Mar 30, 2026
Genotoxic Effects of Extremely Low-Frequency Electromagnetic Fields Among Workers of the Tunisian Company of Electricity and Gas
- Imene Kacem1,
- Rania NAKHLI1,
- Nejib Mrizak1
- 1Occupational Medicine Department, Faculty of Medicine of Sousse, Tunisia
Protocol Citation: Imene Kacem, Rania NAKHLI, Nejib Mrizak 2026. Genotoxic Effects of Extremely Low-Frequency Electromagnetic Fields Among Workers of the Tunisian Company of Electricity and Gas. protocols.io https://dx.doi.org/10.17504/protocols.io.yxmvm8136g3p/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: March 29, 2026
Last Modified: March 30, 2026
Protocol Integer ID: 314084
Keywords: emf exposure, frequency electromagnetic fields among worker, frequency emfs among worker, exposure to emf, electromagnetic field, frequency emf, frequency electromagnetic field, gas electromagnetic field, electricity, genotoxic effect, assessing genotoxicity, emf, electrophysiological signal, genotoxic effects of extremely low, environmental exposure, power lines in home, pathophysiological effects on the human body, tunisian company of electricity, power line, dna damage, exposure to such field, pathophysiological effect, transmission through power line, childhood leukemia, electricity production, fields with frequency, cytogenetic effect, power plant worker, including childhood leukemia, primary dna damage, voltage power line, cellular responses to dna damage, epidemiological study, carcinogenic to human, exposed human, incidence of various cancer, electric charge, primary dna damage in vivo, exposure
Abstract
Electromagnetic fields (EMFs) are generated when electric charges are in motion. These fields result from the combination of two waves—one electric and one magnetic—that propagate at the speed of light. According to the World Health Organization, EMFs are defined as fields with frequencies equal to or below 300 Hz. Exposure to EMFs may be of natural origin, including terrestrial sources and electrophysiological signals. It may also be of artificial origin, emanating from power lines in homes, telephones, televisions, and all household appliances. Environmental exposure arises from high-voltage power lines, mobile telephony relays, radio and television broadcasting transmitters, radars, and detection gates. Power plant workers are chronically exposed to EMFs generated during electricity production, transmission through power lines and transformers, and distribution networks. These EMFs, ubiquitous in both daily life and occupational environments, have attracted significant research interest regarding their physiological and pathophysiological effects on the human body. The study by Wertheimer et al., published in 1979, raised concerns about a possible association between EMF exposure and childhood leukemia. Since then, an increasing number of studies have suggested a link between exposure to extremely low-frequency EMFs and the incidence of various cancers, including childhood leukemia. Since 2002, these fields have been classified as Group 2B (possibly carcinogenic to humans) by the International Agency for Research on Cancer. Furthermore, additional effects have been suggested through in vivo and in vitro studies. Some authors have reported that exposure to such fields may disrupt neuroendocrine activity and lead to stress, depression, anxiety, learning disorders, and sleep disturbances. Mattsson and Simkó also reported that biological processes, systems, and components—such as cell proliferation, cell cycle regulation, apoptosis, metabolism, cell differentiation, and physiological cell functions—may be affected by EMF exposure. Some epidemiological studies support the hypothesis that low-frequency EMFs may induce primary DNA damage in vivo and cytogenetic effects by suppressing apoptosis, altering cell proliferation, and activating genes and proteins involved in cell cycle control and cellular responses to DNA damage. Serap Celikler et al. reported chromosomal aberrations in peripheral blood lymphocytes of workers occupationally exposed to 50–60 Hz EMFs. However, studies in this field remain inconclusive, with often contradictory findings that are difficult to interpret due to methodological biases in studies directly assessing genotoxicity in exposed humans. In this context, the present study was conducted to evaluate the genotoxic effects of low-frequency EMFs among workers in a power generation plant.
Guidelines
**Statistical Analysis**
- A descriptive analysis was performed for all variables.
- The Chi-square test was used to assess differences in sociodemographic variables between the exposed and non-exposed groups.
- The Mann–Whitney U test was used to compare Comet assay indices between the two groups.
- To analyze the effects of different levels of electromagnetic field exposure on Comet assay indices and flow cytometry parameters, Kruskal–Wallis and Mann–Whitney U tests were applied.
All statistical analyses were performed using SPSS software, version 23.
Materials
**Materials and Methods**
**Study Design**
Analytical cross-sectional study conducted in 2021 over 6 months.
**Study Population**
Two groups:
- Exposed group**: Workers from units A, B, C, and D of a STEG power plant
- Non-exposed group**: Administrative workers from the same company (Sousse North district)
Groups were age-matched.
