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Abstract. The study of geochemical aspects of the transformation of migration properties of heavy metals under the influence of anthropogenic loading of pyrogenic origin has been given insufficient attention. We studied the concentration of heavy metals in soils by atomic absorption analysis. The results indicate the transformation of their migration properties. The diversity and versatility of behaviour of chemical elements in environmental components after fire was noted. In different ecological conditions, it is possible to observe a wide range of quantitative values of geochemical migration or accumulation of any particular chemical element. The analytical results show that the contents of migrant elements, pH values, areas of disasters which are approximately in the same conditions, but passed by the grass or upper fire differ quite tangibly. Heavy metals that hit the environment can form difficult soluble hydroxides. In addition, in the soil solution, there is a probability of the formation of hydroxocomplexes with different amounts of hydroxide ions by metals. The range of precipitation of hydroxides and the region of predominance of soluble hydroxocomplexes have been studied by constructing concentration-logarithmic diagrams. On the basis of the calculations it can be argued that the influence of technogenic loading of pyrogenic origin influences the geochemical migration of heavy metals . Compounds Fe 3+ at the pH = 4.5-14, Cu 2+ at pH = 7-14, Cr 2+ at pH = 7-9, Zn 2+ at pH= 8-11, Ni 2+ at pH = 8-14 have the lowest migration potential. Compounds Pb 2+ at pH = 9-12, Fe 2+ -pH = 9.5-14 have the lowest migration potential also. In a more acidic environment, soluble substances are formed, but at a pH increase of only 0.5-1, they can decrease their mobility by an order of magnitude which contributes to their concentration in the soils after the fire. In a neutral soil reaction, most of the heavy metals (Al, Cr, Zn, Cu, Fe (II), Ni) are in a slightly soluble form (in the form of hydroxides), with insignificant, migration capacity which leads to the accumulation of these chemical elements in the soil. It is necessary to allocate heavy metals moving in a neutral environment (Fe (II), Cd, Co, Mg, Mn) into a separate group. Any increase in pH values contributes to their fixation. The obtained calculations can be used to predict the geochemical migration of heavy metals in soils which result from anthropogenic disasters of a pyrogenic origin. України, Харків, Україна, e-mail: asotskiy@nuczu.edu.ua 3 Харківський національний автомобільно-дорожній університет, Харків, Україна, e-mail: alenauvarova@ukr.net 4 Національний університет цивільного захисту України, Харків, Україна, e-mail: prv1984@ukr.net Aнотація. Дослідженням геохімічних аспектів трансформації міграційних властивостей важких металів за впливу техноген-ного навантаження пірогенного походження приділено недостатньо уваги. Проведено дослідження концентрації важких ме-талів у ґрунтах методом атомно-абсорбційного аналізу. Результати вказують на...

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The purpose of this study is geoecological analysis of the risk of natural fires and other emergencies of an ecological nature based on the location of high-risk objects in the territory of the Kharkiv region. The following tasks were solved in the work: calculation of the risk of an ecologically dangerous event depending on the density of placement of objects of high danger in the region; Creation of a chart-map on the level of danger of environmental threat in the districts of the region; the search for the dependence of the area of forest fires on the density of the population, the number of high risk facilities, etc. An analysis of the influence of anthropogenic factors on the occurrence of natural fires on the example of the Kharkiv region was carried out. Distribution of potential risk and population density in the studied area allows us to obtain quantitative estimation of social risk for the population. Excessive population density in some areas of the region is one of the factors that increase the material and social risk of the territory and population of the region from natural disasters and man-made disasters. We created mapping zoning of multi-level districts of the region, the risk of an emergency reflects the patterns of spatial structure of potential sources of emergency situations and allows to increase the readiness of the executive and authorized services to act in the event of sudden emergencies and to act for their prevention. Available data allowed us to estimate the density of the placement of potential sources of man-made emergency situations for all districts of the region, which gives us the right, with a certain degree of conditionality, to speak about the extent of the technogenic danger of the territory of the studied areas of the Kharkiv region. We propose to apply a complex factor taking into account the population density, density of placement of objects of high danger and the proportion of high risk objects in the area of the forestry organization in comparison with the total number of objects in the region. For the simultaneous evaluation of both natural and anthropogenic conditions of forest fires in the region, we propose to use the methodology of scoring on which they are evaluated in a four-point system, taking into account the five main characterizing indicators : population density; forest area; the density of high risk facilities; climatic and weather conditions; the share of high risk facilities. Comparison of information on the average number of fires on the lands of the forest fund of Kharkiv region over the past ten years with the results of our typology of the areas shows some correlation. The results of studies on the assessment of the risks of the occurrence of fires depending on natural and anthropogenic factors can be used for zoning similar areas and forecasting the fire situation.

In soils after fires trace metals sharply change their migration ability and can form poorly-soluble hydroxides which are hazardous chemical formations, the nature of which has not been fully explored until now. In addition, in interstitial water, there is a probability of the formation by metals of hydroxocomplexes with different amounts of hydroxide ions. We studied the range of dynamics of migration capacity of sedimentation of hydroxides and the region of predominance of soluble hydroxocomplexes by developing logarithmic concentration diagrams (LCD). We developed logarithmic concentration diagrams, the equation of formation of prevailing forms, using which it is possible to clearly determine the regions of maximum sedimentation (accumulation) of hydroxides and hydroxocomplexes of heavy metals after the influence of the pyrogenic factor. The obtained calculations of the results of the predictive modeling of the dynamics of migration capacity and postpyrogenic migration geochemical processes in ecogeosystems have been organized and systematized. The determined patterns can be useful for the analysis of possible geochemical migration (accumulation) of heavy metals in ecological systems in the study of technogenic and ecological situation after fires. Based on the calculations made, mathematical models of heavy metals` behaviour are developed, which are useful for drawing up a forecast estimation of the dynamics of their geochemical migration and accumulation in ecological systems as a result of the influence of the technogenic loading of the pyrogenic factor. The conditions of concentration and migration of compounds of heavy metals were determined, and the equation for calculating the concentration of mobile forms of trace metal compounds has been developed. The developed map of the activity of geochemical migration of heavy metals under the influence of the technogenic loading of pyrogenic factor will make it possible to elaborate the migratory capacity of trace metals and provide a forecast of their behaviour in ecological systems after fires. This will allow preventive measures to be taken to ensure environmental safety and prevent adverse effects on human health and the condition of the components of the environment. The creation of similar cartographic material may be extrapolated to other regions of Ukraine, affected by technogenic loading of pyrogenic factor. The development of logarithmic concentration diagrams allows us to predict the capacity of compounds of lead, nickel, chromium,and copper for migration or accumulation of heavy metals due to changes in the acidity of soils under the influence of the pyrogenic factor. Having used the map of the soils of the Kharkiv region, we analyzed and provided a forecast of the migration ability of lead compounds in cases of fire in different types and subtypes of different environmental conditions.