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We studied the biological effect of chronic exposure to multifrequency electromagnetic fields simulating the effects of 5G NR/IMT-2020 mobile communication systems. Male Wistar rats were exposed to 24-h radiation (250 μW/cm 2 ) for 4 months. The exploratory activity of the animals and blood concentrations of ACTH and corticosterone were evaluated at the end of each month of exposure and 1 month after exposure. The results suggest that exposure to multifrequency electromagnetic field simulating the effects of 5G systems affected functional activity of the hypothalamus-pituitary-adrenal axis and was stressful in nature., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature.)

In the article there are presented data on the probable adverse effects of electromagnetic fields generated by means of mobile cellulary radio communication equipment, a comparative analysis of hygienic rating and methods of measurement of their parameters in Russia and abroad has been performed, and the ways of harmonizing hygienic rules have been outlined, the necessity of further research to risk assessment of the use of cellular radio communication devices by population and preventive measures have been substantiated.

The article presents results and prospects of studies on problem of unfavorable effects caused by electric and magnetic fields on human health, and working out hygienic regulation of the factor in occupational and ambient surroundings.

The results of portable radio-station "Radiy-301" electromagnetic fields (EMF) emission measurement and specific absorption rate data evaluation has shown that workers' exposure EMF levels may elevate hygienic norms and hereupon can be health risk factor. Possible way of portable radio-station EMF dosimetry enhancement by means of domestic and international approaches harmonization is considered.

The analyses of Institute activity main directions are briefly presented as well as Institute role in preventive medicine development, occupational health and industrial ecology key problems solving, international collaboration development, and WHO Global Plan of Action on Workers' Health 2008-2017 realization in the Russian Federation.

The authors analyzed a state of hygienic regulation of electromagnetic fields in Russian Federation and abroad, justified necessity of hygienic regulation of electric and magnetic fields in frequency range of 3 Hz - 30 kHz, specified MAL for electromagnetic fields at workplace, that match recommendations of international organizations on non-ionizing rays safety.

The modern experimental radiofrequency electromagnetic field dosimetry approach has been considered. The main principles of specific absorbed rate measurement are analyzed for electromagnetic field biological effect assessment. The general methodology of specific absorbed rate automated dosimetry system applied to establish the compliance of radiation sources with the safety standard requirements (maximum permissible levels and base restrictions) is described.

Theoretical and experimental dosimetry can be used for adequate evaluation of the effects of radiofrequency electromagnetic fields. In view of the tough electromagnetic environment in aircraft, pilots' safety is of particular topicality. The dosimetric evaluation is made from the quantitative characteristics of the EMF interaction with bio-objects depending on EM energy absorption in a unit of tissue volume or mass calculated as a specific absorbed rate (SAR) and measured in W/kg. Theoretical dosimetry employs a number of computational methods to determine EM energy, as well as the augmented method of boundary conditions, iterative augmented method of boundary conditions, moments method, generalized multipolar method, finite-element method, time domain finite-difference method, and hybrid methods combining several decision plans modeling the design philosophy of navigation, radiolocation and human systems. Because of difficulties with the experimental SAR estimate, theoretical dosimetry is regarded as the first step in analysis of the in-aircraft conditions of exposure and possible bio-effects.

Given growing computational resources, radiofrequency electromagnetic field dosimetry is becoming more vital in the study of biological effects of non-ionizing electromagnetic radiation. The study analyzes numerical methods which are used in theoretical dosimetry to assess the exposure level and specific absorption rate distribution. The advances of theoretical dosimetry are shown. Advantages and disadvantages of different methods are analyzed in respect to electromagnetic field biological effects. The finite-difference time-domain method was implemented in detail; also evaluated were possible uncertainties of complex biological structure simulation for bioelectromagnetic investigations.

The authors justified an estimated induced current density as a criterial parameter for hygienic regulation of exposure to rarely repeated ultrashort electromagnetic impulses of nanosecond duration in electrical discharge devices applied in scientific research. The authors defined a threshold for harmful effects of the impulse, set maximal allowable levels of exposure for the devices operators. Methodic and regulatory documents were specified and approved to provide electromagnetic safety for personnel working in impulse fields.

High-power broadband electromagnetic pulses of nanosecond range duration have been found to adversely affect the health status and working capacity of electric charge plant operators. A system of measures to protect the workers from exposure to such pulses, which is based on the hygienic regulation of the exposure, has been implemented.

The authors briefly present data on state of hygienic regulation of electromagnetic fields in Russian Federation and abroad, describe differences in criteria and approaches to regulation. Based on data analysis, the authors suggest possible harmonization of national and foreign norms and prospective research trends in assessing biologic influence and hygienic regulation of electromagnetic fields.

The authors consider topics of evaluating electromagnetic factors on workplace of medical personnel in physical therapy office, specify adequate method to define occupational risk, based on data of hygienic and timing studies.

The article contains descriptive notes for results of research works conducted within Scientific Council and aimed to solve problems of strengthening health and preserving work longevity for workers.

The authors revealed that potent broadband electromagnetic impulses in nanosecond range have negative influence on health state and performance of electric discharge facilities operators. Created system of measures protecting workers from such impulses is based on hygienic regulation of the exposure.

Using materials of 2-year comparative study of information supply for scientific research in occupational medicine, conducted through social hygienic polls, the authors demonstrated peculiarities of informational supply and its significance for optimizing the scientific work. Informational supply of scientific research in occupational medicine requires complex approach including availability of information resources and technologies, increased material and technical basis of research organizations, developed intraregional and international cooperation with similar national and foreign organizations.

Transverse epidemiologic study of work conditions and health state among workers of Civil Aviation Department Running Radiotechnic and Communication Equipment revealed higher relative risk for arterial hypertension and coronary heart disease, occurrence of these diseases in younger age in individuals exposed to electromagnetic rays of ultra high frequency and high frequency ranges, when compared to occupational group matching by occupational and general characteristics excluding exposure to electromagnetic rays.

