Impacts on Natural Ecological Systems


EMFs have been reported to alter the behavior and orientation of birds, the growth characteristics of Dugesia (flatworms) and Physarum polycephalum (slime mold), and the metabolism of bees. Experiments have also shown that the fields can be perceived by fish and amoebas.

Several investigators have studied the effects on bird orientation of low-frequency EMFs emanating from a large low-frequency antenna. In pilot studies, Graue observed that the headings of homing pigeons were slightly altered in the vicinity of the antenna (36). In more detailed studies, Southern constructed cages on the ground directly over the antenna and explored the effect of the EMF on the instinctive directional preferences of ring-billed gull chicks, 3-9 days old. When the chicks were released in the center of the cage with the antenna turned off, they showed a directional preference for the southeast; when the antenna was energized the birds dispersed randomly and exhibited no mean bearing (37). Larkin and Sutherland carried out radar tracking of individual migrating birds flying over the antenna at altitudes of 80-300 meters. When the antenna was activated, or when its operating condition was being changed (off to on, on to off), departures from straight and level flight occurred significantly more often than when the antenna was not operating (38). In other radar-tracking studies, Williams reported changes in the flight direction of migrating birds of 5-25° when the antenna was activated (39).

Marsh traversely sectioned two species of Dugesia and subjected them to 310-420 v/m at 60 Hz, applied along the antero-posterior regeneration axis (normally, the worms will regrow a head or tail, whichever is appropriate to the site). In a significant number of animals the normal regeneration pattern was disrupted, resulting in bipolarity-the production of two heads or two tails in the same animal (40). In the Physarum experiments, Goodman et al. simultaneously applied 0.7 v/m and 2 gauss, 45-75 Hz and delays in the rate of cell division and alterations in cell activity in the exposed cells were seen (41).

The effect of power-frequency fields on bees has received considerable attention. When bee hives were placed on grounded metal plates slightly below a simulated power line, it was found that the electric field (11 kv/m) caused grossly abnormal behavior (42). The bees exhibited great restlessness as recorded by temperature change in the hive, and the degree of defense of social territory was abnormally increased. Some bees, including the queen bee, were herded together and stung to death. Honey and pollen were no longer stored, and the cells which were already filled with honey were emptied. Hives which had been established a short time prior to initiation of field exposure were abandoned a few days after exposure was begun. When the experimenter prevented the queen bee from leaving the hive, the swarm departed without her. In hives which had been well established prior to the initiation of field exposure, all apertures were closed off by the bees, resulting in death of the entire swarm due to lack of oxygen. In laboratory studies it was found that 3-50 kv/m caused changes in the metabolism and activity of bees (43). There are at least two other reports of EMF effects on bees (44, 45).

McCleave (46) showed that eels and salmon were able to perceive 0.007 v/m at 60-70 Hz; this appears to be the most sensitive EMF-induced biological effect yet reported in any animal. The studies point to a susceptibility to EMFs in a diverse array of creatures, the significance of which, in relation to natural ecological systems, cannot presently be satisfactorily determined. Despite this, the studies suggest that there are impacts on such systems.

Chapter 11 Index