The Risk of Natural Radioactivity
in the Environment
A clinical & paraclinical experience on Ramsar Inhabitants
Ali Shabestani Monfared, Seyed Mohamad Javad Mortazavi
Babol University of Medical Sciences, Babol, Iran
Rafsanjan University of Medical Sciences, Rafsanjan, Iran
Introduction
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There has always existed on earth a natural background radiation to which all
living organisms are exposed.
There exists the regions like Kerala in India, Yangjiang in China and Ramsar in
Iran that the background radiation is much higher than the others in the world.
[Sohrabi & Durrani, 1990- Wei, 1998- Nair, 1999]
High natural background radiation areas (HBRA) have been extensively studied
around the worlds. [UNSCEAR, 1988- Mishra et al, 1990- Mortazavi et al, 2002Monfared et al, 2003]
Introduction (Cont.)
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The beautiful coastal city , Ramsar, located at the foot of the Elborz
mountain and overlooking the Caspian sea, involves the highest
background radiation among the whole residential areas in the world.
[UNSCEAR, 2000]
Introduction (Cont.)
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The radioactivity of the area is mainly due to Ra-226 and its decay
products, which have been brought up to earth surface by the water of
hot springs.
There are more than 50 hot springs with different concentrations of
radium in the Ramsar which are usually used as spas by the residents
and visitors.
Introduction (Cont.)
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The HBRA of Ramsar has been the subject of concern in the last forty
years for a high level of radiation measured in some spots as high as
240 mSv y-1 .[Sohrabi & Esmaili, 2002]
It may be of interest to note that the maximum dose for radiation
workers is 20 mSv y-1 and in order to prevent the possible radiation
effects like cancer and genetic diseases, the dose to public should be
less than 1 mSv y-1 . [Publication No. 60 , ICRP (1991 b) ].
Objective
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Several studies have been performed to assess the effects of the high
background radiation on inhabitant health in Ramsar from different
aspects such as cytogenetic studies (Fazeli & Assaei,1993), biological
studies (Mortazavi et al, 2002) and immunological studies (Zakeri et al,
2004).
The purpose of the present research was to study the health situation
of the inhabitants of HBRA in Ramsar from the medical point of view.
In this article, the most important point was to survey the present
health status as an end point in radiobiological assessment of the
inhabitants.
Materials & methods
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Among the whole inhabitants in Talesh Mahaleh in Ramsar as HBRA
(127 families-504 people) and Chaparsar area with normal level of
radiation (NBRA) (142 families – 506 people) [totally 1010 persons],
(101 families- 402 persons) and (98 family-374 persons) [totally 776
persons], were selected respectively because of their permanent
residency in the area and matching of some variables like sex, diet etc.
Chaparsar
(NBRA)
Talesh mahale
(HBRA)
Materials & methods (Cont.)
Phase Ι
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After explaining the aim of the study for the individuals and satisfying
them a questionnaire was prepared through observation to be sure that
other intermediate factors affecting on the health are matched.
It was included demographic features , a few socio-economical and
health features like age, sex , job ,education , income , period of
residency , technical hygienic features of residential buildings , the way
in which treating- hygienic services are received, diet, etc.
Some items have been completed through available data in local health
center of the areas.
Materials & methods (Cont.)
Phase IΙ
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Another questionnaire in the form of modified Beck Test was also
prepared to determine the range of depression among the puberty that
lived in the two areas (298 people with the age of (34.3 ±11.21 years).
Medical doctors examined the inhabitants and blood and urine samples
were taken and analyzed.
Results
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The preliminary results of the phase 1 was presented at 6th International
conference on HLNRA in Osaka-Japan, 2004 & The 4th International Conference
of Low Radiation (WONUC), Hamilton, Ontario, Canada,2005 and is going to be
published in IJLR 3 (3),2006.Also the complementary results of phase1 was
presented at World Congress on Medical Physics and Biomedical Engineering,
COEX Seoul, Korea,2006.
Results showed that distributional frequency of the member of each family in
two areas was equal (p-value = 0.083 ). Also in both areas the difference
between the number of members of each family was not statistically significant
(p-valve = 0.077).
