Objective To evaluate the possible effects of power frequency electromagnetic fields (EMF) (50 Hz)on the health condition and neurobehavioral function of workers in transformer stations.
Methods Intensity of EMF at transformer stations of 18 factories was measured with HI-3604 EMF radiation meter. Neurobehavioral function of 105 electricians and 110 controls were examined with Neurobehavior Core Test Battery(NCTB)recommended by World Health Organization(WHO). Some neural discomfort symptoms of the two groups were recorded by questionnaires. Hematological indices of the two groups were determined including IgG, IgM, IgA, leukocyte formulae(neutrophil, lymphocyte, monocyte, eosinophil, basophil), erythrocyte indices(hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration)and platelet.
Results Electric field intensity of 220 kV transformer stations was significantly higher than that of 35 kV transformer stations(P < 0.01), but the magnetic field intensity in the two kinds of workplaces were not significantly different(P > 0.05). It showed that in the exposure group the emotional state of tension, depress, anger, fatigue and confusion appeared more obviously than those in the control group (P < 0.05), but the score of vigour was lower (P < 0.05). The average scores of Benton visual retention, correct tapping dots and sum tapping dots of electricians were all lower than those of controls (P < 0.05). The prevalence of headache, dizzy, insomnia, dreamful and hypomnesia in electricians were higher than those in the control group(P < 0.01). Average lymphocyte count of electricians was higher than that of controls(P < 0.05), but mean corpuscular hemoglobin concentration level of electricians was lower than that of controls(P < 0.05). There was no significant difference of IgG, IgM and IgA between the two groups.
Conclusion Neurobehavioral function of electricians working under power frequency electric fields may be impaired to a certain extend. Long term exposure to power frequency electric field may induce neural symptoms and slight alterations in some hematological indices, but it is not concluded that occupational exposure to 50 Hz EMF can influence their immune system.
DownLoad: