Дата публикации: 02 октября 2018
Автор(ы): Nikolai YELANSKY
Публикатор: Научная библиотека Порталус
Номер публикации: №1538501421

Nikolai YELANSKY, (c)

In the 1990s, the attention of international science circles was drawn to Kalmykia - one of the southern regions of Russia. The republic was put on the list of ecological calamities because its natural environment had been so badly affected by that time that there appeared signs of this territory becoming a desert - the first of its kind in the whole of Europe.

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by Nikolai YELANSKY, Dr. Sc. (Phys. & Math.), Head of Department of Studies of Composition of the Atmosphere, RAS Institute of Physics of the Atmosphere, RAS Institute of Physics of the Atmosphere named after A. Obukhov

Kalmykia occupies the western part of the Precaspian depression (most of which lies below the world ocean level) and the Kumo-Manychskaya basin which are divided by the Yergenskaya upland and washed by the Caspian Sea from the southeast. According to the Ministry of Ecology of the republic by the end of the last century 20 percent of its territory became barren of vegetation. Perennial plant species have vanished in many areas, being replaced with casual ephemerals* commonly occurring in steppes and deserts. In 1998 the percentage of losses of local forests was the biggest in Russia - 48.78 hectares for every 1,000 hectares of land And the neighbouring Volgograd, Rostov and Astrakhan regions, although far "behind" Kalmykia in this respect, were also among the "leaders" in this respect having respectively 2.32, 8.06 and 6.03 hectares per 1,000 ha of forests, while the country's average did not exceed 0.4 ha for every 1,000 ha. Threatened were tree plantations near the Kalmyk village of Godzhur (half way between Elista and Volgograd) planted some 120 years ago Prof. Vasiliy Dokuchaev - the founder of the teaching of genetic soil science. At the same time the republic has been faced with a deteriorating probe of water shortage and biospheric pollution has increased on a dramatic scale as being mainly associated with industrial discharges in the neighbouring regions.

This deteriorating environment has had its impact on the health of the population. According to the Health Ministry of the republic by the start of the 1990s the rates of lung disorders and cancer, especially in regions bordering on the Volgograd and Astrakhan regions were among this country's highest.

* Ephemerals - annual plants, typical of steppes, semideserts and deserts. - Ed .

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Rate of formation of trichloracetic acid (TCA) in nature: a - in conditions of actual air pollution; b - in its absence.

This deplorable picture was observed in Kalmykia by the end of last century and aroused due concern on the part of the international scientific community within the framework of the UN program for the protection of the environment there was set up in the republic in 1997 an International Center for Desertification. On the initiative of the European Union and with the support of Kalmykia's President Kirsan Ilyumzhinov, studies were launched for identifying the in-depth processes in the natural environment of the Caspian region. Scientists of the RAS Institute of Physics of the Atmosphere named after A Obukhov which were already engaged in studies of the peculiarities of the gas, aerosol and water balance of the Precaspian (near- Caspian) region were joined by specialists of the Scientific-Research Physical- Chemical Institute named after L. Karpov (Moscow, the All-Russia Scientific- Research Institute of Railway Transport, the RAS Institute of Forestry, the RF HYDROMETCENTER, the Max Plank Institute of Chemistry and the Center of Ecological Studies (FRG), the Potchefstreme University (South African Republic), the Institute of Meteorology (Austria) and other research centers.

This international army of researchers had at their disposal IFA research stations, a mobile railway lab, specially equipped cars and trucks and several temporary observation stations at different places of this country. Some of the most instruments were used registering very low concentrations of all the basic substances which impact the oxidation parameters of the atmosphere. The high accuracy of measurements was verified by regular calibrations and comparisons with world standards.

In the first place, over the whole European territory of Russia data was obtained on the levels in the air of all chemically active and hothouse gases and aerosols, their natural and antropogenic sources identified as well as the

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channels of their transfer and the peculiarities of chemical transformations in the atmosphere. After that experts studied the processes of formation in the natural environment of toxic chlor-organic compounds from precursor substances released into the atmosphere by human activities. Samples of pine needles were gathered all the way from Dagestan to Murmansk and of some species of wormwood, etc. and the levels of the absorbed chloroacetic acids determined (mostly pesticides). Experts build digital models of their synthesis in the air and water and in plant cells.

At the final stage, experts investigated the complex mechanisms of the impact of atmospheric pollution on the flora of the Precaspian region, the degree and nature of its degradation and its consequences.

Already at the start of this work it became clear that the natural environment of Kalmykia is very sensitive to the negative factors of human activities which also manifest themselves there stronger that in other regions. Thus vegetation to the north of Elista was found to contain unusually high for this country levels of tricnloroacetic acid. Near the aforesaid village of Gozhur in 1997 pine needles contained up to 69 meg per kilo of dry matter. On all other investigated territory this level did not exceed 10 mcg/kg (expect samples taken 40 km to the south of the Astrakhansky gas- condensate Plant and also near the Russian-Finnish border on the Kola Peninsula- respectively 27 and 39 mcg/kg). This chemical occurs in such considerable amounts only in the most polluted regions of Central Europe and the United State.

