A 50 Hz, 14 mT magnetic field is not mutagenic or co-mutagenic in bacterial mutation assays

We used bacterial mutation assays to assess the mutagenic and co-mutagenic effects of power frequency magnetic fields (MF). For the former, we exposed four strains of Salmollella typhimuriurm (TA98, TA100, TA1535, TA1537) and two strains of Escherichia coli (WP2 uvrA, WP2 uvrA/pKM101) to 50 Hz, 14 m T circularly polarized MF for 48 h. All results were negative. For the latt er, we treated S. typhimurium (TA98, TA 100) and E. coli (WP2 uvrA, WP2 uvr A/pKM 101) cells with eight model mutagens (N-ethyl-N'-nitro-N-nitrosoguani dine, 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, 4-nitroquinoline-N-oxide, 2-aminoanthracene, N-4-aminocytidine, t-butyl hydroperoxide, cumen hydrope roxide, and acridine orange) with and without the ME The MF induced no sign ificant, reproducible enhancement of mutagenicity. We also investigated the effect of MF on mutagenicity and co-mutagenicity of fluorescent light (ca. 900 1x for 30 min) with and without acridine orange on the most sensitive tester strain, E. coli WP2 uvrA/pKM101. Again, we observed no significant d ifference between the mutation rates induced with and without ME Thus, a 50 Hz, 14mT circularly polarized MF had no detectable mutagenic or co-mutagen ic potential in bacterial tester strains under our experimental conditions. Nevertheless, some evidence supporting a mutagenic effect for power freque ncy MFs does exist; we discuss the potential mechanisms of such an effect i n light of the present study and studies done by others. (C) 2000 Elsevier Science B.V. All rights reserved.