Evaluation of Extremely Low Frequency (ELF) Electromagnetic Fields and Their Probable Relationship with Hematological Changes among Operators in Heavy Metal Industry

Document Type : Original Paper


1 M.Sc., in Health Science, Tehran University of Medical Sciences, Tehran, Iran

2 Professor, Health Science Dept., Tehran University of Medical Sciences, Tehran, Iran

3 Associate Professor, Public Health Science Dept., Tehran University of Medical Sciences, Tehran, Iran

4 M.D., Sepahe Eslam Makhsus Highway, Defense Industries Organization (D.I.O), Armament Industries Group.Hadid Industries


Introduction: It is important that biological and health effects from the induction of currents and fields in the body by extremely low frequency (ELF) fields are fully explored to determine the effects produced at the molecular, cellular and organ levels. The objective of this study was to evaluate the intensity of ELF electromagnetic fields and its probable relationship with hematological changes among operators in a heavy metal industry site. This is a case study. In the present study, 205 workers exposed to electromagnetic fields (EMF) were working in four categories: (1) induction furnace workers, (2) induction hardening workers, (3) welders, (4) computer operators.
Material and Methods: A variety of methods for exposure assessment have been devised and applied to epidemiological studies of the effects of EMF in occupational settings. The methods range from rather crude job-classification methods, to sophisticated job-exposure matrix (JEM) modeling based on personal exposure measurements and reconstruction of past exposure. Monitoring procedures were carried out to measure the levels of exposure to ELF electric and magnetic fields. The strength of the electric and magnetic fields were measured by a dosimetric method (NIOSH 203).Workers’ blood samples were collected and analyzed for identifying different blood parameters. The results of hematological changes of workers in their medical files were also used for evaluation.
Results: Measurements showed a high strength of ELF field at the induction furnace workplace. Total electric field ranged from 2.3 to 2452.3 V/M and magnetic field from 1 to 325.1 μT. In other workshops including induction hardening, total electric field ranged from 2.45 to 68.5 V/M, magnetic field from 1.3 to 20.4 μT, total electric field from 1.02 to 11.23 V/M, magnetic field from 0.12 to 3.25 μT in the welding department and finally for computer operators this range was 20.1 to 186.2 V/M for electric field and 0.07 to 0.25 μT for magnetic field.
Conclusion: Mean value of WBC and MCV increased significantly among exposed induction furnace workers group (P < 0.05), but RBC decreased. Mean value of WBC, MCHC and MCV increased significantly among the exposed induction hardening workers group (P < 0.05), but RBC and Hgb decreased. Mean value of WBC, MCV and Hgb increased significantly among the exposed welders group (P < 0.05), but Hgb in relation with age decreased. Mean value of RBC and MCH decreased significantly among exposed computer operators group (P < 0.05).


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