Biological effects of electromagnetic fields of extremely low frequency

Elektromagnetska polja ekstremno niskih frekvencija (30-300 Hz) javljaju se u blizini provodnika dalekovoda i drugih provodnika visokog i srednjeg napona, u podstanicama i u industriji. Veliki broj osoba koje rade na opsluživanju ovakvih postrojenja i uređaja je profesionalno izložen ovakvim promenljivim poljima. U izvesnoj meri može biti izloženo i stanovništvo koje živi i boravi u blizini dalekovoda i transformatora, a i pri upotrebi električnih aparata u domaćinstvima. Problem biološkog dejstva promenljivih elektromagnetskih polja još uvek se ne može potpuno sagledati, a naročito posledice dugotrajnog profesionalnog izlaganja. U nekim zemljama su kod radnika opisane funkcionalne promene na nervnom, kardiovaskularnom, hematopoetskom i gastrointestinalnom aparatu. Međutim, veći broj autora nije mogao da nađe ovakve promene. Uglavnom, nisu nađeni specifični simptomi, ni organske promene. Smatra se da intenziteti električnog polja do 20 kV/m ne predstavljaju opasnost po zdravlje i da nema potrebe ograničavati ekspoziciju poljima do 10 kV/m.The strongest of the extremely low frequency (ELF) electromagnetic fields are those surrounding long-distance power lines, other high-voltage transmission lines and conductors in substations. These fields occur also near electrical distribution lines and in industry (from low-frequency induction furnaces, large electric motors, transformers, some welding and cutting electric arc processes, etc.). Exposure of the general population occurs from living in the vicinity of high-voltage transmission lines, in houses from electrical wiring configurations and from common household appliances. Subjective complaints and functional disturbances in the nervous, cardiovascular, haematopoetic and gastrointestinal systems of exposed workers have been reported in some countries. Results of studies of long-term exposure to electric and magnetic fields in other countries do not agree with these data. In general, adverse effects, specific symptoms or organic changes have not been observed. It is considered that exposure to electric fields up to 20 kV/m does not constitute a danger to health and that there is no need to limit exposure to fields below 10 kV/m