Effects on wildlife
As well as possible effects on humans, possible effects of EMFs on various animals (for example, cows, sheep, pigs and horses) have been studied. No detectable effects of EMFs have been found on, for example, health, milk production, fertility, behaviour, and carcass quality.
This is reflected in Government policy which states:
“There is little evidence that exposure of crops, farm animals or natural ecosystems to transmission line EMFs has any agriculturally significant consequences.”
(National Policy Statement, EN-5)
A vast majority of the research on EMFs and flora and fauna was conducted in the 1970s and 1980s. Since then, little research on this subject has been performed, reflecting the general agreement that EMFs have not been shown to have any detectable effects.
Effects on bees
There has been some focus on the potential impacts of EMFs on bees. There were a number of studies which looked at the strip of land along overhead lines in the USA, because it is protected from development. It was found that those areas can be particularly attractive to bees and many of these routes are used by commercial beekeepers.
In the UK, a partnership between the British Beekeepers Association and National Grid successfully set up a number of colonies at transmission substation locations.
A few individual papers have suggested that EMFs can impact the pollination and foraging of bees, but real life observations do not support these conclusions. Bees can, however, be affected if the hive is under (or close to) an overhead line and they receive microshocks, but this can be eliminated by screening the hive. Other than microshocks, which are preventable, there does not seem to be evidence of EMFs or overhead lines adversely affecting bees.
Effects on bats
Bats use echolocation to detect prey and to aid navigation. This operates in the frequency range of 20 kHz to 200 kHz. Power lines do not produce significant fields at these frequencies and are therefore highly unlikely to interfere with the bats’ navigation or foraging. Nor are there any reports of this happening with existing power lines.