HUMAN EXPOSURE TO MAGNETIC-FIELDS - A COMPARATIVE-ASSESSMENT OF 2 DOSIMETERS

Two types of dosimeters for measuring human exposure to 60 Hz magnetic fields were compared. Fifty adults wore the single-axis, wrist model AMEX (average magnetic field exposure system) and the triple axis, hip-pocket or pouch model AMEX-3D meters for 2 days. Ninety-six percent of the tests were accomplished without apparent dosimeter failure, The average root mean square magnetic flux density measurements with the AMEX-3D (mean = 0.10 mu T, S.D. = 0.07, range = 0.03 - 0.31) were significantly higher than with the AMEX meter (mean = 0.07 mu T, S.D. 0.05, range 0.02 - 0.27 mu T) (t test, P < 0.01). There was substantial correlation between the AMEX and the AMEX-3D measurements (Pearson's correlation coefficient = 0.65, P < 0.01) but poor concordance (Intraclass correlation coefficient = - 0.25). These results suggest that there is a wide variation in exposure to extremely low frequency magnetic fields in the population. Magnetic field measurements with the AMEX-3D are nearly always higher than with the AMEX dosimeters. Caution is advised when comparing magnetic field measurements made with different types of dosimeters. (C) 1994 Wiley-Liss, Inc.