Occupational Thorium Exposure or Self-Poisoning?
Thoriated electrodes are used in TIG (Tungsten Inert Gas) welding [1]. Thorium intake may happen during grinding and welding operations using thoriated electrodes [2]. The use of thoriated tungsten electrodes may be at the origin of a potential hazard [3]. The annual commited effective dose from inhalation of 232Th, 230Th, 228Th and 228Ra is usually below 1mSv for a full-time TIG welder [4]. Electrode consumption during welding was primarily the result of tip sharpening. Indeed, less than 3% of weight loss was attributable to the welding process [5].
Thorium exposure during tungsten inert gas welding with thoriated tungsten electrodes.
The exposure to 232Th from TIG welding with thoriated electrodes has been determined at five different workshops. Welding with both alternating and direct current was investigated. The exposure levels of 232Th were generally below 10 mBq m(-3) in the breathing zone of the welders. Two samples from AC welding showed significant higher exposure levels, probably due to maladjustment of the TIG welding power source. Samples of the respirable fraction of 232Th from grinding thoriated electrodes were also collected showing exposure levels of 5 mBq m(-3) or lower. A dose estimate has been made for two scenarios, one realistic and one with conservative assumptions, showing that the annual committed effective dose from inhalation of 232Th, 230Th, 228Th and 228Ra, for a full-time TIG welder, in the realistic case is below 0.3 mSv and with conservative assumptions around 1 mSv or lower. The contribution from grinding electrodes was lower, 10 microSv or lower in the realistic case and 63 microSv or lower based on conservative assumptions. The study does not exclude occurrence of higher exposure levels under welding conditions different from those prevailing in this study.
Music and Ethical Responsibility
Introduction 1. Meaning and ethics in music 2. Experiencing music 3. Framing elements of musical experience 4. Improvisation and ethical responsibility 5. Musical improvisation as festival 6. Music, proximity, ethics 7. Ethical responsibility and other people's music Conclusion: ethical responsibility in musical experience.