MONITORING OF RADIONUCLIDES IN ... - Terviseamet

GEOLOGICAL SURVEY OF ESTONIA
MONITORING OF RADIONUCLIDES IN
GROUNDWATER OF ESTONIA
REIN PERENS
LEHTE SAVITSKAJA

HYDROGEOLOGICAL MAP OF ESTONIA

THE OBJECTIVES OF THE NATIONAL
GROUNDWATER MONITORING
- to survey the state of natural groundwater resources
(water supply supply,
, chemical composition, etc.)
-to to monitor the changes (groundwater quality, water table,
water supply) caused by human activities
-to to obtain the information necessary for decision-making
decisio making
on national level and for international co-operation.
co operation.
-help help to elaborate recommendations for the future
at reducing the impact of human activities.

Methodical basis
The total indicative dose of year is
calculated calculate according to European Union
drinking water directive 98/83/EC and
96/29/Euratom recommendations recommendations
from
the results determination 226 226Ra, Ra, 228 228Ra, Ra,
234 U, and 238 238U. U.
Percentage
ercentage of dissolved isotopes of
uranium during the constitution of the
total indicative dose very small (99% of TID constitute
account of 226 226Ra Ra and 228 228Ra. Ra.
Natural radioactivity of the groundwater
is mainly related with the radioactivity of
waterbearing rocks.

Water samples have analysed in
laboratories
Latvian Testing Laboratory of Material
Radioactivity. Laboratory is determining the
dissolution in water of 226 226Ra Ra and 228 228Ra, Ra, but not
concentration of 234 234U U and 238 238U. U.
Laboratory of Radiation and Nuclear Safety
Authority of Finland ( STUK ). Analyses of 226 226Ra Ra ,
228 Ra, 234 U and 238 U.
Radium Institute of St.Petersburg
St. Petersburg
Radiation Protection Centre of Estonia
Institute of Physics University of Tartu

The groundwater bodies of Quaternary aquifer
system

The groundwater bodies of Devonian aquifers

The values of radionuclides and total indicative
dose (TID ) in groundwater of Devonian aquifers

The groundwater bodies of Silurian- Silurian Ordovician
aquifer system

The values of radionuclides and TID of
groundwater of S-O S aquifer system

The distribution of Ordovicin-Cambrian Ordovicin Cambrian aquifer

The values of radionuclides and TID of
groundwater of Ordovician-Cambrian Ordovician Cambrian aquifer

The groundwater bodies of Cambrian-Vendian
Cambrian Vendian
aquifer system

The changes of the groundwater abstraction and
potentiometric levels of Cambrian-Vendian
Cambrian Vendian aquifer
system

The values of radionuclides and TID of
groundwater of Cambrian-Vendian
Cambrian Vendian aquifer system

The values of radionuclides and TID of
groundwater of Voronka aquifer

The values of radionuclides and TID of
groundwater of Gdov aquifer

Concentrations of 210 210Po Po and 210 Pb in
groundwater of Cambrian-Vendian
Cambrian Vendian aquifer system

Concentration of radionuclides and TID in
groundwater of Cambrian-Vendian
Cambrian Vendian aquifer system

Biggest explored concentration of
radionuclides in the groundwater of
Cambrian–Vendian groundwater body is
probably related with big concentrations of
radioactive substances what are occurring at
times in weathering part of crystalline
basement (granite, gneiss, ) in bedrock. They
are with primal origin.

In nowadays the groundwater of Cambrian–Vendian
Cambrian Vendian quifer
system is enriching with radioactive substances thanks to
inflow of the pressuring groundwater of the crystalline
basement

The concentration of radionuclides is lower in area of
buried valleys, where recharge of Cambrian–Vendian
Cambrian Vendian
groundwater body occur with infiltration water.

