Occupational exposure to intermediate frequency and extremely low frequency magnetic fields among personnel working near electronic article surveillance systems

Abstract

Cashiers are potentially exposed to intermediate frequency (IF) magnetic fields at their workplaces because of the electronic article surveillance (EAS) systems used in stores to protect merchandise against theft. This study aimed at investigating occupational exposure of cashiers to IF magnetic fields in Finnish stores. Exposure to extremely low frequency (ELF) magnetic fields was also evaluated because cashiers work near various devices operating with 50 Hz electric power. The peak magnetic flux density was measured for IF magnetic fields, and was found to vary from 0.2 to 4 µT at the cashier's seat. ELF magnetic fields from 0.03 to 4.5 µT were found at the cashier's seat. These values are much lower than exposure limits. However, according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) occupational reference levels for IF magnetic fields (141 µT for the peak field) were exceeded in some cases (maximum 189 µT) for short periods of time when cashiers walked through the EAS gates. As the ICNIRP reference levels do not define any minimum time for exposure, additional investigations are recommended to determine compliance with basic restrictions. Even if the basic restrictions are not exceeded, persons working near EAS devices represent an exceptional group of workers with respect to exposure to electromagnetic fields. This group could serve as a basis for epidemiological studies addressing possible health effects of IF magnetic fields. Compliance with the reference levels for IF fields was evaluated using both broadband measurement of peak fields and the ICNIRP summation rule for multiple frequencies. The latter was generally more conservative, and the difference between the two methods was large (>10-fold) for EAS systems using a 58 kHz signal with complex waveform. This indicates that the ICNIRP multiple frequency rule can be unnecessarily conservative when measuring complex waveforms.

A pilot study on the reproductive risks of maternal exposure to magnetic fields from electronic article surveillance systems

“…MHz IF fields thus occurs only when they pass by the gates at short distance (which may happen several times per day according to Roivainen et al, 2014). Cashiers working in the supermarkets were also exposed to static MFs.…”

Effects of intermediate frequency magnetic fields on male fertility indicators in mice

“…The magnetic flux densities used were 12 and 120 μT. The higher flux density exceeded the International Commission on Non-Ionizing Radiation Protection reference level (100 µT in the frequency range 3 kHz–10 MHz) for occupational exposure (ICNIRP, 2010) and was higher than the maximum exposure levels (up to 60 µT) found around EAS systems used in supermarkets and libraries (Roivainen et al, 2014). …”

“…However, much less data are available on possible health effects of intermediate frequency (IF) fields between the ELF and RF ranges from 300 Hz to between 100 kHz and 30 MHz (upper limit depends on how RF is defined; Ahlbom et al, 2008; Litvak et al, 2002; Kurokawa et al, 2004). Intermediate frequency EMF are increasingly used at work and at home in applications such as electronic article surveillance (EAS) systems (Roivainen et al, 2014), induction heating cookers, magnetic resonance imaging machines, and inductively coupled wireless power transmission (Floderus et al, 2002; ICNIRP, 2008). …”

Measurements of intermediate-frequency electric and magnetic fields in households

“…Previous research on IF field emitting sources has tended to focus either on occupational sources (Aerts et al, 2014;Floderus et al, 2002;Joseph et al, 2012a;2012b;Liljestrand, 2003;Nelson and Ji, 1999; Van den Bossche et al, 2015;VMBG, 2003;Wilén, 2010) or on non-residential appliances such as electronic article surveillance (EAS) systems (Harris et al, 2000;Joseph et al, 2012c;Kang and Gandhi, 2003;Martínez-Búrdalo et al, 2010;Roivainen et al, 2014;Trulsson et al, 2007), smartboards, and touch screens (Van den Bossche et al, 2015). Research on residential IF sources, on the other hand, is limited.…”