Passive Radon Measurements

Atomic Energy Organization of Iran
Iran Nuclear Regulatory Authority (INRA)
Ramsar the Radioactive Nature
Presented by:
Naser Rastkhah
Head of INRA
Ramsar is a coastal city located in the north of Iran . And is well known for highest
level of natural radiation among the worlds high levels of natural radiation areas
(HLNRAs) such as : Kerala in India, Yangjiang in China, Guarapariin in Brazil ,
… ).
Since 1959 this area is recognized as HLNRA and has been the subject of
environmental radioactivity and epidemiological studies. Several national and
international research teams visited the area and curried our research projects
An international conference on high levels of Natural
Radiation was held in Ramsar jointly with WHO , UNEP
and IAEA in 1990
The natural radiation in Ramsar is mainly due to the transfer of the dissolved
radium in water to the ground surface through the hot springs. So the natural
gamma dose rate is high in some areas. Outdoor gamma dose rate is dependent
on the distribution of hot spring residues including Ra-226. In some places it is
22μGy/h at height of 1 m and 73μGy/h on the surface.
Hot Springs as a Source of Natural
Radionuclide in Ramsar Region
There are more than 9 hot springs with different
concentrations of Ra-226 in Ramsar which
people believe that they do well for rheumatism,
neurotic and muscular pains, and skin diseases.
Inhabitants who live in some houses in this area
receive annual doses as high as 132 mSv.
Cytogenetic studies show no significant
differences between people living in the high
background radiation areas comparing to those
living in normal background areas.
Radon concentration at many homes is higher comparing
to those homes constructed in normal areas.
(Houses, Schools and
Some homes constructed with the stones containing high value of Ra-226
and having high level of Radon-222 concentration (3kBq/M3)
Since 1996, “High Natural Radiation Research Center” has been established in
Ramsar to conduct research projects on high natural background radiation and
epidemiological studies at the national and international level.
Some laboratories such as radioecology, sample preparation as well as dosimetry
have been established and equipped with the radiation detection equipments.
equipments in use for Gamma
dose measurement
Passive Method:
TL environmental Dosimeter
Active Method:
Proportional Gamma counter
Passive Radon Measurements
(in Air)
Radon Diffusion
-Lexan Polycarbonate
Electrochemical Etching Condition:
15% KOH+40% C2H5OH+45% H2O
-Field Strength : 32 kV/cm
2 kHz
-Temperature: 25◦C
Pylon AB-5
Active Radon Measurements
Measurement of dissolved Radon in water
A comprehensive action plan approved and scheduled by INRA in 2008
which consisted of 4 projects:
a) Preparing the natural radioactivity map of Ramsar including measurement of
gamma dose rate on the ground surface, radionuclide content of the soil, radium226 and Rn-222 content of the drinking water, Rn-222 concentration at homes
following standard protocols.
b) To determine precisely the exposure of people considering all pathways such as
inhalation, ingestion and external exposure.
c) To do a health surveillance programe for the people living in the area
considering natural exposure.
d) To provide guidelines and solutions to the inhabitants to reduce their exposure
considering the social and economical impacts.
The area of Ramsar is about 729.8 Km2. The central and most populated area
(Red line) was selected for investigation and was divided to 2500 cells of
dimension 50x50 m2. The gamma dose rate was measured at 5 Cm and 100 Cm
above the ground using scintilation survey meter. Maximum, minimum and
average dose rate along with the georaphical specification of the cells registered
for each cell.
Gamma dose rate measurement at 1 m above the ground
Project a) was ended by 2012 and Gamma Dose map of Ramsar at 1
meter above the ground was prepared. This project shall be extended to
cover also the suburb of Ramsar
150 <
150 <
< 300
Project a) Gamma Dose map of Ramsar at 5 Cm above the ground was
150 <
150 <
< 300
INRA in Corporation with the Road, Housing and Urban
Development Research Center approved the Regulation for
the protection of buildings agaist the penetration of Radon
gas to be implemented in high natural radiation areas
More budget and investment is needed to complete high
natural background radiation research center of Ramsar.
All researchers and interested research institutes and
universities are highly welcomed for defining and performing
common projects jointly with INRA as well as sponsorship to
equip laboratories
Thank you for your attention