The authors proved electromagnetic environment for staff servicing radiolocation, navigation and communication systems in civil airports to be very severe: electromagnetic irradiation of broad frequency spectrum, in impulse and continuous generation mode, varying in intensity and time, with low telluric conditions in shielded chambers, with equivalent noise levels more than by 15 dBA exceeding the allowable ones.

A retrospective cohort study of mortality in the personnel of power-supply plants in the European regions of Russia was carried out. The exposure of the personnel to electromagnetic fields of power-line frequency (PF) was taken into account. Statistically non-significant raise of mortality from leukemia was found, compared to low mortality rates due to all other causes including cancer of any type. Standardized mortality ratio (SMR) was equal to 2.03 (95% CI = 0.23-7.31). In the retrospective case-control study the haemoblastosis development risk under occupational PF EMF exposure was evaluated. The data of 571 "cases" and 1208 "controls" interview showed that odd ratio (OR) was 1.64 (95% CI = 0.8-3.1). In another retrospective case-control study the risk of the haemoblastosis development in children due to parents PF EMF occupational exposure was evaluated. The data of 208 "cases" and 319 "controls" interview showed that the odd ratio (OR) was 1.69 (95% CI = 0.7-3.3). A retrospective cohort study of mortality in a settlement situated near a high-voltage (500 kV) substation, which took into account PF EMF levels in residential areas, revealed low mortality rates, except leukemia mortality (SMR 1.3; 95% CI = 0.2-7.0). The obtained data do not allow excluding a possibility of PF EMF leukogenic effect.

The article covered results of studied hygienic regulation of occupational exposure to electromagnetic fields for preservation of workers' health. Examples of examined professionals who run radar, navigation and communication means in civil airports proved adequacy of the approaches applied. The authors formulated prospective directions to further improve hygienic regulation of occupational exposure to electromagnetic fields.

Physical factors of occupational environment and surroundings (noise, vibration, non-ionizing electromagnetic radiation, microclimate, etc) frequently could be considered stressing hazards, as cause marked functional changes in cardiovascular and nervous systems, in hematologic, immune and cytochemical values. These changes demonstrate adaptation and compensation processes or disadaptation and subsequent asthenic, astheno-vegetative and hypothalamic syndromes.

The authors present results of hygienic, physiologic and experimental studies and mathematic simulation of biologic effects. Experimental studies (by functional state of CNS and immune system, cytologic examination of rats' lens epithelium) on 450 and 900 MHz frequencies prove the intensity of 1,900 MW/cm2 to be hazardous for animals and supraliminal.

Review of standards show that many countries still have no hygienic regulations concerning the electric and magnetic fields of commercial frequencies. National standards have been developed by only a few countries. In a number of countries guidelines for protection from the electric fields have been elaborated with the magnetic component disregarded. National standards show a significant difference, too. In most cases the maximum admissible levels are approximate and ignore potential synergetic biological effects of the agents; many of them do not set an adequate coefficient of the hygienic margin or foresee possible carcinogenous risk.

The epidemiologic study covered causes and levels of mortality in the settlement situated near electric power supply line (voltage is 500 kV). The work used retrospective cohort method adjusted for evaluation of mortality in general population. The study revealed no higher mortality risk with all the causes totally and with leading causal groups under influence of high frequency electromagnetic fields. However, higher relative mortality risk with leukemia and suicide appeared statistically insignificant.

The retrospective cohort study covered causes and mortality levels among the staffers working at 6 objects of power supply line (voltage of 500 kV) in Vladimir, Gorky, Rjazan, Ulyanovsk and Lipetsk regions. The mortality in general and concerning specific causes demonstrated no increase in connection with exposure to industrial electromagnetic fields. The relative risk of mortality with leukemia appeared to be insignificantly higher.

Sharp EEG changes are recorded in bioelectrical activity of the dorsal cortex and dorsal ventricular edge in marsh tortoises in conditions of free movement during solving of an extrapolation task (a test of elementary reasoning ability). These changes of a pathological character, accompanied by neurotic states, were observed in some animals having correctly solved the task several times in succession (2-5), beginning with the first presentation. Such changes of EEG and behaviour were not found in tortoises that committed errors at first presentations of the task and only gradually learned correct solving. Formation of the adequate behaviour can proceed by two means: on the basis of elementary reasoning ability and learning. Disturbance of adequate behaviour in the experiment with characteristic changes of EEG testifies to a difficult state of the animal during solving of the extrapolation task.

In experiments with ablation of the forebrain dorsal cortex in turtles it has been established that this structure plays a significant role in first solving of an extrapolation task (6-19 times) and looses its integrating role at multiple test solving (40-195 times). The obtained data testify to the presence of two types of animals adaptive behaviour in solving the extrapolation task: based on operation with empirical laws of movement and manifested at first task presentations (elementary rational animals activity), and that based on learning and appearing after multiple reiterations of the experimental situation in the form of motor conditioned reflex of passing the obstacle from the corresponding side.

Turtles Emys orbicularis (14 individuals) with ablated middle-anterior parts of the forebrain dorsal cortex proved unable to solve a problem calling for extrapolating the direction of the movement of a food stimulus. Intact turtles (11 individuals) and those (six individuals) which underwent control operations (including ablation of the posterior part of the dorsal cortex) correctly solved the problem, beginning with its first presentations. A conclusion has been drawn on the significant part played by the middle-anterior parts of the forebrain dorsal cortex coinciding in turtles with the convergence zone of different afferent systems, in the integration of a complex form of behaviour linked with the pursuit of and search for a food object after its disappearance from the animal's visual field.