**Inclusion Criteria**
- Employment duration 3e1 year
- Age between 20 and 50 years
**Exclusion Criteria**
- Cardiovascular or genetic diseases
- Antioxidant use or recent imaging
- Smokers
- Refusal to participate
**Data Collection**
Based on:
- Questionnaire
- Physical examination
- Biological assessment
- EMF measurement
**Questionnaire**
- Sociodemographic data
- Lifestyle habits
- Occupational data
- Medical history
**Physical Examination**
- Weight and height measurements
**Biological Assessment**
- Blood samples collected (5 ml)
- DNA damage: Comet assay and flow cytometry
- Apoptosis: Annexin V FITC kit
**EMF Measurement**
Exposure assessed using time-weighted average (TWA):
TWA=[X1 ×t1 +⋯+Xn ×tn] /8
- Measurements taken at 1 meter height
- Duration: 2 minutes per location
- Devices: TES-1394 and HI-3604 (3 axes: X, Y, Z)
Troubleshooting
Literature Review
Bagheri et al. [3] conducted a cross-sectional study on DNA damage following long-term exposure to extremely low-frequency EMFs among thermal power plant workers. Inclusion criteria were full-time employment, at least 2 years of work experience, and age between 20 and 50 years. Exclusion criteria included cardiovascular or genetic diseases, antioxidant medication or supplement use, and recent medical imaging within the past two months. Two groups were included: 102 exposed workers and 136 non-exposed subjects. DNA damage was assessed using flow cytometry and the alkaline Comet assay. The study concluded that Comet assay indices were higher in the exposed group.
Rezvan Zendehdel et al. [4] conducted another cross-sectional study including 29 exposed workers and 28 non-exposed administrative staff. Groups were matched for gender, age, work experience, and smoking status. DNA strand breaks were assessed using the Comet assay, showing significant increases in DNA damage indicators among exposed workers.
An Indian study evaluated chromosomal aberrations using metaphase analysis and the micronucleus test in 70 subjects (50 exposed, 20 non-exposed). Results showed significantly higher chromosomal damage in exposed individuals, increasing with duration of exposure (P 0.05) [11].
An Italian study on welders exposed to ELF-EMFs assessed cytogenetic effects using micronuclei and sister chromatid exchange (SCE). The exposed group showed increased micronuclei frequency and decreased SCE, suggesting partial evidence of genotoxicity [13].
An in vitro study (2014) on Vero cells exposed to ELF-EMFs (100 Hz, 5.6 mT) showed increased DNA damage, longer comet tails, and increased S-phase cells, suggesting DNA strand breaks likely due to reactive oxygen species [14].
Another study on human lymphocytes exposed in vitro to 50 Hz magnetic fields found no significant DNA damage or synergistic effects with ionizing radiation [15].
A 2014 study evaluating epinephrine levels, DNA integrity, and oxidative stress among workers exposed to high-voltage substations found increased oxidative stress and DNA damage in exposed individuals [16].
Study Procedure
Data collection was carried out over a period of 6 months. Workers from units A, B, C, and D of the STEG power generation plant were invited to participate in a face-to-face interview to complete the questionnaire. They also underwent a physical examination and blood testing. The non-exposed group was selected from administrative staff of STEG in the Sousse North district. They underwent the same physical examination and blood tests and completed the same questionnaire as the exposed group.
Statistical Analysis
A descriptive analysis was performed for all variables.
The Chi-square test was used to assess differences in sociodemographic variables between the exposed and non-exposed groups.
The Mann–Whitney U test was used to compare Comet assay indices between the two groups.
To analyze the effects of different levels of electromagnetic field exposure on Comet assay indices and flow cytometry parameters, Kruskal–Wallis and Mann–Whitney U tests were applied.
All statistical analyses were performed using SPSS software, version 23.
Protocol references
[1] World Health Organization. [2] Wertheimer et al. [3] International Agency for Research on Cancer. [4] Bagheri et al. [5] Rezvan Zendehdel et al. [6] Mattsson and Simkó. [7] Serap Celikler et al. [10] Mattsson and Simkó (2012). [11] Indian study on chromosomal aberrations. [12] Serap Celikler et al. [13] Italian study on welders. [14] In vitro study on Vero cells. [15] Study on human lymphocytes. [16] 2014 study on epinephrine levels.
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4-Rezvan Zendehdel, Il Je Yu. DNA effects of low level occupational exposure to extremely low frequency electromagnetic fields (50/60 Hz). Toxicology and Industrial Health 2019, Vol. 35(6) 424–430.
5- Wertheimer N, Leeper E (1979). Electrical wiring configurations and childhood cancer. Am J Epidemiol, 109, 273-84.
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7-International Agency for Research on Cancer Working Group on the Evaluation of Carcinogenic Risks to Humans 2002
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