Dl. Mccormick et al., Chronic toxicity oncogenicity evaluation of 60 Hz (power frequency) magnetic fields in B6C3F(1) mice, TOX PATHOL, 27(3), 1999, pp. 279-285
A 2-yr whole-body exposure study was conducted to evaluate the chronic toxi
city and possible oncogenicity of 60 Hz (power frequency) magnetic fields i
n mice. Groups of 100 male and 100 female B6C3F(1), mice were exposed to pu
re, linearly polarized, transient-free 60 Hz magnetic fields at flux densit
ies of 0 Gauss (G) (sham control), 20 milligauss (mG), 2 G, and 10 G; an ad
ditional group of 100 male and 100 female B6C3F(1), mice received intermitt
ent (1 hr on/1 hr off) exposure to 10 G fields. A small bur statistically s
ignificant increase in mortality was observed in male mice exposed continuo
usly to 10 G fields; mortality patterns in all other groups of mice exposed
to magnetic fields were comparable to those found in sex-matched sham cont
rols. Body weight gains and the total incidence and number of malignant and
benign tumors were similar in all groups. Magnetic field exposure did not
increase the incidence of neoplasia in any organ, including those sites (le
ukemia, breast cancer, and brain cancer) that have been identified in epide
miology studies as possible targets of magnetic field action. A statistical
ly significant decrease in the incidence of malignant lymphoma was observed
in female mice exposed continuously to 10 G fields, and statistically sign
ificant decreases in the incidence of lung tumors were seen in both sexes e
xposed continuously to 2 G fields. These data do not support the hypothesis
that chronic exposure to pure, linearly polarized 60 Hz magnetic fields is
a significant risk factor for neoplastic development in mice.