The magnetic flux density (1 mT) selected for this study is twofold the reference level proposed in the European Community for occupational expsoure (500 µT; European Community, 1999; based on the guidelines of ICNIRP, 1998).
Positive (NaN3 exposure (genotoxic to plants)) and negative controls were set up for each series of experiments.
Exposure duration: continuous for 1, 6, and 24 hours
|Exposure duration||continuous for 1, 6, and 24 hours|
|Setup||The magnetic field (MF) was generated by a system consisting of a pair of parallel coils in a Helmholtz configuration. Each coil had a 16.5 cm external diameter and a 6 cm width. The distance between coils was 12 cm. The coils consisted of 1000 turns of copper wire (diameter 0.71 mm) wound in circular loops and assembled as a set of two bifilar wires. The current in the two coils could be switched parallel to generate the MF or nonparallel to mutually annul the MF generated by each of the coils (sham-exposure). The exposure system generated a horizontal MF. Plant cuttings were placed exactly at the point of maximum MF intensity and uniformity.|
|magnetic flux density||1 mT||-||measured||-||-|
Exposure of Tradescantia inflorescences to the extremely low frequency magnetic field for 1, 6, and 24 h resulted in a time-dependent increase in micronucleus frequency. The results indicate that a 50 Hz magnetic field of 1 mT field strength is genotoxic in the Trad-MCN-test and suggest that this assay may be suitable as a biomonitor for detecting the genotoxicity of extremely low frequency magnetic field in the field.