How does radiation caused by mobile networks affect the environment, including animals, insects and plants? Observation guidelines have been available and research activities have been under way for many years now. Yet, this research is on a relatively small scale and is not comparable to the intensive research on the effect it has on human beings. Still, does the fifth generation of mobile communications bring with it an increase in environmental pollution?
The existing studies on the effects of radiation caused by mobile networks on animals and plants show that to date, it has not been possible to establish any significant damage to the environment – that is, damage that is discernible and can unmistakably be traced back to mobile communications. The one known, scientifically proven effect of radio frequency fields on organisms is the heating effect. However, the fields generated by transmission installations are not strong enough to cause biologically effective heating in a living thing.
Further European studies on the effects of the new mobile telecommunications standard on the environment are planned. The Federal Government is also active in this area: in November 2019 the Federal Office for Radiation Protection (BfS) organised an international workshop on the possible effects of low- and radio frequency fields on plants and animals. The outcome confirmed the current state of research: it has not been possible to establish any effects in this area, and further research is needed.
To date, research has not identified a danger to any individual plant or plant species. A French working group reports that under laboratory conditions, plants react to short-term exposure to electromagnetic fields (EMFs) with changes in metabolism similar to a mild stress response. Thanks to messenger substances (e.g. abscisic acid), the entire plant reacts even if only part of it is exposed to the fields. This is similar to responses seen when only part of the plant is attacked by pests or suffers mechanical damage (e.g. when a branch breaks off or a hedge is cut). The responses depend on the species, age and growth stage of the plant in question. All in all, the observations made do not indicate any threat to the plants and are in line with normal physiological reactions that might be seen in response to other environmental factors (heat, dryness, pests). Members of the public have observed sick trees in the vicinity of mobile communications transmission installations. A single publication, based on data collected subjectively, supports these observations, but it cannot be viewed as scientific evidence because of its methodological deficiencies.
Further European studies on the effects of the new mobile telecommunications standard on the environment are planned. For an overview of the studies carried out to date and their findings, please visit the BfS website.
Do animals suffer damage because of mobile communications? Bats are frequently mentioned in this connection, since they are able to fly close to transmission installations. Yet, according to information from environmental protection organisations and authorities, there are no reliable scientific indications of bats being harmed by EMFs from mobile base stations. A significantly higher level of exposure to bats was caused by modifications made to roofs and roof trusses in the course of the expansion of transmission installations, as the bats’ summer or winter habitats were located in these structures. A British study has shown only that they avoid radar installations in their immediate surroundings. The assumption is that either these bats are able to sense the heating effect caused by electromagnetic fields in the immediate vicinity of a transmission installation or that some form of acoustic perception is involved. The latter is sometimes referred to as the microwave auditory effect.
A study from Switzerland has shown that on a farm located near a cell tower, cataracts were more common in calves than on other farms. However, the study is considered to be deficient because the animals observed were subject to other stress factors (motorways, oil pipelines, power supply lines, railway services).
In Germany, there is a single farm where a high number of miscarriages of piglets has been observed and linked to the proximity of a mobile communications transmission installation. However, many other parameters have been completely ignored here. No similar cases have been described anywhere else in Germany.
A further experimental study also dealt with cows. Specifically, researchers exposed ten of these animals to a mobile frequency of 900 megahertz (MHz). The concentration of enzymes in the blood indicated that the cows were under stress, however also that the values in question were predominantly within the normal physiological range. According to the Federal Office for Radiation Protection (BfS), the validity of the study is limited because the trial group was too small. Here too, the initiators of this research work were unable to establish clearly whether the effects could be put down exclusively to electromagnetic fields or whether other disruptive factors also played a role.
To date, there have been no observations concerning animals living in the wild. Studies have most commonly been carried out on laboratory rodents. These are used primarily to evaluate risks to human beings, though in principle, provided due consideration is given to specific parameters (body size, wavelength, resonance), the results can also be applied to other mammals. To date, only thermal effects have been demonstrated. Under real-life conditions, the legal limit values protect both humans and animals from the established effects.
Many bird species are able to orient themselves towards the Earth’s static magnetic field. It is known that this ability can be temporarily impaired by fields in the frequency range of a few MHz (up to a maximum of 25 MHz), but these frequencies are well below the range used by mobile communications.
Media reports of birds dying within range of 5G test areas are incorrect. In the Hague, to take one specific example, the birds in question had been poisoned by yew tree berries.
Because the relevant studies are deficient, scientists have not been able to verify that there has been a dangerous change in the behaviour of honeybees in the vicinity of transmission masts. Further studies from Stuttgart, Switzerland and India have partly exhibited methodological deficiencies. To date, none have proved that there are any other effects on bees.
The only known ecological field research on the incidence and diversity of pollinators in relation to their distance from mobile communications installations took place on two Greek islands. The fields generated by mobile communications installations were measured and correlated with the incidence of these insects. The findings were inconsistent: the numbers of some insect species dropped as the strength of the electric field rose; however, these numbers even increased regarding other insect species. The impact on species diversity varied from island to island. It remains open as to whether the correlations shown are also causal. They do not indicate any acute threat to the respective insect populations.
For future applications in the radio frequency range (5G applications > 6 GHz), wavelengths will be reached that roughly match the insects’ bodies, and this may cause resonance effects. In other words, insects would be absorbing more energy than they did with previous mobile communications standards, although current calculations indicate that they will not be in any actual danger.
Some people see a connection between insect die-off and radio frequency electromagnetic fields. However, in an answer to a parliamentary question, the Federal Government likewise classified this connection as not plausible. Insect die-off is a widespread phenomenon and is also found in areas where there are no electromagnetic fields. Equally, it began in the early 1990s, before the full-coverage expansion of mobile communications.
An overview of all the studies on the behaviour of bees can be found here.
Research into the effects of electromagnetic fields on wild animals and plants is especially thin on the ground. Key reasons for this were identified during a web conference that was part of an EU-financed project for exchanging views and information on biodiversity and ecosystem services. There was, for example, a frequent lack of standardised and controlled technical structures for experiments. Equally, scientists had conducted very few outdoor tests. Available studies are, for the most part, laboratory-based and have only limited significance as regards the natural world. In November 2019 an international workshop organised by the BfS took place; this was entitled “Environmental effects of electric, magnetic and electromagnetic fields: Flora and Fauna”. The aim was to examine the current state of research and knowledge on the topic of mobile communications and the environment and to initiate further appropriate research. Further information and a report on this public event can be found here.