Environmental Geochemistry of Moscow metropolitan area

Golovin, A.A., Moskalenko, N.N., Sokolov, L.S.

 

(Project Geoecology and Geochemical Mapping of Russia,

Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements (IMGRE), Moscow, 121357, Russia; 15 Veresayeva St., Moscow, Russia;

e-mail: nmoskalenko@mtu-net.ru)

 

ABSTRACT

 

The multi-scale envirogeochemical mapping of Moscow Region (1:1,000,000; 1:200,000; 1:50,000) allowed to reveal pollution sources and sinks in soil, surface water, stream sediments, snow cover, and vegetation. A vast range of toxic chemical elements, pesticides, and radionuclides were found in the environment. Polluted area covers from 10 to 40% of the territory studied. Envirogeochemical mapping allows the capturing of representative quantitative data on chemical composition, structure, area and shape of anomalies in all the environment components studied, thus, identifying and contouring the ecologically unfavorable territories and pollution sources. Geochemical mapping data may be useful to many end-users, as well as for the development of the natural resource cadastres, land-cost evaluation, pollution damage evaluation, and assessment of alternative projects for the natural resource utilization. All the data collected is currently integrating into the Arc View GIS.

 

INTRODUCTION

 

Moscow Region is located at the Russian Platform in the forest zone. The main land use type is agricultural and industrial, with subordinate mining. The multi-scale envirogeochemical surveys have been conducted in the Moscow Metropolitan Area, hosting the largest industrial enterprises and almost 10% of population of Russia, since 1976. All the data collected during the years of study were processed, reinterpreted, and a series of maps, depicting the envirogeochemical features of the area, were plotted.

 

METHODS

 

The study includes the following major stages: sampling, data processing, and map compilation. 1:1,000,000-scale envirogeochemical survey of Moscow Region: sampling media included surficial environments, i.e. soil (natural (A1-horizon, B-horizon) and agricultural), surface water, stream sediments, ambient atmosphere (by snow cover sampling). Average sampling density was 1 point per 100 km2. 1:200,000-scale envirogeochemical study of Moscow Metropolitan Area: sampling media were surficial environments, i.e. soil (natural (A1-horizon, BC-horizon) and agricultural), surface water, stream sediments, ambient atmosphere (by snow cover sampling), and vegetation. Average sampling density was 1 point per 4 km2. Detailed 1:50,000 and larger-scale envirogeochemical study of Moscow City and its administrative districts. Besides surficial environments, sampling media included underground and ground water, bio-substrates (infant hair). Average sampling density          >4 points per 1 km2. Thus the whole system can be estimated ecologically, i.e.: pollution source — atmosphere, soil, water — vegetation, human population. The samples were analyzed for 40 chemical elements (OESA), pesticides and radionuclides (137 Cs).

The integrated envirogeochemical assessment of Moscow Region has been made using the analysis of pollution level combinations of different environment components taking into consideration landscape geochemical zonality and land use features of the territory. Pollution level was evaluated by the Zc index (Zc is the integrated pollution index characterizing the additive sum of background-normalized contents of chemical elements).

 

GIS is ideal tool for modern interpretation, integration and presentation of data on environmental geochemistry of the Moscow Metropolitan Area from a wide variety of age, scale and formats. Data bases and data volumes collected in the more than 20 year period are the basis for the GIS «Moscow Metropolitan Area: The Complex Envirogeochemical Assessment». Using the capabilities of ArcView 3.1 and domestic data processing program GEOSCAN, this GIS will include a variety of analytical, synthetic and predictional digital envirogeochemical maps and data bases on the content, character, intensity, ecological risk and dynamics of environment pollution in the Moscow Metropolitan Area and Moscow Region. GIS enables the spatial analysis of pollutant flows in the environment components, the modeling of ecological situations. The developing GIS will be an open system which may be added with new geochemical data.