MODULATED INDICATIVE DOSE OF GROUNDWATER
OF CAMBRIAN-VENDIAN CAMBRIAN VENDIAN GROUNDWATER BODY

The biggest concentration of radium has been got
in the so-called so called relict water of Cambrian–Vendian
Cambrian Vendian
groundwater body in surroundings of Maardu

Simulated total indicative dose of groundwater of
Cambrian-Vendian
Cambrian Vendian aquifer system

Correlation between the TID and the concentration
of Chlorides in groundwater of Cambrian- Cambrian
Vendian aquifer system

Correlation between the TID and the concentration
of sodium in groundwater of Cambrian-Vendian
Cambrian Vendian
aquifer system

Changes of the chemical composition of the groundwater
of Cambrian-Vendian
Cambrian Vendian aquifer system in Tallinn

Total indicative dose in groundwater of Cambrian- Cambrian
Vendian aquifer system

222 Rn)
Radon ( 222Rn)
Radioactive exposure to radon takes place
by inhalation and accounts for half the
average dose for a human being
The highest concentration of radon
determined in groundwater of Estonia is
45 Bq/l
It does not pose a high risk in drinking
water as it escapes easily after aeration of
the water

Tritium ( 3H) H)
Concentration of tritium ( 3H) H) in
groundwater is prevalently related
human caused radiological
contamination and less with cosmic
emission.
Taking into consideration
groundwater’s very good protection,
big concentration of tritium is not
probable in Estonian groundwater.

Conclusions
From the showed table appears that only
16% % from the explored water of wells
correspond about the total indicative dose
on the requirement of the drinking water
(0,1 mSv/year).
mSv/year).
By the data of explored wells of
Cambrian–Vendian
Cambrian Vendian aquifer system, system,
the
total indicative dose is at the most (66%) (6 %)
between 0,10–0,40
0,10 0,40 mSv/year mSv/year
Concentration of tritium ( 3H H ) in
groundwater of Cambrian-Vendian Cambrian Vendian aquifer
system is low, usually less than 10 Bq/l

In all ll others groundwater bodies and
aquifer systems , witch occur in
Estonia (Ordovician– (Ordovician Cambrian,
Silurian–Ordovician, Silurian Ordovician, Devonian and
Quaternary) Quaternary , the groundwater
accords to limits of drinking water by
the total indicative dose, it means
that TID is lower than 0,1 mSv/year.
mSv/year.

The water of Cambrian–Vendian
Cambrian Vendian
aquifer system not corresponding to
requirement of quality about the
drinking water in part of the total
indicative dose, is problem because
this groundwater are using in
community of water supplies all
West-, West , North- North and East-Estonia East Estonia areas
From all water necessary using 35 %
is satisfying exactly with this aquifer
system

Caused from that Estonian
Groundwater Commission made
proposal to Social Minister to allow to
use groundwater of the Cambrian–
Cambrian
Vendian aquifer system as drinking
water if from this coming annual
indicative dose to 0,2 mSv/ mSv year.
It will be necessary to establish the
continuous programme for
monitoring of radionuclides.
It will be necessary to provide
intercalibration of laboratories

Unified solution is probably missing.
First of all should be analyzed
already existing water intake
possibilities. If in water intake is with
different depth wells, opening to
Cambrian–Vendian
Cambrian Vendian aquifer system, system
and becomes evident that from
upper aquifer (Voronka ( Voronka) ) opening
wells is possible to get drinking
water which corresponds to
requirement of quality, then existing
water intake should be rebuilded.
rebuilded.

It is necessary to weigh in one’s
mind possibilities of mixing different
aquifers water, specially where could
be possible to use Ordovician–
Ordovician
Cambrian or others upper aquifers
water in proportion, what would
assure the quality of drinking water
accordance to requirement.

From the above-said above said would be
necessary to make in working water
intakes exhaustive analysis for
utilizing optimal solutions in
Cambrian–Vendian
Cambrian Vendian aquifer system, system,
what with time would be vastly
economical from the closing existing
water intakes, observation new
drinking water sources and building
intakes..

Thank you for
your attention