Chronic exposure of Sprague-Dawley rats to 20 kHz triangular magnetic fields

Purpose:As a continuing study of 20kHz triangular magnetic fields (MF) [Lee et al. 2006], we investigated the chronic toxicity and possible health effects of exposure to 20kHz MF at the flux density of 30μT, which is the limit standard for the occupational population in South Korea, with the use of Sprague-Dawley rats. Materials and methods:Rats were exposed to 20kHz triangular MF at 30μT Root Mean Square for 8h/day for 18 months. Body and organ weights were measured and urinalysis, hematological and blood biochemistry analyses were performed in individual animals. Histopathological evaluation was also performed for the brain, thymus, lung, heart, liver, kidney, intestine and reproductive organs, including tumour tissue. Results:The mortality patterns in male or female rats exposed to magnetic fields were compared to the mortality patterns found in sex-matched sham control animals. Significant alteration of body weight was not observed with MF exposure. No significant differences were seen in sham-exposed and MF-exposed animals based on urological factors, hematological factors and blood biochemistry. Total tumour incidence was not different between sham-exposed and MF-exposed animals. Conclusion:Our results suggest that chronic exposure to 20kHz triangular MF with 30μT flux density did not increase toxicity in rats.