 

RESULTS AND DISCUSSION

 

The small-scale studies showed that ~20% of the Moscow Region territory have critical and potentially critical category of the ecological state, i.e. anomalously high pollution level in all four environment media studied: soil, surface water, stream sediments, and ambient atmosphere. First of all, it is Moscow City, and its nearest industrial satellite-cities (Khimki, Podol’sk, Lyubertsy, Shelkovo), also as E and SE parts of the region (Electrostal, Orekhovo-Zuevo, Bronnitsy, Voskresensk, Egor’evsk, Kolomna, Serpukhov, etc.). More favorable situation occurs in the north of the region where only several critical zones have been contoured (Klin, Solnechnogorsk, Dmitrov, Sergiev Posad, and Krasnozavodsk). The most favorable ecological situation exists in the west of the region.

 

The intermediate-scale survey covered an area of 4800 km2, and pollution was revealed in all environment components sampled. Anomalies with high pollution level (Zc >32) are located mainly in the central, E and NE parts of the territory studied and are connected with central and eastern parts of Moscow and industrial centers to the NE and E of Moscow. It is noteworthy that the areal extent of the high-intensity anomalies differs in various environment media: 12,000 km2  in stream sediments, 1000 km2 in soils, and 600 km2 in vegetation (birch). Comparative to the anomalies in vegetation, those in soils and stream sediments are successively shifted eastward, following the general runoff direction.

 

Along with accumulation, some chemical elements display depletion in the environment media of the urbanized territories. Thus, Ag, Zn, Cu, Pb, Ni, and Sn accumulations in soils of Moscow and Podol’sk are conjugated with zones depleted in Mn, B, Sc, Ti, Zr, Ga, and V. This regularity gains contrast in case multiplicative anomalies of the group members are considered and/or ratios of the element’s groups. Using this technique, well-expressed zones are contoured around cities and towns of the region, first of all, Moscow. The latter is surrounded by a «halo» 10-20km wide.

 

The detailed envirogeochemical mapping of Moscow territory has been conducted three times during the past 20 years. Long and intensive economic activities resulted in unfavorable ecological situation existing across 50% of the city area and causing an increased disease incidence level. Approximately 25% of the city area is characterized by a very unfavorable ecological situation. Anomalously increased concentrations of Ag, Zn, W, Pb, Cd, Cu, Sn, Mo, Bi, As, Sb and other toxic chemical elements are fixed in soil, grounds, sewage and storm run-off, sludge, stream sediments, vegetation, infant hair. The relic, historically developed, soil pollution covers mainly the central part of Moscow where toxic metal concentration in grounds reaches the level of industrial ores, e.g., Pb, Zn, Cu content in the northern part of municipal district Mar’ina Roscha reaches 1% and more.

 

At the same time, the following fact should be emphasized: during a 10 year period          (1977—1987) the area of high pollution level (Zc>32) has grown from 24 to 77% of the total city area, and in 1993 it decreased to 26% (Fig. 1). This fact is explained by a very simple reason — sharp production recession; hence, the significant reduce of pollutant emission and sewage discharge, which, in turn, resulted in natural purification of soil. Nevertheless, the areas of maximum soil pollution (Zc>128) which covered 7% of the city territory in 1987

(just 3% in 1977) did not change a lot in 1993 (6%). This fact testifies the total soil degradation at the territories of the maximum soil pollution. The soil here lost its self-purification potential.

Thus, the multi-scale envirogeochemical mapping of intensely urbanized areas allows to solve the following ecological problems:

·      guiding of the global, regional and detailed studies of regularities and mechanisms relevant to transformations and interactions of the poly-genetic hierarchical mass flows developed in natural and man-made urban systems;

·      evaluation of the environment state caused by additive effects of natural and technogenic factors, and its health effect;

·      revealing of technogenic pollution sources;

·      predicting of changes in geosystems;

·      defining the guidelines of rational nature management, and develop the top priority measures for nature conservation.

 

 

                             I                                                   II                                               III

              

 

Fig 1. Moscow Metropolitan Area: Soil Pollution Dynamics

Years of envirogeochemical mapping: I - 1977; II - 1987; III - 1993;

Zc values (integrated pollution index): <16 - acceptable, 16—32 - tense,

32—64 - critical, 64—128 - emergency, >128 - ecological disaster