significant changes, but animals exposed to 25 or 50 µW/cm2 exhibited EMF-induced alterations with
time dependencies that differed with each animal. For a given exposure duration, the WBC was above
the normal level in some animals, and below it in others; as a result, the average values varied little
during the study. At 500 µW/cm2, however, even on the average there was a pronounced leukopenia
and Iymphocytosis.
Gonshar exposed rats to 2.4 GHz, 7 hours/day for 30 days and studied the effect on the levels of
alkaline phosphatase and glycogen (two indicators of cellular activity) in the neutrophils (12).
Glycogen increased following 3 days' exposure at both 10 and 50 µW/cm2; after 7 days' exposure it
decreased to the control level. In contrast to this apparent adaptational response, there was a sustained
depressing effect on glycogen content at 500 µW/cm2 which was still observed after 30 days' exposure.
At all three intensities, the alkaline phosphatase levels first increased then decreased below the control
level within 30 days.
Ferrokinetic studies demonstrated that iron metabolism was affected and that erythrocyte
production (measured by 59Fe incorporation) was significantly decreased in rabbits exposed to 2.95
GHz, 3000µW/cm2, for 2 hours daily (15). The effects seen after 37 days of irradiation with a pulsed
EMF were comparable in magnitude to those seen after 79 days exposure to a continuous-wave EMF.
Rats exposed to 130 gauss, 50 Hz, for 4 hours/day, exhibited a 15% reduction in RBC after 1
month's exposure: the RBC level returned to normal within a month after removal of the field (10).
Because comparable results were obtained using widely different EMFs, the blood-composition
studies suggested to us that the EMF-induced alterations were mostly transient compensatory reactions
of the body to a change in the electromagnetic environment. To determine the relation between
magnitude and direction of the response and the conditions of application of the external EMF, we
looked for changes in hematological parameters of mice due to short-term exposure to a full-body
vertical 60 Hz electric field of 5 kv/m (13). To ensure maximum statistical sensitivity every mouse was
sampled twice, once after exposure to the field for 2 days and once following a 2-day nonexposure
period. There were four consecutive experiments, two with males and two with females. In each there
were two groups: one for which the control period preceded the exposure period (nF-ðF), and one in
which the pattern was reversed (F-ðnF). On "day 1" of each experiment the mice were divided into the
two groups and the electric field was applied to one-half the population. On "day 3" the blood
parameters were measured in each mouse and immediately thereafter the exposed and nonexposed
groups were interchanged. On "day 5" the blood parameters were measured again and the mice were
killed.
Blood was collected from the ophthalmic vessels and it was therefore necessary, before
applying the field, to determine the influence of the first blood collection procedure on the values
measured after the second such procedure. We measured the blood parameters in two groups of mice,
one male and one female, under conditions that were identical in all respects to those employed during
the field-exposure portion of the study, and we found that the method of blood collection had a
tendency to produce higher RBC, Hct, and MCV values and lower values of Hb, MCH, and MCHC
(Table 7.1).
Blood
ELECTROMAGNETISM & LIFE - 94