by Alexander ZHIGALIN, Dr. Sc. (Geol. & Mineral.), RAS Institute of Geoecology

One of the many elements of human environment-to which we are exposed all the time and which we remain completely unaware of - are what experts call geophysical fields. Ignoring this factor, however, makes it practically impossible to tackle successfully current ecological problems if and when they arise.

Geophysical fields can be both - natural and "artificial", or man-made. The former include gravitational, magnetic, electrical, temperature, seismic and radiation ones. They are determined by processes occurring in the near-Earth space and/or the structure of our planet itself, the properties and state of its matter. The combined effect of the aforesaid natural fields during the whole geological history of the Earth has determined its present state and appearance and made it fit to sustain the life of many organisms, including Homo sapiens.

It would be fair to say that life on our planet had originated, and has been developing, under the prevailing effects of gravitational, geomagnetic and temperature fields-the three "whales" which the biosphere has been resting upon all this time. With respect to the ecosystems they, as all the other natural fields, are a homotropic (constantly present) factor. That is why their moderate cyclic or periodic variations, observed since ancient times and to this day, should not be regarded as a factor of transformation of our ecological environment fraught with a threat to the existence of man as a biological species. And it even became possible to modify the situation from the middle of the 20th century thanks to the advent of powerful means of influencing, or "shaping", our environment, including what specialists call technogenic (artificial) physical fields.

And there is really no denying the fact that the life of the human community today involves using a vast energy potential, some of which is always wasted, causing what we call technogenic pollution. In addition to other well-known factors thereof - like the chemical and biological ones - an important role in the shaping of a general geoecological situation belongs to physical fields in as much as this impacts energy exchanges between the living, or animate, and the inanimate nature, the functioning of bioorganisms and can alter in a radical way the "quality" of our environment.

Technogenic physical fields, combined with their natural analogues, have produced what we call new energy conditions for the biosphere. These changes have been most pronounced in areas of intensive economic development. In some ecosystems the degree of the resulting disbalances has reached a critical level. These include the saturation with electromagnetic and other artificially induced physical fields, changes of microseisms at a local and even regional level, there occurs what we call induced seismicity, increased

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Changes of technogenic vibrations field during 24 hours (Moscow).

radiation background, etc. As a result, all organisms without exception have to try and adapt to the new and unfamiliar conditions which may or may not fit their adaptive responses and can therefore upset the stability in the animal and vegetable world.

Technogenic physical fields are generated by industrial units and equipment, building machinery, transport facilities and domestic appliances - the manifold "products" of our civilization which attest to the unquestionable formation of what specialists call the noosphere. The strongest generators of all sorts of physical fields are the mining and iron-and-steel industries. These are followed by electricity and heat generation, urban construction, municipal services, farming and transport industry The defense sector stands somewhat apart, operating as it does in basically different "modes" at times of peace and during military conflicts. In the former case it produces its own impact upon the industry and municipal services and in the latter - it starts acting in its own peculiar ways providing for the dominant role of peculiar kinds of the generated physical fields and an increased technogenic impact upon the environment and biological objects.

From the standpoint of ecology, the most "active" are the vibrational (dynamic), noise (acoustic), temperature, electric (electromagnetic and electrostatic) and radiation fields. And the less dangerous fields - according to present-day assessments - are the magnetic one and induced seismicity.

The vibration field is produced by mechanical vibrations emanating from their sources and propagating within the upper layers of earth. In urban centers, for example, microvibrations persist practically everywhere both day and night while in other places their level can be very high from 8 o'clock in the morning until midnight and going down during the night.

One very important problem of today is the acoustic field or sonic oscillations. Noise is an ever-present fact of life of all major urban and industrial centers. Thus in American cities noise level has increased by an average of 30 dB over the past few decades, reaching 85 to 105 dB in the biggest urban centers. The noise level at the famous Place d'Opera in Paris approaches that of the Niagara Falls. As for Moscow, it takes quite a prominent place among its "noisy" rivals. Noise levels in its main streets reach -

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Changes of the magnetic component of the electromagnetic field in industrial (a) and residential (b) urban areas:

1 - field level on weekdays in summer;

2 - on days-off in summer;

3 - on weekdays in winter;

4 - on days-off in winter.

es 81-87 dB and remains at this count for 15 to 18 hours a day, dropping down from 2 to 4 hours at night only. Within its residential areas it ranges from 56 to 66 dB per day depending on the proximity of various industrial units.

Within the system of technogenic physical fields a prominent place belongs to the temperature, or heat field. This is produced by heat-releasing industrial units (such as smelters), "hot" mining technologies, steam and hot water pipelines, heated underground facilities, etc. - everything which upsets the natural temperature regime in the upper layers of the lithosphere. Heat fluxes generated in this way stand no comparison to what we call the natural planetary sources. What is more, within the large urban areas the summary heat fluxes from the ground amount to no more than 30 percent of the total reaching the earth surface, with the remaining 70 percent being of technogenic origin. Heat fluxes of this kind are especially dangerous in permafrost regions with prevailing frozen ground with temperatures from 0.6 to 4.2⁰ C (close to 70 percent of Russian territory), since its variations within the limits of 2-3 ⁰ C in upper soil can cause significant anomalous soil deformations and such phenomena as collapses and subsidences.

