Occupational exposure to electromagnetic fields of workers with implants

Gernot Schmid

Publikation: AbschlussarbeitDissertation

Abstract

The EU Workers' Directive 2013/35/EU (EU 2013) on minimum health and safety requirements regarding the exposure of workers to electromagnetic fields was transposed into the national law of the Member States in 2016 in order to harmonize the level of protection of workers from adverse health effects caused by electromagnetic fields in the workplace within the European Union. After more than seven years of experience with practical exposure assessment based on this legal framework, several open questions and problems still exist, mainly caused by gaps and/or inconsistencies in important definitions. Some of these gaps and inconsistencies are highlighted in this work and three of them are analyzed in more detail, keeping the focus on exposure to low-frequency magnetic fields, as this is practically the situation that most frequently leads to field strengths close or even above the action levels defined in 2013/35/EU. As in many cases such magnetic field exposures occur in a highly localized manner in the area of the hands, particular attention was paid to the exposure of the hands. With regard to the first of the three topics analyzed in detail, i.e., the assessment of magnetic field exposure with a non-sinusoidal time course, in depth analyses of practically relevant waveforms clearly showed that one of the methods (“Simple Assessment on Physiological Basis”) described in the non-binding guide for practical implementation of 2013/35/EU may lead to a systematic underestimation of exposure by up to 20 dB or even more compared to the reference method specified in 2013/35/EU. It must therefore be recommended not to use this method in the form in which it is presently published in the non-binding guide. The computational analysis of the second issue, i.e., the exposure assessment using oversimplified body models (such as homogeneous circular disks, as suggested even in valid international standards), clearly indicated the inappropriateness of such models due to the missing heterogeneous anatomical structure of the real body, which leads to the tendency of underestimating the actual exposure when using such oversimplified body models. Consequently, the approach of estimating induced electric field strength inside the human body by using homogeneous disk models should be replaced by more appropriate methods in the future. The third topic addressed in detail in this work, i.e., the assessment of exposure of a worker’s hand bearing metallic implants used for osteosynthesis after the most common bone fractures of the hand (Herbert screw and volar radius plate), reveals the high degree of complexity of a reliable exposure assessment for workers bearing such implants and working close to or with devices creating strong and highly localized magnetic fields. The results show that the induced electric field strengths may be substantially increased by the implant. The extent of this increase, however, is highly dependent on the implant’s position inside the body, the field distribution and orientation with respect to the anatomical structure and the implant’s orientation and the implant’s geometry. Consequently, a simple and general guidance for a reliable exposure assessment for persons with (all kinds of) metallic implants seems to be impossible without the drawback of being overly conservative for most of the practically relevant exposure scenarios. However, extended systematic computational analyses for the most common and most relevant implant types in the context of workplace assessment may enable a reasonable guide for many situations.
OriginalspracheEnglisch
Gradverleihende Hochschule
  • Aristotle University of Thessaloniki
DOIs
PublikationsstatusVeröffentlicht - Juni 2024

Research Field

  • Seibersdorf Labor

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