Second East European Radon Symposium SEERAS 2014 , May 27-30, 2014, Nis, Serbia

FIRST RESULTS ON REMEDIAL TECHNIQUES AGAINST RADON

IN AREA OF BAITA-STEI (ROMANIA)

Alexandra Cuco ş (Dinu) , C. Cosma, B. Papp, L. Suciu, O.A. Dumitru, G. Banciu, C. Sainz

Babeş-Bolyai UniversityEnvironmental Radioactivity and Dating Center

Cluj-Napoca, ROMANIA

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DESIGN OF SURVEY

IRART PROJECT: “ Implementation of Radon Remediation Techniques in Dwellings of B ǎiţa Uranium Mine Area ”

Project POS CCE ID 586 - SMIS 12487/ 160/ 15.06.2010The European Regional Development Fund

2010 - 2013� Main objective: DEVELOPMENT OF EFFICIENT MITIGATION SOLUTIONS AGAINST POPULATION EXPOSURE TO RADON THROUGH INNOVATIVE RESEARCH WITH INTERNATIONAL COOPERATION

� ACTIVITIES: indoor radon measurements in 303 houses, detailed diagnostic measurements, development, test (PILOT H OUSE) and implementation of remedial measures in 20 houses of Ştei-Băiţa radon-prone area� Project Director Constantin Cosma, Project Manager C arlos Sainz, Executive Coordinator Alexandra Cuco ş (Dinu)� FIRST MITIGATION IN ROMANIA, with EU expertise-Vali dation Experts M. & M. Neznal, L. Quindos, A. Poffijn

Page � 3Romania /Bihor map and Baita-Stei zone Investigated Baita-Stei area

Baita-Stei area : is situated in the northwest of Romania (West Carpathian Mountains) at 120 km southeast of Oradea

LOCATION

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Uranium Mine� was the largest surface of uranium deposit in the world (open pit mine)� uranium content was 1-5% in the radiometric sorted material, in some zones reaches 30-40% (in pitchblende mineral)� in the operating period 1952-1998 ~ 20,000 tons of metallic uranium were sent in RU� Băiţa river pass through this deposit, also through the localities: B ăiţa, Nucet, Fânaţe, Cîmpani and Ştei.

� 1998-2014: 4100 integrated measurements of indoor radon CR-39� 905 typical housesMain radon sources� high Rn concentrations in soil� high RP in 85% of houses ( 200)� uranium tailing as building material

Uranium mine

AM = 292 Bq/m 3

Max Val = 3653 Bq/m 3

AM for Romania = 126 Bq/m 3

(excluding Ştei-Băiţa)

The arithmetic mean of indoor radon concentrations in Ştei-Băiţa radon-prone area, 1x1 km grid cells.

(Cosma C., Cucoş (Dinu) A. , Dicu T., (2013), Preliminary results regarding the first map of residential radon in some regions in Romania, Radiation Protection Dosimetry , 155(3), 343-350.Sainz C., Dinu A ., C. Cosma et al., (2009), Comparative risk assessment of residential radon exposures in two radon-prone areas, Ştei (Romania) and Torrelodones (Spain), Science of The Total Environment , 407 (15), 4452-4460. Dinu Alexandra , PhD thesis „Correlations between indoor radon and lung cancer incidence in Ştei-Băiţa Uranium Mine area”, 2009)

PRELIMINARY RESULTS - FIRST ROMANIAN INDOOR RADON MAP

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DESIGN OF SURVEY IRART project 2010-2013

Measurements of radon in houses:

� Basic methodsRadon screening by integral methods (nuclear track detectors CR-39, RSK type, RadoSys)���� 2 campaigns of measurements (winter 2010, spring 20 11)���� 303 randomly selected houses from interested area���� 3-4 rooms/house���� 2300 measurements (2x1150)

� Special methods for radon diagnostics before mitigation in 20 selected houses with radon level higher than 600 Bq m -3: continual indoor monitoring, radon exhalation measurements (soil and building materials) by gamma and alpha spectrometry, measurements of so il radon and permeability around, gamma dose

� Follow-up of mitigation efficiency after mitigation by integrated measurements and continual monitoring

A. Cuco ş (Dinu), C. Cosma et. al, (2012), Thorough investigation on indoor radon in Băiţa radon-prone area (Romania), Science of The Total Environment , 431, 78–83.

