Analytical considerations in assessment of workplaces exposed to NORM Erich Hrnecek, ARC Seibersorf research GmbH 9th European ALARA Network workshop on „Occupational Exposure to Natural Radiation“

Overview: Current legal situation in Austria Studies Radon NORM TIG – welding: Analytical Strategy Conclusions

Current legal situation in Austria Council Directive 96/29 EURATOM Strahlenschutz-EU-Anpassungsgesetz BGBl. Teil I Nr. 146, 20th August 2002 § 36d Maximum exposition of workers from 222Rn, U, Th, cosmic radiation according to dose limit category A § 36f Fields of work, where increased exposition 222Rn, U, Th can be expected have to be defined by regulatory authority In these fields of work, it will be obligatory to evaluate the potential exposure of workers and to report the results to the authorities Fields of work have to be defined in Radiation Protection Ordinance

Studies: Radon 1991 – 2001: Austrian National Radon Project (ÖNRAP) Investigation of Radon exposure distribution in Austrian homes Map of Radon potential for Austrian standard dwellings H. Friedmann, BfS Ber. 24/2002 H. Friedmann et al, Env. Int 22, S 677 (1996)

Studies: Radon 1997 – 1999: Radon concentrations in drinking water Map of Rn concentrations Cat. 1: 85% < 100 Bq/l Cat. 2: 85% < 300 Bq/l Cat. 3: >15% > 300 Bq/l Areas with enhanced Radon concentrations in drinking water can be identified Workers in waterworks H. Friedmann, BfS Ber. 24/2002

Studies: Radon Thermal spas: Radon galleries for medical treatment Badgastein 222Rn: 44 kBq/m³, up to 350 kBq/m² Aerosol composition varies with ventilation conditions: G. Wallner, Rad. Env. 7, 397 (2005). ~1.8 mSv during treatment

Studies: NORM No comprehensive survey on NORM exposure in Austria exists Potential exposure: Rare earth industry Mining Oil and gas industry Use of Th in industrial processes Current study on TIG – welding

Motivation: Welding Project from Austrian Social Insurance for Occupational Risks to assess exposure of workers during welding Exposure to UV - radiation Exposure to electromagnetic fields Exposure to Th during TIG - welding

Motivation Tungsten Inert Gas shielded welding with thoriated Tungsten electrodes containing 1% (WT10) to 4% (WT40) ThO2 Inkorporation by Inhalation during welding during sharpening of electrodes

Studies on radiation exposure of workers Corresponding to 0,7 – 7,6 mSv/a effective dose 1,7 – 37,8 Bq/a 232Th Urine excretion analysis Sternad, Kratzel, Forts. im Strahlensch. 1998 Main exposure from electrode sharpening welding < 6 Bq/a, 4,5 mBq for each electrode sharpening Air sampling welding sharpening Ludwig, Seitz, IRPA9, 1996 1 of 3 cases increased Inhalation welding to 3,6 Bq/a sharpening to 0,8 Bq/a Tietze et al., Schweißen&Schneiden 1998 Possible risk exists (AC-TIG) < 0,1 to 144 Bq/a 232Th incorporation Ludwig et al., Health Phys. 1999

Analytical Strategy Analysis of welding electrodes Inhalation of airborne welding fumes Inhalation of dust from electrode sharpening Excretion analysis of workers Particle analysis

Analytical Strategy Analysis of welding electrodes WT10, WT20, WT30, WT40 1,0 - 4,0 % Thorium Alpha Spectrometry charakteristic isotope ratios 228Th/232Th 230Th/232Th Isotopic signature of electrodes

Analytical Strategy Inhalation of airborne welding fumes study of TIG welding during instruction courses for welders (standardized working environment) Stationary air sampler: Gravikon PM4: 4 m³/h Personal air sampler: Gilian Instr. Corp.: 3,5 l/h mg/m³ air concentration of dust Thorium: Alpha Spectrometry

Analytical Strategy

Analytical Strategy Exposure to welding fumes Personal air sampler: 0,2 – 1,0 mg/m³ Stationary air sampler: 0,1 – 0,5 mg/m³ Welding fumes contain ~ 3 % electrode material Air concentration depends on worker and ventilation conditions

Analytical Strategy Inhalation of dust from electrode sharpening Electrode grinding machines with / without suction system Stationary air sampler Personal air sampler ~ 90 mg / Electrode sharpening 1 – 6 mg/m³ air concentration of dust Thorium: Alpha Spectrometry

Analytical Strategy Excretion analysis of workers instruction courses for TIG welders at Austrian Institute for Welding Technology Sampling during courses 48 h urine sample, feces sample Sampling after vacation Alpha Spectrometry Distinction of exposure from electrodes and natural background (food) by isotope vector

Analytical Strategy: Particle analysis Welding robot DC - TIG welding (Steel) AC - TIG (Aluminium) Measurements with impactor and stationary air sampler

Analytical Strategy: Particle analysis

Analytical Strategy: Particle analysis Cascade Impactor Berner - Impactor LPI Rot25 10 Stages 25 l/min Measuring range: 0,016 µm - 16 µm Determination of particle size distribution Maximum concentration: 0,03 – 0,06 µm Th - analysis: Alpha Spectrometry Particle Analysis: SIMS

Conclusions Current situation in Austria Radon: Survey on Radon in water and houses exist Radon: Additionally, some data are available on thermal spas NORM: Fields of work have to be defined by legislation Study on Th-exposure from TIG welding in progress

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