Radon concentration in drinking water and supplementary exposure from South-East of
Kinga Szacsvai, Tamas Neda, Szilard Poszet, Alexandru Szakacs
Sapientia Hungarian University of Transylvania, Faculty of Sciences and Arts, Cluj-Napoca,
From the public health point of view, the investigation of the radon and radium content
of drinking and mineral waters and the estimation of their contribution to the radiation
exposure are our current tasks now days.
Radon is an inert radioactive gas whose concentrations in ground water are reportedly
related to a number of factors including emission of radon from surrounding rocks,
temperature, pressure, and rainfall and earthquake activities. Generally, higher radon
concentration is observed in waters of low mineralization. Also, the radon activity
decreases with the depth of the area where the water circulates. When water containing
radon is used in the home for showering, washing dishes, and cooking, radon gas escapes
from the water into the air.
The aim of this work is to measure the radon concentration of drinking well waters
and calculated the effective dose per year.
The places where we measured it was in 94 location in South-East of Transylvania (Brasov,
Covasna and Mures county).
In the present study, the measurements of radon were carried out using the LUK-VR
system based on radon gas measurements with Lucas cells. The LUK-VR system consists
of a LUK-3A device and a VR scrubber dedicated for radon measurements in water samples.
The VR-scrubber consists of a glass vessel of 500ml volume where a known quantity
of water sample (300ml) is introduced. The principle of operation is that the concentration
of the radon dissolved in the water sample is mixed with the air that is on the top
of the water level; within the scrubber volume. Following this, air is then transferred
from the scrubber to be measured for radon using the Lucas cell method.
Concentrations of the radon were determined in 165 selected well water samples of
this region of Romania. The results showed radon concentrations within the range of
0.1 – 10.02 Bq/l with an average value of 1.89 Bq/l.
The use of the water can be one of the factors that increase the indoor radon concentration.
At the same time drinking of radon rich waters can contribute to the internal irradiation.
this reason is important to control the radon activity concentration of waters. The
corresponding annual effective ingestion dose due to radon from water was determined
from drinking water used (1l/person/day) by the population inhabiting the area. For
the dose conversion factor the 3.5·10-9 Sv/Bq value has been used, proposed by UNSCEAR
and adopted by the European Community too. The calculated annual effective dose from
radon was located between 0.128-10.02 μSv/year.
The radon measurements were performed using the Lucas cell method with short counting
time during the non-equilibrium state between radon and its progeny. The short counting
time allowed the large number of water samples to be measured fast, so to avoid delays
within the survey program.
In most of cases, the measured values are not high and do not exceed the radioprotection
standards recommended by national and international institutions (US, EPA).