The average monthly income as one of the effective indicator on health
standard, regardless of lack of clear answers in both areas was equal (p-value
= 0.852) which is confirmed by applying non–parameteric tests.
The findings showed that the number of disabled children and the cause of their
disability (using the precise fisher test p – value = 0.197) and the frequency of
depression and sex and age distribution of it, among the inhabitants of the two
areas would not be statistically different.
Results (Cont.)
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In both areas the sex distribution and the standard of education were
the same. The average of the residency period in Talesh mahaleh was
38 ± 24 and in Chaparsar was 40 ± 24 years and the difference was not
statistically significant (p-value = 0.086).
Some other criteria such as hygienic-technical situation of the two
areas , storey and rooms , situation of the passages lead to these
places, availability to hygienic drinking water , building skeleton, bath
and lavatory, system of sewage disposal and dumping ground , keeping
animals in the residential areas, etc, were the same.
Although the fuel for heating system in both areas was not a like, there
exist hygienic and separate chimneys.
On account of being one medical center, there could not be observed
any difference in receiving medical services.
Results (Cont.)
Area
Age
(years)
Residency
period
(years)
Congenital
disabilities
(No.)
Cancer
(No.)
Cardiac
diseases
(No.)
Age of
death
(years)
Depression
(No.)
**
Talesh
mahaleh
n= 402
35.34
±
20.76
38 ± 24
2
2
17
61 ± 24
3
Chaparsar
n=374
33.83
±
20.58
40 ± 24
2
3
14
66 ± 15
2
* The differences were statistically significant (p<= 0.05)
** It was studied in 298 people in two areas.
Results (Cont.)
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The mean age of the inhabitants, in HBRA and NBRA were 35.34 ±
20.76 and 33.83 ± 20.50 years respectively and the difference was not
statistically significant.
We found in the first phase of the study that the frequency of a few
special diseases like cancer and cardiac disease in the HBRA could be
less than the region with ordinary background radiation . However, the
lower frequency of cancer and cardiac diseases in HBRA inhabitants
was not confirmed by clinical examinations and paraclinical tests in the
second phase of the study and there was no significant differences
between the frequency of these diseases in the people who lived in
those areas.
Results showed that the rate of mortality has not been changed
significantly since last year (p-valve = 0.678) and also the distribution
of frequency of the causes of death was not different (p-value =
0.513).
The distribution of frequency of abortion in the two areas were equal
(p-value = 0.363).
Discussion & Conclusion
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Results showed that some important indicators on health such as
economic and social features and a few hygienic indicators among the
two residential areas were statistically equal. Therefore the possible
observable changes in frequency of some diseases and health problems
in the two areas could be independent from these factors.
Results showed that the frequency of a few problems like congenital
disabilities, abortion and depression among HBRA and NBRA
inhabitants, as well as mortality rate, cardiac diseases and
malignancies was similar.
On the basis of ICRP recommendation for preventing of possible
radiation effects like cancer and genetic diseases , the dose to
population should be less than 1 mSv y -1
So this value for HBRA inhabitants is increased from 55 to 200 times
and the lack of illness effect after receiving this dose cannot be
adapted with this protection regulation (Mortazavi et al, 2002)
Discussion & Conclusion
(Cont.)
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Some studies indicated that this level of radiation can be safe for
human health (Ghiassi-nejad,2002) and to some extent this point is
appropriate to the present study.
The results showed that the frequency of some diseases and
malignancies in HBRA is similar to the NBRA. Perhaps this finding
represents the stimulation of immunity system through radiation
(Ikushima, 1999).
The outcomes which deal with no increasing the frequency of
malignancies with HBR can be compared with some of other reports
(Feinendegen & Bond, 1989 - Cohen, 2002) .
These findings also might be related to radiation adaptive response
(Monfared et al, 2003).
Uncertainties & further
researches
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The design of present study (cross sectional study) provides a situation
analysis, rather than investigation of the effect of HBR on health.
Although we used census method, lack of population in HBRA in
Ramsar is a main source of uncertainty .
A cohort study is going to established in cooperation with Japanese
colleagues.
In conclusion, our study may have not provided a strong support that
living in HBRA in Ramsar is safe, but it definitely addresses the need
for further extensive epidemiologic studies.
Is radiation
dangerous for
health?