCES
(1) Gofman J.W., 1981, Radiation and Human Health Sierra
Club Books.

(2) Adams JAS, 1982, in KG Vohra et al.(ed.) Natural Radiation
Environment, p. 676.
(3) World Health Organization, 1959, Effects of Radiation on
Human Heredity : Investigation of Areas of High Natural
Radiation Geneva.
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HBGR health-review p

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(4)

Gopal Ayengar, 1972, Peaceful Uses of Atomic Energy,
IAEA Cont 49, 1972.

(5)

Kochupillai N., Verma I.C., GrewalM.S., Ramalinga-Swamy V.,
1976, " Down's Syndrome and Related Abnormalities in an

Area of High Background Radiation in Coastal Kerala1-,
Nature, Vol. 262.

(6)

S undram K., 1977, " Down's Syndrome in Kerala"* Nature
Vol. 267.

(7)

Verma, I.C., Kochupillai N., Grewal M.S., Ramachandran K.,
Ramalinga-Swamy V., 1977, Nature Vol. 267.

(8)

Bureau of Economics and Statistics, Government of Kerala,
Sample Registration Scheme, Annual Report 1971, issue No.8<

(9)

Padmanabhan VI, 1987, Radiation Caused Genetic Diseases
in Chavara- Neendakara- Kerala, India, Aie Anatomy of
Non-Debate, International Perspectives in Public Health,

Vol. 3, Issue 1, pp. 20-25.

(10)

George, KP, 1981, Quoted in KSB Rose, (1982), Review of
Health Studies .;t Kerala, Nuclear Energy, Vol. 21, No.6,

pp. 399-408.
(11)

KG Vohra (1982) tn Vohra et al. ibid, p. 3.

(12)

Raja Ramanna, Telegraph, Calcutta, Mardh 3, 1984.

( Back ground Papers for XVI Annual fleet of MFC)
Based on the Paper Presented at the Bangalore
Work-shop organised by the Govt, of Karnataka
& Citizens Aginst Nuclear Energy, Bangalore

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