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MEASUREMENT EQUIPMENTS

� Integrated Measurements:

� Continuous measurement devices:

Alpha guard and Radim 3C RAD7 Radon S cout Ramon

���� Radosys System���� CR-39 nuclear track detectors

� Soil radon measurement:

� Gamma dose measurement:���� Gamma Scout

���� LUK 3C scintillation detection with Lucas cells

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INDOOR RADON RESULTS

20 (6)866511352.4133.216118830Other

22 (52)13730541362.5151.8343251233Cellar

31 (193)9120161962.2197.1253273618Bedroom/ Living

18 (44)9812781312.2141.3191196247Kitchen

% (No> 300

(Bq m -3)

C.V.

(%)

Max

(Bq m -3)

Median

(Bq m -3)

GSD

(Bq m -3)

GM

(Bq m -3)

SD

(Bq m -3)

AM

(Bq m -3)Frequency

Type of room

a. Descriptive statistics for the radon measurement s by room type within dwellings of B ăiţa-Stei area .

28 (84)7411861942.0191.4 178241 303Total

30 (26)505932241.7214.0 121244 86Câmpani

39 (28)6210672391.8236.3 172279 71Fânaţe

7 (1)513371501.8150.2 87172 15Nucet

22 (29)9511861482.2162.9 215227 131Băiţa

% (No.) >300

(Bq m -3)

C.V.

(%)

Max.

(Bq m -3)

Median

(Bq m -3)

GSD

(Bq m -3)

GM

(Bq m -3)

SD

(Bq m -3)

AM

(Bq m -3)

Number of

housesLocation

b. Descriptive statistics of indoor radon concentra tions in monitored dwellings of Băiţa-Stei radon-prone area.

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A.M. = 241 Bq/m 3

G.M. = 191 Bq/m 3

Median = 194 Bq/m 3

P=0.21: Shapiro-Wilk test

Log-normal distribution of average concentration in 303 houses

A. Cuco ş (Dinu), C. Cosma et. al, (2012), Thorough investigation on indoor radon in Băiţa radon-prone area (Romania), Science of The Total Environment , 431, 78–83.

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STUDIES ON MITIGATION METHODS IN PILOT HOUSE

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RADON MITIGATION. RADON REMEDIATION EFFICIENCY

RADON REMEDIATION EFFICIENCY:

where C after and Cbefore are the annual means of integrated radon concentrat ions

before and after remediation

Main radon sources in houses : radon entry from subsoil (70-80%) and radonemanation from building material (20-30%).

Remedial measures in 20 inhabited houses, 2-3 rooms on average/ housewith indoor radon levels > 600 Bqm -3

RADON MITIGATION METHODS IMPLEMENTED IN THE MAJORITY OF HOUSES: an active sub-slab ventilation system based on perf orated tubes drilled combined with insulated membranes .

[%]100×−

=before

afterbefore

C

CCR

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Ventilator/FanRadon sumpPipesMembraneAutomatic surveillance

systemAccessories

DEMO: THE MITIGATION SOLUTION

an active sub-slab ventilation system

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EXAMPLE: Protocol study and remediation of Baita 215 house

Diagnostic protocol :

- Radon index of the building site – soil radon

measurement and permeability

- Inspection of the house - to find the main

entrance radon sources

- Detection of leakages from the floor

- Continuous measurements of indoor radon

- Radon exhalation on the floor

- External gamma radiation

Parameters of the ground :cA75 = 54,3 kBq.m-3

k75 = 1.6 10-11 m2

RP = 65,9high radon index

Average indoor radon: about 1200 Bq.m-3

in inhabitable rooms

���� very fast fluctuations of indoor radon

concentration were observed

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Radon mitigation techniques in 2010-2011

Active soil depressurization :pipes under the floor, reconstruction of floors and

an extractor with a fan

(220 V / 30 W / 110 mc/h )

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0

500

1000

1500

2000

2500

09.0

3. 0

0:00

10.0

3. 0

0:00

11.0

3. 0

0:00

12.0

3. 0

0:00

13.0

3. 0

0:00

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3. 0

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15.0

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16.0

3. 0

0:00

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3. 0

0:00

18.0

3. 0

0:00

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3. 0

0:00

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3. 0

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3. 0

0:00

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3. 0

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3. 0

0:00

26.0

3. 0

0:00

27.0

3. 0

0:00

time [dd.mm. hh:mm]

C R

n [B

q/m

3]

bedroom 1

bedroom 2

accumulation

extraction

72-77272bedroom 2

89-1211102bedroom 1Active soil depressurization

pres.C afterC before

Eff.

(%)

C med.RoomMitigation type

Monitoring of radon concentration during accumulati on and depressurisation by the fan

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RADON REMEDIATION EFFICIENCY(evaluation of the most mitigate room/ house and av erage for all rooms in the house)

95.195.1Max65.273.7Min

65.4-95.181.485.4AVERAGE68.7-87.576.987.51741395BedroomPilot house21

95.195.195.1961958BedroomNucet 920.70.3-73.77273.7219834BedroomFanate 18919.88.4-93.290.893.2771127BedroomFanate 11818.

65.4 - 81.865.281.82141177BedroomFânaţe 5917.66.7 - 74.470.674.48673389KitchenFânaţe 2316.

78.278.278.2122560LivingCâmpani 10315.72.6 - 84.377.084.386548BedroomCampani 7114.

82.882.882.891530BedroomCampani 5713.79.1 - 85.386.485.31551059BedroomBaita 22812.75.5-88.481.988.41171010BedroomBaita 21511.67.5-90.779.190.71121205BedroomBaita 21310.83.5-94.29394.2911557BedroomBaita 2069.

75.9 - 80.478.380.4152771LivingBăiţa 2048.65.678.878.8113534BedroomBaita 1387.90.390.390.392948BedroomBăiţa 1276.

80.5 - 8284.582.0137761BedroomBaita 1195.88.3 - 90.689.590.61001062LivingBăiţa 764.

87.787.787.7107872LivingBaita 75 B3.85.3 - 85.485.385.4143982BedroomBaita 75 A2.71.1 - 88.379.088.31591354BedroomBaita 61.

After remediation

Before remediation

Variation range

Eff. (%)

Average Remediation

Eff. (%)all rooms

RemediationEff.(%)

Annual CRn (Bq m -3)

RoomHouse adressNo.

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1. Indoor radon measurements and radon (soil and wat er) also gammameasurements confirm the Baita-Stei zone as a radon prone area.

2. Average value of indoor radon was almost the sam e in the preliminary and measurements during the IRART project, respectively 247 and 292 Bq/m -3.

3. Based on the last campaigns of measurements (abou t 2300 measurements in two seasons, in 303 houses) were selected 20 houses for remediation .

4. A pilot house was selected and here were tested t he first remediation measures by pressurisation and depressurisation in 3 points ne ar the walls and one in central position. The study was completed by using anti-radon membran es.

5. Measurement of soil potential (radon concentration a nd permeability) proved that radon index is high and very high in this area .

6. Different methods of remediation were used and final average efficiency was 81.4%, in good accord with RADPAR Project results.

7. The concentration of radon in those 21 houses was reduced from the average of 992 Bqm -3 at the average of 160 Bqm -3 and the associated health impact on the population living in these houses means a reduction of almost half of the cases of lung cancer , estimated on the basis of the linear risk model o f Darby and BEIR VI models.

���� the Remediation Efficiency/ room: 85.4% (73.7- 95.1%)� the Remediation Efficiency/ house (all average rooms): 81.4% (65.2 - 95.1%)� active soil depressurization has been found the mos t efficient method

CONCLUSIONS

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FUTURE PERSPECTIVES, FORTHCOMING CHALLENGES

Information campaigns to raise awareness of the pop ulation

� national guidelines to perform indoor radon measure ments

� national reference levels concerning population exp osure to indoor radon in Romania

� clear assignment of responsibilities to competent a uthorities

� incorporate the radon control requirements in natio nal building codes

� improvement of preliminary radon map for Romania

� an effective radon policy - financial resources required for evaluation and monitoring of the radon situation

NATIONAL INDOOR RADON MONITORING PROGRAM

� a National Radon Survey is necessary in order to have a significant and reliable assessment regarding the Radon situation a nd to define areas where further targeted indoor survey should have priority and a r emediation could be expected

To set-up specific radon legislation

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THANKS FOR YOUR THANKS FOR YOUR

ATTENTION !ATTENTION !