AIMS: Various living organisms and human workers and children were tested for any biological action resulting from exposure to radiations from Video Display Terminal (VDTs).
MATERIALS AND METHODS: VDTs were powered by a 50-Hz alternating voltage of 220 V. Measured electric and magnetic fields were 13 V/M and 50 nT, respectively. Living organisms were maintained under their normal breeding conditions. Control values were obtained before switching on the VDT.
RESULTS: Various effects related to the irradiation time have been demonstrated, i.e. a growth delay in algae and Drosophila, a body weight deficiency in rats, abnormal peaks of mortality in Daphnia and Drosophila, teratological effects in chick embryos and developmental and behavioural disturbances in rats.
In humans, after 4 hrs of working in front of a VDT screen, an increase in tiredness and a decrease of the resistance of the immune system were observed. In prepubertal children, 20 min of exposure was sufficient to induce neuropsychological disturbances. In human testicular biopsies cultured in vitro for 24 hrs in front of a VDT screen, mitotic and meiotic disturbances, accompanied by degenerative aspects of the cells and a significant disorganization of the seminiferous tubules were demonstrated. In humans exposed for 4 and 8 hrs in front of a VDT screen, a decrease of the Na+/K+ ratio and an increase of the urea concentration in urine had been observed, related to a depolarization of the cell membrane.
CONCLUSION: The embryonic and neonatal periods in animals and prepubertal young people showed a high sensitivity to the electromagnetic VDT radiation. At the cellular level, significant perturbations in meiosis and mitosis had been demonstrated. It can be hypothesized that the radiation can act as a depolarizing factor of the cellular membrane, as demonstrated by an important modification of the urinary ionic balance and of the cellular metabolism in workers. By the way of a concomitant activation of the sympathetic nervous system, a local stress status appears and step by step assails all the body and, consequently to be an original cause of the perturbations currently pointed out in VDT users.
An experimental apparatus has been developed and tested that aims to prevent the harm from VDT radiation. Known commercially as the EMF-BioshieldŽ system from S.E.I.C., it insures an effective protection against the harmful biological effects of VDT radiation.