Registered in the northern part of the republic in 1997 - 1998 were record for Eurasia concentrations of oxibromide in the atmosphere. And nitrogen oxide in near-earth air, despite the less developed local industries, turned out to be as high as in industrial regions. Accumulated in aerosol particles were many salts which contained chlorine, bromine and iodine. Their levels were also high in water and in soil. For example, in salt lakes in Kalmykia's south-east the levels of chlorine and bromine reached 153 and 0.88 g/l respectively. In certain places ground water contained high levels of chlor- organic compounds. In Godzhur local very pure, apparently spring water had a level of tetrochloretilene (solvent used for chemical cleaning, degreasing etc.) in the summer of 1997 reached 505 ng/l - much higher than in the polluted waters of the Volga and rivers of Central Europe (150 - 300 ng/l).

Wk were surprised by an unusually high levels in the air of active halogen-bearing compounds. This attests of intense photochemical reactions produced by volative organics of antropogenic origin.

Now, what are the reasons of the aforesaid anomalies? Naturally enough, and like in all other places, a certain role was played by industrial, agricultural, transport and housed pollutions as well as not always rational uses of natural resources. From the major industrial units around Kalmykia its air basin was contaminated by dangerous organic substances and active oxidants-oxides of nitrogen, sulfur and carbon. Thus iron-and-steel and engi-

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neering plants of Volgograd annually discharged into the atmosphere in the 1980s some 230 thous. t of gases and solids in the form of aerosols. The Astrakhan pulp- and-paper plant added considerably amounts of chlorine, and no lesser harm was done by coal-mining units of the Rostov region and Ukraine.

Certain contribution to the environmental pollution of Kalmykia was provided by transport of gases and aerosols from Central and Eastern Europe. This was clearly registered not only on the European territory of this country, but also in Siberia. In the near-Caspian region the impact such "imported" pollutions is great and possible greater than that of the local ones. The thing is that being dissolved in drops of rain, these substances get into ground water, sediment in the Volga basin and flow into the Caspian Sea from where they actively evaporate back into the atmosphere.

Active accumulation of toxic substances was also promoted by the geographic and climatic features of the republic. During the warm months there prevailed eastern and south-eastern winds. They brought evaporations from the Caspian and polluted air from the Astrakhan region which filled numerous valleys crossing the Yergensk upland. Powerful nightly inversions of temperature and fogs promoted intense dry and wet precipitation of harmful substances which letter found their way into soil and ground water. At the same time high summer temperatures and plenty of sunshine sharply boosted the photochemical processes in the atmosphere and in the biosphere in general. As a result the vegetation was in the conditions generally comparable with those in the deserts.

What is more, the soils and lakes of Kalmykia and water of the Caspian Sea are characterized by high concentrations of salts with plenty of chlorine, bromine, iodine, fluorine and their compounds. The latter are absorbed by solid and liquid aerosol particles which are lifted by the constant local winds into the atmosphere. Many such substances are brought from the drying

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Sea of Azov* and solonchaks (saline soils) of Central Asia. A substantial contribution to the balance of halogens comes from brine dumped in oil drilling, emanations from the leaves of halophytes (vegetation which "sucks up" salts from depths of tens of meters) and gases from numerous cracks of the earth crust.

The combination of all these factors has produced a unique mechanism of formation in the air, ground water and plants of this region, of toxic compounds which have an unusually strong impact on the local natural environment. This mechanism can be visualized in the following way: volatile halogenized carbohydrates of antropogenic origin are oxidized in the course of chemical transformations producing many active compounds in the air. Some of these are dissolved in rain, salt waters of local lakes, the Caspian Sea and water aerosols. As a result of such reactions in solutions molecules of chlorine, bromine and other halogenes get into the atmosphere and enter into photochemical reactions with ozone, producing again active halogen compounds. The essence of this cycle consists in the fact that for every one atom of chlorine, bromine and iodine there come out two at the first liquid phase. In the specific conditions of Kalmykia this process becomes explosive and causes discharges into the atmosphere from brines of vast amounts of halogens. When the air and water contain metylchloroform or tetrochloretilene there is a possibility of rapid formation from them of mono- or trichloracetic acid.

For weakened plants these represent tangible threat even at low concentrations because they accumulate in the stems and leaves in abnormally high amounts, depressing photosynthesis and plant growth. Degradation of the flora, in its turn, produces soil salinity thus increasing the levels of salts in the air and in the presence of antropogenic pollutions - of generated toxic compounds, thus closing the viscous circle. What is more, the affected plants consume less carbon dioxide and release more water vapors, causing soil dehydration and desertification of the area.

