To study whether exposure to 50 Hz circularly polarized magnetic fields of up to 350 mT for 30 weeks is associated with the increase in the incidence of DMBA-induced malignant lymphoma/lymphatic leukemia in mice in a dose-incidence manner. Furthermore, the experiment was conducted twice to confirm the reproducibility of the data.
New-born mice were initiated with a single subcutaneous injection of 60 µg DMBA within 24 h after birth. After weaning, the animals were randomly divided into five groups of 100 mice each (50 females and 50 males each). One group served as a cage control. The other four groups of mice were sham-exposed or exposed to either 7, 70, or 350 µT magnetic fields.
|Exposure duration||22 h/day, 7 days/week for 30 weeks|
|Setup||two orthogonal sets of four square coils; for the horizontal MF: length of coils = 2379 mm; outer coils = 52 turns, inner coils = 22 turns; for the vertical MF: length of coils = 2530 mm; outer coils = 52 turns, inner coils = 22 turns experimental area in the center of the coils: 1.3 x 1.3 x 1.3 m; animals in plastic cages on wooden shelfs in this area|
|Sham exposure||A sham exposure was conducted.|
The cumulative proportions of mice with malignant lymphoma/lymphatic leukemia in the magnetic field-exposed groups were not significantly higher than those in the sham-exposed group of each sex in individual experiments and in males and females combined in each experiment, and in all the mice from the two experiments combined.
The results provided no evidence to support the hypothesis that power frequency magnetic fields are a significant risk factor for hematopoietic neoplasia.