Another important ecologo-geophysical factor is the electric (alternating and permanent) artificial fields. They occur in two "versions" - as electromagnetic fields in a broad frequency range from 50 Hz (industrial frequency) to 0.1 MHz- 300 GHz (radiofrequency band) and in the form of a constant or weakly changing electric field (atmospheric electricity, field of stray, or vagabond currents, transmissible electric fields, etc.).

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And it should be stressed that a strong or continues technogenic electromagnetic field produces but an insignificant impact on the biosphere, while causing serious complications in the functioning of our nervous, cardio- vascular, reproductive and other vital functions. A prominent role in this respect also belongs to electrostatic fields generated by air ions. They produce a physiological effect on living organisms at all stages of their development. And it has been proved experimentally that negative air ions (mainly ions of air oxygen) stimulate man's vital functions whereas positive ones in most cases produce a negative effect and, present in high concentrations, can even cause some ill effects. On the other hand, serious ailments can be caused by prolonged inhalation of air void of ions of both kinds.

But the most dangerous kind of environmental pollution today are technogenic radiation fields. These are produced by sources of radioactivity containing natural or man-made radionuclides which are used in scientific research, industrial, medical and other purposes and also by radionuclides contained in building materials and even domestic gas.

Peaceful uses of nuclear materials also have a significant role to play in geoecological changes, and a vivid case in point is the current situation in the Urals region of this country Over the past 40 years it has been the scene of 38 nuclear reactors operating there on a permanent basis. There are also several centers for reprocessing of radioactive materials and radioactive disposal sites. The aggregate activity of such objects belonging to the MAYAK agency approaches one bin Cu (for comparison: the Chemobyl disaster discharge in 1986 approached 60 mln Cu). What is more, the Ural region entombs the traces of Soviet nuclear tests conducted at the Novaya Zemlya site up until 1990. A nuclear accident at MAYAK which occurred in 1957 released into the atmosphere some 20 mln Cu of radionuclides. And what we call the geologo- geophysical conditions of the region are such that even without these man- made discharges background levels of radiation here are almost twice as high as Russia's average.

Another fact of the matter is that the operation of an atomic power station of one GW during one year produces about 100 thousand tons of radioactive waste. Operating in 26 countries now are close upon 500 electricity generating nuclear reactors with an aggregate capacity of about 300-340 GW. And one can easily figure out the total amounts of the accumulated radioactive wastes.

An appreciable contribution to the deteriorating ecological situation is provided by what we call technogenic seismic field (induced seismicity). This covers some minor quakes such as those produced by the filling of large artificial lakes, pumping out of large volumes of water from underground oil and gas-bearing strata and underground nuclear tests.

This kind of technogenic seismicity has begun to manifest itself in what used to be traditionally "safe" regions. For example, seismic activities have been stimulated by what we call mounting stresses on geological strata in the area of the Verkhnekamsky deposit of potassium salts caused by the growing volumes of oil extraction. Since 1993 quakes of strength of 4 to 5 points on the Richter scale have been registered here every two years. Major hydrotechnical projects are also having a marked effect on the levels of seismic activity. Thus, when dams are up to 10 m high, seismic disturbances amount to no more than fractions of a percent of the total, but this value reaches 21 percent when dams are 100 to 150 m high.

What one would like to say in conclusion is that physical fields of various kinds - natural and technogenic - are superimposed one upon the other producing near the surface of the earth a persistent energy potential - what we call the energy sphere. Today this layer is boosted by energy-intensive technologies as a result of which many geological and biological processes and ecological changes turn out to be hard to predict on the one hand, and mostly negative on the other from the point of view of ecosystems stability. As for Homo sapiens, he has managed to avail himself of his exceptional adaptability in order to overcome the problems which he himself produced in the course of the accelerated development of science and technology. But the situation can become critical when a certain level of intensity is reached. This will be especially apparent in places of what we call considerable anomalies of natural physical fields when technogenic ones are superimposed upon them.

Laboratory experiments and natural observations prove that living organisms, human including, are most sensitive to "fast" (faster than the natural rate of adaptation of a given organism) changes of the physical field, or background. In such cases one can expect adverse effects which can seriously disrupt the vital functions of living organisms. One such example is the response of what we call "weather-sensitive" patients to magnetic storms and sharp changes of atmospheric pressure.

Summing it up, one can say that both natural and technogenic fields can and should be viewed as a major ecological factor. Its influence manifests itself in different ways when we analyze the performance of separate ecosystems. Some of them, which have a greater "ecological strength margin", suffer less when entering the noosphere of today, while others degrade to a greater of lesser extent, or even perish or change beyond recognition. All of these things are the cost - considerable, or not very much so? - for the development of our new technocratic civilization.

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