* See: R. Timofeev, "Destinies of Two Seas", Science in Russia, No. 6, 2003. - Ed .

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Such were some of the findings of the international team of scientists in the late 1990s. But as from 2001 there has been a clear tendency for an improvement of the ecological situation in the republic. The levels of trichloracetate dropped by nearly two times in pine needles. Across Kalmykia on the average there has been a 10 percent rise in the levels of photosynthesis of the main varieties of wormwood and in pastures productivity. The most encouraging has been the data for 2003: the levels of pesticides continue to drop, the conditions of vegetation by all parameters are the best for the past 7 years of observations, organic pollution of ground water and soil are minimal. In air near the ground the levels of oxidants have somewhat decreased same as the salt aerosols. There have been signs of reself-recovery of some forest belts which had appeared to be dead already.

Having said all that, what could have produced such radical ecological changes for the better on the aforesaid territory? Clear enough this is no sign of dwindling industrial discharges in neighbouring regions. It has rather been the other way round-all of these factories and plants have been boosting production and, regrettable, the volumes of their discharges. Intensive development of new gas and oil deposits in the region has also been accompanied by mounting discharges of carbohydrates.

The actual cause of the improvement is different. Over the past few years the weather in the republic has markedly changed for the better and the levels of precipitation have been rising since 1998. Extremely low winter temperatures have been few and far between. The frequency of western summer winds has increased, and they bring in clouds and precipitation, reduce maximum daytime temperatures of air add ground and increase night temperatures. Weaker eastern winds cause much lower concentrations of salt particles in the air which has also been promoted by delayed drying of local salt lakes in summer, reduction of aerosol emissions from their surface and halophyte vegetation on their banks.

But is this positive "perestroika" (favorite Russian term for socio-political improvements) is only temporary, or does it signal a warming of the regional climate? According to specialists the process in this region are part and parcel of general European changes resulting from global warming. And the ability of the tendency is beyond any shade of a doubt. It is born out by the results of years of observations by the world network of weather stations. At the ground level during the 20th century temperature rose by an average of 0.6±0.2°C. According to dendrochronological* and other paleoclimatic studies, this is the highest figure over the past one thousand years.

The biggest changes for night and winter temperatures of the air have been registered over continents in the Northern hemisphere: extremely low temperatures were more rare, "frost-free" period has become longer, the area under snow-cover has been reduced as well as the time when rivers and lakes are covered with ice. As compared with the 1950s the area under ice on the Arctic seas has been reduced by 10 - 15 percent in spring and summer. During the whole of last century the amount of precipitation rose by 0.5 - 1.0 percent over a decade. Heavy showers and snowfalls have become more frequent, but the frequency of periods of excessive humidity has not increased.

These manifestations of the global warming fit exactly the forecasts of Russian Academy experts for the next 50 years made on the basis of some complex and sufficiently reliable digital models. According to these assessments by the middle of this century the mean annual temperature in Russia's southern region will rise by 0.5 - 1.0°C because of warmer winters. The repetion of what we call cyclonic circulation will increase and, consequently, of westerly winds and cloudy days, the amplitude of daily temperature changes will be reduced, the volume of precipitation will increase by 10 - 20 percent, the total volume of discharge of the Volga into the Caspian Sea will grow by 5 - 10 percent.

On the whole weather changes of this kind will have a favorable impact on the socio- economic development of this country. Improvements of what we call the agroclimatic situation have been observed already during the last decade: crop yields have increased and risks for farming due to changing climate have been reduced on greater territories. If this tendency continued, and practically all forecasts confirm this expectation, by the middle of this century there will be a marked increase in the size of areas fit for farming, the vegetation period will become longer, there will be better conditions for the wintering of crops and gardens and for farm work. This can invite changes for the better in the conditions of the population, especially in the Far North, Siberia and the Far East and this will be due to warmer winters and shorter periods of ice cover on the seas and inland lakes.

Having said all that, awe know that climate, like weather forecasts do not always come true. But the actual improvements in the south of Russia have been fitting forecasts with amazing accuracy. Therefore when they speak and write about the climate warming leading to desertification, that does not mean that it is this very region which will be affected? There is no denying the fact that positive climate changes in Kalmykia and the neighbouring Astrakhan and Volgograd regions have already improved the course of ciogeochemical processes reducing the probability of high concentrations of ozone and toxic organics. And the warming should bring benefits to the country as a whole. And problems which it could cause-heavy showers or damage to engineering communications because of the "retreating" permafrost - these can all be prevented by means of the rational uses of the natural resources and economic activities.


* Dendrochronological climate studies-reconstruction and prognostication of climate conditions by studying annual rings of timber. - Ed .

Опубликовано на Порталусе 02 октября 2018 года

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