title: Chronic exposure of Sprague-Dawley rats to 20 kHz triangular magnetic fields.
abstract: OBJECTIVE
  As a continuing study of 20 kHz triangular magnetic fields (MF) [Lee et al. 2006 ], we investigated the chronic toxicity and possible health effects of exposure to 20 kHz MF at the flux density of 30 microT, which is the limit standard for the occupational population in South Korea, with the use of Sprague-Dawley rats.
  
  
  METHODS
  Rats were exposed to 20 kHz triangular MF at 30 microT Root Mean Square for 8 h/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.
  
  
  CONCLUSIONS
  Our results suggest that chronic exposure to 20 kHz triangular MF with 30 microT flux density did not increase toxicity in rats.
authors.affiliation: Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Hae-June
authors.initials: HJ
authors.lastname: Lee
authors.forename: Youn-Myoung
authors.initials: YM
authors.lastname: Gimm
authors.forename: Hyung-Do
authors.initials: HD
authors.lastname: Choi
authors.forename: Nam
authors.initials: N
authors.lastname: Kim
authors.forename: Sung-Ho
authors.initials: SH
authors.lastname: Kim
authors.forename: Yun-Sil
authors.initials: YS
authors.lastname: Lee
mesh_terms: D000016:Abnormalities, Radiation-Induced; D000818:Animals; D001774:Blood Chemical Analysis; D001835:Body Weight / Q000528:radiation effects; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D008280:Magnetics; D008297:Male; D008325:Mammary Neoplasms, Experimental; D009929:Organ Size / Q000528:radiation effects; D009928:Organ Specificity / Q000528:radiation effects; D011829:Radiation Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012098:Reproduction / Q000528:radiation effects; D018570:Risk Assessment; D013997:Time Factors; D016482:Urinalysis; D014916:Whole-Body Irradiation